ML20235S455

Responds to NRC Re Violations Noted in Insp Rept 50-304/87-12.Corrective Actions:Max Allowable Snubber lock- Up Velocity Being Revised from 100 Inches to 40 Inches Per Minute & Temp of Snubber Testing Environ Will Be Controlled

ML20235S455
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	10/01/1987
From:	Butterfield L COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
3655K, NUDOCS 8710090004
Download: ML20235S455 (5)

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. Commonwealth Edloon One Fir:2 National Plaz2, Chicago, Illinois V Address RJply to: Post Offics Box 767 -

.( Chicago, Illinois 60690 0767

- !pi October 1, 1987

'Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulatory Commission-Region III 799 Roosevelt Road-Glen Ellyn, IL 60137

Subject:

Zion Nuclear Power Station Unit 2'  ;

Response to Inspection Report No. .;

50-304/87-12 NRC Docket No. 50-304

Reference:

September 1, 1987 letter from J,J. Harrison

" to Cordell Reed

Dear Mr. Davis:

This letter is in response to the~ inspection conducted by J.A. Gavula of your office on April 20-22, and August 18, 1987, of activities at Zion Nuclear Power Station. The referenced letter indicated that certain activities appeared to be in noncompliance with NRC requirements. Commonwealth Edison Company's response to.these violations

'are provided in the Attachment to this letter.

If you have any further questions on this matter, please direct them to this office.

Very truly yours, g

L. D. Butterfield l Nuclear Licensing Manager Cs

-Attachment cc: NRC Resident Inspector - Zion J. A. Norris - NRR 3655K 8710090004 871001 PDR ADOCK 05000304 G PDR OCT 5 1987 '

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", i ATTACHMENT l

ZION NUCLEAR POWER STATION RESPONSE TO NOTICE OF VIOLATION VIOLATION #1 As a result of the inspection conducted on April 20-22, and August 18, 1987, and in accordance with 10 CFR part 2, Appendix C - General Statement of Policy and Procedure for NRC Enforcement Actions (1985), the following violation was identified:

10 CFR 50, Appendix B, criterion XI, as implemented by Commonwealth Edison Topical Report CE-1-A, " Quality Assurance Program for Nuclear Generating Stations", and Commonwealth Edison corporate Quality Assurance Manual, Nuclear Generating Stations, " Quality Requirements", requires that i

test procedures include provisions for assuring that the test is performed under suitable environmental conditions, and that acceptance limits in applicable design documents are incorporated.

Contrary to the above, procedure TSS 15.6.48, Revision 12, contains the following deficiencies:

a. The allowable ambient temperature range for conducting functional tests on safety related hydraulic snubbers is not specified.

(304/87012-01A)

b. The acceptance criteria for hydraulic snubber " locking velocity" does not account for the operating environment of the hydraulfr.

snubber. (304/87012-01B)

CORRECTIVE ACTION TAKEN AND RESULTS ACHIEVED The effect of potential variations between snubber test temperature and the operating environment temperature on snubber lock-up velocity has been evaluated. The evaluation concluded that these potential variations need to be addressed. Therefore, the following actions will be implemented;

1) The maximum allowable snubber lock-up velocity is being revised ,

from 100 inches per minute to 40 inches per minute.

2) The temperature of the snubber testing environment will be controlled.

3) Compensation for the potential temperature variations discussed above will be instituted. The operating temperatures will be based upon actual temperature surveys.

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1 CORRECTIVE ACTION TO BE TAKEN TO AVOID FURTHER VIOLATION As discussed above, Commonwealth Edison Company's evaluation has concluded that three broad actions are needed. The implementation of these i

three actions will be as discussed below.

1) procedure TSS 15.6.48 is in the process of being revised to change the "as found" functional test acceptance criteria from 100 inches per minute for maximum allowable lock up velocity to 40 inches per minute. This revised acceptance criteria is based upon ITT Grinnell's Technical Report pHD 7579-s-1 dated October, 1977 and recent discussions with ITT Grinnell.

2) procedure TSS 15.6.48 is in the process of being revised to include monitoring hydraulic fluid temperature during functional testing j and snubber adjusting after rebuild as recommended per ITT Grinnell Hydraulic Shock and Suppressor Tester Model 5434-3 for '-1/2" to 6" Cylinders". The hydraulic fluid shall be maintained at a temperature between 65 and 85 degrees Fahrenheit. The testing equipment utilized for snubber testing has already been altered to provide snubber testing temperature data.

The applicable snubber population at Zion primarily (approx. 82%)

consists of 1-1/2" cylinder size snubbers. ITT Grinnell Report #

pHD-6500-7, January 5, 1979, demonstrates that for this size snubber, the lockup velocity is affected only slightly by increases in temperature below 120*F. Actual plant temperature data compiled by the technical staff for a period of time when the Unit 2 containment was essentially at its maximum operating temperature indicates that the snubber population has an average maximum temperature environment of 93.9'F. Additional data for the vertical pipe chase and steam tunnels (typically the warmest out-of-containment locations) indicate an average maximum temperature of less than 90*F. Using this information, combined with that provided by pHD-6500-7, the increase in lockup velocity from 80*F to 95'F can be shown to be approximately 30%.

These calculations are conservative since they exceed the maximum ambient temperature experienced by the majority of the snubbers at Zion and are based upon conservative data presented in pHD-6500-7.

3) As discussed above, the lockup velocity can increase by approximately 30% when subjected to 95'F temperature. Additional concerns remain for the portion of the applicable snubber population above 1-1/2" size (approx. 18%), as well as for those snubbers mounted axially to uninsulated pipes. The temperature affects on lockup velocities are expected to be greater for these instances.

pWR engineering has contracted Engineering Analysis Services (EAS) to assist in resolving these concerns. This firm is particularly well suited to this task since it is staffed largely by former Grinnell employees, many of whom were instrumental in the early development of the industry accepted practices regarding hydraulic snubbers. Each snubber location will be evaluated for effects of operating temperature upon test criteria.

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3 DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED TSS 15.6.48 will be revised to alter the acceptance criteria for lockup velocity and to control test temperature by January 1, 1988.

The temperature correction factors required to adjust the acceptance criteria for snubber lockup velocity will be implemented prior to the next functional snubber test, currently scheduled for March 1, 1988.

VIOLATION #2 As a result of the inspection conducted on April 20-22 and August 18, 1987, and in accordance with 10 CFR part 2, Appendix C - General Statement of policy and procedure for NRC Enforcement Actions (1985), the following violation was identified:

10 CPR 50, Appendix B, Criterion V, as implemented by Commonwealth Edison Topical Report CE-1-A, " Quality Assurance program for Nuclear Generating Stations", and Commonwealth Edison Corporate Quality Assurance Manual, Nuclear Generating Stations, " Quality Requirements," requires that activities affecting quality shall be prescribed by documented instructions of a type appropriate to the circumstances.

Contrary to the above, Commonwealth Edison did not have any procedure that prescribes the type or the extent of the engineering evaluations required by Zion's Technical Specification paragraph 4.22.1.A.3 (304/87012-04)

CORRECTIVE ACTION TAKEN AND RESULTS ACHIEVED The specific characteristics of the required evaluation have been identified to include consideration of the effect the failed support might have had on the supported component. Its purpose is to assess the current ]

operability of the supported component, j I

CORRECTIVE ACTION TO BE TAKEN TO AVOID FURTHER VIOLATION Zion Technical Staff will develop a procedure pertaining to specifics of snubber and hanger operability ard the course of action taken after identifying a particular restraint inoperable. This guidance provides examples of supports in deficient conditions and categorizes each deficient indication as to whether the support is considered inoperable. The extent of the engineering analysis performed to satisfy Technical Specification paragraph 4.22.1.A.3, depends on the mode of failure of the support. The type of engineering analysis performed, specifically for snubbers, range j from a visual examination on the associated piping in both directions from the failed support and adjacent hangers, to a formal engineering analysis )

performed by an architect engineer for failures l l

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. which may be detrimental to the piping in normal modes of operation. Until such time that this procedure is issued, Zion Technical Staff shall notify PWR Engineering of any inoperable snubbers found to receive concurrence as to the extent of the engineering analysis to be performed.

DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED The procedural guidance discussed above will be implemented by January 1, 1988.

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