ML19326C380
| ML19326C380 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/28/1977 |
| From: | Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| References | |
| NUDOCS 8004220919 | |
| Download: ML19326C380 (1) | |
Text
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November 28, 1977 Docket No. 50-313
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Arkansas Power and Light Company ATTH: Mr. William Cavanaugh III Executive Director of Generation and Construction Post Office Box 551 Little Rock, Arkansas 72203 Gentlemen:
The enclosed IE Circular 77-14 is forwarded to you for information. No written response is required. Should you have any questions related to your understanding of this matter, please contact this office.
), % n)4 a.wu4 E. Morris Howard Director
Enclosures:
- 2. List of IE Circulars -
Issued in 1977 4
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NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Circalar No. 77-14 Date: November 22, 1977 Page 's of 2 SEPARATION OF CONTAMINATED WATER SYSTEMS FROM NON-CONTAMINATED PLANT SYSTEM This circular describes an event which occurred at a nuclear power facility; however, the generic implications may be applicable to test reactors, fuel cycle facilities, and major by-product material processors.
In June 1977, the licensee for Beaver Valley I reported that make up water from a primary water storage tank (PWST) contaminated the plant water treatment system, which in turn supplies the in-plant domestic (potable) water system. The plant domestic water became contaminated with a tritium concentration of 7xE(-3) uCi/ml. The domestic water was contaminated for approximately six hours before the condition was detected by the licensee and controls were established over the use of in-house water. No significant exposure of plant personnel resulted from the event; however, five individuals showed positive levels of tritium by urinalysis. No release to tha offsite environment above maximum permissible occurred.
The PWST receives processed reactor coolant water from the Boron Recovery System which has been purified through evaporation, degasi-fication and demineralization to remove radioisotopes other than tritium. The PWST is used to supply primary grade water to the reactor coolant system and is normally kept separated from the water treatment system.
The cross connection between the primary grade water system and the water treatment system occurred when an isolation valve was inadvertently left open during valve line-up operations to recirculate the PWST. The procedure which specified the required line-up was being used for the first time since preoperational testing and did not list the subject valve.
In addition to the valving error, however, a design error resulted in connecting a line from the PWST to a water treatment system line at a position upstream of two series stop-check valves.
In the proper con-figuration, the line would have been connected downstream of the stop-check valves, which would have prevented back flow of water from the primary grade water system to the water treatment system even with the isolation valve left open.
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