ML17229A158
| ML17229A158 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 12/06/1996 |
| From: | Wiens L NRC (Affiliation Not Assigned) |
| To: | Plunkett T FLORIDA POWER & LIGHT CO. |
| References | |
| TAC-M96355, NUDOCS 9612120246 | |
| Download: ML17229A158 (3) | |
Text
~OR RK00+
O IOl C
/y
++*++
UNITED STATES NUCLEAR REGULATORY COMMISSION INASHIHGTOMy 0 C 2055540M December 6,1996 Mr. Thomas F. Plunkett President, Nuclear Division Florida Power and Light Company Post Office Box 14000 Juno Beach, Florida 33408-0420
SUBJECT:
10 CFR 50.46 LARGE BREAK LOSS OF COOLANT ACCIDENT EVALUATION MODEL FOR ST.
LUCIE PLANT UNIT 1 (TAC M96355)
Dear Mr. Plunkett:
In our letter of October ll, 1996, we informed you about the problems that we had identified concerning changes in the large break loss-of-coolant accident (LBLOCA) evaluation model of Siemens Power Corporation (SPC) for pressurized water reactors (PWRs) to comply with 10 CFR 50.46.
The changes to the 19&6 approved LBLOCA evaluation model were to correct an error of non-physical behavior in the prediction of heat transfer coefficients during core reflood.
The range of concern for core reflood rates following the LBLOCA is for rates of 1 inch per second to 1.77 inches per second 'in that the 1986 model predicted a peak in the heat transfer coefficients within this range and then the non-physical behavior of decreasing coefficients with increasing reflood rates.
The SPC 1991 model which was also discussed in the October ll, 1996, letter is not an acceptable LBLOCA model.
We stated in the letter of October ll, 1996, that the 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 changes, and take whatever actions are required to assure compliance with 10 CFR 50.46 for St. Lucie Unit l.
You were also requested to attend a public meeting on October 16, 1996, at the Nuclear Regulatory Commission 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 letters dated October 25 and November 7,
- 1996, and documented the assessment that you had presented at the October 16, 1996, meeting of the PCT for the LBLOCA and the corrective actions that have been undertaken, both short-term and long-term, for St. Lucie Unit l.
In the first letter, you stated that the 1986 model has been modified to have a linear function of the heat transfer coefficients in the range of reflood rates from 1 inch per second to 1.77 inches per second and that the PCT calculated for the modified l986 model is 2027'F, which is well below (i.e., greater than 150'F below) the PCT acceptance criterion of 10 CFR 50.46.
NIIC R<E CmTEII CIIPV
)20057
t Mr. Thomas F. Plunkett Because the information in the first letter was based on computer calculations which had not received a formal verification from SPC and your quality assurance
- programs, the second letter was sent to provide the same results based on the verification by the quality assurance programs.
The reflood rate is within the range of concern during the time period when PCT is approached in that it drops from a value of about 2 inches per second at 75 seconds into the LBLOCA to a value of about 1.2 inches per second at 150 seconds.
In your
- letters, you concluded that St.
Lucie Unit 1 is in compliance with 50.46 and that the modified 1986'model was conservative for the values of heat transfer coefficient throughout the range of reflood rates of interest and corrects the non-physical behavior of the model.
Based on our review of your letters, we conclude that the modified 1986 model, by assuming a linear function of the heat transfer coefficients in the range of reflood rates from 1 inch per second to 1.77 inches per second, is conservative with respect to the measured values and corrects the non-physical behavior of the 1986 model that we identified in our letter of October ll, 1996.
Therefore, we conclude that this model is an acceptable model, in accordance with 50.46(a)(l)(i), for determining that St. Lucie Unit 1 meets the acceptance criteria of 50.46.
Based on the above information, we conclude that you have properly addressed the concerns raised in our letter of October ll, 1996.
Sincerely, Leohard A. Wiens, Senior Project Manager Project Directorate II-3 Division of Reactor Projects-I/II Office of Nuclear Reactor Regulation Docket No. 50-335 cc:
See next page DISTRIBUTION
- Docket File PUBLIC --
St. Lucie Rdg.
S.
Varga J. Zwolinski
'GC ACRS J.
Johnson DOCUMENT NAME:
G:iSYLUCIEi5046-TWO.STL To receive a copy of this docuaent, indicate in the box:
>>C>>
= Copy without attachment/enclosure
>>E>> >> Copy with attachment/enclosure
>>N>> = No co y OFFICE PDII-3/PM PDII-3/LA lggg
W SRXB kP9Z PDII-3/D NAME DATE 11/
/96 BCla ton 11/
/96 JDonohe 11/
/9 TCollins 1+ N. 9'/96 FHebdon 11/
/96 OFFICIAL RECORD COPY
= ~/
rortM~
Mr. T. F. Plunkett Florida Power and Light Company ST.
LUCIE PLANT CC:
Senior Resident Inspector St. Lucie Plant U.S. Nuclear Regulatory Commission 7585 S.
Hwy AIA Jensen
- Beach, Florida 34957 Joe Myers, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 M. S.
Ross, Attorney Florida Power 5 Light 11770 US Highway 1
North Palm Beach, FL 33408 John T. Butler, Esquire
- Steel, Hector and Davis 4000 Southeast Financial Center Miami, Florida 33131-2398 Mr. Thomas R.L. Kindred County Administrator St. Lucie County 2300 Virginia Avenue Fort Pierce, Florida 34982 Mr. Bill Passetti Office of Radiation Control Department of Health and Rehabilitative Services 1317 Winewood Blvd.
Tallahassee, Florida 32399-0700 Regional Administrator Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, NW. Suite 2900 Atlanta, Georgia 30323 H. N. Paduano, Manager Licensing 5 Special Programs Florida Power and Light Company P.O.
Box 14000 Juno
- Beach, Florida 33408-0420 J.
A. Stall, Site Vice President St. Lucie Nuclear Plant P.O.
Box 128 Ft. Pierce, Florida 34954-0128 J. Scarola Plant General Manager St. Lucie Nuclear Plant P.O.
Box 128 Ft. Pierce, Florida 34954-0128 Mr. Kerry Landis U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W. Suite 2900 Atlanta, Georgia 30323-0199 E. J.
Weinkam Licensing Manager St. Lucie Nuclear Plant P.O.
Box 128 Fort Pierce, Florida 34954-0128