ML19199A496
| ML19199A496 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/17/1976 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7905030014 | |
| Download: ML19199A496 (3) | |
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CT.C 17 '50 Docket fo. 50-320 MDORANDU'4 FOR:
D. Vassallo, Assistant Director for Light Fater Reactors.
Division of Project Managecent FRCH:
R. L. Tedesco, Assistant Director for Plant Systems, Division of Systcas Safety
SUBJECT:
STATUI CF THE OPEN ITEMS IN THE DPAFT SAFETY EVALUATIn.'
REPORT FOR ThREE '4ILE ISLMiD h"JCLEAR STATIC:1, UNIT 2 Plant Name: Three Mile Island nuclear Stacion Cocket Nur ber:
50-320 Milestone Number: 24-04 Licensing Stage: OL hSSS Supplier: Babcock & Wilcox Architect Engineer: Curns & Roe Containment Type: Dry Resconsible Branch & Project Manager: thR-2; H. Silver Recuested Cenpletion Date: November 22, 1976 Review Status:
Incomplete Enclosed is the status of the open ite:s in the draft Safety Evaluation Report for the Three fille Island, Unit No. 2.
This report has been prepared by tne Containment System Branch after having reviewed additional infor-mation provided by the applicant in Amendment 4A of the FSAR.
The status of the fcur outstinding items identified in our draft SEP is sumarized in the following paragraphs:
1.
P.eactor Cavity Analysis At the tir.e our draft SER was written, the applicant indicated his intention of using shield plugs to minimize the neutron strea'ning from the reactor cavity. Because of the uncertainties in the olug dynamics analysis, the staff requested additional infer-ation frc-the applicant.
In response to our concerns, the aonlicant decided to renove the shield plugs and provide a neutron shield platfom Centact:
F. Eltawila, CSE
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GEO 1i G75 D. Vassallo aoout 6-l/2 feet above the reactor vessel seal flange that wculd be pemanently fixed and restrained from movement. Due to anticinated construction difficulties, the applicant has ncw decided to replace the neutron shield platform with hinged tanks filled with water that would swing out of the way to provide the vent area necessary to relieve the pressure build-up in the reactor cavity following a pipe break. 'Je have not completed our evaluation of the applicant's analysis of the behavior of these water filled tanks under postulated accident conditions, and we will report on the resolution of this matter in a suoplement to the Safety Evaluation Report.
2.
Main Steam Line Break Accident Aralysis In the draft SER, we reported that the applicant had not analyzed the containment response for a spectrum of pcstulated main steam line breaks at different power levels, and that we would require further infomation to complete our review. We have received additional information regarding the main steam line break accident analysis in Amendment 44 to the FSAR which we are reviewing. We are calculating 0
a contairnent temperature that is 75 F higher than the temperature calculated by the apolicant, andpplan to meet with the applicant to resolve this discrepancy and discuss the adequacy of the environnental equipment qualification program. We will recort on the resolution of this matter in a supplement to the Safety Evaluation Report.
3.
Centainment Purgine Durinc ?!omal plant Goeration The applicant has indicated his intentien of limiting containment purging during normal plant operation to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per year (about 1 percent of the tine). We find this approach acceptable. However, the FSAR dces not reflect the applicant's intentions. The acolicant should include the above limitation on the use of the containment purge systen in the FSAR, and propose an approcriate Technical Specification. We will report on the resolution of this matter in a supplecent-to the SER.
4.
Containment Heat R eeval Systens In the draft SER. we reported that the 'iSSS vendor reanalyzed the containment spray system perfomance. The analysis indicated that the sodium hydroxide tank (SHT), sodium thiosulfate tank (STT), and borated water storage tank (CWST) would not draw dcwn tocether as previously credicted. This would result in the enetying of the SFT and STT up to twenty-two minutes before reaching the OST level setpoint.
'de have recuested the applicant to evaluate the effect of uneven drawdown on syste: cerfomance, including the Dotential for m
scrav aua o cavitation.
'dc will recort on the rasolutien of this matter in a s n:olement to the SER.
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Contain ent Su-m Our draft SER does not identify any unresolved concerns with the contairment sump. However, in recent discussions with the applicant regarding the codel testing that is being done on the Three "ile Island, Unit 2 suno design, we noted that the recirculation piping intakes are not physically separated by screening as required by Ragulatory Guide 1.82.
We have discussed this matter with the applicant. The apolicant has indicated that they will include in their study the effects of such screening on vortex femation and will provide us with further infornation.
Since none of the previously identified outstanding itens has been resolved to our satisfaction, no changes to our draf t SER are necessary at this time.
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