ML19253A486
| ML19253A486 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/13/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Short T OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7909100131 | |
| Download: ML19253A486 (1) | |
Text
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UNITED STATES PDR:HQ
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REGION IV
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August 13, 1979 Docket..o.
50-285 Omaha Public Power District ATTN:
T. E. Short, Assistant General Manager 1623 Harney Street 0:naha, Nebraska 68102 Gentleten:
Enclosed is IE Bulletin 79-21 which requires action by you with regard to your PUR power reactor facility with an operating license.
Should you have any questions regarding this Bulletin or the actions required by you, please contact this office.
Sincerely, n
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'Karl V. Seyfri, I
Director
Enclosures:
1.
List of IE Bulletins Issued in the Last 6 Months cc:
R. L. Andrews, Manager Fort Calhoun Station Post Office Box 98 Fo r t Calhoun, Nebraska 68102 80.:.$. !S
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Bulletin No. 79-21 Date: August 13, 1979 Page 1 of 2 TEMPERATURE EFFECTS ON LEVEL MEASUREMENTS Description of Circumstances:
On June 22, 1979, Westinghouse Electric Corporation reported to NRC a potential substantial safety hazard under 10 CFR 21.
The report, Enclosure No. 1, addresses the effect of increased containment temperature on the reference leg water column and the resultant effect o1 the indicated steam generator water Icvel. This effect would cause the indicated steam generator level to be higher than the actual level and could delay or prevent protection signals and could also provide erroneous information during post-accident monitoring.
Enclosure No. I addresses only a Westinghouse steam generator reference Icg water column; however, safety related liquid level measuring systems utilized on other steam generators and reactor coolant systems could be affected in a s-imilar manner.
Actions To Be Taken By Licensees:
For all pressurized water power reactor facilities with an operating license:*
1.
Review the liquid level measuring systems within containment to determine if the signals are used to initiate safety actions or are used to provide post-accident monitoring information.
Provide a description of systems that are so employed; a description of the type of reference leg shall be included, i.e., open column or sealed reference leg.
2.
On those systems described in Item 1 above, evaluate the effect of post-accident ambient temperatures on the indicated water level to determine any change in indicated level relative to actual water level. This evaluation must include other sources of error including the ef fects of varying fluid pressure and flashing of reference leg to steam on the water level measure-ments. The results of this evaluation should be presented in a tabular form similar to Tables 1 and 2 of Enclosure 1.
3.
Review all safety and control setpoints derived from level signals to verify that the setpoints will initiate the action required by the plant safety Df '
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analyses throughout the rangeg r instrumentation, including ac 1
3' 9 these setpoints.
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