ML20198D047
| ML20198D047 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 05/15/1986 |
| From: | Donohew J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8605230112 | |
| Download: ML20198D047 (7) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION e
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I WASHINGTON, D. C. 20555
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May 15, 1986 Docket No. 50-219 LICENSEES:
GPU Nuclear Corporation Jersey Central Power and Light Company FACILITY:
Oyster Creek Nuclear Generating Station
SUBJECT:
APRIL 25, 1986, MEETING WITH THE STATE OF NEW JERSEY BUREAU OF RADIATION PROTECTION TO DISCUSS THE STAFF'S EVALUATION TO DEFER REPLACEMENT OF THE CORE SPRAY SPARGERS FROM CYCLE 10R OUTAGE On Friday, April 25, 1986, a meeting was held at NRC, Bethesda, Maryland, with the State of New Jersey Bureau of Radiation Protection (State) to discuss Amendment 70 to the Oyster Creek license. This amendment provided the staff's Safety Evaluation (SE) dated January 26, 1984, on the Oyster Creek core spray sparcers. This amended Paragraph 2.C.(7) of the license to allow inspections by a method acceptable to NRC of both spargers and repair assemblies at each refueling outage instead of requiring the spargers to be replaced. The basis for this amendment was in the SE.
The amended Paracraph 2.C.(7) stated:
Inspections by a method acceptable to the NRC of all accessible surfaces and welds of both core spray spargers and repair assemblies at each refueling outage will be perfermed so that meaningful comparisons of any indications with previous inspections can be made. Results of the inspections along with an evaluation of the safety significance of any new or progressing indications will be provided to the Comission's staff for review. Authorization will be obtained from the Commission's staff before the plant is restarted from the refueling outage. Should the staff detennine that new cracks or further progression of existina cracks has occurred resulting in unacceptable degradation of safety margins, the sparger will be replaced prior to restart.
The State suggested, in its letter dated January 3, 1984, that the staff post-pone its decision on Amendment 70 until the staff had completed its independent review of the adequacy of the flow of water from the existing core spray system.
This staff review is the review of the adequacy of core spray in a steam environment which was completed with an SE being issued on July 20, 1984.
The staff addressed the State's concern in its SE dated January 26~, 1984. The staff concluded that it was not necessary to delay Amendment 70.because its review on the adequacy of core spray in a steam environment was independent of Amendment 70. The staff stated the following in its SE:
"On January 11, 1984, the staff received a letter dated January 3, 1984, from Mr. David M. Scott proposing that the Comission delay ' issuance of this amendment until evaluation of the nozzle spray effectiveness has been completed.
However, the nozzle spray effectiveness in steam environ-ment is being evaluated by the staff for the Oyster Creek plant, which is separate from and unrelated to the evaluation of the core spray sparger PDR ADOCK 05000219
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. cracking.
In regard to this amendment, it should be noted that the distribution of spray flow through the repaired sparger was evaluated previously in Amendment 34 dated November 24, 1978.
In its evaluation, the staff concluded that the distribution in spray flow from the repaired
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i sparger will not be significantly different from the previously accepted distribution from the uncracked and unrepaired sparger. The effect of crack leakage on total sparger flow has been accounted for by increasing the Technical Specification requirement on flow rate from the soarger.
Therefore, the staff does not believe it is necessary to delay this amendment until completion of the evaluation of the nozzle spray i
effectiveness.
The staff evaluation of the core spray sparger e#fectiveness in a steam environ-ment was issued July 20, 1984. The findings of that SE are in Attachment 2.
The second findino in Attachment 2 refers to a review which was part of the Oyster Creek reload core application for operating Cycle 10. This review was concluded by the staff and reported in Section 2.3 of its SE for Amendment 75 dated August 27, 1984. The conclusion was that the licensee's modified evalu-ation methodology to account for uncertainties in core spray distribution at elevated reactor system pressures was accepted by the staff.
The State requested this meeting to explain its concern about the cracking in safety system oi' ping in aeneral and to discuss the staff's evaluation in Amendment 70 for the core spray sparger in particular.
The State explained it has great interest in the core spray spargers at Oyster Creek. Oyster Creek is a relatively old plant in a highly populated area. The State has concluded that there is more potential for radiation exposure to the population from accidents at Oyster Creek than at the other New Jersey nuclear power plants. -
0 The State stated that the core spray system is an important system to protect the core and should be in the best condition. The State explained that the licensee has the replacement core spray sparger on site. The State further stated that it was concerned that the licensee may request a change to license condition Paragraph 2.C.(7) to require inspections only every other refueling outage.
The staff stated that it would like to have the sparger in perfect condition; however, if it can be proven that an existing system can perform its intended safety function this system is acceptable to the staff. The conclusions of the staff in the SE issued on the core spray sparcer system were that (1) the system is expected to perform it's safety function and (2) inspection of the spargers before restart from a refueling outage will prevent operation of Oyster Creek with a sparger degraded to the point it cannot perform this function.
In Amendment 47 dated May 15, 1980, the staff added a license condition to reouire the replacement of the existing cracked core spray sparger during the Cycle 10 Refueling (Cycle 10R) outage. Operation with a cracked sparcer for an interim fuel cycle was permitted based on repairs to the sparger using repair bracket assemblies. Since the time of Amendment 47, experience from other inspections at BWRs gave the staff confidence that it was not necessary to replace the sparger in the Cycle 10R outage. This conclusion is in the staff's 'SE for Amendment 70.
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. The staff stated that replacement of a sparger would be a high cost in person-rem exposure to the workers doina the work to replace the sparger.
1 This cost was not considered by the staff in its SE for Amendment 70 deferring-the replacement of the core spray sparger from the Cycle 10R outage.
The staff stated that it believes the stresses which caused the crack in the sparger were relieved by the crack. As explained in the SE dated January 26, 1984, the indications are that there is only one crack in one sparger and it is throuchwall. The staff originally believed that the sparger materials were in poor metallurgical condition and required the license condition in Amendment 47 requiring the replacement of the sparger in the Cycle 10R outage. The staff reconsidered this position in Amendment 70 and concluded then with additional data from inspections of the spargers in the Cycle 10R outage that the sparcers were in fact in reasonably good metallurgically condition and should last the life of Oyster Creek. The staff stated that no BWR has replaced a core spray sparger.
The staff stated that there will be a good NRC-approved inspection program of the core spray sparger in the Cycle 11R outage. There has also been an upgrading of the qualification of examiners since the Cycle 10R outage at 3
Oyster Creek.
4 The staff explained that it evaluated the repairs of cracks in the isolation condenser before the restart of Oyster Creek from the Cycle 10R outage. This evaluation is in the staff's SE dated September 20, 1984. The staff concluded that the inspections and repairs were performed satisfactorily and the plant could be safely returned to power.
The State expressed its concern about pipes that have cracks and may or may not leak. The staff explained that it is not accepting cracks in pipes that leak. The staff accepts approved methods of repairing cracks to return the pipe to at least its original integrity and accepts appropriate time periods to repair the cracks.
The State and the staff discussed the staff's evaluations of the core spray distribution in a steam environment. The staff's evaluation is in its SE dated i
July 20, 1984, and August 27, 1984 (Section 2.3).
The staff stated (1) that 1
for small breaks to the reactor coolant system (RCS) the pressure is maintained in the RCS and the licensee has.shown that one needs only steam cooling to cool the core and (2) that for large breaks to the RCS the pressure is not I
maintained.in the RCS and the licensee has shown there will be enre spray from the spargers to cool the core.
The State pointed out that the new core spray sparger onsite is a newer and better design than the existing core spray spargers in the RCS. The staff stated that it has in its SE judged that the existing soargers are adequate and meet the minimum requirements for the safe operation of Oyster Creek.
The State expressed its appreciation to the staff for having this meeting and for having the technical discussion on the basis for the staff's decisions in Amendment 70 dated January 26, 1984. The staff said that it will keep the State informed of the meetings to be held with the licensee on the results of the licensee's inspections of the core spray sparger, isolation condenser piping l
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. and recirculation piping in the Cycle 11R outage.
This outage began in April 1986 and is scheduled to end in October 1986.
\\ M MT Ted
(: Ja N. Donohe Jr., Project Manager BWR Project Dir ctorate #1 Division of BWR Licensing Attachments:
1.
List of Attendees 2.
Findings of Staff's Safety Evaluation dated July 20, 1984 cc:
R. Bernero G. Lainas B. D. Liaw W. Hazelton G. Holahan M. Caruso P. Lohaus, Region I F. Young, OSP Distribution Docket File NRC PDR/ Local PDR PD#1 Reading JZwolinski/CJamerson JDonohew OELD LHarmon EJordan BGrimes JPartlow TBarnhart WJones ACRS (10)
OPA Oyster Creek [ Gray File]
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DATE :5/d/86 5/lk/86
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0FFICIAL RECORD COPY i
Oyster Creek Nuclear Generating Station Oyster Creek Nuclear Generating Station cc:
Ernest L. Blake, Jr.
Resident Inspector Shaw, Pittman, Potts and Trowbridge c/o U.S. NRC 1800 M Street, N.W.
Post Office Rox 445 Washington, D.C.
20036 Forked River, New Jersey 08731 J.B. Liberman, Esquire Commissinner Bishop, Liberman, Cook, et al.
New Jersey Department of Energy 1155 Avenue of the Americas 101 Commerce Street New York, New York 10036 Newark, New Jersey 07102 Eugene Fisher, Assistant Director Regional Administrator, Reaion I Division of Environmental Quality U.S. Nuclear Regulatory Commission Department of Environmental 631 Park Avenue Protection King of Prussia, Pennsylvania 19406 380 Scotch Road Trenton, New Jersey 08628 BWR Licensing Manager GPU Nuclear 100 Interpace Parkway Parsippany, New Jersey 07054 Deouty Attorney General State of New Jersey Department of Law and Public Safety 36 West State Street - CN 112 Trenton, New Jersey 08625 Mayor Lacey Township 818 West Lacey Road Forked River, New Jersey 08731 D. G. Holland Licensing Manacer Oyster Creek Nuclear Generating Station
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Post Office Box 388 Forked River, New Jersey 08731 P. B. Fiedler Vice President and Director Oyster Creek Nuclear Generating Station Post Office Box 388' Forked River, New Jersey 08731 1M"
ATTACHMENT 1 MEETING WITH STATE OF NEW JERSEY
- TO DISCUSS THE STAFF'S SAFETY EVALUATION ON DEFERRING REPLACEMENT OF CORE SPRAY SPARGER APP.IL 25, 1986 NAME ORGANIZATION J. Donohew NRC/NRR/ DBL K. Tosch State of New Jersey
- R. Green State of New Jersey
- i P. Lohaus NRC Region I M. Caruso NRC/NRR W. Hazelton NPC/NRR/ DBL F. Younc NRC/0SP
- Department of Radiation Protection
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ATTACHMENT 2 STAFF SAFETY EVALUATION DATED JULY 20, 1984 OC CORE SPRAY EFFECTIVENESS IN A STEAM ENVIRONMENT Evaluation Findinos 1.
The minimum bundle flowrate predicted in the licensee's analysis was arrived at using the General Electric design methodology for determining core spray distribution. We have reviewed the licensee's analysis and find it acceptable.
2.
In order to demonstrate acceptable consecuences for certain small break loss-of-coolant accident scenarios the licensee has re-analyzed the small break cases with a modified evaluation methodology. This was done because of uncertainties in core spray distribution at elevated reactor system pressure. This issue is currently being reviewed in DSI/RSR as part of their review of the Oyster Creek reload core application presently before the Commission.*
3.
The licensee has determined the minimum required bundle spray flowrate needed to achieve Appendix K heat transfer coefficients with a method sunported by spray cooling test results. We accept this determination because it is well supported by test data.
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4.
We have reviewed the uncertainty factor applied in the determination of minimum bundle spray flowrate and find it acceptable based on comparisons of test results with calculated results.
- Staff issued its evaluation in Amendment 75 dated August 27, 1984.
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