ML19322C585
| ML19322C585 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/22/1976 |
| From: | Moeller D Advisory Committee on Reactor Safeguards |
| To: | Rowden M NRC COMMISSION (OCM) |
| References | |
| TASK-TF, TASK-TMR NUDOCS 8001170910 | |
| Download: ML19322C585 (4) | |
Text
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October 22, 1976 Honorable Ibrcus A. Rowden Chairman U. S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
REPORT ON THREE MILE ISLAND NUCLEAR STATION, UillT 2
Dear Mr. Rowden:
During its 198th reeting, October 14-16, 1976, the Advisory Committee on Reactor Safeguards completed its review of the application of the Central Power and Light Company, Metropolitan Edison Company, Jersey (Applicants) for a license to operate and Pennsylvaaia Electric Company Three Mile Island Nuclear Station, Unit 2.
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project was also con-sidered during a Subcommittee meeting held in Harrisburg, Pennsylvania, on September 23 and 24,1976.
Members of the Committee visited the facility on September 23, 1976.
During its review, the Comittee had
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the benefit of discussions with representatives and consultants of the i
Applicants, General Public Utilities Service Corporation, the Babcock and Wilcox Company (B&W), Burns and Rowe, Inc., and the Nuclear Regula-tory Commission (NRC) Staff. The Committee also had available the documents listed below.
The Committee reported on the application for a construction permit for Unit 1 on January 17 and April 12, 1968, and for an operating license for Unit 1 on August 14, 1973.
The Comittee reported on the application for a construction permit for Unit 2 on July 17,1969.
The Three Mile Island Nuclear Station, Units 1 and 2, is located on Three Mile Island near the eastern shore of the Susquehanna River, about 12 miles southeast of Harrisburg, Pennsylvania. About 2380 people liye within a two-mile radius of the site (the low population zone).'
The minimum exclusion distance is 2000 feet.
The nearest population center is Harrisburg (1970 population 68,000).
Several changes have been made to bring the Babcock and Wilcox Emergency Core Cooling System (ECCS) evaluation model into conformance with the requirements of 10 CFR 50.46, and Appendix K to Part 50.
Analyses of a spectrum of break sizes appropriate to Three Mile Island, Unit 2 have been completed using the approved B&W generic evaluation model.
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a9 lionorable 11 arcus A. Rowden October 22, 1976 i
results of the analyses for the reactor coolant pump discharge break, believed to be the " worst" brcak, show raximum allowable linear heat generation rates as a function of elevation in tha reactor core ranging from 15.5 to 18.0 kilowatts per foot. Corresponding calculated post-accident peak clad temperatures range from 20020F to 21460F. The flRC 4
Staff has identified additional information that it will require to complete its review and the Applicants' submittal is expected by the end of 1976.
The Applicants propose to use both in-core and ex-core instrumentation to assure accuracy of measurement of core power distri-butions. The Committee believes that the proposed monitoring methods may be acceptable, but that an augmented startup program should be employed, and that satisfactory experience at 100% steady state power and during transients at less than full power should be obtained.
This experience should be reviewed and evaluated by the liRC Staff prior to operating at up to full power in a load following mode.
The Committee wishes to be kept infornr, A question has arisen concerning asymmetric loads on the reactor vessel and its internal :tructures for certain postulated loss-of-coolant accidents in pressurized water reactors. The Staff has required the
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Applicants to supply further information in order to complete its assess-A ment of this matter. This issue should be resolved in a manner satis-factory to the liRC Staff.
The question of whether Unit 2 requires design modifications in order to comply with WASil-1270, " Technical Report on Anticipated Transients Without Scram for Water-Cooled power Reactors", remains an outstanding i
issue pending the t!RC Staff's completion of its review of B&W generic analyses of anticipated transients without scram. The Committee recom-mends that the tiRC Staff, the Applicants and B&W continue to strive for an early resolution of this matter in a tranner acceptable to the flRC Staff.
The Committee wishes to be kept informed.
Emergency plans have been developed to allow plant shutdown and mainte-nance of safe shutdown in the event of a traximum probable flood.
Such a postulated flood would top the levee surrounding the plant by several fee t.
Included in the plan is the fastening of water tight steel panels in doorways and other openings of safety related structures.
The Com-mittee believes that the details of this plan; particularly relating to re-entry into the station during the post-flood period, need to be more clearly dalineated.
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lionorable 14 arcus A. Rowden October 22, 1976 i
The Comittee supports the NRC Staff's program for evaluation of fire protection in accordance with Branch Technical Position APCSB 9.5-1, Appendix A, " Guidelines for Fire Protection for Nucicar Power Plants".
The Comittee recommends that the NRC Staff give high priority to the l
completion of both cwner and Staff evaluations and to recomendations for Three lille Island Unit 2 and other plants nearing completion of i
construction in order to maximize the opportunity for improving fire protection while areas are still accessible and changes are more feasible.
The Committee notes that long-term post-accident operation of the plant to maintain safe shutdown conditions may be dependent on instrumentation
~and electrical equipment within containment which is susceptable to l
ingress of steam or water if the hermetic seals are either initially i
defective or should become defective as a result of damage or aging.
l The Comittee believes that appropriate test procedures to confirm continuous long-term seal capability should be developed.
4 The Committee recommends that further review be made of the battery supplied DC power system to assure that non-essential loads do not interfere with its safety function.
The Committee recomends that
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further review be made to assure no unacceptable effects such as release of hydrogen into the plant can occur from the failure of a hydrogen charging line.
The Comittee also recommends that studies be made to assure that failure of an instrument line cannot cause plant control-1 ability problems of significance to public safety.
The management organization proposed by the Applicants to delineate the safety related responsibilities of the off-site and on-site personnel of the Three 1411e Island Station left open questions as to how these responsibilities are to be discharged during normal working hours and during evening, night, and weekend shifts. This matter should be re-solved to the satisfaction of the NRC Staff.
The NRC Staff is still reviewing various issues related to accidents leading to loss of fluid in the steam generator secondary side, such as steam line breds.
The Comittee wishes to be kept informed of the resolution of these issues.
The Committee recomends that, prior to comercial power operation of Threc I411e Island Unit 2, additional means for evaluating the cause
'and likely course of various accidents, including those of very low l
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Honorable Marcus A. Rowden
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a4-Iz7%gw Octobe probability, should be in hand in
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timely decisions concerning i:os ibl order to provide improved bases for Committee wishes to be kept info 1
s e off-site emergency measures N
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further review the Three Mile IslThe The e'
pplicants and the flRC Staff should and that such measures should be implcou and Nuclear Station for meas emented where practical.ty and Other generic problems relating to l in the Corraittee's report entitled "S arge water reactors are discussed to Light Water Reactors:
tatus of Generic Items Relatin appropriately by the fiproblems relevant to the Three Mil Report No. 4", dated April 16 g
, 1976.
Those The relevant items are:RC Staff and the Applicants as s le 6, 7, 8; IIC - 1, 2, 3, 4, 5 II - 1, 2, 3, 4, 5, 6, 7, 9 o utions are found.
, 6, 7.
The Advisory Committee on Reacto
, 11; IIA - 1, 4, 5, completion of construction and pre opregard l
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able assurance that Three P,ile Island N erational testing, there is re operated at power levels u uclear Station, Unit 2 can be and safety of the public. p to 2772 MWt without undue risk to the health I
Sincerely yourg, Dade W. Moeller Pgrences Chairman 1.'
Three Mile Island Nuclear Stati i
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I Report (April,1974) with Amendm on, Unit 2 Final Safety Analysis
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ents 1 through 44.
Safety Evaluation Report Three Mile Island Nuclear (StatiNUREG-0107) related to o j
on, Unit 2, dated September,1976
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