ML19220B498
| ML19220B498 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/23/1976 |
| From: | Silver H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904260395 | |
| Download: ML19220B498 (5) | |
Text
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UNITED STATES 4
NUCLEAR REGULATORY CCMMISSION
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Q(flj WASHtNGTON, O. C. XX45 h,
April 23, 1976 DOCXET NO:
'g APPLICANT:
Met Ed F ACILITf :
P.ree Mile Island, Unit 2 SLMtARY OF MEETING CN CPEN ITE!!S Representatives of the applicant andhis contractors met with members of the staff on April 1 and 2,1976 te discuss open items in the staff review.
Items discussed are summari:ed below.
During the meeting, two advance copies of Amendment 39 were handed to NRC, and referred to as appropriate in the discussion.
April 1, 1976 Containme.t Purging To clarify past discussic.s on this subject, NRC reiterated the two basic choices for OL plants such as D'I-2.
The first, essentially probabilistic approach, permits the use of large purge valves without analysis if purging is restricted to less than 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> cer year in operating modes. The second requires addressing the complete posi-tion BTP -CSB 6-4, including all analyses, if purging during operating modes exceeds 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year.
If the second approach is selected, the appli.. ant should include definition of the ne+' for purging, other possible means of accomplishing t!.e same go 1s, and the burden to the applican' in cost and time to implement otner fixes. For
'CtI-2, it was noted that temperature and humidity control during the summer months (Unit 1 purges 48-7? hours per week for 3 months to permit frequent access for plant operation) is the reason for exces-sive purging.
It vas suggested that tne program for evaluation of the heat problem on Unit 1 be presented, along with a description of design and installation improvements in Unit 2.
If future fixes are proposed, their timing should be discussed and interim tech specs suggested.
Information on leak tight'tess.and testability of the purge valves should be included.
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. 2 General information available on the heat load problem on Unit I was presented, and corrective steps described. Presumably, data of. results of these fixes will be available this summer.
The applicant will again consider their position of this item.
Containment Sorav The staff concern regarding assurance of maintenance of containment spray sump NPSH after chemical tank drawdown was discussed, as was assurance of adequate uniform chemical injection. The applicant again discussed his testing procedures and indicated that if initial results were not satisfactory, eductors or other flow adjusting devices would be added and the system retested. The possibility of using hydra:ine in lieu of sodium thiosulphate was also discussed. Performance of the chemical additive system within design criteria must also be assured assuming single active component failure.
Main Steam Line Break (0 242.7)
Discussion centered on the systems available to mitigate the effects of this accident. Questions were raised concerning sources of mass and energy considered in the analysis, which will be addressed further in written communication as appropriate.
In addition to the above items, other NRC concerns and open itens were reviewed. Further identification of those items remaining will be made in the near future as appropriate.
Acril 2, 1976 Steam Line Break 0 21.50)
The applicant seamari:ed the present status of their analysis in response to this question. The presumed worst single failure (from the point of view of effect on the core) is the failure of the turbine stop valves to close. More realistic modeling of system parameters has been utili:ed, and is centinuing in the area of the steam generator. Thus far, short term return to power is indicated.
It was stated that B5W has no informa-tion on the effect of this return to power onthe fuel at the particular conditions of this case, but will verify this with the applicant. NRC noted the desirability fo reviewing all available information on this subject.
Discus: ion continued on systems available to mitigate the effects on this accident; the applicant noted the similarity of this design to Oconee, SMUD, and other older 36W plants. NRC agreed to review our position on this matter.
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e Possible system changes to improve the results of the analysis were discussed briefly, including such things as faster MSIV operation.
tripping feed pu=ps, etc. Codes used in the analysis were also dis cus sed.
The applicant indicated ccepletion of the analysis, including other single failures, is expected in approximately 10 weeks.
LPI Crossconnect The applicant reviewed the status of this item (Item 6 in our letter of March 5,1976), noting they have reviewed all appropriate breaks and incorporated all pertinent data by reference. No credit is taken for LPI, only HPI, and the Final Acceptance Criteria are satisfied oy a considerable margin.
RSB noted that since flow out of the core exceeds flow in, it canno+
be said that abundant cooling is provided.
In addition, the reliability of abundant cooling should be incieased by minimizing manual operaticn of valves or other components.
In response, the applicant noted that adequate cooling exists without the LP pump until the BWST is drained, about 56 minues, providing ample time for manual valve operation. With regard to " abundant" flow, the applicant indicated that they felt that the wording of 10 CFR Part 50.46 status that compliance with that section satisfies GDC 35 (abundant core cooli'tg).
In any event, they stated that since the LPI crossconnect is physically in place, the addition of check valves or cavitating venturis is quite costly and cannot be done before plant startup. NRC will consider this =atter further.
Sumu Testing (Item 9, Marci 5, 1976 letter)
The applicant noted the revisions in Amendment 39 covering model testing.
The staff pointed out that since calculations indicate that at runout flow there may be insufficient NPSH available for the LPI pumps, flow tests to verify calculations will be necessary. Discussion ensued on the feasibility and adequacy of various means of doing this, but no decision was reached. The staff stated that suitable model tests will be considered in satisfying the requirements of Regulatory Guide 1.79; a position covering this will be contunicated shortly.
ATWS The staff noted that a letter covering ATWS requirements is forthccming.
r Moderate Energy Pice Breaks ((tem 1, March 5,1976 letter)
The applicant reviewed the information in Amendment 39.
. Control 3uilding HVAC (Item 2, March 5,1976 letter)
Recalculation with both pu=ps operating indicates a room temperature of 166 F will be reached. 'Ihe applicant noted that the motor rating of 140 F is for 40 year continuous operation, and that the manufacturer (GE) has stated, and will document, that short term operation at 166 F is sacisfactory.
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Harley J lver, Project Manager Light '4fter Reactors Branch 82 Divisica of Project Management
Enclosure:
List of Attendeees c_o
ENCLOSURE LIST OF ATTENDEES NRC APRIL 1,1976 APRIL 2, 1976 H. Silver X
X F. Eltawila X
X J. Shapaker X
C. Anderson X
W. Pasedag X
R. McDermott X
X H. Clayton X
P. Baranowsky X
J. Ma::etis X
J. Watt X
G. Kelley X
F. Odar X
GPU Lou Lanese X
X Ed Wallace X
X Met Ed Joe Moran X
BSW A. Calnick X
R. Borsum X
,