ML20092B867
| ML20092B867 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 06/03/1984 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | NORTHERN STATES POWER CO. |
| Shared Package | |
| ML20090B446 | List: |
| References | |
| NUDOCS 8406200400 | |
| Download: ML20092B867 (7) | |
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7590-01 UNITED STATES OF A!! ERICA NUCLEAR REGULATORY COMt!ISSION In the Matter of
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Docket No. 50-263 NORTHERN STATES POWER C0f'PANY (Monticello Nuclear Generating Plant)
EXEMPTION I.
The Northern States fower Conpany (NSP/the licensee) is the hcider of Facility Operating License No. DPR-22 (the license) which authorizes operation of the l'onticello Nuclear Generating Plant, located in Wright County, Mir,nesota, at steady state reactor core power level not in excess of 1670 megawatts thermal. The license provides, among other things, that it is subject to all rules, regulations and Orders of the Conmission now or hereafter in effect.
II.
Section 50.54(o) of 10 CFR-Part 50 requires that primary reactor containments for water-cooled power reactors be. subject to the requirements of Appendix J of 10 CFR Part 50, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors," published on February 14, 1973. Appendix J contains the leakage test-requirements, schedules, and acceptance criteria.for tests of._the leak-tight integrity of the primary reactor containment'and systems and components which penetrate the containment; and on August 1975,-
each licensee was requested to review thetextent to which its' facility rret these requirements.
8406200400 840603 PM ADOCK - 05000263 P
pg
. On September 19, 1975, flSP submitted its evaluation of the Monticello fluclear Generating Plant, and assessed its compliance with the rule.
Sub-sequently, the licensee submitted a combination of proposed Technical Speci-fication changes, exemption requests, and proposed design modifications as fiSP's overall plan for achieving ccmpliance with the requirements of Appendix J.
The licensee requested certain exemptions frcm the requirements of Appendix J in a letter dated flay 5,1976. On October 28, 197,6 a meeting was held with the licensee to discuss certain aspect's of the exemption request. At this meeting, the licensee provided additional information to support various positions. The minutes of this meeting along with the submitted information and interchanged agreements were documented in a suirmary dated flovember 12, 1976.
In the May 5, 1976 and in the fiovember 12, 1976 documents, f4SP requested exemption from Type 8 testing of certain instrument lines, Type C testing of certain valves, and from Type 8 testing of pressure and frequency of the drywell air locks, as required by Appendix J.
The Franklin Research Center, as a consultant to NRC, has reviewed all of the licensee's submittals and prepared a Technical Evaluatico Report (TER) of its findings.
The fiRC staff has reviewed the TER and has noted its findings in the Safety Evaluaticn dated April 1984 The staff has concurred in the TER's bases and findings concerning the conclusions on the exemption reouest.
The conclusion on proposed modifications to the piping and changes to the Technical Specifications are also noted in the Safety Evaluation along with the exception taken by the staff to one position assumed by our con-sultant.
. III.
We have found acceptable the following requests for exemption.
1.
Section III.C.1 of Appendix J requires, in part, Type C testir.o of con-tai.nment isolation valves which are required to operate intermittently under post-accident conditions. The licensee has requested an exemption from Type C testing requirements for the following valves:
a) M0-2006, 2007 Torus Spray Linb b) M0-2008, 2009 Torus Recirculation Li.ne c) M0-2020, 2021 Drywell Spray Line.
He have reviewed the licensee's submittals and drawings and have determined that:
a)
Valves, M0-2006 and 2007, in the torus spray line may be exenpt from Type C testing because they are sealed by water frca the residual heat removal (RHR) pumps under post-accident ccnditions; b)
Valves, M0-2008 and 2009, in the torus recirculation line may be exempt from Type C testing because they are sealed by water from the suppression pool, provided the packing of these valves is not exposed to leakage coming from the torus spray line (fl0 2010 and 2011); and c)
Valves, M0-2020 and 2021, in the drywell spray line may be exempt from Type C testing because they are sealed by water frcm the RHR-pumps under post-accident conditions.
2.
Section III.C.2 of Appendix J requires, in part, that Type C testing be performed at the peak calculated accident pressure (Pa), which for Monticello is 41 psig. NSP requested an exemption from this requirement
4 for the Main Steam Isolation Valves (fiSIVs) to continue testing at 25 psig in accordance with current Technical Specifications rather than at (Pa) as required by Appendix J.
The MSIVs are leak tested by pressurizing between the valves.
The MSIVs are angled in the main steam lines in the direction of flow'to. afford better sealing upon closure. On this basis, we conclude that testing at a reduced. pressure of 25 psig is acceptable. A test pressure of Pa acting under the t' board disc is sufficient to lift the n
disc off its seat, and result in excessive leakage into the reactor vessel. This would result in a meaningless test.
The proposed test' calls for a test pressure _of 25' psig to avoid lifting the disc at the inboard valve. The total observed leakage through both valves (inboard and outbcard) is then conservatively assicned to the penetration.
3.
NSP requested an exemption from the frequency of Type B testing of the air lock. Specifically, they requested an exemption to do'a three-day test of the air lock when it is in use rather than after each use. The revised rule. required testing-of the air locks as follows:
a.
Every-six months atia pressure of-not -less than Pa-(and after periods lwhen the air lock is. opened and containment integrity.is not - requi red).
b '.
Within three days of opening (or every three days during periods of frequent opening) when contair. ment integrity is reouired,'at:
a pressure.of..Pa or at a reduced pressure 'as ' stated in the
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-Technical Specifications.
M i
..A
. Our consultant, the Franklin Research Center (FRC), has reviewed the licensee's proposal. Whenever the air lock was opened during the operating cycle, and containment integrity was ree.uired, the air lock gasket would be tested following closure if it had been greater than three days since the last leakage test.
FRC concluded that the licensee's proposal to test air lock gaskets within three days of an air lock opening is acceptable.
We agree with the FRC's-conclusion that the air lock gasket leakage be tested within three' days frcm an air lcck opening. We further agree with the FRC's conclusion that the. air lock testing frequency should make adequate allowances to detect potential-deterioration of air locks through normal'use. However, when the air.
1cck remains closed, that is, there is no opening or closing of the doors to.cause degradation'of seals or damage /to. door mechanisms, we find that the reduced pressure testing frequency proposed by the licensee would be. adequate-to assure that the air lock door: seal
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integrity is maintained.
The staff. has reevaluated thei six-month test.. requirement and has -
developed a revised position which meets the' objectives ~~of. Appendix _J
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- requireme'ntsTfor' containment < air lock door tests..This rev.ised position E
still-requires the containment air lock' to be tested at 'six-month intervals at a pressurejof Palin ac~cordance 'with Appendix ',~ exceptJ that.this test. intervallmay be extended'up to the next refueling. outage' 5(up to 'a maximum interval between Pa ' tests of;24 months) if'there have; 1been no air lock openings sinceithe last succes'sfulltest'at Pa. Thkl s
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intent of the Appendix J requirement is to assure that the air lock door seal integrity is maintained and that no degradation has occurred as a result of' opening of the air lock doors between testing intervals at Pa.
This' position satisfies the objectives of the requirement.
The licensee will be required to propose appropriate modificaticns to the Technical Specifications.
19.
Accordingly, the Corraission has determined that,. pursuant to 10 CFR 50.12, an exemption is authorized by law and will not endanger life or. property or the.
- ccmmon defense and security and is otherwise in the public interest. Therefore, the. Commission hereby approves,the following exemption requests:
1..
Exemption -is granted from the requirements of.III.C.1 of. Appendix.J pertaining to the Type.C testing of.the torus spray line.(M0-2006, 2007)'
valves; and the drywell : spray line (M0-2020 'and _2021) valves.. Similarly,
'~ exemption is granted from the requirements of III.C.1~of. Appendix J-.
pertaining to the Type C testing of~the torus recirculation line.'(M0-2008-and 20009)ivalves provided the packing of these valves is not expo' sed toi leakage coming from the torus spray 1ine (M0-2010~ and'2011).
-;2 Exemption.is granted.from the requirements ofiSedtion(III.C.2~ of _ Appendix
-J: pertaining.tc the ; Type C testing of-the: Main' Steam Isolation Valves ~, at
- a _tes't pressure of.Paf(peak. calculated-accid.ent pressure). LTesting at--
a reduced pressure of 25'psig is' acceptable'because of the.~ unique _' design. -
(cf thelvalv'es.
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.a 3.
Exemption is granted to test air lock gaskets within 3 days of an air lock opening.
The NRC staff has determined that the granting of these cyemptions will not result in any significant environmental inpact anc that pursuant to 10 CFR E0.5(d)(4), an environmental impact statement or negative declaration and environmental impact appraisal reed not be prepared in ccnnection with this action.
FOR'THE NUCLEAR REGULATORY CCFMISSION
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~ 'Dar'rell' 'G. Eise'nhu't', Di recter Divisicn of Licensing Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this 3rd day of June,1984.