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Weapons of Mass Destruction (WMD)

B.1.0 EXISTING FACILITIES AND OPERATIONS

B.1.1 TANK WASTE

From 1943 to 1988, the primary purpose of the Hanford Site was to produce weapons-grade plutonium (Pu) and other defense-related material to support the national defense mission. Plutonium production occurred in a nuclear reactor when a uranium-238 (U-238) atom in a fuel rod absorbed a neutron released from the splitting of another atom. After the fuel rods spent the required length of time in the reactor, the fuel was removed and processed to recover the Pu. The first processes to recover Pu were developed to exclusively separate Pu from the other elements in the fuel rods. Later, processes were developed to also recover U, which was then recycled back into the reactor fuel process. Processing fuel elements involved performing chemical separations to isolate and recover the Pu and U from the spent fuel elements. Chemical waste, the by-product of these separations, created the need for large-capacity, onsite storage. The tank farms, which are a group of interconnected underground storage tanks, were designed and built to accommodate the chemical waste. The first 149 storage tanks built were single-shell tanks (SSTs), which are reinforced-concrete tanks with a single steel tank. The last 28 tanks built were double-shell tanks (DSTs), which are reinforced-concrete tanks with two steel tanks. The locations of the tanks are shown in Figures B.1.1.1 and B.1.1.2.

Figure B.1.1.1 Hanford Site

Figure B.1.1.2 Tank Farm Locations in 200 East and West Areas

Chemical separations processing generated approximately 1.5E+09 liters (L) (4.0E+08 gallons [gal]) of waste. More than 1.1E+09 L (3.0E+08 gal) of waste was sent to the SSTs and DSTs throughout the production period. Volume reduction practices were used to maintain waste volumes within the available tank space. Through liquid evaporation, waste concentration, and decanting (liquid removal following solids settling) dilute waste to the ground, this waste volume has been reduced to approximately 2.1E+08 L (5.6E+07 gal) (Hanlon 1996). The decanting, or discharging, of settled SST waste to the ground was stopped in 1966; no tank waste from SSTs or DSTs has been intentionally discharged to the ground since that time. Liquid discharged to the ground was sent to cribs (drain fields) to drain into the soil. This practice resulted in soil and groundwater contamination. These cribs are past practice units that are not within the scope of the TWRS EIS.

Underground transfer lines (pipelines) transferred liquid waste from the processing plants to the tank farms. Routing the liquid waste from a plant to a specific tank farm was controlled by valve pits and diversion boxes. Diversion boxes, which are concrete-walled pits located in the ground with a removable top at ground level, allowed a jumper or spool piece to be installed to control the routing of the waste and minimize the number of pipelines. After the waste transfer was completed, the volume change in the tank was logged for future reference.

B.1.1.1 Description of Single-Shell Tanks

The SSTs were the first large volume tanks constructed. The 149 SSTs at the Hanford Site vary in size from 2.1E+05 to 3.8E+06 L (5.5E+04 to 1.0E+06 gal). Figure B.1.1.3 shows a typical SST. The SSTs consist of a reinforced-concrete shell surrounding a carbon steel tank. Each of the larger tanks has multiple access points called risers that provide access to the tank from the surface. The risers are either sections of pipe or square concrete pits that connect to the top of the tanks, which are 1.8 to 2.5 meters (m) (6 to 8 feet [ft]) below grade. The risers, between 10 and 110 centimeters (cm) (4 and 42 inches [in.]) wide, are used for monitoring instruments, camera observation, tank ventilation systems, and sampling. Wells drilled into the ground around the tanks are used for monitoring and detecting leaks in the SST farms.

Figure B.1.1.3 Single-Shell Tank General Configuration

The sizes and quantities of SSTs that were built in the 200 Areas are shown in Table B.1.1.1.

Table B.1.1.1 Single-Shell Tank Summary

The tank farms are located close to the center of the 1,450-square-kilometer (km2) (560-square-mile [mi2]) Hanford Site (shown in Figure B.1.1.1) in the 200 Areas. The 200 Areas are specific areas of operation and are divided into the 200 East Area and the 200 West Area, which are approximately equal in size. The tank farms are approximately 8 kilometers (km) (5 miles [mi]) from the Columbia River at their closest point. There are 66 SSTs in the 200 East Area and 83 SSTs in the 200 West Area. These tanks are arranged in groups called farms, which range from 4 to 18 tanks. Building the tanks in farms allowed the tanks to be interconnected within the farm, thereby reducing the number of pipelines between the processing plants and the tank farms. The tank farm concept also allowed the use of cascades, in which the first tank overflowed into the second tank, the second into the third, and so on within the tank farms to allow solids settling. The solids contain a majority of the radionuclides, except for Cs-137, iodine-129 (I-129), and technetium-99 (Tc-99), which are more prevalent in the liquid phase.

The 200 West Area has 83 SSTs in six tank farms. These tanks supported operations of T Plant, U Plant, the Plutonium Finishing Plant (PFP), and the Reduction-Oxidation (REDOX) Plant as described in Section B.1.1.6.

There are 66 SSTs in the 200 East Area associated with operations of the Plutonium-Uranium Extraction (PUREX) Plant and B Plant. North of the PUREX Plant are three tank farms with a total of 26 tanks. North of B Plant on the northern edge of the 200 East Area are three tank farms with a total of 40 SSTs.

B.1.1.2 Description of Double-Shell Tanks

The DSTs were developed as a design improvement over the SSTs. The DSTs have double-carbon steel tanks inside a reinforced-concrete shell, as shown in Figure B.1.1.4. There is an annulus or space between the two steel tanks with equipment to detect and recover waste in the event that the inner tank develops a leak. Each tank has multiple risers connecting the tank with the surface above. These risers are different diameters or sizes depending on their intended use. The risers for the DSTs are used for the same purpose as the SST risers (i.e., monitoring instruments, camera observation tank ventilation systems, and sampling). Each DST tank has its own leak detection pit that is connected to the bottom of the tank and monitored for tank leaks.

Figure B.1.1.4 Double-Shell Tank General Configuration

The DSTs are approximately 23 m (75 ft) in diameter, 15 m (48 ft) tall, and cylindrical in shape with a concrete-domed top. All of the tanks are buried in the ground with the tops of the domes located approximately 2 m (7 ft) below the surface. Twenty-four of the tanks have a capacity of 4.4E+06 L (1.2E+06 gal), while four of the tanks have a capacity of 3.8E+06 L (1.0E+06 gal). Tank farm operations restrict the total volume allowed in the tanks to approximately 76,000 L (20,000 gal) below maximum capacity.

The 25 DSTs in the 200 East Area are located just north of the PUREX Plant. Twenty-one of the DSTs have a capacity of 4.4E+06 L (1.2E+06 gal) and four of the DSTs have a capacity of 3.8E+06 L (1.0E+06 gal). The 21 DSTs in service are operating between 75 and 97 percent of allowable volume capacity. The waste in the DSTs is primarily liquid with small volumes of sludges and saltcakes. There have been no leaks from the DSTs.

B.1.1.3 Miscellaneous Underground Storage Tanks

In addition to the 177 underground storage tanks previously discussed, there are approximately 20 active and 40 inactive miscellaneous underground storage tanks (MUSTs). The EIS alternatives also address the disposition of the waste in the MUSTs. The inactive MUSTs were used during processing and waste transfer operations and were not intended for use as long-term storage tanks. The MUSTs that were used primarily for solids settling, adding caustic, and catch tanks are also currently inactive. The characteristics of the waste contained in the inactive MUSTs is expected to be similar to the SST waste. The active MUSTs still are used as receiver tanks during waste transfer activities or as catch tanks to collect potential spills and leaks.

Most of the inactive MUSTs were interim stabilized and isolated before September 1985. The MUSTs range in size from 3,400 to 190,000 L (900 to 50,000 gal). There is a wide range in the amount of waste currently in the MUSTs. While most of the MUSTs are empty or nearly empty, several inactive MUSTs contain residual sludges and liquid. The volume of waste in all the MUSTs combined is less than one-half of 1 percent of the total tank inventory (WHC 1995n).

B.1.1.4 Existing Transfer Lines

When the tank farms were constructed, they were connected to the process facilities by underground transfer lines. Associated with these transfer lines are subgrade valve pits and diversion boxes. Valve pits and diversion boxes provide a means to route waste to specific tank farms with a minimum number of transfer lines. In addition, there is an existing cross-site transfer system to transfer waste between the 200 East and 200 West Areas. Some of the older transfer lines are blocked or plugged up and cannot be used for waste transfers. All of the existing transfer lines are buried below grade to use the natural radiation shielding of the ground. Most of the transfer lines installed during early operations are single-wall carbon-steel pipe lines, while later lines are double-wall pipe lines with a stainless-steel inner pipe encased in an outer carbon-steel pipe. The valve pits and diversion boxes are below grade concrete structures that are covered with removable concrete panels. A new replacement cross-site transfer system is under construction and scheduled to begin operations in 1998.

B.1.1.5 Support Facilities

Support facilities provide utilities and other operations to help manage the tanks and tank waste. The following is a list of the primary existing support facilities required to continue managing the tank waste.

  • Steam is provided by the 284-East Steam Plant. The Steam Plant was built in 1943 with a design life of approximately 20 years. The boilers operate below capacity and require a high level of maintenance.
  • Water, both sanitary and process, is delivered to the 200 Areas by the Hanford Site Water System.
  • Electrical power is delivered to the Hanford Site by the Bonneville Power Administration. The 200 Areas have one substation with two independent transformers.
  • Road and rail access is established to the 200 Areas.
  • Tank waste and new waste undergo evaporation at the 242-A Evaporator to reduce waste volume requiring storage. The 242-A Evaporator has recently been upgraded.
  • Evaporator condensate is treated at the Effluent Treatment Facility to remove contaminants before being discharged.

B.1.1.6 Tank Waste

Sources of the Waste

Several different chemical separations processes were used in the past for separating and recovering Pu and U from irradiated reactor fuels at the Hanford Site. Common steps to the different recovery processes included chemically removing the fuel element cladding, dissolving the fuel in nitric acid, chemically processing the fuel to separate the Pu, and in some instances separating the U from the dissolved fuel mixture.

The first processing for Pu recovery started in 1944 at T Plant and 1945 at B Plant using the bismuth phosphate process. Both plants used bismuth phosphate to precipitate Pu from dissolved spent fuel solutions. The extraction waste was classified as a metal waste and contained 90 percent of the fission products and 99 percent of the U. This waste was sent to specific SST tank farms in the 200 East and 200 West Areas.

In January 1952, the REDOX Plant began operating as the worlds first nuclear solvent extraction plant using the REDOX process. The REDOX process extracted Pu and U into a hexone solvent in a continuous solvent extraction process.

In January 1956 , the PUREX Plant began operating. PUREX used tributyl phosphate (TBP) in a kerosene base as a solvent to extract U and Pu from the fuel elements that had been previously dissolved in a nitric acid solution. Both the REDOX and PUREX process recovered Pu, U, and neptunium (Np) from spent reactor fuel.

All of the acidic aqueous waste was made alkaline by adding sodium hydroxide or calcium carbonate before storing in the underground storage tanks.

The PFP took the plutonium nitrate product from PUREX Plant and REDOX Plant and further refined it into Pu metal. The PFP used a process similar to PUREX Plant to further purify the Pu and produce a finished Pu product from the PUREX Plant output. The PFP sent waste to the tank farms that was low in radioactivity and high in metallic nitrates. Before PFP was operating, the plutonium nitrate paste was transported to Los Alamos National Laboratories for processing.

Because U was not recovered in the bismuth phosphate process it was sent to the tank farms during B Plant and T Plant operations. The U Plant was built and operated to recover the U from B and T Plant tank waste. This U recovery operation required the recovery of B and T Plant waste from the tank farms.

Midway through U Plant operations the process of scavenging or precipitating Cs with ferrocyanide was started to remove the Cs from the liquid waste. This scavenging operation precipitated the Cs in the tanks as solids, allowing the liquid to be decanted and sent to the cribs. This practice allowed for the discharge of clarified liquid and provided additional tank space. This process was completed in 1957 (WHC 1995b).

B Plant was also operated as a waste fractionization plant in the 1960's to early 1980's. Cesium and Sr were recovered as waste by-product and the secondary waste containing complexants (ethylenediaminetetraacetic acid [EDTA] and hydroxyethylenediaminetriacetic acid) were sent to the tank farms.

As a result of using the tanks to hold waste from such a variety of operations, the tank contents have changed as time passed. While records were kept as transfers were made, the inter-tank piping allowed the tank contents to cascade from one tank to another. Consequently, the tanks now contain a variable mixture of sludge, precipitated salts (saltcake), and liquid. Characterization on a tank-by-tank basis would be required to determine the actual contents of any given tank.

Waste Types

The waste stored in DSTs is reported by waste type stored in individual tanks. There are seven waste types associated with DSTs.

  • Concentrated complexant waste is concentrated product from evaporating dilute complexed waste.
  • Concentrated phosphate waste is waste originating from the decontamination of the N Reactor in the 100-N Area.
  • Dilute complexed waste is characterized by a high content of organic carbon including organic complexants. The main source of dilute complexed waste in the DSTs is the liquid-removal operations from the SSTs.
  • Dilute noncomplexed waste is low-activity liquid waste.
  • Double-shell slurry is waste that exceeds the sodium aluminate saturation boundary in the evaporator without exceeding receiver tank composition limits.
  • PUREX Plant neutralized cladding removal waste (NCRW) is the solids portion of the PUREX Plant NCRW. This NCRW waste was sent to the tank farms as a slurry and is classified as transuranic (TRU) waste.
  • PFP TRU solid is solid TRU waste from PFP operations.

B.1.1.7 Current TWRS Activities

The TWRS program was established in 1991 to safely manage and dispose of radioactive and chemical or mixed waste that has been generated at the Hanford Site. The current TWRS program mission is to dispose of the radioactive tank waste (includes current and future tank waste) and the Sr/Cs capsules in an environmentally sound, safe, and cost-effective manner.

Continued Operations of Tank Farm System

Numerous tank waste activities are ongoing to provide for the continued safe storage of the tank waste until remediation measures are implemented. These activities consist of a number of routine activities as well as a number of additional activities required for safe storage.

Routine operations include management oversight, regulatory compliance and reporting activities, and operations and maintenance of facilities and equipment. Tank monitoring activities support waste management by gathering information on waste temperature, liquid levels, solid levels, and tank status. Leak detection activities involve in-tank liquid level monitoring, leak detection monitoring of the annulus for the DSTs, drywell monitoring around tanks for increases in radioactivity levels, and groundwater monitoring.

TWRS safety management activities include the following:

  • Calculating operational waste volume projections that involve comparing projected waste volumes against tank capacity. The projections also provide for identification and management of risk that could negatively impact available tank storage space;
  • Combining compatible waste types. Transferring tank waste between tanks and tank farms through the existing cross-site transfer system to provide the required tank space and to address safety issues;
  • Implementing a waste minimization program to reduce the generation of new waste requiring storage in the tanks. This program includes job preplanning and identification of new technologies such as low volume hazardous waste decontamination practices to limit the generation of new waste. A waste minimization support program for non-TWRS waste generators is used to encourage waste minimization practices;
  • Screening and characterizing the waste on a tank-by-tank basis to gather data in support of safety and remedial action design activities;
  • Isolating and removing pumpable liquid from SSTs to reduce the potential of future leakage (interim stabilization by saltwell pumping); and
  • Operating the 242-A Evaporator to concentrate waste and treating evaporator condensate at the Effluent Treatment Facility

These activities are not within the scope of this EIS because they were addressed in previous National Environmental Policy Act (NEPA) documents: the Safe Interim Storage of Hanford Tank Waste EIS (SIS EIS) (DOE 1995i), Waste Tank Safety Program Environmental Assessment (DOE 1993h), Disposal of Hanford Defense High-Level, Transuranic and Tank Wastes EIS (DOE 1987).

Tank Monitoring and Maintenance

As part of its routine operations, the Hanford Site has an extensive tank farm surveillance program in which tanks are monitored for temperature, surface level, and interstitial liquid level (in tanks having low-activity waste [LAW]) as required to safely manage and operate the tank farms. There are pressure and gas monitors on some tanks. The surface level inside the tanks is monitored either manually with an installed tape or with automated instrumentation.

Watchlist tank temperatures are monitored with automated equipment where installed, and manually where required. The automated systems allow temperature monitoring on a continuous basis. Watchlist tanks that require manual readings are done on a weekly or monthly basis. All Watchlist tanks are reviewed for increasing temperature trends. Non-Watchlist tank temperatures are monitored at 6-month intervals.

Fifty-eight of the SSTs and two of the DSTs have liquid observation wells installed for monitoring the level of interstitial liquid within the waste. Liquid observation wells are installed in SSTs that are known to have, or may have, greater than 1.95E+05 L (50,000 gal) of drainable liquid. The liquid observation wells are fiberglass or plastic pipe, sealed at the bottom, extending from the ground level down into the tank and through the waste to within 2.5 cm (1 in.) of the tank bottom. Gamma and neutron probes are used to monitor changes in the interstitial liquid level. Changes in liquid level would indicate fluid leakage either into or out of the tank, or could be an indication of the presence of gas within the waste if the observed liquid level changes are consistent with atmospheric pressure changes. The two steel liquid observation wells that are installed in the DSTs are used only for special monitoring purposes.

Radiation measurements are taken in the drywells surrounding the SSTs, in the leak detection pits, and the space between the liners of the DSTs. An increase in the radiation levels in any of the monitoring wells or pits would indicate a possible tank leak.

Safety Issues

All U.S. Department of Energy (DOE) facilities that store hazardous or radioactive materials have documented authorization bases that establish a range of operating parameters (e.g., temperature, pressure, concentration) within which routine operations are conducted. These authorization bases also evaluate the effects of potential accidents, abnormal events, and natural disasters.

The possibility of driving heavy equipment over an unstabilized tank during construction or operations, which potentially could result in a tank closure collapse was considered. To reduce the potential for this accident, engineered features would be installed and administrative controls used to prevent large vehicles from driving on top of the tank domes. These engineered barriers would be mechanical barriers such as closely spaced posts installed around the tanks or tank farms.

Watchlist Tanks

Concern over waste tanks having the potential for releasing high-level radioactive waste to the environment resulted in the passing of Public Law 101-510, Section 3137, Safety Measures for Waste Tanks at Hanford Nuclear Reservation, also known as the Wyden Amendment. In response to this law, DOE developed a set of criteria to identify tanks with potential safety concerns as Watchlist tanks. Current published information indicates that there are 50 Watchlist tanks, with 10 tanks listed in more than one of four different Watchlist categories based on specific safety concerns. The four different Watchlist categories include flammable gas, ferrocyanide, high organic content, and high-heat generation. The tanks in each category are shown in Table B.1.1.2 (Hanlon 1995 and Cowan 1996 ). As safety issues are resolved or mitigated, the number of tanks on the Watchlist is expected to change.

Table B.1.1.2 Watchlist Tanks

The flammable gas Watchlist identifies those tanks whose contents have the potential to generate/retain and release hydrogen gas at levels above the flammability limit, which is approximately 4 percent hydrogen by volume. Hydrogen and ammonia are generated within the tanks through radiolysis or radiation-induced decomposition and chemical reactions. If flammable concentrations are reached and an ignition source is present, the potential reaction could cause a radioactive release or provide an energy source to facilitate other reactions within the tank. Currently there are 25 hydrogen-generating tanks in this category. Tank 101-SY is currently being mitigated by using mixer pumps to stir the waste and allow hydrogen gas to be released gradually to prevent episodic releases of hydrogen that are above the lower explosive limit. Other tanks are being screened and evaluated to assess their magnitude of the risk from flammable gas generation, storage, and intermittent release.

The ferrocyanide Watchlist tanks are a concern because of the potential for self-propagating reactions if ferrocyanide in sufficient concentration comes in contact with an oxidizer (nitrates and nitrites) at a high temperature. The measured temperatures in all the ferrocyanide tanks are at or below 60 C (140 F), well below the 180 to 200 C (360 to 390 F) temperature required for self-propagating reactions to occur. The list of tanks with ferrocyanide was developed based on assessments of tank contents using process information. As tank characterization progresses, tanks with insufficient quantities of ferrocyanide for self-propagating reactions will be removed from the Watchlist. Currently, there are 14 tanks listed in this category.

There are 20 tanks in the high-organic Watchlist category. These are tanks that are estimated or have the potential to contain 3 percent total organic carbon on a dry weight basis. The concern with these tanks is that at elevated temperatures above 180 C (360 F), the organics in the tanks could result in self-propagating reactions with the nitrate and nitrite. These tanks are checked for the presence of an entrained or floating organic solvent layer that might pose a risk from a slow pooled or wicked fuel burn. Studies are underway to gain a better understanding of the high-organic safety issues. The differences between the measured tank temperatures and the temperatures required to sustain a reaction are large; therefore, the probability of a reaction is considered very low.

Currently one tank, tank C-106, is in the high-heat Watchlist category because of its content of heat-generating sludge. The heat generation is caused by decaying Cs and Sr in the sludge. The concern with the high-heat tank is that the heat-generating sludge could boil off or evaporate the liquid from the tank, which would raise the sludge temperature. If the temperature within the tank rises above the allowable limit for the tank materials, structural failure of the tank and collapse of the tank dome may result. While the tank currently is considered sound, water must be added periodically to keep the sludge wet and provide evaporative cooling.

Unreviewed Safety Questions

DOE has a formal administrative program to identify, communicate, and establish corrective actions for known or suspected operating conditions that have not been analyzed or that fall outside of the established authorization bases as an Unreviewed Safety Question. Following the identification of an Unreviewed Safety Question, a review is conducted, and corrective action is taken if applicable. Following the review process, the Unreviewed Safety Questions may be closed from an administrative standpoint, which means that conditions surrounding the safety issue have been analyzed. However, the conditions upon which the safety issue is based may still exist and may require mitigation, controls, or corrective action. In this way, safety issues and Unreviewed Safety Questions are related. The safety issues that were identified under the Watchlist program were also analyzed as Unreviewed Safety Questions. Those issues that had not been addressed in the documentation authorization basis were established as Unreviewed Safety Questions. Following the review processes, the Unreviewed Safety Question can be closed while the tank remains on the Watchlist for resolution of the safety issue. The Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) (Ecology et al. 1994) requires the resolution of all Unreviewed Safety Questions by September 1998.

Technical evaluation and mitigative actions have resulted in closing the following Unreviewed Safety Questions: ferrocyanide (closed in March 1994); floating organic layer in tank C-103 (closed in May 1994); and criticality (closed in March 1994). Criticality was addressed on a tank farm basis and did not result in identifying any individual tanks to be added to the Watchlist tanks. Criticality would be an issue during tank waste retrieval and transfer, and would be evaluated on a tank-by-tank basis during final design. Closure of the Unreviewed Safety Questions was accomplished by defining the parameters (e.g., concentrations and temperature) of potential reactions that could lead to an uncontrolled release, collecting physical and chemical data on the waste, and establishing safety operating specifications.

The remaining Unreviewed Safety Questions are undergoing resolution. Mitigative action has been implemented for tank SY-101, the most widely known flammable-gas generating tank. This mitigative action involved installing a mixer pump to control the periodic release of flammable hydrogen gas and provide for more frequent and gradual releases of hydrogen. This mitigative action reduces the maximum concentration of flammable gas that can exist in the tank and greatly reduces the potential for an uncontrolled gas burn.

There is a safety screening and characterization program ongoing to determine if any additional tanks should be placed under special controls. Recently all 177 tanks, Watchlist and non-Watchlist, were placed under flammable gas controls, which means that flammable gas generation/retention may exist in all 177 tanks and special safety measures will be taken during maintenance, monitoring, and waste transfer activities. Until the necessary characterization data are obtained, the tank farm system will continue to operate under a conservative management program to maintain a safe operating envelope. Additional data may allow for relaxed operating procedures, where appropriate. Volume Four, Appendix E contains a more detailed description of the tank safety issue.

Interim Stabilization to Prevent Further Leakage

DOE removed all SSTs from service in November 1980 and initiated a program to remove all pumpable liquid and stabilize the tank waste until final disposition. This effort, known as interim stabilization, is currently ongoing. Approximately 30 tanks remain to be interim stabilized and these will be complete by the year 2000.

There are 67 confirmed or assumed leaking SSTs in the 200 Area tank farms. Over the years, these tanks have leaked an estimated 2.3E+06 to 3.4E+06 L (600,000 to 900,000 gal) of liquid to the soil column. All but five of the SSTs that are assumed leakers have been interim stabilized to minimize potential releases to the environment (Hanlon 1996).

An ongoing vadose zone characterization program that was initiated in April 1995 (DOE 1995t) is providing new baseline characterization data on the potential contaminant distribution in the vadose zone sediments beneath and in the vicinity of the SSTs. This has resulted in some recent information for the SX Tank Farm. The characterization effort relies on geophysical logging of existing drywells using a spectral gamma logging system with a high-purity intrinsic germanium detection device to provide assays of gamma-emitting radionuclides near the drywells (Brodeur 1996).

Ten of the 15 tanks in the SX Tank Farm are assumed or verified as leaking, as discussed in Volume Five, Appendix K. Ninety-five drywells ranging in depth from 23 m (75 ft) to 38 m (125 ft) from ground surface were logged with the Spectral gama logging system in the SX Tank Farm. The most abundant and highest concentration radionuclide detected was cesium-137, which was detected in "virtually every borehole" (Brodeur 1996). Cesium-137 was detected at the following depths in several drywells: 23 m (75 ft) in drywells 41-09-03 and 41-08-07, 32 m (105 ft) in 41-09-04, 27 m (90 ft) in 41-11-10, and 38 m (125 ft) in 41-12-02.

Other gamma-emitting radionuclides detected include cobalt-60, europium-152, and europium-154, which generally were found near the surface and are believed to be the result of spills (Brodeur 1996). Cobalt-60 was found in drywell 41-14-06 only. It was detected at a depth of 17 to 23 m (55 to 76 ft) below ground surface. The data are unclear as to whether relatively immobile contaminants such as cesium-137 would be found dispersed laterally within the vadose zone (i.e., at observed concentrations laterally several meters from the drywells) at the depths of over 30 m (100 ft) based on ambient conditions and vadose zone contaminant transport via advective flow in interstitial pore spaces. This suggests that there may be other transport mechanism(s) occurring such as those discussed in Volume Five, Section K.4.1.3. The viability of any other potential transport mechanism has not yet been demonstrated but is one of the objectives of the ongoing investigations.

Interim stabilization consists of saltwell pumping and is intended to reduce the volume of free waste liquid in the SSTs and minimize potential liquid losses to the environment. Interim stabilization is accomplished by reducing the supernatant liquid content of a tank to less than 190 m3 (50,000 gal). The jet-pump system used to remove pumpable liquid continues operating until the pumping rate falls below 0.19 L/min (0.05 gal/min). The pumping effort may use the LR-56(H) cask truck for emergency pumping of leaking SSTs. Liquid removed from the SSTs is transferred to a DST. Interstitial liquid (within the solid pores) remains in the SSTs following interim stabilization. The 30 tanks that require saltwell pumping are scheduled to be completed by the year 2000.

Waste Characterization

The tank waste characterization process involves determining the physical, radiological, and chemical properties of the waste. Considerable historical data are available that have been used to estimate the contents of the storage tanks. Historical data, which are based on invoices for the purchase of chemicals and waste transfer and processing records, provide a basis for an overall inventory of the waste in the tanks. Historical tank content estimates have been completed for the DSTs and the solid waste in the SSTs (WHC 1995b). These estimates provide an inventory of the radioactive and mixed waste stored in the SSTs and DSTs.

Waste characterization is performed to help resolve safety issues, allow for the safe storage of the waste until waste treatment operations begin, and support planning and design decisions for implementing the remedial alternative selected. A considerable amount of inventory information is available from process records and past sampling activities. However, this information is not considered adequate to characterize the waste in individual tanks to support safety, treatment, and design activities.

There is an ongoing waste characterization program that is using waste sampling and analysis, in situ measurements, monitoring, surveillance, and waste behavior modeling to provide more detailed and accurate characterization data for the contents of each tank. Current agreements between DOE, the Washington State Department of Ecology (Ecology), and the U.S. Environmental Protection Agency (EPA) require that all characterization reports be issued by September 1999. Prior to disposal system final design, additional data requirements may be generated.

The tank waste is classified as liquid, sludges, or saltcake. Liquid is made up of water and organic compounds (e.g., solvents that are both heavier and lighter than water) with dissolved salts. Sludges are mixtures of insoluble (will not dissolve in tank liquid) metal salt compounds that settle out of solution after the waste is made alkaline for storage. A majority of the radioactive elements are contained in the sludges. However, radionuclides such as I-129, Tc-99, and Cs-137 are more prevalent in the liquid phase. Salts or saltcake are primarily sodium and aluminum salts that crystallize out of solution following evaporation. These three types of waste exist in the tanks in numerous combinations and proportions resulting in complex combinations of waste with varied physical and chemical properties. Sludges have been found with consistencies from mud to hardened clay. Layers of organic compounds have been found in some tanks floating on the top of solid waste, and crusts have formed in some tanks where a layer of solids has formed on top of the tank liquid.

Present data indicate that the SSTs as a group have on a volume basis 65 percent saltcake, 33 percent sludges, and 2 percent liquid, although the percentages of these differ greatly between tanks.

The DSTs have more than 77 percent liquid with 9 percent sludges, 10 percent double-shell slurry, and 4 percent saltcake (Hanlon 1995). These percentages may change as additional data become available and as waste transfers take place. SST and DST chemical inventory estimates, based on historical data, are provided in Volume Two, Appendix A of the EIS.

Evaporating Liquid in the 242A-Evaporator

The 242-A Evaporator is used to manage waste volume by evaporating the water from the tank waste. Recent evaporation campaigns have removed several million gallons of water from the tank waste. This water would be transferred to the Effluent Treatment Facility for treatment and release to the State-approved land disposal site. Following evaporation, concentrated waste would be returned to the DSTs.

B.1.1.8 Proposed TWRS Activities

Several tank waste activities are planned for implementation in the near future. These activities will address urgent safety or regulatory compliance issues.

Newly Generated Waste

At present, the DSTs are used to store waste generated from ongoing site activities. Future DST additions are expected to come from routine operations. These waste additions would involve loading the waste as liquid or slurry into a tank truck or railcar at the generating facility, transporting the waste to the tank farms, and unloading and transferring the waste into existing DSTs for storage. This waste would be transferred using existing rail or tanker truck systems. Section B.9.2 contains a description of the LR-56(H) truck. Facilities generating waste requiring transport to the tank farms include:

  • 300 Area laboratory and facility cleanout;
  • Cleanout waste from PUREX Plant, PFP, and B Plant;
  • Decontamination waste from T Plant;
  • Routine laboratory waste; and
  • Cleanout of K Basins.

Additional information on newly generated waste is contained in Volume Two, Appendix A.

Safe Interim Storage

One issue that requires action is the safe storage of tank waste in the interim period before implementing actions for the permanent remediation of tank waste. To address this issue, the SIS EIS was prepared to consider alternatives for maintaining safe storage of Hanford Site tank waste (DOE 1995i). The actions considered in the SIS EIS include interim actions to 1) mitigate the generation of high concentrations of flammable gases in tank 101-SY; and 2) contribute to the interim stabilization of older SSTs, many of which have leaked.

The most pressing interim need identified by DOE and Ecology was for a safe, reliable, and regulatory compliant replacement cross-site transfer capability to move waste between the 200 West and 200 East Area tank farms. This transfer capability is needed because the 200 West Area has far less useable DST capacity than there is waste in SSTs. The replacement waste transfer capability would provide a safe, reliable, and regulatory compliant means to move waste from the 200 West Area to the available DST capacity located in the 200 East Area.

Based on tank waste management and operation activities when the SIS EIS was prepared, the following needs were addressed:

  • Removing saltwell liquid from older SSTs to reduce the likelihood of liquid waste escaping from corroded tanks into the environment. Many of these tanks have leaked, and historically, new leaks , either known or assumed, have developed in these tanks at a rate of more than one per year;
  • Providing the ability to transfer the tank waste via a regulatory compliant system to mitigate any future safety concerns and use current or future tank space allocations;
  • Providing adequate tank waste storage capacity for future waste volumes associated with tank farm operations and other Hanford Site facility operations; and
  • Mitigating the flammable gas safety issue in tank 101-SY.

The alternatives evaluated in the SIS EIS provide DOE with the ability to continue safe storage of high-level tank waste and upgrade the regulatory compliance status with regard to Resource Conservation and Recovery Act (RCRA) (40 Code of Federal Regulations [CFR] 260) and the Washington Administrative Code (WAC) Dangerous Waste Regulations (WAC 173-303).

On December 1, 1995, DOE and Ecology published their Record of Decision for the SIS EIS in the Federal Register (FR) (60 FR 61687). The decision was to implement most of the actions of the preferred alternative, including:

  • Construct and operate a replacement cross-site transfer pipeline system;
  • Continue operating the existing cross-site transfer pipeline system until the replacement system is operational;
  • Continue operating the mixer pump in tank 101-SY to mitigate the unacceptable accumulation of hydrogen and other flammable gases; and
  • Perform activities to mitigate the loss of shrub-steppe habitat.

The existing cross-site transfer system has been used to transfer waste from the 200 West Area for 40 years. This underground pipeline system is at the end of its original design life. Currently, four of the six lines are out of service and unavailable to perform transfers because of plugging. The two useable lines do not meet current engineering standards such as double-containment and leak detection, which are required for waste management facilities. The design and operation of the replacement cross-site transfer system will meet the requirements of RCRA and WAC for secondary containment and Tri-Party Agreement Milestone M-43-07, which required construction of the replacement cross-site transfer system to commence by November 1995. Construction of the cross-site transfer system has begun and the system is scheduled to be operational in 1998.

DOE will continue to use the existing cross-site transfer system until the replacement cross-site transfer system is operational to provide access to 200 East Area DSTs for storage of 200 West Area facility waste and retrieved liquid waste from SSTs. Saltwell liquid retrieval will continue to reduce the risk to the environment from leaking SSTs. Operational procedures will ensure the integrity of the existing cross-site transfer system before any waste transfers. The current planning base estimates that the existing cross-site transfer system will operate for approximately 625 hours during 5 transfers before the replacement cross-site transfer system is operational in 1998.

The mixer pump in tank 101-SY was proven to be effective in mitigating the flammable gas as a safety issue in that tank during more than 1 year of operation. DOE and Ecology revised their preferred alternative between release of the Draft and Final EIS, based on the demonstrated success of the mixer pump, and determined that the construction of new tanks to resolve safety concerns was not necessary.

Based on new information available to DOE regarding nuclear criticality safety concerns during retrieval, transfer, and storage actions since the issuance of the Final SIS EIS, DOE has decided to defer a decision on the construction and operation of a retrieval system in tank 102-SY. Through an ongoing safety evaluation process, DOE recently revisited its operational assumptions regarding the potential for the occurrence of a nuclear criticality event during waste storage and transfers. Changes to the Tank Farm Authorization Basis for Criticality approved in September 1995 were rescinded by DOE in October 1995, pending the outcome of a criticality safety evaluation process outlined for the Defense Nuclear Facility Safety Board on November 8, 1995. Until these criticality safety evaluations are completed, the Hanford Site will operate under the historic limits, which maintain reasonable assurance of subcritical conditions during tank farm storage and transfer operations. Of the actions evaluated in the Final SIS EIS, only the retrieval of solids from tank 102-SY was affected by the technical uncertainties regarding a criticality. Based on the quantities of Pu in tank 102-SY sludge, retrieval of the solids falls within the scope of the criticality safety issues that will be evaluated over the next few months. As a result, a decision on retrieval of solids from tank 102-SY was deferred in the SIS EIS Record of Decision. Also, pending the outcome of the technical initiative to resolve the tank waste criticality safety issue, transfers of waste (primarily saltwell liquid) through tank 102-SY will be limited to noncomplexed waste. Tank 101-SY mixer pump operations, interim operations of the existing cross-site transfer system, operation of the replacement cross-site transfer system, saltwell liquid retrievals, and 200 West Area facility waste generation all would occur within the applicable criticality limits and would be subcritical.

Privatization of Tank Farm Activities

Currently, DOE is considering contracting with private companies for waste remediation services for the tank waste. DOE is interested in encouraging industry to use innovative approaches, and in using competition within the private marketplace to bring new ideas and concepts to tank waste remediation. The goal of the privatization effort is to streamline the TWRS mission, transfer a share of the responsibility, accountability, and liability to industry, improve performance, and reduce cost without sacrificing worker and public safety or environmental protection. DOE has issued a TWRS Privatization Request for Proposal and has received two bids to treat tank wastes (Briggs 1996) . DOE plans on issuing contracts to perform the first phase of the work in late summer 1996 . As currently envisioned, DOE would select contractors to construct and operate commercial demonstration facilities for two tank waste separations and LAW immobilization facilities, one of which may include a high-level waste (HLW) vitrification facility. If these commercial demonstrations are successful, DOE may use the lessons learned from those demonstration facilities and proceed with contracting for full-scale facilities to remediate the remainder of the tank waste. The planning process for these privatization activities is not complete. This planning process is subject to the final decision concerning remediation of the tank waste, which is the subject of this EIS.

Tank Farm Upgrades

Upgrades to the tank farms are planned to improve the reliability of safety-related systems, minimize onsite health and safety hazards, upgrade the regulatory compliance status of the tank farms, and place the tank farms in a controlled, stable condition until disposal is complete. Upgrades planned include 1) instrumentation including the automatic tank data gathering and management control system and the closed-circuit television monitoring to minimize personnel exposure; 2) tank ventilation to replace outdated ventilation systems; and 3) an electrical system to provide electrical power service with sufficient capacity and in compliance with current electrical codes (WHC 1996c). These three components of the tank farm upgrades are not addressed in the TWRS EIS but will be the subject of other analyses.

Upgrades to the existing waste transfer system that would be used in conjunction with the replacement cross-site transfer system also are planned. Waste transfer system upgrades are included in the TWRS EIS and discussed in Section B.3.0.2.

Initial Tank Retrieval System

This project would provide systems for retrieval of waste from up to 10 DSTs. Initial tank retrieval capabilities also would allow consolidation of compatible tank waste to create additional DST storage capacity and support passive mitigation such as diluting hydrogen-gas-generating Watchlist tanks should that become necessary. Retrieval of waste and transfer from all tanks is addressed in this EIS so the Initial Tank Retrieval System project is a subset of the actions included in this EIS and is not addressed separately.

Waste transfer system upgrades are an element of the Tank Farm Upgrades Project included in the TWRS EIS. Waste transfer system upgrades are discussed in Section B.3.0.2.

Hanford Tanks Initiative

Under this program, several waste retrieval activities discussed in the TWRS EIS would be demonstrated in support of the ex situ alternatives. This program would reduce the uncertainties associated with waste retrieval by developing and demonstrating the technologies required to meet retrieval requirements. The Hanford Tanks Initiative includes activities associated with waste retrieval and tank closure. Those activities associated with waste retrieval are covered under this EIS while activities associated with the closure would be the subject of future NEPA analysis.

This program would demonstrate equipment and systems for removal of tank residuals from tank 241-C-106 that are expected to remain following initial retrieval by sluicing. The objective would be to retrieve sufficient waste to meet waste retrieval requirements. This program also would attempt to develop technologies and criteria to retrieve waste from known or assumed leaking SSTs.

B.1.2 CESIUM AND STRONTIUM CAPSULES

B.1.2.1 Background

The cesium chloride (CsCl) and strontium fluoride (SrF2) capsule program separated the heat-generating Cs and Sr from the tank waste. To reduce the heat being generated in the tanks, a portion of the tank waste was recovered and processed to isolate the Cs and Sr. Removing the heat-generating isotopes from the waste allowed safe storage of the waste. Cs and Sr were removed from existing tank waste through the waste retrieval and treatment program or by treating the waste as it came out of the processing facility before it was put into the waste storage tanks. The Cs and Sr capsule inventory now stored at the Waste Encapsulation and Storage Facility (WESF) is the result of separating Cs and Sr from other waste. The Cs and Sr were converted to chloride and fluoride salts, respectively, and encapsulated for storage. The retrieval and processing activities started in 1967 and lasted until 1985. The storage of the capsule inventory at WESF is an ongoing activity. The capsules are currently designated as waste by-product, which means they are available for productive uses if uses can be found. If and when they are determined to have no potential productive uses, they would be managed and disposed of as HLW consistent with the TWRS EIS alternative selected for implementation.

The majority of the Sr was removed from tank waste sludges obtained from eight tanks in the A and AX Tank Farms. Additional Sr was recovered directly from PUREX Plant waste. Cs is relatively soluble in the tank liquid, which allowed Cs recovery from tank liquid from numerous tanks. The majority of the Cs was recovered from liquid waste produced at the PUREX or REDOX Plants using an ion exchange recovery process.

A capsule configuration was selected for containing the stabilized CsCl and SrF2 salts because it provides a physical form suitable for long-term storage. Details of capsule construction are shown in Figure B.1.2.1. Of the 1,577 Cs capsules initially fabricated, 249 have been subjected to destructive testing or repackaged into smaller sources and will not be returned. Similarly, of the 640 Sr capsules that were initially fabricated, 39 have been subjected to destructive testing or repackaging and will not be returned. At present, approximately 1,328 Cs and 601 Sr capsules are either stored onsite or will be returned to be stored at WESF by the end of 1997 . The number of capsules could increase if any existing capsule or cut-up capsule contents are repackaged.

Once recovered, the Cs was converted to CsCl, which was melted and poured into a type 316-L stainless-steel capsule, which was then capped and sealed by welding. This capsule was placed inside another capsule and sealed by welding on an outer cap. Figure B.1.2.1 illustrates the general configuration and original design dimensions of the capsules. Later design revisions incrementally increased the inner and outer wall thicknesses. The majority of the capsules produced have the thicker walls. The Cs content of the capsules is primarily Cs-137, with a half-life of 30.17 years, releasing 8.7E-2 watts per gram (W/g) of initial Cs. This decay emits a beta ray 5.4 percent of the time with a maximum energy of 1.2 million electron-volts (MeV), and a beta ray 94.6 percent of the time with a maximum energy of 0.5 MeV. The less-frequent decay mode creates stable barium-137 (Ba-137). The more-frequent decay mode creates Ba-137m, a metastable isotope that decays to the stable Ba-137 through a gamma ray of energy 0.66 MeV.

Figure B.1.2.1 Capsule Details

The Ba-137m has such a short half-life (2.5 minutes) that it can be thought of as occurring simultaneously with the decay of Cs-137. The second decay adds 3.4E-1 W/g of initial Cs. The curie and thermal loading of the Cs capsules at various time periods is provided in Volume Two, Appendix A.

The Sr was converted to SrF2 salt and was physically packed into a metal capsule. The metal alloy used for the SrF2 inner capsules was Hastelloy C276, which is a high-temperature corrosion-resistant alloy. After welding a cap on the inner capsule, the entire capsule was placed into a type 316-L stainless-steel outer capsule and an outer cap was welded in place. The Sr content of the capsules is primarily Sr-90, which has half-life of 28.6 years. The Sr-90 decay emits a beta ray with a maximum energy of 0.5 MeV releasing 1.6E-1 W/g of initial Sr. This creates yttrium-90 (Y-90), which decays to stable zirconium-90. The Y-90 has such a short half-life (3 hours), that it can be thought of as occurring simultaneously with Sr-90. The second decay in this chain manifests itself in the emissions of a beta ray with maximum energy of 2.3 MeV, releasing an additional 7.7E-1 W/g of initial Sr. The curie and thermal loading of the Sr capsules at various time periods is provided in Volume Two, Appendix A. The high-temperature corrosion-resistant alloy is required for the SrF2 capsules, because the Sr-90 decay chain results in higher capsule temperatures than experienced with the CsCl capsules.

The Cs capsules, which are strong emitters of penetrating gamma radiation, were shipped offsite in limited numbers and used for commercial irradiation purposes. The Sr capsules were used as heat sources because the primary radiation emitted by Sr is contained within the metallic capsule, which in turn heats the capsule. The capsules have also been used by DOE programs for fabricating radioactive sources and various research activities at Pacific Northwest National Laboratory, Sandia National Laboratory, and Oak Ridge National Laboratory. Several studies have been performed that document the integrity of the Cs and Sr capsules and their ability to continue safe storage. Corrosion data indicate that attack on the capsule walls from the CsCl would be very low.

The Cs capsule program was terminated, and the approximately 778 CsCl capsules that were at commercial facilities are in the process of being returned to the Hanford Site. Current plans call for all Cs capsules to be returned to the Site by the end of 1997 . The commercial uses of the Cs capsules varied, with the majority of them used for sterilizing medical equipment and supplies. The offsite commercial uses of the CsCl capsules are shown in Table B.1.2.1

Table B.1.2.1 Offsite Commercial Uses of Cesium Chloride Capsules

B.1.2.2 Description of Cesium and Strontium Capsules

The Cs and Sr capsule program was performed between 1974 and 1985 at WESF to remove the heat-generating Cs and Sr isotopes from the tank waste because they generated sufficient decay heat to evaporate the water from the tank waste. Hypothetically, after all the tank wastewater had evaporated, the waste would continue to heat and had the potential to initiate a self-propagating reaction or destroy the structural integrity of the tank. Between 300 and 400 C (570 and 750 F), the oxidizing chemicals present (such as sodium nitrate) could have reacted with the organic chemicals remaining in the tank. This possibility was initially avoided by replacing the water that had evaporated; a more permanent solution was to substantially decrease the concentration of the heat source. The program to decrease the tank concentration and package the Cs and Sr was carried out between 1974 and 1985 at WESF, which is annexed to B Plant in the 200 East Area. The program timeline is shown in Figure B.1.2.2.

Figure B.1.2.2 Capsule Program Timeline

A capsule consists of a sealed inner metallic tube containing the radioactive material inside an outer metallic capsule providing secondary containment. The double-walled capsule is used to provide added safety for confinement (see Figure B.1.2.1).

Current and Planned Activities

The only ongoing and planned activities for the capsules are the continued storage of the capsules in WESF, return of the remaining capsules to WESF, and attempts to find productive uses for the Cs and Sr capsules. The Cs and Sr capsules are currently stored in water-filled basins at WESF in the 200 East Area. WESF is directly adjacent to B Plant in the 200 East Area, and is approximately 5,600 square meters (m2) (60,000 square feet [ft2]), approximately one-fifth the size of B Plant.

The capsules are stored, in a retrievable manner, in racks at the bottom of the pool cells, which are filled with water to a depth of 4 m (13 ft). The storage racks provide for controlled capsule storage locations within the pools. WESF has a total of eight pools, five that are active and used for capsule storage, one that is used for temporary storage, and two that are not used but are maintained. Storing the capsules under water cools the capsules and provides radiation protection for WESF workers. All of the storage basins are monitored for radiation, which would indicate a capsule leak.

Currently, B Plant is scheduled for deactivation by the year 2001. DOE currently is upgrading WESF to operate independently of B Plant because in the past, o peration of WESF was dependent on the operation of B Plant.

DOE is in the early planning stages of considering whether the capsules should remain in WESF or be placed in alternative locations for storage. Among the possible alternatives that may be considered are placing the capsules in the proposed Canister Storage Building originally planned to store HLW.

No decisions have been made to proceed with any alternative storage options. For purposes of analyzing impacts in the TWRS EIS, it is assumed that the capsules will remain in WESF until disposal. If DOE decides to change the method or location for the interim storage of the capsules, an appropriate NEPA review would be performed. A Cs and Sr capsule management program will provide for management of the capsules until final disposition has been implemented.

Capsule safety concerns have not been broken down into specific categories. However, the dominant safety issue for the capsules is the integrity of the storage facility. As it currently exists, the storage facility at WESF has no provision for handling a situation in which the cooling water is lost. If a catastrophic event such as an earthquake were to occur and cause a failure in the basin or its water supply, there is no engineered system to provide secondary containment or an alternate water supply, although efforts are underway to resolve this issue. The impacts of such an event are discussed in Volume Four, Appendix E of the EIS.

DOE is pursuing alternative uses for the Cs and Sr capsules. If no future uses for these capsules are found, the capsules eventually would be designated as HLW and managed and disposed of consistent with the Tri-Party Agreement and the TWRS EIS alternative selected for implementation.

B.1.2.3 Volume and Activity Comparison Between Capsules and Tank Waste

The volume of the material in all of the Cs and Sr capsules combined is approximately 2 cubic meters (m3) (70 ft3), which is very small in comparison to the 2.1 E+5 m3 ( 7.5 E+06 ft3) in the waste storage tanks. Although the amount of material in the capsules is small, the amount of radioactivity contained in the capsules is approximately 35 percent of the total activity of the waste storage tanks and the capsules combined. Thus, separating and encapsulating the Cs and Sr from the other tank waste resulted in containing a large portion of the radioactivity in a small volume.

B.1.2.4 Current Monitoring and Maintenance

Monitoring and maintenance activities for the capsules involve calculating the annual inventory, physically verifying that the inner capsule can still move independently of the outer capsule, and using online radiation monitors to detect pool cell water contamination. The annual inventory provides the exact storage location and accountability for all of the Cs and Sr capsules stored at WESF.

The Cs capsules are "clunk-tested" on a quarterly basis. This involves physically grasping one end of a capsule with a pool tong and rapidly moving the capsule vertically approximately 15 cm (6 in.). This allows the inner capsule to slide within the outer capsule, making a "clunk" sound that is easily heard and felt by the operator performing the test. This test verifies that the capsule has not bulged.



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