ML18152A601
| ML18152A601 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 11/25/1987 |
| From: | Chandu Patel Office of Nuclear Reactor Regulation |
| To: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| REF-GTECI-A-49, REF-GTECI-RV, TASK-A-49, TASK-OR TAC-59988, TAC-59989, NUDOCS 8711250103 | |
| Download: ML18152A601 (7) | |
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DoQ.ket Nos*. 50-280 and 50-281 Mr. W. L. Stewart Vice President - NucJear Operations Virgin i:a E 1 ectri c~ and'-P;<>wer Company P.O. Box 26666 Richmond, Virgin'ia 23:t61
Dear Mr. *Stewart:
DISTRIBUTION Docket Fi *1 e e
NRC & Local PDRs PD22 *Reading S. Varga G. Lainas D. Miller C. Patel A, '*";t I( \\ (,I),-***
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Gray Files SUBJECi~: FRACTURE TOU~HNESS REQUIREMENTS FOR PROTECTION AGAINST
. PRESSURIZED,THERMAL S~OCK EVENTS (TAC NOS. 59988 AND 59989)
We have completed* our :review of the multi-plant action (MPA A-21) relating to fracture toughness' reql!irement~ f.9r,protection against thermal shock events delineated
. in 10 CFR 50. 61
- We find that the pressure vessels for Surry Units 1 and 2 meet the fracture
'toughness requirements of 10 CFR 0 50.61 for 40 calendar years of operation.
Our evaluation is provided in Enclosures 1 and 2 for Surry Units land 2 respectively.
This completes our review cin the MPA,l\\-21.
It,is our understanding that you have already implemented'. the requirement from this MPA.
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The report{ng and/or recordke1p,ng requirements contained in the enclosures affect few~r than 10 respondehts; therefore, 0MB clearance is not required under P.L.96-511.
Enclosures:
As stated cc w/enclosures:
See next page LA:PD22 DMiller 11/ /87 PM:PD22 CPatel:bd 11/ /87 Sincerely, Chandu P. Pate, Project Manager Project Directorate II-2 Division ~f Reactor Projects-I/II Office of Nuclear Reactor Regulation D:PD22 HBerkow 11 /
/87
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Docket Nos. 50-280 and 50-281 Mr. W. L. Stewart Vice President - Nuclear Operations Virginia Electric and Power Company P.O. Box 26666 Richmond, Virginia 23261
Dear Mr. Stewart:
SUBJECT:
FRACTURE TOUGHNESS REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS (TAC NOS. 59988 AND 59989)
We have completed our review of the multi-plant action (MPA A-21) relating to fracture toughness requirements for protection againstvthermal shock events delineated in 10 CFR 50.61.
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We find that the pressure vessels for Surry Units 1 and 2 meet the fracture toughness requireme ts of 10 CFR 50.61 for 40 calendar years of operation.
Our evaluatio v'ded in Enclosures 1 and 2 for Surry Units 1 and 2) respectively! ~
This completes our review on tlm MPA A-21. It is our understanding that you have already implemented the requirement;~ this MPA.*
The re rti~~d/ recorcU(eepingAequirem ts cont~d iryt:ne en91<)su~
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affe fe~~e t~~ 10 resp.ondenty, theref e, 0MB ~ra~cp/is no_yrequJ,red
~,~, ~ und r P.L. 96-5 1.
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Enclosures:
P,s stated cc w/enclosures:
See next page Sincerely, Chandu P. Patel Project Manager Project Directorate II-2 Division of Reactor Projects-I/II Office of Nuclear Reactor Regulation
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555
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e SURRY UNIT 1, SAFETY EVALUATION FOR FRACTURE TOUGHNESS REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERMAL SHOCK EVENTS (10 CFR 50.61)
By letter dated January 23, 1986, as supplemented November 26, 1986, December 12, 1986, and April 30, 1987, the Virginia Electric and Pow r Company (the lfcensee) submitted information on the material properties and the fast neutron fluence (E~ 1.0 MeV) of the reactor pressure vessel in comp iance with the requirements of 10 CFR 50.61.
The staff has reviewed these sub ittals to assure that the licensee has properly identified the controllng bel line material from the standpoint of pressurized thermal shock (PTS) and provided proper justifications for the copper and nickel contents and the initial RTNnT*
Also, the staff used this information in estimating the fluence to the pressure vessel at the end of 40 calendar years of operation and in calculating the corresponding value of the RTPTS for assuring the compli~nce with 10 CFR 50.61.
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The controlling beltline material from the standpoint of PTS stkes13til:ii1it.Y"'
was identified to be the lowe('shell longitudinal weld L2, weld wire heat number ir99L44.
Using the material properties of the controlling material submitted by the licensee and using the guidance provided in 10 CFR 50.61, the staff has included the following information in its evaluation for the RTPTS" Cu (copper content,%}
0.35 Ni (nickel content,%)
0.67 I
(Initial RTNDT' °F) 0 M (Margin, °F) 59 CF (Chemistry Factor, °F}
236.6 The methodology of the fluence calculation was based on the discrete ordinates code DOT with an ENDF/B-IV based cross-section set. The scattering is treated with a P approximation and plar.t.:i!specific sources were used.
The power distribu~ion for operating cycle 8 was used for the extrapolation to the end of the 40 calendar years of operation.
The power uprating from 2441 MWt to 254-6 MWt in cycle 11 has also been taken into account.
The code has been benchmarked by Westinghouse.
Its predictions for the surveillance capsule locations are within +/-15% of the measured values.
An S6 cf.ngular quadrature was used.
The tJ lower shell longitudinal weld L has Deen identified as the controlling material. The weld L, is at an azimuthal location of J.45° (315°).
The fluence for this location was~estimated for 40 calendar years,bperation for Surry Unit 1 or an accumulated 28.8 effective full power years of operation as estimated by the licensee. The value of the peak axial fluence at this az-imuthal lo16tion for 40 calendar years of operation with energies E~l.O MeV is 0.639 x 10 J n/cm-.
This value is used in the following equation specified in 10 CFR 50.61 as applicable for the Surry Unit 1.
The fluenc estimate is conservative.
The methodology, the crossisections and the approximations used by licensee are acceptable.
'RTPTS where:
Therefore: = I+M+(-10+470 x Cu+350 x Cu x Ni) x f0*27 I = Initial RTNDT M = Uncertainty Margin Cu= w/o Copper in longitudinal weld L2 Ni= w/o Nickel in longitudinal
= 0°F
= 59°F
= 0.35 weld L2
= 0.67 f
= Peak axial fluence (E> 1.0 MeV) on
~Fluence longitudinal weld L2 for f_.40 calendar years of operation in f._ units of 1019n/cm2
= 0.639 o-27
= 59+(-10+470 x 0.35+350 x 0.35 x 0.67) x(o.639)
= 268.6°F Thus, the estimated RTprs is lower than the applicable PTS rule screening criterion of 270°F for longitudinal welds.
Based on above evaluation,the staff concludes that the licensee has properly identified the controllipg beltline material from the standpoint of the PTS rule and provided proper justification for the material and initial RTNnT*
Also, the staff finds tha~Surry Unit 1 pressure vessel meets the tougrtness requirements of 10 CFR 50,~l for lf.O calendar years of operation.
In view of:
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{a) the~ressuretl'emperature updating requirements for the fracture toughness of the beltl1ne material in 10 CFR 50 Appendix G, and (b) the fact that the RTPTS value is readily available from the calculation of the tressure Jemp!:!rature limits, and
{c) the staff desire to be informed on the current value of the RTPTS for
- PWRs, all
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_ -Q~(we request that the licet.ee submit a r~valuation of the RTPTS and a compari-5'~
son to the prediction of original submittal along with the futur~ressure-1i(()A.)-
Jemperature operating limits which are required by 10 CFR 5~1Appendix G.
It l!should be noted that this reevaluation is a requirement by --ro CFR 50.61, whenever core loadings, surveillance measurements, or other information indicate a significant change in projected values.
SURRY UNIT 2, SAFETY EVALUATION FOR FRACTURE TOUGHNESS REQUIREMENTS FOR PROTECTION AGAINST PRESSURIZED THERM/\\L "_\\ *. \\~*~
SHOCK EVENTS {10 CFR 50.61)
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su.Stef, By letter dated January 23, 1986, as supplemented No ember 26, 1986, the Virginia Electric and Power Comp ny (the license*e) submitted information on the material properties and the ast neutron flu ce {E.> 1.0 MeV) of the reactor pressure vessel in comp iance with the equirements of 10 CFR 50.61.
The staff has reviewed theses bmittals to as re that the licensee has properly identified the beltline aterial from the standpoint of pressurized thermal shock {PTS)
Also, the staff used this information in estimating the fluence to tne pressure vessel at the end of 1 - calendar years of operation and in calculating the corresponding v ue of the RTPTS for assuring the compliance with 10 CFR 50.61.
lj-0 The controlling beltline material from the standpoint of PTS su~~ptibility was identified to be the lower shell longitudinal welds Ll and L2, weld wire heat number 8Tl762.
Using the material properties of the controlling material submitted by the licensee and using the guidance provided in 10 CFR 50.61, the staff has included the following information in its evaluation for the RTPTS" Cu (copper content,%)
0.29 Ni (nickel content,%)
0.55 I (Initial RTNDT' °F) 0 M (Margin, °F) 59 CF {Chemistry Factor, °F) 182. 1 The methodology of the fluence calcula~on was based on the discrete ordinates code DOT with an ENDF/B-IV based cross-section set. The scattering is treated 1:1ith a P3 t".pproximation and plantfspecific sources were used.
The* power distribu'i:ion for operating cycle 8 was used for the extrapolation to the end of th~ calendar years of operation. The power uprating from 2441 MWt to 2546 MWt in cycle 11 has also been taken into account.
The code has been benchmarked by Westinghouse. Its predictions for the surveillance capsule locations are within +/-15% ot. the measured values.
An S6t!ngular quadrature was used.
The intermediate-td'~lower shell longitudinal welds L and L2 have been identified as the controlling material; therefore, the app~icable value of the fluence is the axia.l peak at the weld.
The fluence est"inmte is conservative. Future low leakage core loadings were assumed.
The methodology, the cross*'sections and the approximations used by licensee are acceptable.
e The equation specified in 10 CFR 50.61, as applicable for the Surry Unit 2 is:
RTPTS where:
Therefore:
= I+M+(-10+470 x Cu+350 x Cu x Ni) X f0.27 I = Initial RT NDT
= 0°F M = Uncertainty Margin
= 59°F Cu = w/o Copper in the lower shell longitudinal weld L1,L2
= 0.29 Ni = w/o Nickel in longitudinal we.ld L1,L2
= 0.55 f
= Peak Fluence (E:!! 1. 0 MeV) lower shell longitudinal weld L1,L2 in
- units of 1019n/cm2
= w'- ~~ 7 f4
(),.J.7 RTPTS
= 59+(-10+470 x 0.29+350 x 0.29 x 0.55) x ~-~
0'i_2_7 ___ 1(0*7/LI)
= ~
ti.~S'(jr Thus, the estimated RTPTS is lower than the applicable PTS rule screening criterion of 270°F.
Based on above evaluation the staff concludes that the licensee has properly identified the controlling beltline material from the standpoint of. the PTS rule and provided proper justification for the material and initial RTNRT*
Also, the staff finds that Surry Unit 2 pressure vessel meets the tougtt ~ss requirements for 10 CFR 50.61 for~ calendar years of operation *.
In view of:
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(a) thet!'ressure~temperature updating requirements for the fracture toughness of the beltlfne material in 10 CFR 50 Appendix G, and
{b) the fact that the RTPTS value is readily available from the calculation
.of thectressure /empetature limits, and
{c) the staff desire to be informed on the current value of the RTPTS for all
- PWRs,
)v._,
we request that the 1icen..£e submit a r@valuation of the RT 5 and a compari-son to the prediction offk;iginal submittal along with the futir-ettressure-
,.P,mperature operating limits which are required by 10 CFR 5~1Appendix G.
It
~hould be noted that this reevaluation ts a requirement by~ CFR 50.61, whenever core loadings, surveillance measurements, or othe.r information indicate a significant change in projected values.
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