ML18057A538
| ML18057A538 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/22/1990 |
| From: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18057A539 | List: |
| References | |
| NUDOCS 9011010098 | |
| Download: ML18057A538 (6) | |
Text
consumers Power POWERINli NllCHlliAN'S PROliRESS Palisades Nuclear Plant:
27780 Blue Star Memorial Highway, Covert, Ml 49043
.October 22, 1990 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
GB Slade General Manager TECHNICAL SPECIFICATIONS CHANGE REQUEST - AUGMENTED INSERVICE INSPECTION PROGRAM FOR STEAM GENERATORS Enclosed is a request for change to Palisades Technical Specification 4.14.
Under the proposed change, the existing Technical Specifications program for augmented inservice inspection of the steam generators will be replaced with an inservice inspection program that is consistent with the inspection program described in Standard Technical Specifications. With the replacement of the
- original steam generators and approval of this Technical Specifications change al.l previous commitments and requirements pertaining to inspection of the original steam generators will be annulled.
We request that the effective date of this change be upon issuance of the Amendment.
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Gerald B. Slade CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachments 90111010098 901022 LJ' PDR ADOCK 05000255 1
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A CMS' ENERGY COMPANY
Consumers Power Company Docket 50-255 Request for Change to the Technical Specifications License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specifications contained in provisional Operating License DPR-20, Docket 50-255, which were issued to Consumers Power Company for the Palisades Plant on October 16, 1972, be changed as described below:
I. Change Revise Technical Specification 4.14 and the associated Basis as indicated on the attached page change sheets.
II.
Discussion 1
The above proposed Technical Specifications change is requested to revise the augmented inservice inspection program for steam generators that is currently described in Technical Specification 4.14.
Under the proposed change, the existing Technical Specifications program for inservice inspection of steam generators will be replaced with an augmented inservice inspection program that is consistent with the program described in the Standard Technical Specifications.
Inservice inspection of Primary Coolant System (PCS) components, including steam generator tubes is necessary to ensure that design basis assumptions are maintained.
Steam generator tube inspections also provide cognizance of tube condition in the event that there is evidence of damage or progressive degradation due to design or manufacturing factors, or inservice conditions that lead to corrosion.
The proposed inservice inspection program for steam generators is based on a modification to Regulatory Guide 1.83, Revision 1, "Inservice Inspection of Pressurized Water Reactor Steam Generator Tubes", and satisfies these objectives.
The existing augmented inservice inspection program for steam generators encompasses several principal attributes: 1) non-destructive examination of a sample of steam generator tubes on a schedular basis, 2) emphasis on tubes that are located in areas where experience has indicated that flaw initiation is most probable, 3) increased monitoring of tubes that were previously identified as degraded, 4) increased tube sample size and inspection frequency following evidence of excess tube degradation, and 5) repair and plugging criteria for degraded and defective tubes.
These same attributes from our existing steam generator inspection program are embodied in the Standard Technical Specifications program for augmented inservice inspection of steam generators, and are also reflected in the inservice inspection program that we have proposed.
In addition to the previously mentioned program attributes, both the existing and proposed inservice inspection programs contain provisions for reporting the results of inspection activities to the Commission.
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** ~~~--~'-*J\\-(JYfferencebetweenth~ -~xi sting and proposed programs is the imperfection depth at or beyond which a steam generator tube will be considered defective.
Under the proposed Technical Specification, a steam generator tube will be considered unacceptable if an indication penetrates 403 or more of the nominal tube wall thickness based on ASME B&PV Code,Section XI, INB 3521.
The existing criteria permits indications that are greater than 403 of the nominal tube wall thickness for tubes that do not exhibit multiple flaw indications. The existing specification also has a separate criteria for tubes that evidence multiple indications.
Neither the Standard Technical Specifications inspection program nor the proposed inspection program contain a separate criteria for tubes with multiple indications. The existing criteria for tubes with multiple indications was developed specifically for the original Palisades steam generators at a time when operational degradation of the steam generator tubes was unpredictable and aggressive due to previous chemistry practices.
The repair criteria reflects previously observed operational degradation rates, as well as the relatively high level of instrument uncertainty that was inherent in eddy current testing (ECT) devices which were available at the time the specification was written.
Early ECT devices often provided ambiguous representations of tube wall condition, including indeterminate evidence of multiple tube wall indications.
ECT devices are now able to depict tube wall condition with significantly greater accuracy.
Additionally, we now utilize an industry proven AVT chemistry that has been demonstrated to minimize operational tube degradation, and we are in the process of replacing our steam generators. After compensating for the effects of reduced operational degradation and increased instrument accuracy, the proposed acceptance criteria of 403 is no less conservative than the existing criteria for tubes with multiple indications.
The proposed change to Technical Specification 4.14 will also result in an acceptance criteria that is as conservative as those described in the existing program for steam generator tubes that do not exhibit multiple indications. This statement can be made despite differences in nominal -
tube wall thickness between the original and replacement steam generators because the proposed 403 acceptance criteria will result in a dimensionally larger thickness of unaffected tube wall.
The proposed specification also clarifies the method used to satisfy the requirement that hydrostatic testing be performed prior to preservice ECT examination of the steam generator tubes.
Analysis of No Significant Hazards Consideration Consumers Power Company finds that activities associated with this change request include no significant hazards; and accordingly, a no significant hazards determination per 10CFR50.92(c) is justified. The following evaluation supports the conclusion that the proposed change does not:
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- 1.
Involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed augmented inservice inspection program will continue to provide assurance that the steam generators are capable of performing their design function as a Primary Coolant System (PCS) boundary under both normal operating and postulated accident conditions and that the release limits of 10 CFR part 100 will not be exceeded.
Under the proposed change, the current inservice inspection program will be replaced by a program that is consistent with the Standard Technical Specifications.
The same principal provisions from the existing inservice inspection program are also reflected in the proposed inservice inspection program.
Therefore, the reliability and integrity of those portions of the PCS boundary associated with the steam generator tubes will not be degraded.
Additionally, the proposed inspection program will direct tube repairs under conditions that are no less conservative than those stated in the existing specification. Consequently, the probability or consequences of an accident will not be increased following implementation of the revised inspection program.
2~ Create the possibility of a new or different kind of accident from any previously evaluated.
The proposed change does not alter the assumptions used in existing accident analyses and embodies each of the principal attributes of the current Technical Specifications program for inservice inspection of steam generators.
The tube plugging limits and principal attributes contained in the proposed Technical Specifications inspection program are no less restrictive than those in the existing inservice inspection program, and assurance of steam generator tube integrity will continue to be provided through a periodic and formalized inspection program.
Therefore, a new or different kind of accident is not created by the proposed change.
- 3.
Involve a significant reduction in the margin of safety.
The margin of safety relative to this change request involves the reliability and integrity of the PCS under normal and accident conditions.
The proposed change will not adversely affect the ability of the steam generator tubes to withstand the design pressure, temperature, and seismic effects that are expected under either normal or postulated accident operating conditions, nor will the change result in a condition that could exceed the release limits of 10 CFR Part 100.
The margin of safety associated with the structural integrity of those portions of the PCS that are associated with the steam generator tubes will be maintained following implementation of the proposed change through our continued use of Technical Specifications limits on primary-to-secondary leakage and a formalized inservice inspection program.
Consequently, there is no decrease in the margin of safety.
III.
Conclusion The Palisades Plant Review Committee has reviewed this Technical Specifications change request and has determined that the change does not involve an unreviewed safety question, and, therefore, involves no significant hazards consideration.
The proposed change has been reviewed by the Nuclear Safety Services Department. A copy of this change request has been sent to the State of Michigan official who is designated to receive such requests for amendment to the Operating License.
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5 CONSUMERS POWER COMPANY To the best of my knowledge, information and belief, the contents of this Technical Specification Change Request are truthful and complete.
By~~Qt David P Hoffman, Vice Pr 1
Nuclear Operations
~
Sworn and subscribed to before me this ~t-A. day of ~
1990.
LeAnn Morse Van Buren County My commission expires June 6, 1994 LeANN MORSE, NOTARY PUBLIC VAN BUREN COUNTY, STATE OF MIC.HJGA.N~
MY COMMISSION EXPIRES 06*0&-94