ML20042F860
| ML20042F860 | |
| Person / Time | |
|---|---|
| Issue date: | 03/06/1990 |
| From: | NRC |
| To: | Udall M HOUSE OF REP., INTERIOR & INSULAR AFFAIRS |
| Shared Package | |
| ML20042F858 | List: |
| References | |
| CCS, UDALL-900306, NUDOCS 9005100086 | |
| Download: ML20042F860 (3) | |
Text
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MARCH 6, 1990,' URANIUM ENRICHMENT LICENSING HEARING SUBCOMMITTEE ON ENERGY AND THE ENVIRONMENT SUPPLEMENTAL QUESTIONS AND ANSilERS QUESTION 1.
Please provide a full description of any accidents that have occurred involving uranium hexafluoride cylinders at privately-owned facilities licensed by the Atomic Energy Commission and the NRC, including, but not limited to, a 1962 incident at Nuclear Fuel Services fuel fabrication plant in Erwin, Tennessee, and the 1986 incident at Sequoyah Fuels, in addition, please list all significant releases to the external environment of uranium hexafluoride that have occurred at AEC/NRC licensed facilities.
ANSWER.
There has been one accident involving the rupture of a uranium hexafluoride cylinder at an NRC-licensed facility.
This is the Sequoyah Fuels incident described in response to Question 6 of Congressman Udall's letter dated February 22, 1990.
It was the most significant release of uranium hexafluoride from a commercial plant.
In December 1984, an overfilled cylinder deformed but did not rupture when it was heated at the Allied-Signal plant in Metropolis, Illinois. The staff is aware of two incidents involving cylinder ruptures at DOE's gaseous diffusion plants at Paducah, Kentucky, in 1960, and Portsmouth, Ohio, in 1978.
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QUESTION 10 (Continued) 2 i
The 1962 event mentioned in the question occurred when the Nuclear Fuel Services plant was owned by Davison Chemical Company. An estimated 16 kilograms of enriched uranium hexafluoride was accidentally released from a system in'which uranium j
hexafluoride was converted to uranium tetrafluoride.
The accident occurred when a temperature override control failed and a teflon liner in a valve in l
I the line connected to the overheated cylinder failed. The uranium hexafluoride escaped from the overheated cylinder into the Metals Building'. Ten of the 16 kilograms of the released material were not recovered by the licensee. No personnel were overexposed, and environmental releases did not exceed regulatory limits.
We have identified one additional incident at Nuclear Fuel Services, Inc., in 1979, involving a uranium hexafluoride process system, but not cylinders, which resulted in a significant release of uranyl fluoride and hydrogen fluoride (the compounds resulting from the contact of uranium hexafluoride with moisture in air). A malfunction of a classified process system resulted in an estimated release of between 300 and 3,000 grams of uranium f rom a stack.
One plant operator could have been overexposed, but bioassay results indicated that the operator was not overexposed.
Using the estimated range of quantities released, the NRC staff calculated that the 50 year bone dose commitment.to.a hypothetical child at the nearest residence ranged between 30 and 300 millirems, which corresponds to the whole body equivalent of 3.6 and 36 millirems. This can be compared to a 500 millirems whole-body dote allowed by i
NRC regulations for an individual in an unrestricted area.
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(Continued)
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lAs part of our examination of emergency preparedness requiren'nts for fuel cycle licensees, the staff considered several other incidents. involving uranium j
i hexafluoride leaks from' valves, gaskets, and process piping.
The most significan_t release has'been the 1986 Sequoyah Fuels cylinder rupture in Gore, Oklahoma. -
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