ML20196H948

Responds to NRC Re Violations Noted in Insp Repts 50-295/88-10 & 50-304/88-11.Corrective Actions:Temporary Mod Installed to Resecure Hydrogen Monitoring Piping & Engineering Analysis Performed on Subj Piping

ML20196H948
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	06/24/1988
From:	Bliss H COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 8807060286
Download: ML20196H948 (5)

Text

. . . - . - .

d X: Commonwealth Edison

.  ;.- _, / One First National Plaza. Chicago. Illinois

. s v 7 Address Reply to: Post Offc; Box 767

\Q Chicago, Illinois 60690 0767 June 24, 1988 '

Mr. A. Bert Davis Regional Administrator U.S. Nuclear Re7Jlatory Commission Region III 799 R%sevelt Road Glen Ellyn, IL. 60137

Subject:

Zion Nuclear Power Station Units 1 and 2 Response to Inspection Report Nos.

50-295/88-010 and 50-304/88-011 NRC Docket No. 50-295 and 50-304

Reference:

May 24, 1988 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 5 through 21, 1988 of activities et 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 is 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, h)

i. /

H. E. B liss Nuclear Licensing Manager

/klj cc: NRC Resident Inspector-Zion J.A. Norris-NRR 4849K

'JUN 2 71988

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ATTRCRMENT ZION NUCLEA9 p0WER STATION RESPONSE TO NOTXCE OF VIOLATION VIOLATION

.10CFR part 50, Appendix B, Criterion III, as implemented by CECO Topical Report CE-1-A, "Quality 7Msurance program for Nuclear Generating Stations," and CECO Corporate Quality Assurance Manual, Nuclear Generating' Stations, "Quality Requirements," requires that design changes shall be subject to design control measures similar to the original design.

Contrary to the above, the containment hydrogen monitoring piping was modified prior to July 1987 without a documented review to verify that the containment penetration was not adversely affected.

CORRECTIVE ACTION TAKEN AND RESULTS ACHIEVED

1. A temporary modification was installed in August 1987, to re-secure the hydrogen monitoring piping in question. The temporary modification consists of the installation of spool pieces (one per unit) which bolt the hydrogen monitoring piping to existing supports. The installation of the temporary modification is consistent with the design specification for existing system piping and was accomplished by use of nuclear work requests (Z-62168, Z-62169). The temporary modification was also reviewed and documented per Zion Administrative Procedure 3-51-4, "procedure Governing the Use of Temporary Jumper Cables, the Lifting of Terminated Wires, The Bypassing of Alarms, or the Installation of Mechanical Blocks or Bypasses".

The spool-piece installations are listed as Mechanical Blocks B-7032 and B-7033 (for Unit 1 and Unit 2, respectively) in the Block / Bypass log, which is maintained in the station control room.

l 2. An engineering analysis (EMD-64019) was performed by Sargent &

l Lundy in' August 1987. The analysis indicated that, with the hydrogen monitoring piping re-secured as describea in item 1, the piping installation would be able to withstand a design basis earthquake with no adverse affect on the containment penetration (p-44).

3. t '.ification M22-1/2-87-55 was initiated to permanently install the l spool-pieces and provide proper engineering re lew for a permanent modification installation. In conjunction with the modification an additional engineering review was requested of, and performed by, Sargent & Lundy. The results of the review, documented in a letter from M.D. Rauckhorst to D.B. Wozniak dated 4/28/88, indicate that even with the hydrogen monitoring piping in its unsupported condition it would have no adverse effect on the containment penetration (p-44) during a seismic event. This is due to the following features of the piping system design.

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The free-ended portion of the piping is located in the Auxiliary Building at elevation 592'-0", while the penetration is located in the Vertical Pipe Chase (P-44) at Elevation 590'-9". Between these two points are approximately 40 feet of piping routed through two walls which act as. guides in the piping system and supported by angle-iron and U-Bolt supports which are standard for piping of this size and type.

Currently, between the penetration P-44 and where it penetrates the Vertical Pipe Chase, there are a minimum of 4 supports. This in combination with the wall penetration acting as guides for the pipe will prohibit any increased loads on the penetration.

CORRECTIVE ACTION TO BE TAKEN TO AVOID FURTHER VIOLATION

1. Final installation of Modification M22-1/2-87-55 will be performed. This will consist of the installation of three additional spool-pieces on each unit's portion of unsupported hydrogen monitoring piping.

2. During the past 12 to 18 months both ZAP 3-51-4 (jumper, lifted lead, block & bypass procedure) and the Zion modification program have been and continue to be, extensively revised. ZAP 3-51-4 will be re-issued under the new title "Temporary Alteration procedure"

.which will compliment ZAP 3-51-1, which governs the processing of nuclear work requests at Zion Station, to identify temporary alterations and document them properly. This will ensure that a proper design review will oe performed and documented prior to the installation of a temporary alteration / modification. These changes, plus the revamping of the modification program, will heighten the awareness of Station personnel as to the need to identify and obtain proper design review for any alterations to equipment at Zion Station.

DATE WHEN PULL COMPLIANCE WILL BB ACHIEVED

1. The installation of raodification M22-1/2-87-55 will be completed by December 31, 1988.

2. Issuance & Implementation of the revised ZAP 3-51-4 "Temporary Alteration program" is scheduled to occur by August 1, 1988.

VIOLATION The Zion Station Technical Specification Paragraph 4.22.3 requires that the installation and maintenance records for each snubber shall be reviewed to verify that the indicated service life will not be exceeded prior to the next scheduled snubber service life review.

Contrary to the above, approximately 140 snubbers, reconditioned in the Spring of 1982, were not identified as needing to be reconditioned, repi; ed or reevaluated in order to extend the service life beyond the indicated seven years.

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CORRECTIVE ACTION AND RESULTS ACHIEVED Zion Station recently introduced 16 month power operation cycles and in turn the preventative maintenance program for hydraulic snubbers has been extended beyond the seven year recommended seal service life. The preventative maintenance program was based upon a' cycle of six refueling outages available to recondition the entire population of hydraulic snubbers. present outage intervals requires this number to be reduced to four refueling cycles to complete reconditioning the hydraulic snubber population. This interval increases the minimum required number of snubbers to be rebuilt each outage from 86 to 126. A total of 129 snubbers were overhauled or replaced during the last Uait 1 cutage, of which 33 were last rebuilt in 1982.

The 1982 Unit 1 overhaul of the snubbers was performed between 02/21/82 and 04/11/82. The next Unit I refueling cycle is scheduled for August, 1989 thereby giving the remaining 139 1982 rebuild vintage of_ snubbers a service life cycle of approximately 7 years, 6 months. Although this time frame is beyond the 7 year recommended servico life, the manufacturer of the hydraulic snubbers installed at Zion stated that:

"Immediate catastrophic seal degredation will not result from continued use of nonleaking seals beyond the recommended seal life. However, the likelihood that seal problems will occur increases as time goes on. Essentially our (Grinnel Corporation) position is that it is the users' prerogative to establish their own seal change out intervals based on successful history under similar environmental conditions" (Reference #1)

It should be noted that Zion Station procedure TSS 15.6.48 entitled Safety Related Hydraulic and Mechanical Snubbers Surveillance was revised prior to the Spring 1988 Unit 1 refueling outage to give a more descriptive root cause analysis for snubber failures. per this program a more detailed investigation was performed of the failure mode of the 11 inoperable snubbers identified during the referenced outage. This investigation found that the major causes of snubber failure were not seal degradation, but mechanical problems such as loosened fittings or adjustment screws, scoring of snubber internals or worn bushings, per these findings, no snubber failures could be attributed to seal degradation alone (Reference

1. 2)

It should be noted that the snubber service life preventative maintenance rebuilds are totally independent of the rebuilds performed due to problems identified per visual inspections. The visual inspection frequency, as required by Tachnical Spec _tications is a function of the actual condition of the snubbers, not the theoretical life of a particular component.

Peference #1 ITT Grinnel Letter dated February 23, 1987, from D.P Brown Reference #2 Zion Technical Specification Surveillance TSS 15.6.48 Unit 1 1988 Outage.

CORRECTIVB ACTION TAKEN TO AVOID FURTHER VIOLATION Due to the number of snubbers identified as inoperable during the referenced outage, an increase in the required visual inspection frequency has been required by technical specification 3.22.A.2.

100% of the inaccessible snubbers were inspected on April 22, 1988 Einding no inoperable snubbers. The increased visual inspection frequency should identify any accelerated seal degradation exhibited by'the snubbers.

Zion Station has reviewed the Service Life Monitorin] Pro; ram for Unit 2 and has determined the "Overstep" of the 7 year seal service sife shall be prevented by increase of rebuilt snubbers per outage.

Zion Station Tech Staff has reviewed rebuild cycles available in the service life monitoring program and has specifically identified the snubbers required to be rebuilt for each of the four st'> sequent Unit 1 & 2 outages to ensure the total population of hydraulic snubbers shall be rebuilt within the recommended seven year service life. This sort of 2he population shall change pending visual inspection findings and shall not be taken as credit for future service life monitoring review required by Technical Specifications, pA_TE WHEN PULL COMPLIANCd WILL.BB ACHIEVED The atation will be in full compilance at the completion of each unit's euDsequent refueling outage.

4849K L

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