B15362, Submits Response to Issue on Behalf of Activities at Unit 3. Written Response to Issue Requested to Be Submitted within 60 Days from Date of NRC Ltr

Submits Response to Issue on Behalf of Activities at Unit 3. Written Response to Issue Requested to Be Submitted within 60 Days from Date of NRC Ltr

ML20092G889
Person / Time
Site:	Millstone
Issue date:	09/13/1995
From:	Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Cooper R NRC (Affiliation Not Assigned)
References
B15362, NUDOCS 9509200139
Download: ML20092G889 (3)

Text

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, - (203) 665-5000 September 13, 1995 Docket No. 50-423 B15362 Mr. Richard W. Cooper, II Director, Division of Reactor Regulation U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415

Dear Mr. Cooper:

Millstone Nuclear Power Station, Unit No. 3 Resn_onse to Issue Provided for Review By letter dated July 19, 1995, m the NRC Staff transmitted an issue raised regarding activities at Millstone Unit No. 3. The purpose of this letter is to provide Northeast Nuclear Energy Company's (NNECO) response to this issue on behalf of Millstone Unit No. 3.

A written response to this issue was requested to be submitted within 60 days from the date of the NRC's letter. This letter does not contain any personal privacy, proprietary, or safeguards information and may, therefore, be placed in the NRC Public Document Room. Accordingly, we have not specifically reiterated the issue listed in the attachment to your July 19, 1995, letter as the 4.nformation was identified as 10CFR2.790 material.

f Summary The positioners associated with safety-related valves in the

, charging, residual heat removal, and atmospheric steam dump syster.s i' are properly mounted and pose no seismic interaction or operability concerns. Amplifying information will be added to the Production Maintenance Management System (PMMS) to clarify mounting requirements within the automated work orders (AWO) and should eliminate future concerns in this area.

! Response These valve positioners and their associated mounting hardware are

nonsafety-related. The safety-related function of the associated air-operated valves (i.e., venting the air off the spring-loaded diaphragm) is accomplished via separately mounted, Quality i Assurance (QA) category 1 solenoids with direct tubing connections to the valve air dome.

(1) R. W. Cooper, II letter to J. F. Opeka, dated July 19, 1995.

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Mr. Ricliard W. Cooper, II B15362/Page 2 September 13, 1995 Proper mounting of the positioner is required to preclude the potential for seismic interaction of the non-QA positioner with safety-related portions of the valves or other safety-related equipment. Proper mounting of the positioner involves use of accepted work practices for installation of threaded fasteners to  ;

maintain the valves' design configuration. However, no special

" seismic" installation practices need be invoked.

For these positioners, snug tightening the mounting bolts using a hand wrench and worker judgement / feel is the recommended practice.

Manual tightening (worker judgement) provides sufficient accuracy and control of fastener prestress for this application. The

positioner mounting bolts do not have the precise prestress i criteria required for other applications (such as pressure boundary

' bolting that endures variations in system pressure and thermal effects). Further, the deadweight and seismic inertial loading of these relatively lightweight positioners on their holting is many orders of magnitude below the allowable stresses for the bolting material. The manual snug tightening technique was utilized on the l charging, residual heat removal, and atmospheric steam dump valves during the fifth refueling outage.

Additionally, a walkdown of some of the subject positioners was performed to provide additional assurance that they were installed i correctly.

. opportunity for Improvement ,

i Although the current maintenance practice is technically sound, '

this concern points to a lack of clarity in the maintenance j instructions provided to workers tasked with mounting non-QA positioners on safety-related valves. Additional information will i

be added to the PMMS for each positioner of this type in order to clarify the mounting instructions provided to the worker within each AWO.

commitments There are no commitments identified in this submittal.

Conclusion The issue identified in the Staff's July 19, 1995, letter has been appropriately addressed. We believe no further action is necessary.

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• Mr., Richard W. Cooper, II E15362/Page 3 September 13, 1995 l

If you have any questions regarding this submittal, please contact l Mr. S. T. Day at (203) 440-2075.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY Yk U

J. F.(Opbka Executive Vice President cc: T. T. Martin, Region I Administrator V. L. Rooney, NRC Project Manager, Millstone Unit No. 3 P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

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