Studies of evaluation basis accidents and beyond evaluation basis accidents have been performed for the pit fabrication and intrusive modification pit reuse operations. The studies postulated a set of accident scenarios that were representative of the risks and consequences for workers and the public that can be expected from operations. Although not all potential accidents were addressed, those that were postulated have consequences and risks that are expected to envelop the consequences and risks of the relocated operations.
A range of hazardous conditions and potential accidents were reviewed as candidates to represent the risks to workers and the public of the replacement pit fabrication and intrusive modification operations at Savannah River Site (SRS) and LANL, respectively. Through a screening process, several evaluation basis accidents and beyond evaluation basis accidents were selected for further definition and analysis. Descriptive information on these accidents is provided in table F.2.3.1-1.
| Accident Scenario | Site | Accident Frequency (per year) | Total Material Released to Environment |
|---|---|---|---|
| 1. Fire-induced release of plutonium from a glove box | LANL | 1x10-4 to 0.01 | 0.24 g plutonium oxide |
| SRS | 1x10-4 to 0.01 | 0.24 g plutonium oxide | |
| 2. Operational release of tritium | LANL | 1x10-6 to 1x10-4 | 21,000 Ci of tritium oxide 24 |
| SRS | 1x10-6 to 1x10-4 | 21,000 Ci of tritium oxide 24 | |
| 3. Mechanical release of nitric acid into confined area | LANL | 1x10-6 to 1x10-4 | 6,100 gal of 80-percent nitric acid in bermed area |
| SRS | 1x10-6 to 1x10-4 | 6,100 gal of 80-percent nitric acid in bermed area | |
| 4. Earthquake-induced mechanical release of nitric acid | LANL | 1x10-7 to 1x10-6 | 6,100 gal of 80-percent nitric acid in bermed area |
| SRS | 1x10-7 to 1x10-6 | 6,100 gal of 80-percent nitric acid in bermed area | |
| 5. Earthquake-induced release of plutonium | LANL | 1x10-6 to 1x10-4 | 0.61 g of plutonium metal |
| SRS | 1x10-6 to 1x10-4 | 0.61 g of plutonium metal | |
| 6. Earthquake-induced release of plutonium | LANL | 1x10-7 to 1x10-6 | 0.63 g of plutonium metal |
| SRS | 1x10-7 to 1x10-6 | 0.63 g of plutonium metal | |
| 7. Wet criticality | LANL | 1x10-7 to 1x10-6 | 5x1017 fissions |
| SRS | 1x10-7 to 1x10-6 | 5x1017 fissions | |
| 8. Mechanical-induced release of plutonium | LANL | 0.01 to 1x10-1 | 7.2x10-12 g of plutonium oxide |
| SRS | 0.01 to 1x10-1 | 7.2x10-12 g of plutonium oxide | |
| 9. Explosive-induced release of plutonium | LANL | 1x10-4 to 0.01 | 0.05 g of plutonium metal |
| SRS | 1x10-4 to 0.01 | 0.05 g of plutonium metal | |
| 10. Fire-induced release of plutonium on loading dock | LANL | 1x10-6 to 1x10-4 | 0.8 g plutonium oxide |
| SRS | 1x10-6 to 1x10-4 | 0.8 g plutonium oxide |
Scenario 1: Fire-induced release of plutonium from a glove box. A fire is postulated within a laboratory which involves cleaning liquid such as acetone or isopropyl alcohol and burns the gloves in a glove box. The fire releases the plutonium contamination from the outer surface of the gloves that are in the glove box. Fire suppression and ventilation systems are assumed to be inoperable.
Los Alamos National Laboratory. The accident frequency is estimated to be in the range of 1x10-4 to 0.01/yr. The estimated release is 0.24 g (8.47x10 -3 oz) of plutonium oxide.
Savannah River Site. The accident frequency is estimated to be in the range of 1x10-4 to 0.01/yr. The estimated release is 0.24 g (8.47x10 -3 oz) of plutonium oxide.
Scenario 2: Operational release of tritium from special recovery line. This postulated accident is initiated by the loss of the inert atmosphere in the disassembly glove box in the special recovery line. As a result of the loss of inert atmosphere, a fire is assumed to start. As the tritium storage container is heated, tritium is released. It is assumed that released tritium bypasses the tritium collection system.
Los Alamos National Laboratory. The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr. For the purposes of this analysis, the release is assumed to be 21,000 curies (Ci) of tritium oxide.
Savannah River Site. The accident is assumed to be applicable at SRS with an estimated frequency in the range of 1x10-6 to 1x10-4/yr. For the purposes of this analysis, the release is assumed to be 21,000 Ci of tritium oxide.
Scenario 3. Mechanical release of nitric acid into confined bermed area. A mechanical failure in a tank, valve, or piping is postulated that releases the entire contents of an 80-percent nitric acid storage tank. The tank is located outdoors within a bermed area. The inventory is confined to the berm surrounding the tank.
Los Alamos National Laboratory. The nitric acid tank contains 23,090 L (6,100 gal) of 80-percent nitric acid. The bermed area is 27 square meters (m 2) (288 square feet [ft 2] ). The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr.
Savannah River Site. The same nitric acid tank and bermed area are assumed to located at SRS. The tank contains 23,090 L (6,100 gal) of 80-percent nitric acid. The bermed area is 27 m 2 (288 ft 2). The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr.
Scenario 4: Beyond evaluation basis earthquake-induced release of nitric acid. A mechanical failure in a tank, valve, or piping is postulated that releases the entire contents of an 80-percent nitric acid storage tank. The tank is located outdoors within a bermed area; however, a beyond evaluation basis earthquake ruptures the berm. The inventory is not confined to the berm surrounding the tank.
Los Alamos National Laboratory. The nitric acid tank contains 23,090 L (6,100 gal) of 80-percent nitric acid. The accident frequency is estimated to be in the range of 1x10-7 to 1x10-6/yr.
Savannah River Site. The same nitric acid tank and bermed area are assumed to be located at SRS. The tank contains 23,090 L (6,100 gal) of 80-percent nitric acid. The accident frequency is estimated to be in the range of 1x10-7 to 1x10-6/yr.
Scenario 5: Evaluation basis earthquake-induced release of plutonium. The forces from the seismic event are applied to the facility and confinement systems within the facility. For the source term analysis, both anchorage failures and support stand failures are assumed to cause enclosures to fall over. On impact with the floor, glove box windows may break or fall out, connecting rings and connections to exhaust ductwork may separate, and solution transfer lines may break. The enclosures may also fail structurally. For the source term analysis, if the seismic margins assessment shows that an enclosure will fail, it is assumed that the enclosure will be breached, and material that becomes airborne will be released to the laboratory. The building structure, high-efficiency particulate air (HEPA) filter plenums, and ductwork from the plenums to the structure will remain a functional confinement barrier following an earthquake.
Los Alamos National Laboratory. The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr. The release is calculated to be 0.61 g (0.02 oz) of plutonium metal.
Savannah River Site. This accident is also assumed to occur at SRS. The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr. The release is calculated to be 0.61 g (0.02 oz) of plutonium metal.
Scenario 6. Beyond evaluation basis earthquake-induced release of plutonium. The forces from the seismic event are applied to the facility and confinement systems within the facility. For the source term analysis, both anchorage failures and support stand failures are assumed to cause enclosures to fall over. On impact with the floor, glove box windows may break or fall out, connecting rings and connections to exhaust ductwork may separate, and solution transfer lines may break. The enclosures may also fail structurally. For the source term analysis, if the seismic margins assessment shows that an enclosure will fail, it is assumed that the enclosure will be breached, and material that becomes airborne will be released to the laboratory. For the beyond evaluation basis earthquake, the building structure, HEPA filter plenums, and ductwork from the plenums to the structure are assumed not to be functional confinement barriers.
Los Alamos National Laboratory. The accident frequency is estimated to be in the range of 1x10-7 to 1x10-6/yr. The release is calculated to be 0.63 g (0.02 oz) of plutonium metal.
Savannah River Site. This accident is also assumed to occur at SRS. The accident frequency is estimated to be in the range of 1x10-7 to 1x10-6/yr. The release is calculated to be 0.63 g (0.02 oz) of plutonium metal.
Scenario 7: Wet criticality. The wet criticality accident occurs in a glove box where the plutonium in solution exceeds the critical mass.
Los Alamos National Laboratory. The wet criticality accident that is postulated results in 5x1017 fissions. The frequency of occurrence of a criticality is estimated to be in the range of 1x10-7 to 1x10-6/yr.
Savannah River Site. The wet criticality is also assumed to occur at SRS. The accident results in 5x1017 fissions. The frequency of occurrence of a criticality is estimated to be in the range of 1x10-7 to 1x10-6/yr.
Scenario 8: Mechanical-induced release of plutonium from a degraded storage container. This postulated scenario assumes a package is dropped and the oxide contents spill onto the room floor. The material at risk is assumed to be 4.5 kg (9.9 lb) of plutonium oxide. No credit is taken for the inner metal container (assumed to have been ruptured by the plutonium oxidation reaction), the inner plastic bag (assumed to have deteriorated), or the outer package (assumed to be a slip-lid can with a degraded seal).
Los Alamos National Laboratory. The accident frequency is in the range of 0.01 to 0.1/yr. The release is estimated to be 7.2x10 -12 g (2.5x10 -13 oz) of plutonium oxide.
Savannah River Site. The accident frequency is in the range of 0.01 to 0.1/yr. The release is estimated to be 7.2x10 -12 g (2.5x10 -13 oz) of plutonium oxide.
Scenario 9: Explosion-induced release of plutonium. This postulated accident is the result of a chemical explosion in an ion-exchange column. The explosion causes a breach of the glove box containing the ion exchange column. It is assumed that the normal ventilation system is inoperable.
Los Alamos National Laboratory. The accident frequency is in the range of 1x10-4 to 0.01/yr. The release of plutonium metal is estimated to be 0.05 g (1.76x10 -3 oz).
Savannah River Site. The accident frequency is in the range of 1x10-4 to 0.01/yr. The release of plutonium metal is estimated to be 0.05 g (1.76x10 -3 oz).
Scenario 10: Fire-induced release of plutonium on loading dock. This postulated scenario involves a fire on the loading dock involving a combustible plutonium contaminated waste drum. This scenario also assumes that the loading dock is open to the atmosphere at the time of the fire.
Los Alamos National Laboratory. The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4/yr. The release is calculated to be 0.8 g (0.03 oz) of plutonium oxide.
Savannah River Site. The accident frequency is estimated to be in the range of 1x10-6 to 1x10-4 /yr. The release is calculated to be 0.8 g (0.03 oz) of plutonium oxide.
Tables F.2.3.2-1 and F.2.3.2-2 list the set of accidents selected to represent consequences and risks to workers and the public from accidental releases of radioactive materials during operations. For each accident, the table identifies the frequency of occurrence and the consequences to a hypothetical worker located at 1,000 m (3,281 ft) from the accident, a hypothetical individual located at the nearest site boundary, and the public out to a distance of 80 km (50 mi). The risks of cancer fatality for the worker, the individual at the site boundary, and the public for the composite set of accidents are also shown.
| Noninvolved Worker at 1,000 Meters | Maximum Offsite Individual | Population to 80 Kilometers | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Accident Scenario | Dose (rem) | Probability of Cancer Fatality25 | Dose (rem) | Probability of Cancer Fatality25 | Dose (person-rem) | Cancer Fatalities | Accident Frequency (per year) | ||
| 1. Fire-induced plutonium release from a glove box | 0.035 | 1.4x10 -5 | 5.8x10 -4 | 2.9x10 -7 | 4.3 | 2.2x10 -3 | 1.0x10 -3 | ||
| 2. Operational release of tritium | 6.5x10 -3 | 2.6x10 -6 | 1.1x10 -4 | 5.5x10 -8 | 0.79 | 4.0x10 -4 | 1.0x10 -5 | ||
| 5. Earthquake-induced release of plutonium - evaluation basis earthquake | 0.099 | 4.0x10 -5 | 1.7x10 -3 | 8.4x10 -7 | 12.3 | 6.2x10 -3 | 1.0x10 -5 | ||
| 6. Earthquake-induced release of plutonium - beyond evaluation basis earthquake26 | 0.10 | 4.1x10 -5 | 1.7x10 -3 | 8.6x10 -7 | 12.8 | 6.4x10 -3 | 5.0x10 -7 | ||
| 7. Wet criticality26 | 8.5x10 -4 | 3.4x10 -7 | 1.4x10 -5 | 7.0x10 -9 | 0.019 | 9.5x10 -6 | 5.0x10 -7 | ||
| 8. Mechanical-induced release of plutonium | 1.2x10 -12 | 4.7x10 -16 | 2.0x10 -14 | 9.9x10 -18 | 1.5x10 -10 | 7.3x10 -14 | 0.05 | ||
| 9. Explosion-induced release of plutonium | 8.1x10 -3 | 3.3x10 -6 | 1.4x10 -4 | 6.9x10 -8 | 1.0 | 5.1x10 -4 | 1.0x10 -3 | ||
| 10. Fire-induced release of plutonium on loading dock | 0.11 | 4.6x10 -5 | 1.9x10 -3 | 9.7x10 -7 | 14.3 | 7.2x10 -3 | 1.0x10 -5 | ||
| Impacts for Composite Set of EBAs and BEBAs27 | |||||||||
| Expected consequences28 | 3.5x10 -7 | 7.3x10 -9 | 5.4x10 -5 | ||||||
| Expected risk (per year) | 1.8x10 -8 | 3.8x10 -10 | 2.8x10 -6 | ||||||
| Impacts for Composite Set of EBAs | |||||||||
| Expected consequences28 | 3.4x10-7 | 7.3x10-9 | 5.3x10-5 | ||||||
| Expected risk (per year) | 1.8x10 -8 | 3.8x10-10 | 2.8x10-6 | ||||||
| Impacts for Composite Set of BEBAs | |||||||||
| Expected consequences28 | 3.3x10-5 | 4.4x10-7 | 3.2x10-3 | ||||||
| Expected risk (per year) | 3.3x10-11 | 4.4x10-13 | 3.2x10-9 | ||||||
| Noninvolved Worker at 1,000 Meters | Maximum Offsite Individual | Population to 80 Kilometers | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Accident Scenario | Dose (rem) | Probability of Cancer Fatality29 | Dose (rem) | Probability of Cancer Fatality29 | Dose (person-rem) | Cancer Fatalities | Accident Frequency (per year) | ||
| 1. Fire-induced plutonium release from a glove box | 0.064 | 2.6x10 -5 | 0.035 | 1.7x10 -5 | 9.5 | 4.7x10 -3 | 1.0x10 -3 | ||
| 2. Operational release of tritium | 0.012 | 4.8x10 -6 | 6.6x10 -3 | 3.3x10 -6 | 1.8 | 8.8x10 -4 | 1.0x10 -5 | ||
| 5. Earthquake-induced release of plutonium - evaluation basis earthquake | 0.18 | 7.4x10 -5 | 0.099 | 5.0x10 -5 | 27.2 | 0.014 | 1.0x10 -5 | ||
| 6. Earthquake-induced release of plutonium - beyond evaluation basis earthquake30 | 0.19 | 7.6x10 -5 | 0.10 | 5.1x10 -5 | 28.1 | 0.014 | 5.0x10 -7 | ||
| 7. Wet criticality30 | 1.5x10 -3 | 6.1x10 -7 | 8.7x10 -4 | 4.4x10 -7 | 0.12 | 6.2x10 -5 | 5.0x10 -7 | ||
| 8. Mechanical-induced release of plutonium | 2.2x10 -12 | 8.7x10 -16 | 1.2x10 -14 | 5.9x10 -16 | 3.2x10 -10 | 1.6x10 -13 | 0.05 | ||
| 9. Explosion-induced release of plutonium | 0.015 | 6.1x10 -6 | 8.2x10 -3 | 4.1x10 -6 | 2.2 | 1.1x10 -3 | 1.0x10 -3 | ||
| 10. Fire-induced release of plutonium on loading dock | 0.21 | 8.5x10 -5 | 0.12 | 5.7x10 -5 | 31.5 | 0.016 | 1.0x10 -5 | ||
| Impacts for Composite Set of EBAs and BEBAs31 | |||||||||
| Expected consequences32 | 6.4x10 -7 | 4.3x10 -7 | 1.2x10 -4 | ||||||
| Expected risk (per year) | 3.3x10 -8 | 2.2x10 -8 | 6.2x10 -6 | ||||||
| Impacts for Composite Set of EBAs | |||||||||
| Expected consequences32 | 6.4x10 -7 | 4.3x10 -7 | 1.2x10 -4 | ||||||
| Expected risk (per year) | 3.3x10 -8 | 2.2x10 -8 | 6.2x10 -6 | ||||||
| Impacts for Composite Set of BEBAs | |||||||||
| Expected consequences32 | 3.8x10-5 | 2.6x10-5 | 7.1x10-3 | ||||||
| Expected risk (per year) | 3.8x10-11 | 2.6x10-11 | 7.1x10-9 | ||||||
24 The maximum amount of material is a hypothetical amount chosen for the purpose of this analysis. HNUS 1996a.
25 Probability (increased likelihood) of cancer fatality to a hypothetical member of the public located at the site boundary or a worker located 1,000 m (3,281 ft) from the accident as a result of exposure to the indicated dose if the accident occurred.
26 A beyond evaluation basis accident (BEBA). All other listed accidents are evaluation basis accidents (EBA).
27 For the offsite population of 747,836, the average probability of cancer fatality/risk of cancer fatality (per year) for the composite set of accidents is 7.2x10-11/3.7x10-12.
28 Result of exposure to the indicated dose if the accident occurs. All values are mean values. Model results.
29 Probability (increased likelihood) of cancer fatality to a hypothetical member of the public located at the site boundary or a worker located 1,000 m (3,281 ft) from the accident as a result of exposure to the indicated dose if the accident occurred.
30 A beyond evaluation basis accident (BEBA). All other listed accidents are evaluation basis accidents (EBA).
31 For the offsite population of 287,977, the average probability of cancer fatality/risk of cancer fatality (per year) for the composite set of accidents is 4.2x10-10/2.2x10-11.
32 Result of exposure to the indicated dose if the accident occurs. All values are mean values. Model results.