ML20038A993

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Forwards LER 81-065/01T-0.Detailed Event Analysis Encl
ML20038A993
Person / Time
Site: Dresden Constellation icon.png
Issue date: 11/16/1981
From: Scott D
COMMONWEALTH EDISON CO.
To: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20038A994 List:
References
81-901, NUDOCS 8111240575
Download: ML20038A993 (2)


Text

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EN Commonwealth Edison C DresdIn Nuclear Power St2. tion R.R. #1 Morris, Illinois 60450 Telephone 815/942-2920 November 16, 1981 l

DJS LTR #81-901 g N/MK r 4 dk James G. Keppler, Regional Director Directorate of Regulatory Operations Region III 9- NOV2 3 jggle-mo U.S. Nuclear Regulatory Commission v.s. $'Es,e " ,-

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Reportable Occurrence Report #81-65/0lT-0, Docket #050-237 is being submitted to your office in accordance with Dresden Nuclear Power Station Technical Specification 6.6.B.l.(b), operation of the unit or affected systems when any parameter or operation subject to a limiting condition is less conservative than the least conservative aspect of the limiting condition for operation established in the technical specifications.

l' 60 D.*'J. Scott Station Superintendent Dresden Nuclear Power Station DJS:lg Enclosure cc: Director of Inspection & Enforcement i

Director of Management Information & Program Control U.S. NRC, Document Mgt. Branch File /NRC l

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NOV ' 9 1981 Q1M0Eo'sbbb s fgg I Sf N0% 19 198f

ATTACHMENT TO LICENSEE EVENT REPORT 81-65/OlT-0 COMMONWEALTH EDISON COMPANY (CWE)

DRESDEN UNIT 2 ILDRS 2 DOCKET #050-237 During a normal shutdown of Unit 2 reactor, the quarterly DOS 250-2 timing surveillance of the Main Steam Isolation Valves was performed. The surveillance testing revealed that valves 203-1A, 203-1B and 203-lD had closure times of 2.6, 2.5, and 1.8 seconds respectively. Tech. Spec.

Table 3.7.1 requires closure time limits of between 3 to 5 seconds. There was minimal effect on plant personnel and public health and safety, because the remaining MSIV closure times were within Tech. Spec. limits and all valves were operable. There have been similar occurrences at Dresden with the last being 81-49-OlT-0 on Unit 2.

The timing mechanisms for MSIV's lA and 1D became misadjusted due to a loss of oil in the hydraulic dampeners. This was caused by the fact that one of the dampener seals had rolled due to improper assembly, which was not detected after the last valve overhaul during the past refueling outage.

The valve dampeners were properly reassembled using new seals.

The timing mechanism for MSIV 1B became misadjusted due to normal valve operation. The timing mechanisms for MSIV's lA, 1B, and ID were all readjusted and timed satisfactorily.

A repair manual will be written to assure proper assembly in the future.

The quarterly timing surveillance of the MSIV's will continue to be performed to ensure proper closure times are maintained.

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