ML20027E260
| ML20027E260 | |
| Person / Time | |
|---|---|
| Site: | 05000000 |
| Issue date: | 07/27/1981 |
| From: | Book H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Higginbotham L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20027A625 | List:
|
| References | |
| FOIA-82-394 NUDOCS 8211120439 | |
| Download: ML20027E260 (2) | |
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July 27,1981 6
i IEHORANDUM FOR:
I.. B. liigginbotham, Chief Radiological Safety Branch, IE:HQ i
FROM: /
H. E. Book, Chief l
/
Radiological Safety Branch, Region V
SUBJECT:
NES-4 (f!AC-1E) CASK STATUS UPDATE On May 7,1981, the NAC-1E cask was transported from San Onofre Unit 1 to a Departent of Energy contractor (Energy Systems Group, a Division of Rockwell International, Santa Susana, CA) for decontamination.
Region V established a line of co:munication with Dr. Remley, !!anager, llealth, Safety and Radiation Services for Energy Systems Group (ESG). Dr. Remley was informed of the previous radiological problems associated with handling of this cask.
Dr. Remley advised us that the dacontamination would be carried out with the cost of materials and labor borneby Nuclear Assurance Corporation (NAC). The ESG decontamination effort was coordinated with Ilr. Charles R. Johnson, Vice President, Engineering 1
and Transportation Services,flAC.
Dr. Remley made it clear that ESG would conduct their activity under DOE purview and would not expect NRC inspector involvement unless significant mechanical defects were observed.
i On !!ay 28,1981, Dr. Remley informed Region V that while moving the cask, about two quarts of solution spilled from the vent. The liquid read 25 r/hr at four inches from the container in which it was collected. No unusual personnel exposures occurred, however cell decontamination was required. The leak was apparently caused by cracking of the vent valve's teflon seat. The Transportation Certification Branch of HMSS was informed of this incident by Region V on June 4,1981.
On June 15, 1981, we learned that about five quarts of solution were removed from the cask. The solution had a pH of 5.
A sample of this solution was poured into a beaker until a dose rate of 35 r/hr was masured at a distance of six inches. Two quarts produced the 35 r/hr dose rate. Additional analysis is being performed to determine isotopic content and quantity.
Results are expected about August 3,1981.
Dr. Realey called on July 21, 1981 to advise us that cask decontamination efforts have been terminated at NAC's request. NAC has spent about $80,000 and feel they cannot justify additional expenditures.
ESG estimates that 150 grams of fuel fragments still remain either in, or under, the fuel basket.
The next step would have likely been to remove the fuel basket and clean the cask barrel. ESG is now holding the cask and is searching for a way to return it to NAC.
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l L. B. Higginbotham July 27,1981 Based on their decontamina ion efforts, ESG speculates that use of the fuel basket with _ failed bundles is conducive to accumulation of fuel products in the four to six inch reservoir located in the bottom of the basket.
Draining of the cask does not result in flushing of this area.
L' hen the cask is placed in a horizontal position for transport, residual fluid in the reservoir may drain into the cask barrel.
Fuel fragments can then accumulate in the vent and drain lines in close proximity to teflon valve internals causing potential leakage pathways and radiological hazards in handling the cask.
In one instance this residual fluid has been found to contain 14 UCi/ml of transuranic isotopes and 480 uCi/ml of gross gamma activity. Such residual activity could conceivably have been discharged into the unsuspecting licensee's spent fuel storage pool.
This could create operational problems for powar reactors trying to' dispose of spent pool filters and cleanup deionizers highly contaminated with transuranic isotopes.
Based on the operating experience with the NFS-4 NAC-ID and NAD-1E casks during the last year (see Region I Investigative Report), we conclude that if used as presently permitted by HRC Certificate of Compliance No. 6698, Revision 14, an unnecessary risk of personnel exposure, loss of integrity, and dispersion of radioactive material exists.
The July 22,1981 ' Order to Show Cause" regarding surface contamination of the NAC-ID cask did not address problems identified in handling of the NAC-1E cask, nor did it address similar i
contamination problems previously experienced in using the NAC-1E cask. We recommend a comprehensive review be initiated by NMSS prior to next use of i
NFS-4 casks.
Specific questions related to the NAC-1E cask can be addressed with G. Yuhas (FTS 463-3748) of my staff.
s;wd by
'. we H. E. Book, Chief Radiological Safety Branch cc:
C. E. IbcDonald, NilSS i
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