HL-5301, Forwards Response to RAI Re 960919 TS Rev Request Re Reactor Pressure Vessel Pressure & Temp Limits

Forwards Response to RAI Re 960919 TS Rev Request Re Reactor Pressure Vessel Pressure & Temp Limits

ML20134B172
Person / Time
Site:	Hatch
Issue date:	01/23/1997
From:	Woodard J GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HL-5301, NUDOCS 9701290321
Download: ML20134B172 (8)

Text

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Georgia Power Company 333 Piedmont Avenue

. . Atlanta. Georgia 30308

• Telephone 404 526-3195 Mailing Address 40 inverness Center Pa#kway Post Office Box 129s Birmingham, Alabama 3520t Telephone 205 868-5086 J. D. Woodard tr,e smfne n ekuc wstem Senior Vee President January 23, 1997 Docket Nos, 50-321 HL-5301 50-366 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant Response to Request for Additional Information on Technical Specification Revision Request:

Pressure-Temperature Limits Gentlemen:

Enclosed you will find our response to a request for additional information on a Technical Specification revision request dealing with reactor pressure vessel pressure and i temperature limits. The original submittal was transmitted to you on September 19,1996. ]

The request for additional information was made during a telephone conference between i l

GPC and NRC representatives on Friday January 10,1997.

The three NRC questions are paraphrased, followed by our response.

Please contact this office if you have further questions.

Sincerely,

(

J. Woodard t

OCVleb (jOf I

Enclosure:

Response to Request for Additional Information on Technical Specification Revision Request: Pressure-Temperature Limits cc: (See next page.)

9701290321 970123 PDR ADOCK 05000321.

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$ Georgia Power d

. U.S. Nuclear Regulatory Commission Page 2 January 23, 1997 i

cc: Georzia Power Comt>any Mr. H. L. Sumner, Nuclear Plant General Manager

, NORMS i

U.S. Nuclear Regulatorv Commission. Washington. D.C.

4 Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reentatory Commission. Region 11 Mr. L. A. Reyes, Regional Administrator Mr. B. L. Holbrook, Senior Resident Inspector - Hatch

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HL-5301

Enclosure Edwin I. Hatch Nuclear Plant l Response to Request for AdditionalInformation on l Technical Specification Revision Request: )

Pressure-Temoerature Limits  !

NRC Ouestion A: l Please provide the details of the calculation of ART and Shift for the limiting beltline (Weld 101-842) for Hatch Unit 2.

GPC Response:

The impact on adjus:ed reference tempeiature (ART) due to irr.idiation in the beltline materials is determined according to the methods in Reg. Guide 1.99, Rev. 2, as a function of neutron fluence and the element contents of copper (Cu) and nickel (Ni). The specific reiationship from Reg. Guide 1.99, Rev. 2 is:

ART = Initial RTmr+ ARTg,n + Margin i Shift = ARTmr + Margin where:

ARTer = [CF) *f(a28.aioioso Margin = 2* (ci 2+ y,2)ir2 CF = chemistry factor from Tables 1 or 2 of Reg. Guide 1.99, Rev. 2,  !

f = 1/4 T fluence (n/cm2 ) divided by 10",

d ci = standard deviation on initial RTmr, l o.s = standard deviation on ARTer,28 F for welds  ;

and 17 F for base material, except that o.s need not l exceed 0.50 times the ARTmrvalue.

For the limiting beltline weld 101-842 CF = 154.5 with %Cu = 0.23 and % Ni = 0.5 f = 1.050el8/le19 for the lower long. shell with thickness of 6.38 inches, ci = 0 F, o3 = 28 F l

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• Enclosure Response to Request for Additional Information:

l Pressure-Temperature Limits Therefore, l ART at 32 EFPY = -50 + 65.9 + 56.0 = 71.9 F Shift at 32 EFPY = 65.9 + 56.0 = 121.9 F i where: I l

Initial RTer = -50 F ARTer = [154.5]*0.105a28 -aio son nim = 154.5*0.427 = 65.9 F Margin = 2*(02+ 28 2)v2 = 56 F l NRC Ouestion B:

Please explain why in the P-T curves for Hatch Unit 2 a shin of 116.6 F was used for the

A' curve and 121.9 F for the B' curve.

GPC Response

The reason for the difference in shin used for Curve A' as opposed to Curves B' and C' is l the relationship of thickness and shin to tM emperatures determined. The smaller thickness (5.38" min and 5.59" max) and nun of 116.6 F produces a more conservative A' curve. The larger thickness (6.38" min and 6.59" max) and shin of 121.9 F produces a more conservative B' and C' curve. See the following example calculations for 1000 psig. l The methods used for the pressure test and heatup/cooldown curves are briefly described below. The core critical operation curve is simply the heatup/cooldown curve plus 40 F, as required in 10CFR50 Appendix G, so the methods for tne heatup/cooldown curves (Curve B') apply to the core critical curves (Curve C') as well.

B.1 Pressure Test Pressure test Km is the calculated value Ki m multiplied by a safety factor of 15. The relationship between Km and temperature relative to reference temperature (T - RTm1),

is:

Km - 26.78 = 1.223 e [0.0145 (T - RTmr + 160)] (B-1)

HL-5301 E-2

.* Enclosure Response to Request for Additional Information:

Pressure-Temperature Limits IL2 Heatup/Cooldown 1 The beltline curves for heatup/cooldown conditions are influenced by pressure stresses and tiiermal stresses:

Km = 2.0 Kim + Ka, (B-2) 1 where: l

. Kim is primary membrane K due to pressure and Ka is radial thermal gradient K due to heatup/cooldown.

The pressure stress intensity factor Kim is calculated by the method described in i section B.1, the only difference being that a safety factor of 2.0 is applied in the B-2 equation, while a safety factor of 1.5 is used in the B-1 equation.

113 Fzample Calculation - 32 EFPl'Prtssure Test at 1000 PSIG The following inputs were used in the beltline limit calculations:

ART . -50 + 116.6 = 66.6 F Vessel Height . . 825.2 inch l Bottom of Active Fuel Height . 208.6 inch l Vessel Radius 110.38 inch l Vessel Thickness Minimum . 5.38 inch I Vessel Thickness Maximum . 5.59 inch  ;

j Beltline Material Sy . 73.9 ksi '

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Pressure was calculated to include hydrostatic pressure for a full vessel:

P = 1000 psi + (825.2-208.6) inch

• 0.0361 psi / inch = 1022 psig Pressure stress:

o = PR/t = 1022 psig

• 110.38 inch / 5.38 inch = 21,000 pi The factor M. depends on (c/S y) and Vt:

c/Sy = 21,000 / 73,900 = 0.284 (use c/Sy = 0.5) 4t = (5.38) 2 = 2.32 M = 2 23 HL-5301 E-3

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.* Enclosure Response to Request for Additional Information: 1 Pressure-Temperature Limits The stress intensity factor, Kim is M.*o:

Kim = 2.23

• 21,000 = 46,800 psiVin = 46.8 ksiVin T - RTmyr:

(T - RTmr) = 1n[(1.5*46.8 - 26.78)/1.223]/0.0145 - 160 (T - RTmr) = 86 F Adding the aJjusted RTwor for 32 EFPY of 67 F:

I T = 153 F i B.4 Example Calculation - 32 EFPYlleatup/Cooldown Cun e at 1000 PSIG '

The following inputs were used in the beltline limit calculations:

ART .. . . ...... . . . .. . -50 + 122 = 72 F ,

Vessel Height .. ... ....... . ...... 825.2 inch Bottom of Active Fuel Height .. .. . . .. . . 208.6 inch Vessel Radius . . . .. . ... ..... . .... .. I10.38 inch Vessel Thickness Minimum . . . . 6.38 inch Vessel Thickness Maximum . . . . 6.59 inch Beltline Material S y . . . . .. . 73.9 ksi 1

The heatup/cooldown curve at 1000 psig uses the same Kim as the pressure test curve, but with a safety fa. tor of 2.0 instead of 1.5.

Pressure was calculated to include hydrostatic pressure for a full vessel: l P = 1000 psi + (825.2-208.6) inch

• 0.0361 psi / inch = 1022 osig Pressure stress:

o = PR/t = 1022. psig

• 110.38 inch / 6.38 inch = 17,700 p_s.i The factor M. depends on (c/S y) and Vt:

o ?y = 17,700 / 73,900 = 0.24 (use c/Sy = 0.5) 4t = (6.38)i/2 = 2.53 M. = 2.43 1

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.o Enclosure l

Response to Request for Additional Information:

Pressure-Temperature Limits 1

l The stress intensity factor, Kim,is M.

• c:

j Kim = 2.43

• 17,700 = 43,000 psiVin = 43.0 ksiVin i'

In addition, c.here is a Kiit erm for the thermal stress. The additional inputs used to 3

calculate Kii are:

i i G = 100 F/hr i C = 6.59 inches, including clad thickness 2

! p = 0.354 ft /hr at 550 F (most conservative value) 4 The absolute value of AT for heatup or cooldown can be calculated from:

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AT = GC2/2p l

For the values above, AT = 43 F The corresponding value of Mi is l Mi = 0.30 Thus, the thermal stress intensity factor, Kii = Mi

• AT, is calculated to be Kii = 12.9 ksidin T - RTer:

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(T - RTmT) = In[((2.0*43.0 + 12.9) - 26.78)/1.223]/0.0145 - 160 (T - RTer) = 121 F Adding the adjusted RTer for 32 EFPY of 72 F:

T = 193 F HL-5301 E-5 l

. Enclosure Response to Request for AdditionalInformation:

. Pressure-Ten perature Limits NRC Ouestion C:

Please provide the correct Initial RTmr temperature shift for Hatch I weld 1-313 heat numbers 90099 and 33A277.

GPC Re5D0nSe:

The correct initial RTwr temperature shifts for the weld 1 313, heat numbers 90099 and 33A277 were provided in the BWRVIP topical report " Bounding assessment of l

l BWR/2-6 Reactor Pressure Vessel Integrity Issues." They are, for heat number 90099,  ;

l -10 F and for heat number 33 A277, -50 F. GPC referenced this report in a November 16, 1995 letter to the NRC.

i These initial RTmr alues v were provided to you in our response to Generic Letter 88-11, dated November 22,1988. However, by letter dated June 3,1994 you requested us to l verify that certain ir formation was accurately entered in the Reactor Vessel Integrity ,

l database (RVID) for Hatch Units 1 and 2. In that letter, an erroneous value of-10 F was l entered for Hatch I weld 1-313, heat number 33A277. Unfortunately, we failed to notify you in our subsequent letter of July 1,1994 that the value was incorrect.

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Therefore, as listed in the above referenced BWRVIP report and in our response to {

GL 8811, the correct initial RTmr value for Hatch I weld 1-313, heat number 33 A277  ;

is -50 F. l f

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