ML20011B070
| ML20011B070 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/19/1981 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Atomic Safety and Licensing Board Panel |
| Shared Package | |
| ML19270A275 | List: |
| References | |
| RTR-NUREG-CR-2083, TASK-AS, TASK-BN-81-30 BN--81-30, BN-81-30, NUDOCS 8111040145 | |
| Download: ML20011B070 (3) | |
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NUCLEAR REGULATORY COMMISSION d\\3 E
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Docket No. '50-312 L PDR EHughes MJollensten-52 OCT2 61981-,2 TERA DSnyder g-NSIC ECase M'?oga'74^* ~
ORB #4 Rdg TNovak MEMORANDUM FOR: Atomic Safety and Licensing Board for Rancho S 6 y
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FROM:
Thomas M. Novak, Assistant Director for Operating Re o
Civision of Licensing
SUBJECT:
BOARD NOTIFICATION - RANCHO SEC0 HEARING (BN-81 30)
This notification concerns the integrity of reactor pressure vessels when subjected to thermal shock and subsequent repressurization during an overcooling transient.
Enclosed is a copy of the October 9,1981 memorandum from William J. Dircks (ED0)'to the Commissioners concerning the " Status Report on Pressurized Thermal Shock." This memorandum enclosed an interim report by the r
Oak Ridge _ National Laboratory (ORNL) on a NRC research program on pressurized thermal shock which presets a preliminary assessment of the threat of pressure vessel failure.
The ORNL results of preliminary analyses predicted failure of the Oconee 1 pressure vessel for the Rancho Seco typo. transient of 1978, f
turbine trip with stuck-open bypass valve, and ".iain steam line break.
The calculated threshold times for failure were 20, 3, and 4 EFPYs respectively.
The owner of the plant, Duke Power Company, was asked to review the analysis for accuracy and a joint NRR/RES team is reviewing the report. The team Plans to complete its assessment with a draft report regarding the validity of the ORNL report within the next two weeks. We will notify the Board of the results of this review.
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f Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing
Enclosure:
As Stated cc w/ enclosure: See next page O hohddhjh PDR
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Ae Sacra nto Municipal Utility Rancho Seco, Docket flo. 50-312 District ccw/ enclosure (s)i David S. Kaplan, Secretary and Christopher Ellison, Esq.
General Counsel Dian Grueuich, Esq.
California Energy C mission 6201 S Street P. O. Box 15830 1111 Howe Avenue Sacramento, California 95813 Sacramento, Califor'nia 95825 Sacramento County Ms. Eleanor Schwartz Board of Supervisors California State Office -
827 7t'h Street, Room 424 600 Pennsylvanir Avenue, S.E., Rm. 201 Sacramento, California 95814 Washington, D. C.
20003
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Business and Municipal Department Docketing and Service Section Sacramento City-County Library Office of the Secretary 828 I Street '
U.S. ' Nuclear Regulatory Commission Sacramento, California 95814 Washington, D. C.
P0555 Resident. Inspector / Rancho Seco c/o U. S. N. R. C.
14410 Twin Cities Road Herald, CA 05538 Dr Richard E. Cole
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Atomic Safety & Licensing Board Panel U.S. Nuclear Regulatory Co=ission Washington, D. C.
20555
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Regional Radiation Representative EFA Recion IX Mr. Frederick 4. Shon 215 Fremont Street Atomic Safety and Licensing Board San Francisco, California 94111 Panel U.S. Nuclear Regulatory Cc =issien Mr. Robert B. Borsum Washington, D. C.
20555 Babcock & Wilcox Nuclear Power Generation Division Elizabeth S. Scwers, Esq Suite 420, 7735 Old Georgetown Road Chairman, Atcmic Safety and Bethesda, Maryland 20014 Licensing Board Panel U.S. Nuclear Regulatory Cor.ission The.as Eaxter, Esq.
Washington, D. C.
20555 Shaw, Pittman, Potts & Trowbridge 1800 M Street, N.W.
Mr. Michael R. Eaton Washington, D. C.
20036 Energy Issues Coordinator Sierra Club Legislative Office Herbert H. Brown, Esq.
1107 9th Street, Room 1020 Lawrence Coe Lanpher, Esq.
Sacramento, California 95814
. Hill, Christopher and Phillips, P.C.
1900 M Street, N.W.
Atomic Safety and Licensing Board Washington, D. C.
20036 Panel U.S. Nuclear Regulatory Core.ission Helen Hubbard Washington, D. C.
20555 P. O. Box 63 O
Sunol, California 94586 e
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Sacramento Municipal Utility District Atomic Safety and Licensing Appeal Board Panel' U.S. Nuclear Regulatory Commission Washington, D. C.
2:5 55 Alan S. Rosenthal, Chairman Atomic Safety and Licensing Appeal Board U. S. fluclear Regulatory Commission Washington, D. C.
20555 Dr. John H. Buck Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Conmission Washington, D. C.
20555 Christine ti. Kohl Atomic Safety and Licensing Appeal Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 California Department of Health ATTN: Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814 s
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MEMORANDUM FOR: Chaiman Palladinoi.
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.s Commissioner Gilinsky Commissioner Bradfoni
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FROM:
William J. Dircks Executive Director far Operations.
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SUBJECT:
STATUS REPORT ON PREMURIZED THERMAL SHOCK In informatio'n ' paper SECY-81-286 on pressurned themal shock'of pressure vessels and in the subsequent briefing of the Comission on June 11, 1981, the Comission.was infomed that Oak Ridge National Laboratory was pre-paring a status report on pressurized themal shock. An interim report focusing on Oconee-1 has now been completed; a preprint copy is enclosed.
. As noted in the enclosed report, the purposes of this ORNL work are to identify what is presently known about this pmblem including major areas of uncertainty and sensitivity, to identify further infomation needs, and to propose and evaluate possible mitigative measures. This interim report organizes what is presently known and presents a preliminary assessment, based on present analysis, of the threat of pressure vessel failure. Although the nominal calculations indicate a proximate threat, the report points out a number.of flaws in the current thermal-hydraulic analysis which reflect a lack of realism. The owner of the plant, Duke
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Power Co., was asked to review the analyses for accuracy; the Duke representatives also challenged the validity of currently available analyses.
In' order to evaluate the conclusions of the report and to assess their significance, a joint NRR/RES team has been set up to review the report as soon as it arrives in NRC.
In particular, the~ staff will evaluate the pmbability of occurrence of the severe overcooling transients assumed and l
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team.will be led by the NRR task mahageri.Roy Woods,' and'it plans to com-i.
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plete its assessment with a draft re' port. in 2 weeks... A.;?>.. 2 7.
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