ML19347E395
| ML19347E395 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/20/1981 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| Shared Package | |
| ML19347E396 | List: |
| References | |
| NUDOCS 8104270232 | |
| Download: ML19347E395 (7) | |
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7590-01 O
UNITED STATES OF A'4 ERICA
!;UCLEAR REGULATORY COM.MISSIOFI In the t1atter of
)
Virginia Electric and
)
Power Conaany
)
(Surr,* Do cr Etation, i Dock et !;os.53-280 and 50-201 Unit !;cs.1 and 2'.
)
)
)
- 00. DER FOR f40DIFIC ATIO" 0F LICENSES I
The Virginia Ele::ric and Power Company (tne licensee) holds Facility Operating License Nos. DPR-32 and DPR-37, which autnorizes the licensee to operate the Surry Fower Station Unit ::cs.1 and 2 ac pc eer levels not in excess c' 2 41 megawatts thermal rated power. The licenses were originally issued on itay 25, 1972 and January 29. 1973 and will exoire on June 25, 2008.
The facilities, which a-e located at the licensee's site in Surry County. Virginia.
are pressurized water reactors (FWR) used for the commercial generation of electricity.
II t
The Reactor Safety Study (RSS), WASH-lCO, identified in a PWR an inter-systen loss of coolant accident (LOCA) which is a significant contributo'r to risk of core melt accidents (Event V).
The design examined in the RS5 -
contained in-series check valves isolating the high pressure Primary Coolant l
Systen (PCS) fror tne Low Pressure Injection Systen (LPIS) piping. The scenario which leads to the Event V accident is initiated by the failure of these check valves to function as a' pressure isolction barrier. This causes an ;veraressurization and rupture of the LPIS low pressure piping which results in a LOCA that bypasses containrient.
81 om oaw P00R.0RSiE
7590-01 In order to better define the Event V concern, all light water reactor licensees were requested by letter dat+d February 23, 1980, to provide the following in accordance with 10 CFR 50.54(f):
1.
Describe the valve configuratiens and indicate if an Event 7 isolation valve configuration exists within the Class I boundary of the high pressure piping connecting PCS piping to low pressure system piping; e.g., (1) two check valves in series, or (2) two check valves in series with a motor coerated v31ve ("C<l; 2.
If either of the above Event V configuentions exist, indicate whether continuous surveillance or periodic tests are being performed on such valves to ensure integrity.
Also indicate whether valves have been known, or found, to lack intecrity; and 3.
If either of the above Event V configurations exist, indicate whether plant procedures should be revised or if plant modifications should be made to increase reliability.
In addition to the above, licensees were asked to perform individual check valve leak testing prior to plant startup af ter the next scheduled outage.
By letters dated March 14 and August 13, 1980, the licensee responded to our February letter. Based upon the NRC revies of this response as well as the review of previously docketed information for the facility, I have concluded in consonance with the attached Safety Evaluation (Attachment 1) that one or more valve configuration (s) of concern exist at the facility. The attached Technical Evaluation Report (TER) (Attachment 2) provides, in Section 4.0, a tabulation of the subject valves.
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7590-01 3-The staff's concern has been exacerbated oue not only to the large number of plants which have an Event Y configuration (s) but also because l
of recent unsatisfactory operating experience. Specifically, two plants have leak tested check valves with unsatisfactory results. At Davis-Eesse, a pressure isolation check valve in the LP15 failed and the ensuing investigation found that vulve internals had become disassembled. At the Sequoyah Nuclear Plant, two Residual Heat Removal (RHR) injection check valves and one RHR recirculation check valve failed because valves jammed open against valve over-travel limiters.
't is, therefore, apparent that when pressure isolation is provided b
- > in-series check valves and when failure of one valve in the pair undetected for a substantial length of time, verification of valve ca. _
integrity is required. Since these valves are important to safety, they should be tested periodically to ensure low prcbability of gross failure.
As a result, I have determined that periodic examination of check valves must be undertaken by the licensee as provided in Section III below to verify that each valve is seated properly and functioning as a pressure isolation device. Such testing will reduce the overall risk of an inter-system LOCA. The testing mandated by this Order nay be accomplished by direct volumetric leakage measurement or by other equivalent means capable of demonstrating that leakage limits are not exceeded in accord-ance with Section 2.2 of the attached TER.
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7590-01 In view o'f the cperating experiences described above and the potential consecuences of check valve failure, I have determined that prompt action is r.ecessary to increase t*e level of assurance that nultiple pressure isolation barriers are in place and will ree2in intact. Therefore, the public health, safety and interest require that this. modification of Facility Operating License Nos. OPR-32 and 0?R-37 be irrediately effective.
III A:cordingly, pursuant to Section 161i of the Atc=f c Energy Act cf 1954, as aranded, and the Cc=missi0n's regulatiens in 10 CFR Parts 2 and 50, IT IS HEREBY ORDERED THAT EFFECTIVE IMMEDIATELY, Facility Operating License M s. CPR-32 and 0?R-37 are codified by th'e addition" of the following recuirements:
1.
Inplerent Technical Specifications (Attachment 3) which require periodic surveillance over the life of tne plant and which specify limiting conditions for operation for PCS pressure isolation valves.
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2.
If check valves have not been (a) individually tested within 12 conths preceding the date of the Order, and (b) found to cocply with the leakage rate criteria set forth in th'e Technical Specifications described in Attachment 3, the MOV in each line -
shall be closed within 30 days of the effective date of this Order and quarterly Inservice Inspection (ISI) HOV cycling ceased until the check valve tests have been satisfacterily (Prior to clo'ing the MOV, pro:edures shall accomplished.
s be implemented and operatcrs trained to assure I
7590-01 that the MOV remains closed. Once closed, the MOV shall be tagged closed to further preclude inadvertent valve opening).
3.
The MOV shall not be closed as indicated in paragraph 2 atcve unless a suppcrting safety evaluation has been prepared. If the MOV is in an emergency core cooling system (ECCS), the safety evaluation shall include a deternination as to whether the. requirements of 10 CFR 50.46 and Appendix K to 10 CFR Part 50 will continue to be satisfied with the MOV closed.
If the POV is not in an ECCS, tha safaty evaluaticn shall include a deter-mination as to whether operation with the MOV closed presents an unreviewed safety question as defined in 10 CFR 50.59(a)(2). If the requirements of 10 CFR 50.45 and Appendix K have not been satisfied, or if an unreviewed safety question exists as defined in 10 CFR 50.59, then the facility shall be shut down within 30 days of the date of this Order and remain shutdown until check valves are satisfactorily tested in accordance with the Techni-cal Specifications set forth in Attachment 3.
- 4. 'The records of the check valve tests required by this Order shall be made available for inspection by the NRC's Office of Inspection and Enforcement.
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7590-01 5
IV The licansee or any other person who has an ir.terest affected by this Order may re:
a hea-ing on this Order within 25 days of its publication in tne Feceral Register.
A request for hearing shall be subnitted to the Secretary, U.S. Nuclear Regulatory Commission, Wasnington, D.C. 20555.
A copy of the request shall also be sent to tne Executive legal Directcr at the saae address, and tn Mr. Michael W. Maupin, Meust:n and Willians, Dcs:
Office Box 1539, Richmond, Virginia 23213. attorney for the licensee.
If a hearing is reqJested by a person other than the licensee, that person shall describe, in accordance with 10 CFR 2.71/(a)(2), the canner in which his or her interest is affected by this Order.
ANY REQUEST FOR A HEARl!G SHALL NOT STAY THE IMMEDIATE EFFECTIVENESS OF THIS ORDER.
If a hearing is requested by the licensee or otner person wno has an interest affected by this Order, the Commission will issue an order designating the time and place of any such hearing. If a hearing is held, the issues to be considered at such a hearing shall be:
(a) Whether the licensee should be required to individually leak test check valves in accordance with the Technical Specifications set forth in Attachment 3 to this Order.
(b) Whether tne actions required by Paragraphs 2 and 3 of Section III of this Order must be taken if check valves have not been tested within 12 months prececing the date of this order.
P00RBRDIAL
7590-01 Operaticr. of the f acility en ter:ns consistent with this Order is not stayed by the pendency cf ar.j proceedings or, this Orcer.
In the event that a need for further acticr. becoces apparent, either in tne course of proceedings on this Order or any other time, the Director will take
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appropriate action.
FOR THE iiUCLEAR REGULATORY COMMISSION G.) h. r m m//
JAf I a-
'Darrell G.
isennut, Director Division o Licensing Effective Date:
April 20, 1981 Bethesda, Maryland Attachments:
1.
Safety Evaluation Report 2.
Technical Evaluation Report 3.
Technical Specifications I
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1 SAFETY EVALUATION REPCRT SURP.Y POWER STATION, UNIT N05.1 AND 2 PRIMARY COOLANT StSTEM PRESSURE ISOLATION '. AVES (WASH-1'03, EVENT V) 1.0 Intreducticn The Reactor Safety Stucy (RSS), WASH-1400, identified in a PWR an intersyste:a loss cf ccclant accident (LOCA) which is a significant contributer to risk cf ccre relt accidents (Event V). The design examined in the RSS contained in-series cneck valves isolating tne high pressure Prirary Ccolant System (PCS) f ecn the Low Pressure Injecticn Systes (LPIS) piping. The scenario wnicn leacs to tne Event V accicent is initiated b, the failure cf these check valves to functicn as a pressure isclaticn barrier.
This causes an overpressurization and rupture of tne LPIS ics pressure piping which results in a LOCA that bypasses containment.
In crcer to better define tne Ever.. Y ccncern, all light water reacter licensecs were requested by 10 CFR 50.54(f) letter, dated February 23, 1960, to identify valve configurations of concern and prior valve test results, if any. By letters dated March 14, 1980 and August 13, 1980, the licensee responded to our request and this inferration was subsequently transmitted tc cur centractor, the Franxlin Researen Center, for verification that the licensee had correctl; identified the subject valve ccnfigurations.
2.0 Evaluation In order to prepare the Technical Evaluation Report (TER) it was r.ecessary that the contractor verify and evaluate the licensee's response to cur February 1900 letter. The NRC acceptance criteria used by Franklin were t
based on WASH-1400 findings, probabilistic analyses and apprcpriate Standard Review Plan requirements. With respect to the. verification of the licensee's l
response to cur infccmaticn request, the Franklin evaluaticn was based en FSAR inferration, ISI/IST site visit data, and other previously dccketed infor; ration.
The attached Franklin TER correctly identifies the subject valve ccnfigurciens.
i 3.0 Conclusien Based on our review cf the Franklin TER, we find that the valve configuraticns of concern have been correctly identified. Since pericdic testing of these PCS pressure isclaticn valves will recuce the probability cf an intersystem LOCA we, therefcre, conclude tnat the recuirerent to test these val.es shculd be incer-i pcrated into the plant's Technical S;ecificaticns.
Dated:
April 20, 1981
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