ML13305A901
| ML13305A901 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/21/1986 |
| From: | Rood H Office of Nuclear Reactor Regulation |
| To: | Baskin K Southern California Edison Co |
| References | |
| REF-GTECI-A-49, REF-GTECI-RV, TAC-59981, TAC-59982, TASK-A-49, TASK-OR NUDOCS 8612040308 | |
| Download: ML13305A901 (5) | |
Text
Docket Nos.:
50-361 NOV 2 11986 and 50-362 Mr. Kenneth P. Baskin Mr. James C. Holcombe Vice President Vice President - Power Supply Southern California Edison Company San Diego Gas & Electric Company 2244 Walnut Grove Avenue 101 Ash Street Post Office Box 800 Post Office Box 1831 Rosemead, California 91770 San Diego, California 92112 Gentlemen:
SUBJECT:
SAFETY EVALUATION OF PRESSURIZED THERMAL SHOCK FOR SAN ONOFRE 2 AND 3 By letter dated January 22, 1986, you submitted information on material properties and fast neutron fluence for the San Onofre 2 and 3 reactor pressure vessels.
The January 22, 1986 submittal was in compliance with the requirements of 10 CFR 50.61, "Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events". The NRC staff has reviewed your submittal and finds that the San Onofre 2 and 3 reactor pressure vessels meet the fracture toughness requirements of 10 CFR 50.61 for 32 years of effective full power operation.
In addition, we request that you submit periodic future re-evaluations of the pressurized thermal shock reference temperature (RT E) and comparisons of these values with the values predicted in your submittal January 22, 1986. Such future submittals could be made at the same time you submit the pressure temperature operating limits required by Appendix G to 10 CFR 50.
If you have any questions regarding this issue, please contact me.
Sincerely, Harry Rood, Senior Project Manager PWR Project Directorate No. 7 Division of Licensina-B
Enclosure:
DIS IBUTION As stated cket File EJordan NRC PDR BGrimes LPDR cc:
See next page NS I NSIC PD7 Reading PD7 D
JLee HRood/t D
hton HRood 11/o1d/86 11-8 htAttorney, OGC 11/-LI/86 11&//86 ACRS (10) 061204039 103 I36 PDR ADOC.
Mr. Kenneth P. Baskin San Onofre Nuclear Generating Station Southern California Edison Company Units 2 and 3 cc:
Mr. James C. Holcombe Mr. Hans Kaspar, Executive Director Vice President - Power Supply Marine Review Committee, Inc.
San Diego Gas & Electric Company 531 Encinitas Boulevard, Suite 105 101 Ash Street Encinitas, California 92024 Post Office Box 1831 San Diego, California 92112 Charles R. Kocher, Esq.
Mr. Mark Medford James A. Beoletto, Esq.
Southern California Edison Company Southern California Edison Company 2244 Walnut Grove Avenue 2244 Walnut Grove Avenue P. 0. Box 800 P. 0. Box 800 Rosemead, California 91770 Rosemead, California 91770 Mr. Stephen B. Allman Manager, Nuclear Department Orrick, Herrington & Sutcliffe.
San.Diego Gas & Electric Company ATTN:
David R. Pigott, Esq.
P. 0. Box 1831 600 Montgomery Street San Diego, California 92112 San Francisco, California 94111 Richard J. Wharton, Esq.
University of San Diego School of Alan R. Watts, Esq.
Law Rourke & Woodruff Environmental Law Clinic Suite 1020 San Diego, California 92110 1055 North Main Street Santa Ana, California, 92701 Charles E. McClung, Jr., Esq.
Attorney at Law Mr. S. McClusky 24012 Calle de la Plaza/Suite 330 Bechtel Power Corporation Laguna Hills, California 92653 P. 0. Box 60860, Terminal Annex Los Angeles, California 90060 Regional Administrator, Region V U.S. Nuclear Regulatory Commission Mr. C. B. Brinkman 1450 Maria Lane/Suite 210 Combustion Engineering, Inc.
Walnut Creek, California 94596 7910 Woodmont Avenue, Suite 1310 Bethesda, Maryland 20814 Resident Inspector, San Onofre NPS c/o U. S. Nuclear Regulatory Commission Mr. Dennis F. Kirsh Post Office Box 4329 U.S. Nuclear Regulatory Commission San Clemente, California 92672 Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 Ms. Ann C. Vasolez, Chief Radiological Programs Division Governor's Office of Emergency Services 2800 Meadowview Road SacraEnento, California 95832 SAN ONOFRE UNITS 2 AND 3, FAST NEUTRON FLUENCE FOP FRACTURE TOUGHNESS REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS (10 CFR 50.61)
By letter dated January 22, 1986, the Southern California Edison Company (SCE),
licensee for San Onofre Units 2 and 3, submitted information on the material properties and the fast neutron fluence (E greater than or equal to 1.0 MeV) of the reactor pressure vessel in compliance with the requirements of 10 CFR 50.61.
The NRC staff has reviewed the San Onofre 2 and 3 pressure vessel material properties, chemical compositions, estimated fluences after 32 effective full power years of operation, and the predicted valves of RT PTS. The results of the staff's review are aiven below.
MATERIAL PROPERTIES AND CHEMICAL COMPOSITION The controllina beltline material from the standpoint of PTS susceptibility was identified to be intermediate shell plate C-6404-2 for Unit 2 and intermediate shell plate C-6802-1 for Unit 3.
The material properties of the controlling material and the associated margin and chemistry factors were reported to be:
Utility Submittal Staff Evaluation Unit 2 Unit 3 Unit 2 Unit 3 Cu (copper content, %)
0.10 0.06 0.10 0.06 Ni (nickel content, %)
0.58 0.58 0.58 0.58 I (Initial RTNDT'o F) 16 40 16 40 M (Margin, 'F) 48 48 48 48 CF (Chemistry Factor, cF) 57.3 30.4 The NRC staff concludes that the controlling material has been properly identified.
The justifications given for the copper and nickel contents and the initial RT are acceptable. The margin has been derived from consideration of the ba L for these values, following the PTS Rule, Section 50.61 of 10 CFR Part 50.
Based on the reported values of fluence, Equation 1 of the PTS rule governs, and the chemistry factor is as shown above.
ESTIMATED FLUENCE AND RTPTS The following evaluation concerns the estimation of the fluence to the pressure vessel for 32 effective full power years of operation and the corresponding values of RT PTS.
-2 The intial San Onofre 2 and 3 fluence calculations were performed for the FSAR.
Later calculations were submitted to the NRC in connection with the PTS issue in CEN-189, dated December, 1981.
These calculations are boundina estimates and ignore future low leakage core loadings. However, even with these conservatisms the 32 effective full power years peak pressure vessel fast neutron fluence is 3.2% for Unit 2 and less than 0.5% for Unit 3 of the fluence required to reach the 10 CFR 50.61 specified limit of RT
= 270 0F. This is due to the very low amount of copper and nickel content Sthe shell plates and welds of the pressure vessels. Therefore, the fluence estimate is conservative and acceptable.
The equation specified in 10 CFR 50.61 as applicable for the San Onofre 2 pres sure vessel is:
RTpts = I+M+(-10+47OxCu+35OxCuxNi)xf0.27 where:
I
= Initial RTNDT
= 160F M
= Uncertainty Margin
= 480F Cu = w/o Copper in shell plate C-6404-2
= 0.10 Ni = w/o Nickel in shell plate C-6404-2
= 0.58 f = Peak fluencelgn she l plate C-6404-2 in units of 10 n/cm for 32 effective full power years = 3.68 Then:
RTPTS = 64+(-10+470x0.10+350x0.10x0.58) x 3.680.27
= 64+57.3x1.42 = 145.5 0F which is less than 270aF i.e. the applicable screening criterion and, thus, is acceptable.
The equation specified in 10 CFR 50.61, as applicable for the San Onofre 3, pressure vessel is:
RTPTS I+M+(-10+47OxCu+35OxCuxNi)xf0.27 where:
I
= Initial RTNDT
= 160 F M
= Uncertainty Margin
= 480F Cu = w/o Copper in shell plate C-6404-2
= 0.10 Ni = w/o Nickel in shell plate C-6404-2
= 0.58 f = Peak fluencelyn she l plate,C-6404-2 in units of 10 n/cm for 32 effective full power years = 3.68
-3 Then:
RTPTS = 84+(-10+470x0.06+350x0.06x0.58) x 3.680.27
= 84+30.4x1.42 = 131.2 0F which is less than 270'F i.e. the applicable screening criterion and, thus, is acceptable.
REQUEST FOR PERIODIC RE-EVALUATION The NRC staff requests that SCE provide a re-evaluation of the RTET for San Onofre 2 and 3 and a comparison to the predicted valves in the Ja hry 22, 1986 submittal along with future pressure-temperature operating limits which are required by Appendix G to 10 CFR 50 (this request for information is covered under clearance No. 3150-0011). It should be noted that this re-evaluation is a requirement of 10 CFR 50.61 whenever core loadings, surveillance measurements, or other information indicate a sionificant change in projected values.
This request is being made in veiw of:
(a) the pressure-temperature updating requirements for the fracture touahness of the beltline material in 10 CFR 50 Appendix G, and (b) the fact that the RT PT value is readily available from the calculation of the pressure temperture limits, and (c) the staff desire to be informed on the current value of the RT PT for all PWRs.