ML20077E501
| ML20077E501 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/31/1991 |
| From: | Cottle W ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-91-00094, GNRO-91-94, NUDOCS 9106100404 | |
| Download: ML20077E501 (5) | |
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$- F Entergy Operations W. T. Cottle May 31, 1991 U.S.
Nut 1 ear Regulat on y Cocuniss lon Mail Stat ion I'l-13 7 Washingt on, D.C.
20555 Attentlon:
!)oc umen t Control Desk Sul j ec t :
Gratal Gulf Nuclear Stat lun Unit 1 Docket No. 50-416 License No. NPI-29 Quarterly Status Report - March 1991 " Degraded Cote Accident flydrogen Cont rol Program" GNRO-41/00004 Gentlemen:
The Grand Gulf Nuclear Station (GGNS), l'n i t I l'ac ili t y Ope rat ing 1.l cense (License No. NPF-29) requires that Entetgy operations, Inc. submit to the NRC quarterly report s on the st at us of the " Degraded Core Accident llydrogen Control Program."
In response to that requirement, Entergy Operatlons, Inc. is submit t lug t he at t actu."1 report covering t he period from January 1, 1941 t hrough March 31, 1991.
Should you have any quest ions c nce rning t his report, please contact W.
K. Ilughey at (601) 437-655'.
Yours truly, mph WTC / Whil/ mt e attachment:
Quarterly St at us Repert for quar t er Ending Mat ch '31 1991 cc:
(See Next Page)
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May 31, 1991 GNRO-91/00094 Page 2 of 3 1
cc:
Mr. D. C. liintz (w/a)
Mr. J. Mathis (w/a)
Mr. R. B. McGehen (w/a)
Mr. N. S. Reynoltis (w/a)
M r. 11. L. Thomas (w/n)
Mr. F. W. Titus (w/a)
Mr. Stewart D. Ebneter (w/a)
Regional Adninistrator U.S. Nuclear Regulatory Commission i
Region II 101 Marietta St... N.W., Suite 2900 t
At lant a..'leorg ia 30323 j
Mr. I.. I..
Kintner, Project Manager (w/a)
Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 11D21 Washington, D.C.
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Attachment to GNRO-91/00094 Quarterly Status Report for Quarter Ending March 31, 1991
" Degraded Core Accident Hydrogen Control Program" Grand Gulf Nuclear Station Docket No. 50-416 Entergy Operations, Inc.
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Attachment to GNRO-91/00094 Quarterly _ Status Report - March 31u1991
'.' Degraded Core _ Accident Hydrogen Control Program" 1.0 Introduction This quarterly status report is submitted to comply with a requirement in the Grand Gulf Nuclear Station (GGNS), Unit 1 Facility Operating License (License No. NPF-29).
This requirement specifies that Entergy Operations, Inc should provide quarterly reports outlining the status of the ongoing research program to address degraded core hydrogen control requirements. This report covers tre first calendar quarter of 1991 ending March 31, 1991.
This report includes brief summaries of any submittals made by Entergy Operations, Inc, during this quarter along with summaries of any meetings between the NRC Staff and Entergy Operations, Inc.
Entergy Operations, Inc. is participating in the Hydrogen Control Owners Group (HCCG) which is conducting generic research and comoleting generic analyses to resolve the degraded core hydrogen control issue.
Since the work completed by HCOG complements Entergy Operations, Inc.'s program to resolve this issue, this report also includes summaries of meetings between the HCOG and the NRC.
The summaries of these meetings included in this report do not reflect a formal HCOG position with respect to any issue and represent only the Entergy Operations, Inc. interpretation of the meetings.
2.0 Summary of Entergy A erations, Inc. Submittals Entergy Operations, Inc. submitted a letter to the NRC dated February 28, 1991 stating that it was Grand Gulf's in' tent to submit its Hydrogen Control Final Analysis within six months after submittal of the HCOG Accepted Topical Report.
3.0 Summary _of HCOG and NRC Meetings On March 21, 1991, a conference call was held between HCOG and the NRC.
The purpose of the call was to determine an acceptable closure path for the SER issues of pressure survivability and spray / unit cooler availability and acceptance of TBU sequences as a hydrogen generation event.
4.0 Hyd_rogen_C_o_ntrol Program St.atus The summaries and status of the Hydrogen Control Program as stated herein do not ceflect the HCOG position with respect to any program and represent only an Entergy Operations. Inc. interpretation of these programs.
The generic research and generic analyses conducted by HCOG to resolve the degraded core hydrogen control issue are complete.
In accordance with this, the NRC issued a Safety Eval'ation Report (SER) on the generic Hydrogen Control Program on August 10 1990.
The SER documented the NRC's review of the generic Hydroge-Control Program and delineated which l
issues were considered closed by ne NRC and which required additional action by the HCOG and/or the individual utilities.
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At t achnient to GNRO-91/00094 4
4.1 Status of Significan.t__ Issues During the HC0G/NRC conference call on March 21, 1991 the following actions were agreed to for the remaining open issues, a.
The SER identified that the TBU sequence described in NUREG-1150 and NUREG-4550 was an appropriate hydrogen generation event (HGE) for use in the HCOG program. While the Tau sequence is similar to the HCOG HGE, several aspects of the TBU sequence need clarification prior to its incorporation, in whole or part, into the generic Hydrogen Control Program.
It is HCOG's opinion that only TBU sequences that have recovery of power and the core should be considered an acceptable HGE.
It is also HCOG's opinion that the NRC should acknowledge this clarification in a supplement to the Hydrogen Control SER.
b.
The SER indicated that credit for containment sprays / coolers cannot be considered in plant unique survivability analyses.
This is considered inconsistent with the HCOG program and past HCOG-NRC discussions.
HC0G has tentatively agreed to address the no spray cases in finalizing the equipment survivability analysis.
It was agreed by both HCOG and the NRC that unit coolers would be available during a HGE, HC0G does however intend to issue a letter to the NRC dealing with spray / cooler availability.
c.
The pressure survivability value identified in tre SER was considered inconsistent with the value that HCOG assigned as the appropriate containment criterion for survivability.
HCOG considers the use of 23 psig to be an acceptable criterion for the evaluation of containment equipment.
HCOG intends to submit a letter to the NRC stating why 23 psig is an appropriate evaluation criterion.
4.2 Planned Activities for the Second_ Quarter of 1991 As noted above, HCOG plans to develop and issue to the NRC letters dealing with spray / cooler availability, pressure survivability criteria and acceptance of TBU sequences as a HGE.
Following acceptable resolution of these issues with the NRC, Entergy Operations will review its schedule for submittal of the GGNS Final Hydrogen Contrc1 Report, identify the remaining work necessary for this submittal anc initiate work on the remaining plant specific tasks.
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