ML19309H587

Responds to IE Bulletin 79-14 Re Initiation of Program to Verify Input Accuracy for safety-related Piping Seismic Analysis.Reviews & Analyses Did Not Identify Deviations That May Affect Operation.Final Rept Will Be Sent

ML19309H587
Person / Time
Site:	Millstone
Issue date:	04/10/1980
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-14, NUDOCS 8005130537
Download: ML19309H587 (3)

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April 10,1980 Docket No. 50-336 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

References:

(1) B. H. Grier letter to W. G. Counsil dated July 2,1979, forwarding I&E Bulletin No. 79-14.

(2) B. H. Grier letter to W. G. Counsil dated August 15, 1979, forwarding I&E Bulletin No. 79-14, Supplement.

(3) W. G. Counsil letter to B. H. Grier dated September 10, 1979 (4) W. G. Counsil letter to B. H. Grier dated November 7,1979 (5) W. G. Counsil letter to B. H. Grier dated December 14, 1979 Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 I&E Bulletin No. 79-14 Reference (1), as supplemented by Reference (2), requested Northeast Nuclear Energy Company (NNECO) to initiate a program to verify the accuracy of input information for seismic analysis of safety-related piping.

NNECO submitted the available results of inspections performed on both accessible

, and inaccessible piping systems, as required by Items 2 and 3 of Reference (1),

in References (3), (4), and (5).

As an update to previously docketed material, NNECO provides the following infor=a-tion with respect to the review program being performed to verify the accuracy of input information for the seismic analysis of safety-related piping.

NNECO has completed the stress reviews identified in Reference (4) and the compari-son of the inspection and measurement results. The major discrepancies resulting from these reviews and requiring reanalysis have been the use of incorrect valve weights and hanger locations. In many instances, the original design valve weight was in excess of the actual valve weight. NNECO does not consider this a serious deviation, but reanalysis is being perfor=ed to ensure that valve weight discrepancies do not effect the pipe hanger locations. In j

cases where measured pipe hanger locations deviated beyond the tolerances i

established for the inspection and measurement program, reanalysis of the hangers was performed. The reanalysis portion of the program is expected to be completed shortly.

The reviews and reanalyses completed to date have not identified any deviations which affect the operability or the safe-shutdown capability of any Category I system.

In Reference (5), NNECO reported that the inspection and measurements of certain valves and velded-pipe attachments covered by insulation in inaccessible areas .

had not been completed. Also, NNECO reported in Reference (5) that inspection and measurements of certain velded-pipe attachments covered by insulation in accessible a eas were not complete. The accessible velded-pipe attachments covered by insulation are located in the main steam, feedvater, and chemical and volume control aystem (CVCS) and were not verified because of the extreme heat

, associated with these systems. The velded-pipe attachments described above represent less tlan 10% of the total number of hangers identified per I&E Bulletin No. 79-14 It is MTECO's intention to remove the insulation en those valves identified above during the 1980 refueling outage to verify the valve manufacturer and documentation for use in the stre.L .: views.

NUECO does not intend to remove the insulation frem the remaining uninspected welded-pipe attachments. Justification for this approach is based on the following considerations:

e No deviations have been identified in any of the velded-pipe attachments inspected to date.

e Reanalysis has not been required for any velded-pipe attachments.

e Insulation has been removed from 85% of the normally accessible velded-pipe attachments and these have been verified to be acceptable.

e All welded-pipe attachments not covered by insulation have been i verified.

e The uninspected welded-pipe attachments represen13 less than 10% of the total number of hangers at Millstone Unit No. 2.

NNECO reiterates that the stress reviews have been completed. The reanalysis l program is expected to be completed shortly. The reviews and analyses completed l to date have not identified any deviations which affect the operability or the safe shutdown capability of any Category I system.

Upon completion of the reanalysis program and the support / restraint reviews which will follow, NNECO intends to submit a final project report.

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We trust you find this ir"ormation sufficient to concur in the above-outlined deviation from the requirwents of References (1) and (2).

4 Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

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i N. G. Counsil Vice President i

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