ML18066A750
| ML18066A750 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/13/1996 |
| From: | Robert Schaaf NRC (Affiliation Not Assigned) |
| To: | Bordine T CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| TAC-M96355, NUDOCS 9612170298 | |
| Download: ML18066A750 (5) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, *D.C. 20555-0001 Mr. Thomas C. Bordine Manager, licensing Palisades Plant 27780 Blue Star Memorial Highway Covert, MI 49043 December 13, 1996
SUBJECT:
PALISADES PLANT -
10 CFR 50.46 LARGE BREAK LOSS OF COOLANT ACCIDENT EVALUATION MODEL (TAC M96355)
Dear Mr. Bordine:
5"o -,;z55 In our letter of October 11, 1996, we informed you about problems that we had identified regarding changes in the Siemens Power Corporation (SPC) large break loss-of-coolant accident (LBLOCA) evaluation model for pressurized water reactors (PWRs).
These problems called into question the model's compliance with 10 CFR 50.46.
The changes were made to the 1986 approved*LBLOCA evaluation model to correct an error in the model's prediction of heat transfer coefficients during core reflood.
The 1986 model predicted non-physical behavior in the heat transfer coefficients within the range of 1 in/sec to 1.77 in/sec. The staff indicated in our October 11, 1996, letter that the revised 1986 model (i.e., the.1991 model) is not an acceptable LBLOCA model.
We also stated in the October 11, 1996, letter that the approved 1986 model had an unacceptable error and we requested, in accordance with 10 CFR 50.46(a)(3)(ii), that you assess the impact of the model error and c~anges, and take whatever actions are required to assure compliance with 10 CFR 50.46 for Palisades.
You were also requested to attend a public meeting on October 16, 1996, at the Nuclear Regulatory Conunission headquarters to present the results of the assessment of the peak cladding temperature (PCT) for the LBLOCA and the corrective actions and compensatory measures that have been undertaken, both short~term and long-term, to demonstrate compliance with 10 CFR 50.46.
An acceptable short-term measure would be to use a demonstrably conservative reflood heat transfer coefficient model; an acceptable long-term measure must be to eliminate the non-physical behavior from the model.
In both cases, the model must comply with Appendix K to 10 CFR Part 50.
The summary of the October 16, 1996, meeting was issued on November 5, 1996.
You submitted a letter dated October 24, 1996, which documented the assessment that you had presented at the October 16, 1996, meeting of the PCT for the t
~----* __ LB.LO.CA_and..the.tO.r'r'e.ctlv.e... actJons __ that_hav.e-been-under-taken,-both-short=term--- -- --/---1---
and long-term, for Palisades.
In that letter, you stated that the reflood.
rate is outside the range of concern during the time pedod when PCT is
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1*,c:;/ /
approached, the PCT.Predicted by the 1986 model is 1890°F, and future VU-v reanalysis using a model corrected for the deficiencies is not expected to result in a predicted PCT above the 50.46 limit of 2200°F.
You further stated 9612170298 6;6~6~55
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-Mr. Thomas t-., Bordi rie - December 13, 1996 that you would work with SPC to ensure that the Palisades LBLOCA analysis would meet the requirements of 10 CFR 50.46.
Because the reflood rate is above 1.77 in/sec during the approach to PCT, you concluded that the non-physical behavior in the 1986 model did not affect the LBLOCA analysis for Palisades.
In your letter, you referred to the conference call held on October 23, 1996, where SPC provided clarification about its discussion of conservatism in the 1986 model in the October 16, 1996, meeting.
In the meeting, the discussion was on the use of a *modified" 1986 model which, for the reflood range of concern, capped the heat transfer coefficients at the coefficient value for 1.77 in/sec to correct the error. Based on the new data shown in the meeting by SPC about the significant conservatism in the modified 1986 model, the staff concluded in that meeting that the licensees involved had taken those actions required by 10 CFR 50.46 to allow continued plant operation.
.We requested, however, that the licensees at the meeting submit all the data that shows the modified 1986 model is conservative over the entire range of reflood rates of concern so that the staff could review the data in determining an acceptable correction to the error.in the 1986 model.
In the conference ca 11 on October 23, 1996, we were informed by SPC that the 1986 model was not as conservative with respect to the measured heat transfer coefficients as was presented in the October 16th meeting.
Based on this new information, the staff has concluded that "capping" the reflood heat.transfer coefficient in the range of concern at the value at a 1.77 in/sec reflood rate has not been demonstrated to be conservative. The staff has informed SPC that the non-physical error in the 1986 model must be corrected using a method that is demonstrably conservative.
SPC has informed the staff of its intention to submit this correction before the end of December 1996.
By letter dated November 22, 1996, you provided clarification to the staff regarding the reanalysis performed to verify continued compliance with 10 CFR 50.46.
You noted that the'l986 code is no longer available as originally run.
Your letter stated that, in lieu of performing a reanalysis using the modified 1986 model, the reanalysis was performed using a corrected heat transfer correlation incorporated in the 1991 model. *You stated that with this clarification the conclusions of your October 24, 1996, Jetter remain valid.
Although the staff has accepted your justification for continued operation of Palisades with use of the corrected 1991 model (i.e., the reflood rate for the plant is outside the reflood range of concern up to the time of PCT), the staff has determined that it is necessary to review in more detail how the reflood heat transfer coeffident correlation is applied using the SPC
methodology-for-the--l:BlO~A-;-Accordingly-, the-staff-requests0-that--you-submit-------------
the information described in the enclosed request for additional information
Mr. Thomas C: Bordtne Consumers Power Company cc:
Mr. Thomas J. Palmisano Plant General Manager Palisades Plant 27780 Blue Star Memorial Highway Covert, Michigan 49043 Mr. Robert A. Fenech Vice President, Nuclear.Operations Palisades Plant 27780 Blue Star Memorial Highway Covert, Michigan 49043 M. I. Miller, Esquire Sidley & Austin
. 54th Floor One First National Plaza Chicago, Illinois 60603 Mr. Thomas A. McNish Vice President & Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administr~t6r, Region III U.S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, Illinois 60532-4351 Jerry Sarno Township Supervisor Covert Township 36197 *M-140 Highway Covert, Michigan 49043 Office of the Governor
-.. ---*---Room--1--""--Capito L.Bu.iJding ____ ------*-
Lansing, Michigan 48913 U.S. Nuclear Regulatory Commission Resident Inspector's Office Palisades Plant 27782 Blue Star Memorial Highway Covert, Michigan 49043
- Palisades-Plant Drinking Water and Radiological Protection Division Michigan Department of Environmental Quality 3423 N. Martin Luther King Jr Blvd P. 0. Box 30630 CPH Mailroom Lansing, Michigan 48909-8130 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N. W.
Washington DC 20037 Michigan Department of Attorney General Special Litigation Division 630 Law Building P.O. Box 30212
.Lansing, Michigan 48909
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August 1996
UNITED STATES
- -.. NUCL~R REPU.~T()RY COMMISSION WASHINGTON, D.C.-~1 REQUEST FOR ADDITIONAL INFORMATION 10 CFR 50.46 LARGE BREAK LOSS OF COOLANT EVALUATION MOPEL CONSUMERS POWER COMPANY PALISADES PLANT DOCKET NO. 50-255 It is requested that the licensee provide the following information for the Large Break Loss-of-Coolant Accident analysis:
- 1.
Maximum linear heat generation rate
- 2.
Reflood rate as a function of time
- 3.
Core collapsed level as a function of time
- 4.
Quench time as a function of core height
- 5.
Core pressure as a function of time
- 6.
Core subcooling a~ a function of time
- 7.
Heat transfer coefficient for PCT location as a functi~n of time
- 8.
Clad temperature for PCT location as a function of time
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ENCLOSURE
-1 December 13, 1996 within.120 day~ of the date of this letter. This information will permit the staff to determine if the application of the corrected 1991 model for Palisades is consistent with the database on which the reflood heat transfer coefficient correlation is based.
If you have any question regarding the enclosed request for information, please.contact me at (301) 415-1312.
Docket No. 50-255.
Sincerely, Original signed by Robert G. Schaaf, Project Manager Project Dtrectorate 111-1 Division of Reactor Proj~cts - Ill/IV Offi~e of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc w/encl:
See next page DISTRIBUTION Docket File
.PUBLIC PD 3-1 Rdg J. Roe E. Adens am ( EGAl) *.
OGC*
ACRS L.-Miller, Riii DOCUMENT NAME:
G:\\WPDOCS\\PALISADE\\PAL96355.LTR To receive a copy of this document, Indicate In the box: "C" = Copy without attachment/enclosure OFFICE PM:PD31 LA: PD31 NAME RSchaaf :mc CJamerson DATE
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