ML17219A352
| ML17219A352 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/10/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17219A351 | List: |
| References | |
| NUDOCS 8702190054 | |
| Download: ML17219A352 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Enclosure 1
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING PROJECTED VALUES ON MATERIAL PROPERTIES FOR FRACTURE TOUGHNESS RE UIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS FLORIDA POWER.AND LIGHT COMPANY ST.
LUCIE PLANT UNIT NO.
1 DOCKET NO. 50-335 INTRODUCTION As required by 10 CFR 50.61, "Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock" (PTS Rule), which was published in the Federal Register July 23, 1985, the licensee for each operating pressurized water reactor "shall submit projected values of RT T (at the inner vessel surface) of reactor vessel beltline materials by g(vying values from the time of submittal to the expiration date of the operating license.
The assessment must specify the bases for the projection including the assumptions regarding core loading patterns.
This assessment must be submitted by January 23,
- 1986, and must be updated whenever changes in core loadings, surveillance measurements or other information indicate a significant change in projected values."
By letter dated January 23, 1986 (L-86-20), as supplemented by letter dated October 2, 1986, the Florida Power and Light Company, the licensee for the St.
Lucie Plant, Unit No. 1, submitted information on the material properties and fast neutron fluence (E > 1.0 Mev) of the reactor pressure vessel in compliance with the requirements of 10 CFR 50.61.
Similar information was also submitted as part of another licensing action by letter dated February 10, 1984.
The following evaluation concerns the estimation of the fluence to the reactor pressure vessel to the end of the current license (July 1, 2010) and the corresponding value of the RTPTS.
By letter dated February 28, 1986, the licensee has applied for a license amendment which would extend the operating license to March 1, 2016.
This review is in progress, and the PTS issue associated with the additional 6
years of operation will be addressed in the safety evaluation associated with the license term extension amendment.
EVALUATION OF THE MATERIALS ASPECTS The controlling beltline material from the standpoint of PTS susceptibility was identified to be the lower shell longitudinal weld 3-203 A, B and C (weld wire heat no.
305242).
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The material properties of the controlling material and the associated margin and chemistry factor were reported to be:
Utilit Submittal Staff Evaluation Cu (copper content, X)
Ni (nickel content, X)
- 0. 30
- 0. 64 0.30
- 0. 64 I (Initial RTNDT F)
H (Margin, ~F)
CF (Chemistry Factor, F)
-56 59
-56 59 198. 2 The controlling material has been properly identified.
The justifications given for the copper and nickel contents and the initial RTN are acceptable.
The margin has been derived from consideration 6 the bases for these
- values, following the PTS Rule, Section 50.61 of 10 CFR Part 50.
Equation 1 of the PTS rule governs, and the chemistry factor is as shown above.
EVALUATION OF THE FLUENCE ASPECTS The methodology for the fluence calculation was based on the discrete ordinates code DOT 3.5 using "CASK" an ENDF/B-IV based cross section set.
The scattering is treated with a Pa approximation, plant specific sources were used with an S8 quadrature.
The lower shell longitudinal welds 3-203 A, 8
and C were identified as the controlling material.
The azimuthal value of the fluence corresponding to the weld 3-203 A, B and C is the applicable value for the estimation of RT T The methodology, the cross sections and the approximations used fry acceptable.
Notes:
a.
The St.
Lucie Unit 1 core support barrel has several holes up to 7 inches in diameter, as crack arrestors for damage suffered from thermal shield vibration.
Reference 2 includes an estimate of the local increase of the fluence to the pressure vessel;
- however, the holes are located at the top of the core support barrel and do not affect the controlling welds.
b.
The estimation of the fluence was divided into parts; i.e.,
up to the end of Cycle 5 and Cycle 6 to 32 effective full power years.
The distinction was necessitated from the removal of the thermal shield at the end of Cycle 5.
EVALUATION OF THE CALCULATED RT The equation specified in 10 CFR 50. 61 as applicable plant is:
RT TS = I+M(-10+470xCu+350xCuxNi)xf
'. 27 PTS for the St.
Lucie Unit 1 where:
Therefore:
I = Initial RT D
M = Uncertaint) kargin Cu = w/o Copper in welds 3-203 A,B,C Ni = w/o Nickel in welds 3-203 A,B,C f = azimuthal fluence on welds 3-203 A,B,C (E > 1.0 MeV) to the end of the current license, in units of 10~9 n/cm2
= -56 F
59 F
- 0. 30
- 0. 64
- 1. 68 RTPTS 56+59+( 10+470x0. 30+350x0. 30x0. 64)xl. 68 0. 27
= 3+198. 2xl. 15 231oF which is lower than 270'F, the applicable 10 CFR 50.61 screening criteria and is acceptable.
CONCLUSIONS The licensee has calculated a
RTp of 230 F for the limiting material at the expiration date of the license.
Be staff calculated 231~F.
This is less than 270'F which is the screening criterion for the limiting material at the expiration date of the license.
This is acceptable and thus meets the requirements of the PTS Rule.
By application dated February 28, 1986, the licensee proposed to extend the end of license date from July 1, 2010 until March 1, 2016.
This review is in progress, and the PTS issue associated with the additional six years of operation will be addressed in the safety evaluation associated with the license term extension amendment.
In order for us to confirm the licensee's projected estimated RT TS throughout the life of the license, we will request the licensee to submit V re-evaluation of the RT and comparison to the predicted value with future Pressure-Temperature sufilifttals which are required by 10 CFR Part 50, Appendix G.
Dated:
February 10, 1987 Principal Contributors:
P. Randall, L. Lois, and E. Tourigny
References 1.
Letter from C. 0.
Woody, Florida Power and Light Company, to F. Miraglia, NRC, dated January 23, 1986.
(L-86-20) 2.
Letter from J.
W. Williams, Florida Power and Light Company, to J.
R. Miller, NRC, dated February 10, 1984.
(L-84-29) 3.
Letter from C.
0.
Woody, Florida Power and Light Company, to A. Thadani, NRC, dated October 2, 1986 (L-86-394)