ML20003E262
| ML20003E262 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/09/1981 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| IAL-81-14, NUDOCS 8104020707 | |
| Download: ML20003E262 (2) | |
Text
i Me-nerg#o UNITED STATES 8
i, NUCLEAR REGULATORY COMMISSION
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'E REGION I 631 PARK AVENUE
D KING OF PRUSSIA, PENNSYLVANIA 19406 Docket No. 50-334 bg s X(
File No. IAL 81-14 y
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'Duquesne Light Company ATTN: Mr. C. N. Dunn 2
APR 011981 > ~-
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Vice President Operations Division co=55 c" 435 Sixth Avenue Pittsburgh, Pennsylvania 15219
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Gentlemen:
This refers to a telephone conversation between Mr. J. A. Werling and Mr. E.
J. Brunner of this office on March 6,1981.
On March 5, 1981, Residual Heat Removal System (RHR) capability was impaired when an erroneous remote level indication resulted in an inadvertent decrease in actual Reactor Coolant System (RCS) water level.
Level was thought to be maintained at the centerline of the RCS reactor outlet piping while an RHR system weld repair was ~eing accomplished.
The actual lower level resulted in o
air entrainment in the RHR piping and pumps and a loss or degradation of core flow for about one hour and ten minutes.
We understand, based on this event and with regard to the matters discussed, you have taken the following actions:
a.
Local surveillance of the temporary RCS level standpipe inside containment will'be performed at least once per hour.
This surveillance will ensure that actual RCS water level is adequate to preclude RHR air entrainment and correlates within 20 percent scale indication of the remote control room recorder.
In the event the local and control room indications disagree by greater than 20 percent, continuous surveillance of the level standpipe will be conducted, until the cause of the disagreement is These actions were implemented by written instructions issued
-corrected.
on March 6,1981, to the plant operators, and will remain in effect at any time the RCS is drained below the range of. control room pressurizer level
. indication.
b.
Written instructions were issued to plant operators on March 6, 1981 to require that during any period of abnormal RHR/RCS level, incore thermocouples and RHR pump currents (amperes) will be periodically monitored and logged.
The~ interval for monitoring these parameters will be discussed and agreed to with this office.
Further, during periods of loss or degradation of RHR-flow, two incore thermocouples, in each core quadrant as well as RHR 1810.4020 7 07
File No. IAL 81-14 2
9 Mk u t pump currents (amperes) will be read and logged every ten minutes until flow is fully restored and or all actions required by your Abnormal Procedure, " Loss of RHR with RCS drained to Mid Span of Loops", are complete.
c.
Ensure that any prior operation of the RHR pumps under cavitating or degraded flow conditions did not damage the pumps, associated piping, or structures. These actions shall be implemented immediately and shall censider the potential damage from reduced pump flow, cavitation, and abnormal' hydraulic forces on the pump, its foundations, and appurtenances.
If our understanding of your planned actions is incorrect, please contact this office by telephone and in writing within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
We further-understand that your evaluation of this event is continuing.
You
~
may propose additional modifications to these commitments based on the results of these evaluations.
Sincerely, J
e Boyce H. Grier Director cc:
F, Bissert, Technical Assistant Nuclear R. Washabaugh, QA Manager J. Werl.ing, Station Superintendent G. Moore, General Superintendent, Power Stations Department J. J. Carey, Ofrector of Nuclear Operations o
R.. Martin, huclear Engineer.
t J. Sieber, Superintendent of Licensing and Compliance, BVPS h
.. _.