Managing Radioactive Waste at the Nevada Test Site

1980 film, with transcript

Catalog description: An overview of how different types of nuclear waste is and can be stored at the Nevada Test Site.

This film is in our catalog.

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00:00 Many types of hazardous materials are used for the production of energy in industrial processes, the treatment of illness, and for national defense.
00:10 The manufacture and use of these materials results in toxic waste which must be disposed of properly.
00:16 Some of the waste produced by the U.S. Department of Energy's research and development programs is radioactive.
00:23 One of the disposal areas for this radioactive waste is the Nevada test site.
00:30 Located 65 miles northwest of Las Vegas, the Nevada test site is the location where the
00:46 Department of Energy conducts underground nuclear weapons tests.
00:51 Radioactive wastes resulting from the nuclear weapons testing program have been disposed
00:56 of at the site for more than 20 years.
01:00 waste from other DOE defense program facilities are also taken to the site for disposal.
01:07 The Nevada Test Site is a remote secure area of 1,350 square miles where experiments involving
01:15 hazardous materials can be carried out safely.
01:20 Radioactive waste management programs at the Nevada Test Site are part of a nationwide
01:25 program conducted by the Department of Energy's Office of Nuclear Waste Management, headquartered
01:31 in Washington, D.C. The programs include both normal day-to-day waste disposal operations
01:38 and research and development projects on new and improved methods for safely handling and
01:44 disposing of radioactive materials produced by both government and commercial nuclear
01:49 operations. Every plant and animal that has ever lived on this Earth has been exposed
01:55 to nuclear radiation for every second of its life by radioactive materials, which occur
02:01 naturally in our environment. In addition to this natural background radiation, we are
02:09 also exposed to radiation from medical diagnosis, nuclear weapons test fallout, and energy production
02:15 and use. There are 106 chemical elements which cannot be divided into simpler substances
02:23 by chemical means. Each of these elements may have up to several radioactive isotopes
02:29 which have half-lives ranging from millions of a second to millions of years. A half-life
02:35 is the time in which half the atoms of a particular radioactive substance disintegrate to another
02:40 nuclear form. The main concern is that radioactive waste materials would longer have lives be
02:46 safely disposed of so that they will not be hazardous to people or the environment.
02:52 Two terms are important in this discussion. Transuranic elements are those elements having
02:58 an atomic number greater than 92, that of uranium. All transuranic elements are produced
03:04 artificially and are radioactive. A curie is the basic measurement of the amount of
03:10 activity of a specific quantity of radioactive material and is based on the rate of decay
03:17 of one gram of radium. The major classes of nuclear waste involved in programs at the
03:23 Nevada Test Site are low-level waste, transuranic waste, and high-level waste. Low-level wastes
03:30 contain less than 10 nanocuries, that is less than ten billionths of a curie of
03:35 transuranic contaminants per gram of material. Some low-level waste may be
03:41 free of transuranic contaminants. In general, low-level wastes have shorter
03:46 half-lives, require minimal shielding, and have small but potentially hazardous
03:51 quantities of radioactive isotopes. Some low-level waste may have much higher
03:57 levels of radioactivity and require heavily shielded, specially designed
04:02 transportation containers. Several types of containers are used to transport
04:07 radioactive materials. Waste with a small amount of radioactivity may be packaged
04:13 in heavy cardboard or plywood boxes. Other higher radioactive substances
04:18 require much sturdier containers. All containers must conform to Department of
04:24 Transportation regulations.
04:27 Low-level waste disposed of at the Nevada test site originates in a number of Department
04:33 of Energy facilities, such as the Rocky Flats plant near Denver, Colorado, where plutonium
04:39 parts for nuclear weapons are produced.
04:43 Depending on the type and amount of radioactive material involved, the waste is carefully
04:48 packed in an appropriate shipping container.
04:51 These containers must conform to U.S. Department of Transportation regulations and be properly
04:56 marked and labeled. The content of each container is documented and a detailed inventory is
05:03 kept on all radioactive material in stock and being shipped to the test site.
05:16 Each step in the operation, gathering the waste material, consolidating it and packaging
05:21 it is carefully planned and checked to ensure that exposure to the plant employees, truck
05:27 drivers, and the public is kept at the lowest level possible, well below the existing radiation
05:33 exposure guidelines.
05:41 The waste materials destined for the Nevada test site are carried by commercial trucking
05:46 firms under regulations established by the U.S. Department of Transportation and the
05:51 states through which the trucks travel.
06:05 Radioactive waste materials also result from a number of activities at the Nevada test
06:09 site.
06:10 Some of the wastes are vehicles, equipment, and debris contaminated by atmospheric nuclear
06:16 test conducted in the 1950s.
06:25 This material is being gathered and placed in two large subsidence craters in Yucca Flat
06:30 formed by underground of Lear tests.
06:33 This debris will be covered by several feet of earth and the location marked with monuments.
06:44 Other low level wastes are generated in test site laboratories and facilities such as the
06:49 decontamination pad where equipment used in the underground testing program is cleaned
06:54 for reuse.
06:56 Rags, protective clothing, and worn out or broken equipment are typical of the waste
07:01 items that are designated for disposal.
07:06 These waste materials are compacted and packaged for burial.
07:11 And inventory and continuous administrative control is kept of all radioactive materials
07:16 on the test site.
07:20 The major low-level disposal area at the Nevada test site is a large continuous trench located
07:26 in Frenchman Flat, a dry lake bed in the southeast section of the site.
07:31 The trench is 20 feet deep, 700 feet long, and has a capacity for the burial of 1,600,000
07:40 cubic feet of packaged radioactive waste. Additional trenches will be dug when needed.
07:48 As the waste containers are stacked on one side of the trench and covered over, the opposite
07:53 side of the trench is extended with the dirt taken to the fill side to be used for future
07:58 covering. The stacked waste is covered with at least seven feet of dirt.
08:06 When a truck arrives at the site, the load is checked by a radiation monitor and the
08:11 containers are unloaded and stacked neatly in place on the side of the trench.
08:16 The exact location of each box along with a record of its contents is carefully documented.
08:23 Although highly unlikely, if it is ever necessary to retrieve a container, the record can be
08:33 checked and the box located then dug out of the trench.
08:39 Strict controls are required on the material shipped to the test site for burial to ensure
08:44 that all Department of Transportation requirements are met.
08:47 The contents must not include liquids, pyrophoric or explosive materials, combustible material
08:53 must be separated from non-combustible and plainly marked.
08:57 Any heat produced by the contents of the container must not adversely affect the chemical or
09:03 physical integrity of the contents or the package. The exterior of the package must
09:08 be free of radioactive contamination upon arrival at the test site. Penetrating gamma
09:14 radiation must not exceed established guidelines during handling, shipment, and retrievable
09:19 storage. Packages with waste containing tritium, a radioactive isotope of hydrogen, are overpacked
09:28 in steel cylinders. The tritium package is surrounded with a special absorbent material
09:34 and the steel container is welded shut prior to burial. Sensitive monitoring equipment
09:40 is used to check for leaks of tritium both before and after the containers are buried.
09:46 Several research programs on low-level waste currently being conducted include studies
09:51 on revegetation to limit the penetration of moisture into the soil, a study on the transport
09:57 mechanism of radioactivity through the soil and a study to develop criteria for deeper
10:02 burial of waste.
10:06 The burial site in Frenchman Flat is continuously monitored by air samplers and other sensitive
10:12 radiation detection equipment.
10:14 All employees at the Nevada test site wear radiation film disseminators, which are checked
10:19 monthly to determine the amount of external radiation exposure that the individual may
10:24 have received. Exposure to individuals is kept at the lowest level possible, well below
10:30 guidelines. Transuranic waste results predominantly from
10:35 reprocessing of spent fuel from nuclear reactors and the fabrication of plutonium components
10:41 used to produce nuclear weapons. Transuranic waste is currently defined as containing more
10:47 than 10 nanocuries of transuranic elements per gram of material and may contain uranium.
10:55 All materials containing more than 10 nanocuries of transuranic isotopes are kept in special
11:00 steel surface containers for 20 years or longer so that the material may be retrieved for
11:06 reprocessing or permanent disposal.
11:13 The radiation burial site in Frenchman Flat is particularly suited to this operation.
11:19 It lies in a closed basin.
11:22 Surface runoff from the infrequent rains flows into the valley where it eventually evaporates.
11:28 The local aquifer is about 600 feet deep and there is no known transport of water from
11:34 the surface to the aquifer.
11:37 in the area are monitored regularly to assure that the water is safe to use.
11:47 Research utilizing high-level waste is conducted under the Nevada Nuclear Waste Storage Investigations Program,
11:54 which involves developing technology for handling, packaging, and storing highly radioactive spent fuel assemblies
12:01 in different geologic mediums.
12:05 The Nevada program is part of the national waste management program conducted by the Department of Energy
12:11 through the Office of Nuclear Waste Isolation, operated by Battelle Memorial Institute at Columbus, Ohio,
12:18 and at other DOE field offices in Savannah River, South Carolina, and Hanford, Washington.
12:24 High level waste may come from two sources.
12:27 They may be intact fuel assemblies that are being discarded after having served their useful life
12:32 in a nuclear reactor and are called spent fuel.
12:37 High-level waste also results from the reprocessing of the spent fuel
12:41 to extract the remaining uranium and plutonium for continued use as reactor fuel.
12:47 These high-level wastes are being considered for disposal in geologic repositories
12:52 or by other technical options designed to provide long-term isolation of the wastes from the biosphere.
12:59 The spent fuel assemblies being used at the Nevada test site
13:02 are from the Florida Power and Light Company's Turkey Point reactor.
13:07 Additional spent fuel assemblies may be obtained from other reactors for use in new programs.
13:13 A nuclear power reactor uses about 200 fuel assemblies in its reactor core,
13:18 producing steam to run electric turbines.
13:21 About one-third of a nuclear reactor's fuel assemblies in the core
13:25 must be removed and replaced every 18 months.
13:28 The spent fuel assemblies are highly radioactive and are stored in water pools near the reactor
13:34 for several years to allow short half-lived radioisotopes to decay.
13:39 A 25-ton truck-mounted transportation cask is used to move the spent fuel assemblies
13:44 from the reactor to the Nevada test site.
13:48 This cask is placed in the reactor water storage pool for the loading of the spent fuel assembly.
13:55 Each fuel assembly is about 13 feet in length and 8 1⁄2 inches square.
14:00 It contains 200 hollow rods filled with uranium pellets.
14:04 The spent fuel assembly is removed from the storage rack and placed in the shipping cask,
14:09 which is then sealed.
14:11 Each step of the operation is closely checked by radiation monitors to ensure that the operators
14:17 do not receive an exposure above established guidelines.
14:22 When the loaded cask is removed from the water storage tank, it is drained, washed and steamed
14:28 clean.
14:29 The cask is then monitored to assure compliance with the Department of Transportation regulations
14:34 for external radiation and surface contamination.
14:38 All of the bolts and seals are checked to assure that there are no leaks.
14:43 The casks used to transport the spent fuel assemblies are designed to withstand accidents
14:48 much more severe than would be expected in a normal transportation situation.
14:54 The certification tests of the transportation casks include having a trailer carrying a
14:59 cask rammed by a railroad locomotive going 80 miles per hour.
15:09 This test showed only superficial damage to the cask without compromising its integrity.
15:15 These casks are one of the safest containers for hazardous material used in interstate
15:21 commerce.
15:27 Several of the spent fuel assemblies were first taken to the Battelle Memorial Institute
15:32 laboratory in Columbus, Ohio, where they were closely examined in a hot cell, which protected
15:37 the operators from exposure to radiation.
15:41 The condition of each assembly was carefully documented.
15:50 Fuel handling operations at the Nevada test site are conducted at the Encapsulation, Maintenance
15:55 and Disassembly, or EMAD facility located on the southwest corner of the test site.
16:01 This building was originally designed and constructed to assemble and disassemble nuclear
16:07 rocket engines.
16:08 When a truck containing the spent fuel assemblies arrives at the Nevada test site, the cask
16:15 and trailer are carefully checked for surface contamination or leaks.
16:20 In the hot bay of the EMAD facility, the cask is unloaded and again closely checked.
16:27 This hot bay is one of the largest facilities of its kind in the world, with dense concrete
16:32 walls and lead glass windows up to 6 feet thick.
16:36 All of the operations involving highly radioactive materials in the hot bay are performed by
16:41 remote control using overhead cranes and sidewall manipulators.
16:46 Each step of the operation is observed and recorded by closed circuit television cameras
16:50 and video tape recorders.
16:54 Following removal from the transportation cask, the spent fuel assembly is placed in
16:58 a stainless steel canister.
17:03 A threaded lid is screwed into the top of the canister and welded closed using specially
17:08 remotely operated equipment designed for this operation.
17:12 The sealed canister is filled with helium to provide a chemically inert environment,
17:17 then is checked for any leaks and surface contamination.
17:22 Two methods of temporary surface and near-surface storage are being evaluated at the Nevada
17:27 test site.
17:28 If adopted, one or more of these methods could be used to store high-level radioactive waste
17:33 materials prior to final disposal or to provide overflow storage capacity for spent fuel.
17:41 For the surface storage, an above-ground sealed silo has been designed to virtually eliminate
17:46 external radiation and withstand a tip-over caused by an earthquake without significant damage.
17:53 The spent fuel assembly is loaded into the silo in the hot bay and then trucked to a pad located
17:58 beside the EMAD building, where it is bolted into place.
18:02 The surface storage cask is made of steel reinforced concrete.
18:06 It is 21 feet high, 9 feet in diameter, and weighs about 95 tons.
18:11 It sits on a reinforced concrete pad 14 feet square and 6 feet thick.
18:17 For the near surface storage, five dry wells, 25 feet deep and 18 inches in diameter, have
18:24 been drilled between railroad tracks near the EMAD.
18:27 The dry wells are 25 feet apart and are equipped with steel liners that have been cemented
18:33 into place.
18:34 A specially designed shielded vehicle mounted on a rail car transports the encapsulated
18:40 fuel assemblies and emplaces them in the dry wells.
18:45 Both the dry wells and surface storage casks are instrumented to collect and record canister
18:50 and liner temperatures, soil temperatures near the wells and radiation levels.
18:57 Once the fuel canisters are in place, workers can move around both the surface storage cask and the dry wells with virtually no exposure to the radiation from the emplaced spent fuel assembly.
19:10 A second experimental program involves the use of 11 canisters containing spent reactor fuel and six canisters containing electric heaters,
19:20 which will be emplaced in the 17 dry wells drilled in the floor of a granite tunnel 1,400 feet beneath the surface.
19:27 Each spent fuel canister is taken to the experimental facility by a specially designed surface transport vehicle which consists of a large steel cask mounted on a low boy trailer.
19:39 The cask is loaded in the E-MAD Hot Bay and then driven to the top of a vertical hole which connects the surface to the granite tunnel.
19:57 Men and equipment are transported to the 1,400-foot deep tunnel in a separate vertical shaft.
20:06 The canister containing the spent fuel assembly is carefully lowered underground through the
20:11 19-inch diameter access hole to a rail-mounted transfer vehicle.
20:16 All of this equipment is controlled from the surface with the operations being monitored
20:20 on closed circuit television.
20:23 When the underground transport vehicle has received the canister, it moves to one of the storage holes drilled on the floor of the tunnel.
20:31 A 5,200 pound concrete cover over the hole is removed
20:35 and the canister is lowered into place along with a shield plug.
20:41 A specially trained team then connects temperature and radiation monitoring instruments in the hole
20:47 and the concrete plug is replaced, covering the hole.
20:52 Two other tunnels in the granite formation on either side of the fuel emplacement tunnel
21:00 have been equipped with electric heaters and monitoring equipment.
21:04 The electrical simulators will be controlled to match the heat output of a spent fuel assembly.
21:10 The object of the experiment is to evaluate the response of granite to the temperatures
21:15 produced by the electric heaters and the combination of high radiation and thermal heat produced
21:21 by the radioactive spent fuel assemblies.
21:25 This data will aid in determining whether or not granite and other crystalline rock
21:29 types are suitable geologic formations for permanent disposal of high level radioactive
21:35 wastes.
21:37 All of the spent fuel canisters are retrievable and will be moved from the various experimental
21:42 locations back to the EMAD building after several years.
21:46 The spent fuel assemblies and the dry wells will then be examined to determine if there
21:51 has been any effect caused by dry storage in an inert atmosphere.
21:57 The information gained from these experimental programs will be used to develop geologic
22:02 repository technology for use in permanent geologic waste disposal programs.
22:10 A third study on high-level waste management involves determining if a geologic formation
22:15 suitable for permanent disposal of high-level waste exists within the boundaries of the
22:20 Nevada test site.
22:23 Any long-term waste management project must be compatible with the prime test site mission
22:28 of underground nuclear weapons testing.
22:31 A waste repository located in the southwest quadrant of the site would not interfere with
22:36 other Nevada test site programs and the search is centered on Yucca Mountain near the test
22:41 site border northwest of the EMAD facility.
22:45 The rock under evaluation at the site is welded tuff, a very hard volcanic formation located
22:52 about 2,000 feet beneath the surface.
22:56 Currently, the area is being drilled to obtain cores of the underground rock formation for
23:05 evaluation by geologists and other scientists.
23:17 Other studies being conducted include surface ecology, seismicity, volcanism, and hydrology
23:23 of the area.
23:27 The effects of ground motion caused by underground nuclear tests are also being studied.
23:32 If a geologic formation is found to be suitable for a permanent commercial high-level waste
23:37 repository, any facility constructed would be licensed by the Nuclear Regulatory Commission
23:44 with consultation and concurrence with the State of Nevada.
23:49 All aspects of these investigations are periodically reviewed by scientific panels whose membership
23:55 represents both the Department of Energy and independent scientific organizations.
24:00 Details and results of these studies are available in open scientific literature and are presented
24:06 to state officials and the public.
24:16 The radioactive waste management programs conducted at the Department of Energy's Nevada
24:20 test site are essential to many of the DOE's defense programs and are helping to solve
24:26 the problems of permanent geologic storage of high-level waste from the nation's commercial
24:31 nuclear power industry.