A09556, Submits Response to Review of RI-91-A-0037 Issues Concerning Plant Activities

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Submits Response to Review of RI-91-A-0037 Issues Concerning Plant Activities
ML20091E101
Person / Time
Site: Millstone Dominion icon.png
Issue date: 08/09/1991
From: Mroczka E
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES SERVICE CO.
To: Hehl C
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20091E089 List:
References
A09556, A9556, NUDOCS 9110310058
Download: ML20091E101 (5)
v • d • e


Text

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August 9, 1991 l i

Docket No. 50-336 L A09553 l l

l i

Mr. Charles V. Hehl, Director Division of Reactor Projects  ;

o U.S. Nuclear Regulatory Commission Region I 475 Allendale Road 1 King of Prussia. Pennsylvania 19406 i

Dear Hr. Hehl:

Millstone Nuclear Power Station, Unit No. 2 RI-91-A-0037 i

Ve have completed our review of Issues 1 and 3 concerning activities at Millstone Station. A request for an extension for Issue 2 is addressed below. As requested in your transmittal letter, our response does not contain any personal privacy, proprietary, or safeguards information. The material contained in this response may be released to the public and placed in the NRC Public Document Room at your discretion. The NRC letter and our response have r(ceived controlled and limited distribution on a i "need to know" basis during the preparation of this response.

ISSUE 1

During review of HP 2720R8, it was noted that there may have been inadequate instructions on the proper use of a torque vrench and crovs foot to establish the proper torque on valves having Namco Seal / connectors.

Specifically the procedure did not, but needed to indicate that unless the crows foot is used at a 90 degree angle to the torque vrench, corrections have to be made and overtorquing may occur.

l

-Please discuss the validity of the above assertions. Please discuss the actions that you may take to determine if the affected Namco Seal / Connectors have been overtorqued. Please evaluate and discuss the

! need to make changes to maintenance procedures to clarify the instructions

! on the use of torque vrenches and adapters. ]

! l l

9110310058 711011 '

PDR ADOCK 05000336 P PDR- 1

Mr. Chsrics V. B.hl, Dirn.cor U.-S. Nuclear Regulatory Commission A09556/Page 2 August 9, 1991 i 1

Responses Northeast Nuclear Energy Company (NNECO) revietied Maintenance Procedure MP i 2720R8 - Namco Seal / Connector Asrembly Installation, the manufacturer's installation manuel and the AV0s that installed the Namco Connectors. The i procedure and the installation manual both specified a torque range of 45 )

to 55 ft-lbs for installing the Namco Connector receptacle to the Namco l limit switch housing. All the AVO Inspection Plans specified a torque range of 45 to 50 ft-lbs for the receptacle installation, which was verified by a 05D inspector.

The AVO also identified the torque vrench that was used during the installation. From dimensions taken from the torque vrench and crovs foot (from the Namco Connector Installation Tool Kit) a calculation was performed to determine the maximum amount of overtorquing that could have occurred. Assuming the maximum torque specified on the Inspection Plan was the actual setthg on the torque vrench, then the maximum torque that vould have been applied to the receptacle / limit switch housing would have been 58 ft-lbs.

Namco was contacted to determine the effect of overtorquing the connector receptacle / limit switch housing by 3 ft-lbs. Namco indicated that the upper torque limit was specified to protect the limit switch housing.

Namco also stated that their Qualification Test Reports contain a caution stating that applied torque is not to exceed 85 ft-lbs. According to Namco's Engineering, 85 ft-lbs is the maximum torque that can be applied that vill not cause deformation or cracking of the limit svitch housing.

The Job Supervisor responsible for installation of the Namco Connectors was interviewed. He vas knowledgeable in the use of torque vrenches with crovs foot adapters and their effect on the actual torque versus the indicated torque. The Job Supervisor produced a sheet of information on computing torque when using an adapter or extension and indicated that this was used during connector instellation to establish the torque vrench setting. The Job Supervisor stated that the torque on the Inspection Plan was the actual torque applied to the receptacle / limit svitch housing.

Based on the above, there is reasonable assurance that the connector receptacle / limit svitch housing was not overtorqued during installation of the connectors. If overtorquing dWoccur, it vould have exceeded the upper limit by only 3 ft-lbs (38 ft-lbs), which is vell below the maximum torque that could cause damage to the limit switch housing (>85 ft-lbs).

In general, torque settings are sufficiently conservative such that overtorquing should not occur.

NNECO does not believe that a procedure change is required or appropriate.

Millstone Unit No. 2 Maintenance procedures provide instruction on how to perform various maintenance tasks and pro. ride guidance on what tools may be required, but the procedures do not provide instructions on how to use tools. The premise that Millstone Unit No. 2 Maintenance personnel are able to properly use the tools of their trade. is a basic assumption made in the preparation of Maintenance procedures.

' %I 1

Mr. Charles V. Behl, Director U. S. Nuclear Regulatory Commission A09556/Page 3 August 9, 1991 ISSUE 2:

Changes vere made to PORC approved Maintenance Forr 2720A3-1, -Cathodic Protection Data Sheet without going to PORC for change approval. The approved data sheet vas changed to allov recording of data in blocks for OG 1, OG 2, OG 3, and OG 4 that were lined through and not to be used.

Please discuss the validity of the above assertions. If any discrepancies are found, please discuss corrective actions taken including any generic procedural compliance issues.

Response

We are still investigating this matter and vill respond when the investigation is complete. We request an additional two-veek extension (to August 24, 1991) to respond.

ISSUE 3:

Certain safety-related Motor Operated Valves had their torque switches improperly balanced during the past outage due to defective torque svitch balancing equipment. Specifically the valves affected are of the SMB-00 2CH508, 2CH509 and 2CH514. The problem may also extend to SMB-000 type, The SMB-00 type valves, 2MS65, 2HS201, SV4188, 2RC403, 2RC405 and 2RB301B.

and SHB-000 defective test equipment has been returned to the manufacturer.

Please state why the Please discuss the validity of the above assertions.

subject valves are considered to be operable. If any of the subject valves are not considered to be operable, please _ discuss corrective actions that have been taken. Please discuss measures that have been taken to ensure that defective equipment is identified prior to use.

Respvases Vhile developing procedures for the Millstone Unit No. 3 torque switch Unit No. 2 and the tester, discrepancies were found between the Hillstone Hillstone Unit Nc 3 torque svitch testers for Limitorque SMB-00 actuators.

The torque svitch testers and the switches set with these testers, vere evaluated by NUSCO and Babcock & Vilcox (B&V) Engineering. Based on this evaluation, three valves required further evaluation; these vere 2CH508, 2CH509 and 2CH514.

NUSCO Mechanical Engineering performed calculations i

vhich shoved the above MOVs met the design requirements for torque switch l settings in both the open and closed directions. Therefore, the MOVs that had the torque switches set by the B&V torque switch testers are considered to be operable.

l The torque switch testers vere purchased from B&V, Upon receipt, the units were inspected for physical damage, proper operation of moving parts and The dial indicators, including calibration.

operation of the dial indicators vere determined to be marginal and they were replaced. The replacement dial indicators were subsequently verified to'be acceptable as installed.

l '

1 l 5 L, Mr. Charles V. Behl, Director U. S. Nuclear Regulatory Commission A09556/Page 4 August 9, 1991 The torque testers are sold as non safety-related products that are provided under B&V Nuclear Engineering and Plant Services Division Quality Assurance Plan for non safety-related products and services. Northeast Utilities is currently working with B&V to develop an action plan to ensure that the problem does not recur. Ve vere aware of this problem and had begun development of this action plan prior to receipt of this concern from the NRC.

After our review and evaluation, we find that these issues did not present any indication of a compromise of nuclear safety. Ve appreciate the opportunity to respond and explain the basis of our actions. Please contact my staff if there are any further questions on any of these matters.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

/ //P W E. JT Rrocika 67 Senio/r Vice President 1, 2, cci V. J. Raymond, Senior Resident Inspector, Millstone Unit Nos.

and 3 C. Venzinger, Chief, Projects Branch No. 4, Division of Reactor E.

Proj ects E. M. Kelly, Chief, Reactor Projects Section 4A

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