ML19276E697
| ML19276E697 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Hatch, Monticello, Dresden, Peach Bottom, Browns Ferry, Nine Mile Point, Fermi, Oyster Creek, Hope Creek, Cooper, Pilgrim, Brunswick, Vermont Yankee, Duane Arnold, Quad Cities, FitzPatrick |
| Issue date: | 03/01/1979 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Stello V Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19276E698 | List: |
| References | |
| TASK-06-02.A, TASK-6-2.A, TASK-RR TAC-07934, TAC-7934, NUDOCS 7903200283 | |
| Download: ML19276E697 (4) | |
Text
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UNITED JTATFS I..
't NUCLEAR REGULATORY COMMISSION o
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W AFHINGTON, 3. C, 20555
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MEMORANDUM FOR:
V. Stello, Jr., Director, Division of Operating Rectors FROM:
D. G. Eisenhut, Deputy Director, Division of Operating Reactors
SUBJECT:
PROPOSED STAFF POSITION FOR THE MARK I LONG TERM PROGRAM IMPLEMENTATION SCHEDULES The NRC granted exemptions from the requirement for design margins in General Design Criterion 50 (by letters dated February 28, 1978) to the licensees of BWR facilities with Mark I containments. The period for the granted exemptions was to apply for about two years while the k
Mark I containment long-term program (LTP) was being concucted. When the LTP is concluded, the design safety margin of each Mark I facility is to be restored to safety margin originally intenced at the time tne the plant was licensed for cperation.
Our review of the LTP has progressed to a point where plant-specific schedules should be established so that we ma < implement and conclude those 4: sues relating to Mark I containment. We had previously con-cluced and advised the Commission that our present goal for completing the LTP, including any modifications significant to safety, was Decemoer 1980. Accordingly, we have developec the encloseo sample letter that requests specific commitments from cach licensee relative to the comple-tion of the Marx I LTP and installation of the associated plant mod-ifications by December 1980. This position also addresses the related issues of the use of quencher safety-relief valve (SRV) discharge devices and licensing fee requirements for the LTP. We intend to transmit this position to each Mark I BWR licensee to promote a timely resolution of the LTP, following your signature.
The Mark I Owners have performed a sufficient number of scooing studies and analyses during the course of the LTP to be aware of these required g.,eral modifications. These modifications incluce (1) installing quencher SRV discharge devices, (2) modifying tne SRV discharge lines and line restraints, (3) truncating downccmers, (4) reinforcing torus supports, (5) installing vent heacer ceflectors, and/or (6) modifying the piping attached to tne torus.
MO32_cro 7_83
2 While considering the target (LTP) ccepletion date of Decemoer 1980, the Mark I Cwners Group has indicated that, althcugh tnay will strive to meet the target completion date, there are certain circumstances in which specific modifications cannot be completed by December 1980 without unscheduled or extended plant outages. A number of utility representatives have advised us that the principal difficulties are associated with limitations in manpower and materials availability and with power demands, especially far multiple-unit licensees.
We have studied the general modifications to find the ones that are "significant to safety" in an effort to determine whether there is a basis for deferring specific modifications. We believe that any modi-fication necessary to satisfy the LTP acceptance criteria will also be necessary to restore the originally intended cesign safety margin.
Thus, the goal of the LTP cannot be completely achieved if any of the modifications are incomplete by the December 1980 deadline.
There is a class of these modifications that may be considered of lesser significance to safety and, if implementation were deferred, would provide significant financial benefit to the licensee by avoiding extended or unscheduled plant outages. For example, although the vent header deflectors are necessary to achieve the stress limits required by the ASME Code, the vent system does not perform the pressure boundary function that is intended by the Code. Furthermore, the vent header deflector design is extremely plant dependent and is usually the last modification to be scheduled.
In additio.1 to the given example, there may be other plant-specific conditions that warrant a similar consider ation.
In considering the potential benefits that cculd be gained by allowing limited extensions of the target completion date, the preposed attached position requires that each licensee specify the modifications to be implemented by December 1980, and clearly identify any modifications tnat will not be completed by that time including a justification for any deferrals on the basis of the "best interest of the public." We will review each of the proposed schedules and, if necessary, will meet with specific utilities to assure that every possible effort is made to complete the modifications as quickly as practical.
. We have been informally advised by the Owners Group that, based on their most optimistic schedules,14 of the 22 operating plants could complete the installation of modifications by December 1980.
The remaining 8 plants could complete modifications during 1981.
These schedules are based on these presently recognized modifications.
Additional modifications may be identified by the plant-unique analysis following the staff's review of the Load Definition Report (LOR) and Plant Unique Analysis Applications Guide (PUAAG). However, these modifications should be relatively minor and schedule adjustments can be made, as necessary, following the staff's review of each plant-unique analysis.
Another issue addressed by this position concerns the use of quencher SRV discharge devices. The staff evaluated the basis for establishing pool temperature limits for the ramshead SRV discharge device and concluded that the threshold temperature (that is, staDility limit) has not been sufficiently demonstrated to justify long tem use of the ramshead device.
(The staff evaluation is included as an enclosure to the attached sample staff letter.) In addition, the staff has found the quencher discharge device to perform in a manner superior to the ramshead device in a wide range of operating condi-tions. For this reason, almost all of the Mark I Owners have already made plans to implement the quencher discharge device. The proposed position requires all Mark I licensees to commit to the use of quencher discharge devices and then to provide the schedule for the installation of these devices.
To complete the exchange of information, the sample letter also includes a discussion of the LTP licensing fee requirements in the proposed posi ti on. These requirements were confimed by a memorandum from D. J. Donoghue to H. R. Denton dated August 28, 1978. Because a r.Jmber of licensees have inquired about this subject, we have incor-porated these requirements for their infomation.
Once we have completed the review of each facility's plant-unique analysis, we intend to devise the necessary administrative vehicle to inform each licensee to begin to implement the commitments and schedules they have provided. In this manner, the timely completion of the LTP will be assured and the schedules will not be prolonged as we near the end of the program.
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For your convenience, we have also enclosed the transmittal memorandum that we are using to commence this action and distribute these letters to the BWR licensees.
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D. G. Eisenhut, Deputy Director Division of Operating Reactors Office of Nuclear Reactor Regulation
Enclosures:
1.
Implementation transmi ttal memorandum 2.
Sample letter to licensees 3.
Staff evaluation regarding suppression pool temperature limi ts
Contact:
C. Grimes X-27111 cc: H. Denton R. Mattson R. Vollmer B. Grimes D. Vassallo J. P. Knight R. Tedesco G. Lainas V. Noonan D. Ziemann T. Ippolito B. Buckley K. Wichman W. Russell C. Grimes
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