ML19343D104
| ML19343D104 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/26/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| References | |
| LSO5-81-03-069, LSO5-81-3-69, NUDOCS 8104090405 | |
| Download: ML19343D104 (6) | |
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NRC PDR NAR 2 61981 L PDR Docket No. 50-219 ORB #5 reading l
LS05-81-03-069 DCr*:tchfield RScholl
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RHermann NSIC WRussell TERA Mr. I. R, Finfrock, Jr.
WPaulson ACRS(16)
Vice President - Ceneration Glainas TNovak Jersey Central Power & Light Company g
Madison Avenue at Punch Bowl Road RTedesco e
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Morristown, New Jersey 07960 A gr
Dear Mr. Finfrock:
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SUBJECT:
SEP TOPIC VIII-4 ELECTRICAL PENETRATIONS OF REACTOR i
CONTAINMENT (0YSTER CREEK) v%s% 4,G/
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Oraft Technical Evaluation Reports (TER) on Topic VIII-4 have been prepar and forwarded to all SEP Licensees for comment. Coments from some licensees (e.g., Northeast Utilities letters dated August 29, 1980 and January 29, 1981) indicated a concern with the model used and assumptions made in the initial conditions and material properties. Unfortunately, most respondents have not provided sufficient technical information nor detailed schematics to support their connents.
Our audit calculations failed to establish that the fault current protection for containment electrical penetrations in SEP facilities is generally ade-ouate. This does not necessarily mean that the protection is inadequate.
Our calculations were simplified and conservative so that there is room to improve the result by using more realistic models.
In addition, licensee connents have indicated that there may be some errors in our calculations.
Nevertheless, our audit did not put the matter to rest and, thus, you are requested to dvaluate the adecuacv af all al&trical nenstrations in '
your facility in accordance with the enclosed position.
Generally, where needed, our position calls for more realistic criculations than were used in our audit.
In relation to current licensing criteria, it provides relief from the need for redundant circuit protective devices in certain instances and specifically provides for using fuses as an alternative to circuit breakers. Other straightforward alternatives such as deenergizing circuits are also provided for.
If any instances arise where your calculations cannot demonstrate circuit protection in accordance with our position, you are requested to infonn us of your intended corrective actions, f
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m e s 1981 In order to complete our review of Topic VIII-4, please provide a report describing the calculations performed and criteria used for evaluating the peneNations for the specific circuits identified in the staff's previous re,oort within 45 days of receipt of this letter.
The report as a minimum should address the following items:
1.
Backup protection for penetrations like ill.
2.
Circuit design and theory of operation for differential ctsPrent protection of pump motor circuits for (a) Motor Faults (b) Conductor Faults at the penetration (single phase and bolted faults).
3.
An analysis of how the design of the line relay and differential protection satisfies the single failure criterion for all faults.
p The requested infonnation will be used to revise our topic Safety Evaluation Report and will be used in the preparation of the integrated assessment for your plant.
Sincerely.
Orl2 :1 31 SIE"8d DY Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
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A report, describing the calculations performed and criteria used for evaluating the penetrations identified in the staff's previous report should be submitted within 30 days of receipt of this letter.
The report as a minimum should address the following items:
1.
Backup protection for penetrations like ill.
2.
Circuit design and theory of operation for differential current protection of pump motor circuits for (a) Motor Faults (b) Conductor Faults at the penetration (single phase and bolted faults).
3.
An analysis of how the design of the line elay and differential protection satisfies the single failure criterion for a'l faults.
The requested information will be used to revise our topic Safety Evaluation Report and will be used in the preparation of the integrated assessment for your plant.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing
Enclosure:
As stated cc w/ enclosure See next page
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Mr. I. R. Finfrock, J r.
Cc G. F. Trewbridge, Esquire Gene Fisher Shaw, Pittman, Potts and Trowbeidge Bureau Chief 1800 M Street, N. W.
Bureau of Radia".f on Protection Washington, D. C.
20035 350 Scotts Road.
Trenton, New Jersey 38523 GPU Service Corpcration AUN: Mr. E. G. Wallace Comissioner Licensing Manager New Jersey Depart.m.ent of Encrgy 260 Cherry Hill Read 101 Comerce Street Parsippany, New Jersey 0705a Newark, New Jersey 01102 Natural Rescurces Defense Council Plant Superintendent 91715th Street, N. W.
Oyster Creek Nuclear Generating Washington, D. C.
20006 Station P. O. Box 333 Forked River, N@ Jersey 08731 Steven P. Russo, Esquire 5
248 Washingten Street Resicent Inspec cr P. O. Box 1060 c/o U.'S. NRC Tc:s River, New Jersey 03753 P. O. Box 445 F0rked River, NW Jersey 08731 Joseph W. Ferraro, Jr., Esquire Deputy Atterney General Directer, Criter ia and Standards State of New Jersey Divisicn Department of Law and Public Safety Office cf Radiaticn Programs 1100 Ray cnd Sculevard (ANR-460)
Newark, New Jersey 07012 U. S. Environmental Protection Agency Ocean Ccunty Library Washington, D. C.
20460 Brick Tcwnship Branch 401 Cha:cers Bridge Read U. S. Envirencer :a1 Prctection Brick Town, New Jersey 08723 Agency Region II Office.
Mayor ATTN: EIS CGORC.INATOR Lacey Tcwnship 25 Federal Plaw P. O. Box 475 New Ycrk, New Ye3 10007 Forked River, New Jersey 08731 Comissioner 2
Department of Public Utilities State of New Jersey 101 Comerce Street Newark, New Jersey 07102 1
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pL M\\M ECLOSURE POSITION ON PROTECTION OF CONTAI A.ENT ELECTRICAL PENETRAT10KS AGAIN51 F AILURES C AUSED B1 F AULT AND OVERLOAD CURREhTS f0R SEP PLANTS Introda: tion As part of the Systeratic Evaluation Frogram (SEF) the NRE staff performed an audit, conparing sample containment electrical penetrations in SEP facilities with current licensing criteria for protection against fault and overicad currents folic =ing a postulated a:cioent. The sie;1ified and conservative recel usec did not sh w that the SEP f acilities reet current licensing Criteria nor did it sho tne existing circuit prote: tion to be adequate. A:cordingly.
the SE8 licensees a t requested to ce cnstrate, using rcre realistic calcula-tiens where ne:essary, that the circuit prete: tion is adequate in accordance with the position described belo=.
Ea:k m ind In licensing new plants, the staf f requires coe;1ian:e witn the recomendations of Regulatory Guioe 1.63 or an acceptale alternative method.
For ea:h contain ent ela:trical penetratien, tee r:tective systems provide primary and backup circuit prote: tion devices to prevent a single failure in con-junction with a circuit everloac frem impairing centainment integrity. The primry and backup prctection devices have trip time vs. current response charac-teristics wnich assure prote: tion against penetration failure.
The protection cevices are periodically tested to verify trip setpcints and adequacy of response.
N: single failure allcws excessive currents in the penetration conductors which will degrade the penetratien seals. Knere external control power is used for actuating the protection systems the power for primary and backup breakers are derived fror separate scur:es. Ovarcurrent signals for tripping primary and backup system devices are ele:trically independent and physically separated.
Staff Audit The safety objective of SEP Topic VIII-4, " Ele:trical Penetrations of Reactor Centainment," is to assure that all electrical penetrations in the containment structure are designed not to fail from electrical faults during a high energy line break (LOCA or secondary system line break).
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We have perforced preliminary evaluations, on a conservative basis, of th: f.. ult, current prete: tion for three samle contain ent electrical penetrations for each cf the eleven SEP plants. The entire penetratien was assured to be initidly at the peak calculated LO~A te perature.
Then, for a given fault current, the tire to heat the wire to the limiting raterial te@erature (usually the reiting point cf the seal raterial) was calcuhted.
This tire was cegared to the tice for the prote:tive device (s) to interrupt the f ault current.
On this basis, several penetrations exceed limiting te peratures if the prirary prote:tien device fails. Others do so without postulating prirary device failure.
Tw of the sa@le penetrations even have reiting teTeratures less than the peak LO~A te perature and thus ex:eed the limits of this redel even if there is ne f ault cdcrent.
(References 1 through 11)
This does not ne:essirily rean that the netrations would actually fail.
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The analysis was ccnsenative, particularly in assuming that the penetration was initially r. the peat calculated contain:ent te.perature.
Tne percatratitrts would not reach such a tegerature fcllcwing an a::ident.
In addition, licensee corrents have indicated that there rey be so.e errors in the cal:ulati:ns.
(For exa ple, Northeast utilities letter date: August 29,1950, Do:L et Nc. 50-245, pr:viding coments en the staff calculations fcr P,illstent. Unit 1). Nevertheless, this audit clearly did not put the ratter to rest.
F:f,i ti on Each SEP licensee is requested to evaluate the edequacy of the existing fault current prote: tion for contain.ent electrical penetrations in accordan:e with the position discussed in ecre cetail belem and to propese recedies where needed in order to reet the position.
1.
The basic requiremer.: cf Regulat:ry Guice 1.63 that all penetration cir:uits, Class IE or non-Class IE, be provided with ever:urrent prote: tion in confonence with the redundancy an: " = stability requirements of IEEE Std 279-1971 should be met; 2.
A single circuit breaker to protect a penetration ser"ing a Clas: IE circuit or i
P a non safety circuit contair.ing only ccmponents that are qualified to Class IE requirements is acceptable provided that each component of such circuit is qualifted tc the accident environment; 3.
A circuit whose loads inside containment are not !equired to mitigate the consequences of accidents may be automatically disconnected from its power source on receipt of an accident signal or it may be maintained dcenergized by positive means such as those outliend in Branch Technical Position ICSB 18 (PSB) of Appendix 8A to the Standard Review Plan whenever cuntainment integrity is required.
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Notes Tor the purpose of evaluating the adequacy of prcie: tion for contain.ent prete: tion, faults should be postulated up to a bolted cable fault insice containrent at the penetrttien (a belted three phase fault for three pha:e circuits). The prirary protection device should have a trip tire vs. current response characteristic that assures against penetration failure under all fault conditions.
Circuit breakers should be tested periodically to verify tb.Eir trip setting value and response time.
Ereaiers should be desig:ed to interrupt the raxin.r possible f ault current for the circuit or backup prete: tion fast response current limiting fuses should be provided.
s.
Ir. ad:ition, fuses ray b! used in lieu cf cir: it brede % as prote:tive desices.
Where fuses are use: d::urentati.cn ef their response charatteristics derived f r:: prodsction testin; should be available for au:::.
It is a::e; table to use less c:nservative rodels than were used in our preliminary evaluati ts provi:ed that they at:ress f ault currents up to belle: f aults and stil; pro,ide reasonable assuran:e it,a; tr.e penetration f er exa 7 e. a rcre realistic init91 teTerature cf the 1
will net fail.
c:ntainren* penetrati:n c:ald be deter:ined rather than assuming the penetration has rea:hed the peak cal:ulate: con
- a nren* a* esphere teG-e rat u rt.
Cir:uits may be e:dified t: reduce tne sh:rt cir:uit current to a::eptable values by the use of current limiting cevices (such as resisters, isolation transformers, and changing transformer taps) external to the containment.
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