Management of Commercially Generated Radioactive Waste - U.S. ...

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methods for remotely handled TRU wastes have potential for both minor and moderate acci-
dents. Indoor storage methods for contact-handled TRU wastes limit the accident spectrum
to minor accidents.
Typical minor accidents involving TRU waste packages include dislodging of surface con-
tamination, rusting through of containers, and mechanical breaching of package. The 70-yr
accumulated dose for the maximum-exposed individual for the largest of these releases is
2 x 10 -4 rem.
Moderate accidents include fires in storage, tornado strikes and drums dropped from a
crane. The 70-yr accumulated dose to the maximum-exposed individual for the largest of
these releases is 4 x 10 -4 rem.
Krypton removed from the FRP dissolver off gas is assumed to be collected in pressur-
ized gas cylinders and stored onsite at the FRP in a separate facility. Three moderate
accidents were postulated for the release of gas from one cylinder (130 kCi). If this
occurs in the operating area or storage corridor, gas would be released via the facility
stack. The 70-yr accumulated dose to a maximum-exposed individual in the public would be
5 x 10 -3 rem. This accident is estimated to occur once every 20 years. Of greater potential
consequence are the employee doses from this accident. A worker in the area of the ruptured
cylinder faces hazards from flying debris and could receive a radiation dose rate of up to
8 rem/min. Immediate evacuation of the area would be required.
4.8.2.3 Radiological Impacts from Reprocessing Waste Transportation Accidents
A reprocessing fuel cycle has potential transportation requirements for spent fuel,
solidified high-level waste, fuel residues, and other TRU wastes. As in the once-through
cycle, safety during transport depends primarily on shipping containers. The containers must
meet standards established by the Department of Transportation and the Nuclear Regulatory
Commission. Packages containing significant amounts of radioactive material must be designed
to prevent loss or dispersal of the radioactive contents, retain shielding efficiency, ensure
nuclear criticality safety, and provide adequate heat dissipation under normal conditions of
transport and under specified (hypothetical) accident damage test conditions (49 CFR 71,
Appendix B). Improbable accidents that exceed the hypothetical tests, accidents due to
equipment failures and accidents that are less severe than the test conditions were consid-
ered here to demonstrate the range of potential occurrences in a transportation environment.
Minor, moderate and severe accidents were postulated for the rail transport of solidi-
fied high-level waste. Minor accidents for this material are similar to those for spent
fuel. A moderate accident could result in a reduction in neutron shielding and a local
hazard of increased neutron exposures. No radioactive material would be released in this
accident. A severe accident involving impact and fire could result in a material release.
This accident is estimated to occur only once every 330,000 years and result in a 70-yr
accumulated dose to the maximum-exposed individual of 10 rem.
Transuranic wastes were considered to be transported in DOT-licensed packages. Three
minor and one severe accident were identified. The worst minor accident is expected to