ML17334A816

Proposed Tech Specs Extending Fuel Peak Pellet Burnup & Increasing Fq Value Limit in Fuel

ML17334A816
Person / Time
Site:	Cook
Issue date:	08/23/1984
From:	INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
Shared Package
ML17334A815	List: ML17334A814 ML17334A816
References
NUDOCS 8409050174
Download: ML17334A816 (18)

Text

Mr. Harold R. Denton AEP:NRC:0745M Attachment A Proposed Revised Technical Specifications Pages for D.C. Cook Unit C

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POWER OISTRIBUTION LIMITS LIMITING CONOITION FOR OPERATION (Cont1nued)

2. Reduce THERMAL POWER as necessary to meet the limits of Specfffcatfon 3.2.6 usfng the APOMS with the latest fncore map and updated R.

b. Identffy and correct the cause of the out,of limit cond1t,fon pr1or ta fncreasfng THERMAL POWER; THERMAL POWER may then be fncreased provided F~ fs demonstrated thorough 1ncore mapping to be w1thfn fts lfmft.

SURVEILLANCE RE UIREHENM 4.2.2.1 The provfsfons of Specification 4.0.4 are not applicable.

4.2.2.2 F~(Z,i) shall be determined to be within fts limit by:

a. Usfng the movable fncore detectors to obtain a power d1stributfon map at any THERMAL POWER greater than SX of RATED THERMAL POWER.

b. Increasing the measured F~(Z,t) component of the po~er distribution map by 3X to account for manufacturing taler ances and further increasing the value by SX to account for measurement uncertafntfes. This product fs defined as F~(Z).

c. Satisfying the followfng relationships at the time of the target fl.ux determination.

Westfn house Fuel Exxon Nuclear Ca. Fuel L

2.10 ~KZ F,(Z) >0.5 Fq(Z) ~

PxE (Z V(Z) F<(Z) < ~xv Z) V(X)

P 4.20 K(Z) <O.S Fq(Z) E (Z) vvv' D.C. Cook Unit 1 Attendant "o 3/4 2-6

POWER OISfRIBUTIOH LIMITS SURVEILLANCE REgUIREMEHTS (Continued) where F~(z) = F~(z,a) at t for which F (Z,x) 3s a maximum T(E )

F<(Z) = F<(E,) at t for which

~F(z, a)

T(E )

is a maximum F~(Z) and F~(Z) ar e functions of core heiaht, Z, and F (Z,a) correspond at each Z to the rod 4 for which T(E is a maximu'm at that Z V(Z) is a cycle dependent, function and. is provided in the Peaking Factor Limit Report. QZ) is defined in Figure 3.2-2 for Exxon Nuclear Company fuel'and in Figure 3.2-3 for Westinghouse fuel. T(E<) is defined in

~ Figures 3.2-4 and 3.2-5. E (Z) is an uncertainty factor to account p

for the reduction in the F~L (E ) curve due to accumulation of exposure prior to the next flux map.

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l<estinqhouse Fuel Exxon Nucl ear Co. Fuel E,(z) = l.o E,(z) = l.o 0.0 EE < 17.62 E (Z) = 1.0 E (Z) = 1.0 + I.0040 x F (Z)] 17.62 < ER < '34.5 P

E,(z) = l.o E (Z) = 1.0+ [.0093 x FO(Z)] 34.5 < ER < 42 2 (Z) = 1.0 + L.0060 x E

F<(Z)] 42.2 < ER < 48.0 D.C. Cook Unit 1 3/4 2-7 Amendment No.

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0 4 6 10 12 Core Height (FT) 3.2-3 K(Z) - Normalized FIGURE

'f F (Z) As A Function Core Height For Westinghouse Fuel

0. C. Cook - Unit 1 3/4 2-11 Amendment No.

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2.2 2'0 2 04) (17.62,2.04) 2.0 {34.5,1.95) 1.9 (42.2,1.86)

= .'." (48.0,1.82)

L u 1.8 =- Fq (Ea) = 2.04 0 0 < Ea <17 62 L = 2.134-.005333 ER 17.62 <Ea <34.5 Fq (Ea) 1.7 -FL (ER) = 2.353-.01169 ER 34.5 < ER <42.2 g

L 42.2 <48.0 1.6 .=-g Fq {Ea) = 2.151-.006897 ER < Ea

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17.62, 1.0) 1.0 34.5, .956) t

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(42.2 ~ 912)

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.0 0.0 <Ea <17. 62 =--

= 1.046-.002614 ER 17.62 <ER <34. 5 4 ~ ~'

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= 1.054-.003381 Ea 42.2 <ER <48. 0 I

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.6 10 20 30 40 50 Peak Pellet Exposure in HklD/KG FjGURE 3.2-4 Exposure Dependent F~ Limit, F0 {Ea), and Normalized Limit T(Ea) as a function of Peak Pellet Burnup for Exxon Nuclear Company Fuel D.C.Cook - Unit 1 3/4 2-23 Amendment No.

2.2 2.1 (0.0,2.10) (42.2,2.10) 2.0 t'

1.9 1.8 1.7 1.6

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-:(O.o,l.no) (42.2,1.00) =

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~ ~ I 0.7 0 10 20 30 40 50 PEAK PELLET EXPOSURE IN MLlD/KG FIGURE 3.2-5

.Exoosure Deoendent FO Limit; F~(ER),'"and Normalized. Limit T(ER) as a Function of Peak Pellet Burnuo for l<estinghouse Fuel D. C. Cook - Unit 1 3/4 2-24 Amendment No.

Mr. Harold R. Benton AEP:NRC 0745M Attachment B Environmental and 10 CFR 50.92 justifications for those Technical Specifications changes (enclosed in Attachment A) associated with the extension of the peak pellet burnup allowed in fuel supplied by Exxon Nuclear Company.

Mr. Harold R. Denton B-1 AEP: NRC: 0745M The Justification for an incr ease in the allowed peak pellet burnup in fuel supplied by Exxon Nuclear Company (ENC) from 42,200 MWD/MTU (42.2 MWD/KG) to 48,000 MWD/MTU (48.0 MWD/KG) is based on analyses performed on the mechanical design, LOCA-ECCS analysis, and review of significant hazards and environmental considerations.

Mechanical design analyses for extended burnup to 48,000 MWD/MTU (48.0 MWD/KG) were performed. The results of these analyses are presented in XN-NF-84-25(P), April, 1984.

XN-NF-84-25(P), April, 1984, states that all current ENC design criteria are satisfied. These criteria are repeated below:

o The maximum end-of-life (EOL) steady-state cladding strain was determined to be negative, thu's meeting the 1.0$ design limit.

The cladding stress and strain during power ramps, calculated under different overpower conditions, do not exceed the design stress corrosion cracking threshold or the 1.0$ strain limit.

The cladding fatigue usage factor of 0.20 is within the 0.67 design limit.

The end-of-life fuel rod internal pressure is less than the system pressure.

The cladding diameter reduction due to uniform creepdown plus creep ovality after fuel densification is less than the minimum initial pellet/clad gap. This criterion prevents the formation of fuel column gapa.

The maximum calculated EOL thickness of the oxide corrosion layer is less than 0.0007 inch, and the maximum calculated concentration of hydrogen in the cladding is 80 ppm. These values are within the design limits of 0.002 inch and 300 ppm,

'espectively.

.An evaluation of the fuel assembly, growth and'the fuel rod growth indicates that the fuel assembly design provides adequate clearances at the design burnup.

Mr. Harold R. Denton B-2 AEP: NRC: 0745M Data on the performance of similar ENC fuel at high burnups can be found in XN-NF-82-06, "Qualification. of Exxon Nuclear Fuel for Extended Burnup", June, 1982. Lead assemblies at H.B.

Robinson have been burned to assembly average'xposures of approximately 48,000 MWD/MTU (48.0 MWD/KG).

A LOCA/ECCS analysis was per formed to extend the peak pellet exposure from 42,200 MWD/MTU (42.2 MWD/KG) to 48,000 MWD/MTU (48.0 MWD/KG). The results of these analyses are presented in XN-NF-83-61, August, 1983, which extends the analyses presented in XN-NF-81-07, February, 1981. The end-of-life calculated peak cladding temperature (PCT) is 1736 F, occurring 262 seconds into the accident at a location .25 feet from the bottom of the active core. Assuming a 42 $ F increase in PCT from an earlier sensitivity study for a conservative estimate of maximum LPSI flow, the PCT will be 1778 F. The analysis of the limiting break for the D.C. Cook Unit 1 reactor with the ENC WREM-IIA and selected EXEM/PWR ECCS evaluation models shows that the reactor can operate at allowed total peaking F of 1.82 and F H of 1.55 at a peak pellet burnup of 48,000 MWD/kTU (48.0 MWD/KG) and continue to meet the 10 CFR 50.46 criteria with analyses performed in conformance to 10 CFR 50 Appendix K requirements.

In a December, 1982 memo from L.G. Hulman, Chief NRC-Accident Evaluation Branch, to Carl Berlinger, Chief, NRC-Core Performance Branch, L.G. Hulman suggested that the Accident Evaluation Branch need not be involved in reload analysis as long as batch average burnup levels do not exceed 38,000 MWD/MTU (38.0 MWD/KG) at discharge. The fuel supplied by Exxon Nuclear Company which is currently in Donald C. Cook Nuclear Plant Unit 1 Cycle 8 is in Region 8 and Region 9. The fuel in Region 8 which will be discharged at the end of Cycle 8 has a design batch average burnup of 32,600 MWD/MTU (32.6 MWD/KG). The remaining Region 8 fuel will be completely discharged at the end of Cycle 9 with a design average burnup of 33,007 MWD/MTU (33.007 MWD/KG) for that batch. The fuel in Region 9 will be completely discharged at the

. end of Cycle 9 with a design batch average burnup of 34,061 MWD/MTU (34.061 MWD/KG). Reactor coolant system activity data for Unit 1 Cycle 8 indicates that some fuel assemblies are leaking, which will result in some design changes for Unit 1

'Cycle 9, with minor effects on the design batch average burnups at'ischaige.- Therefore', the fuel supplied by Exxon'uclear Company will not exceed 38,000 MWD/MTU (38.0 MWD/KG) batch average burnups at discharge, even though the peak pellet burnup may be up to 48,000 MWD/MTU (48.0 MWD/KG).

Mr. Harold R. Denton B-3 AEP:NRC:0745M On the basis of the above evaluations, we believe that the Technical Specifications changes associated with extending the peak pellet burnup from 42,200 MWD/MTU (42.2 WD/KG) to 48,000 MMD/MTU (48.0 MWD/KG) do not constitute a significant hazards consideration under 10 CFR 50.92. Me have further concluded that the extended burnup will not adversely. affect the environment since't will not result in radiological consequences greater than those previously analyzed.

Mr. Harold R. Denton AEP: NRC: 0745M Attachment C Reasons for the increase in F for fuel supplied by Westinghouse.

Mr. Harold R. Denton C-1 AEP:NRC:0745M The Justification for an increase in the F< allowed in fuel supplied by Westinghouse to 2.10 is based on a large break analysis which was performed with the December 1981 version of the Evaluation Model modified to incorporate the BART computer code. The analysis specific to Donald C. Cook Nuclear Plant, Unit 1 is included as Attachment D to this letter.

The most limiting single failure when offsite power is unavailable for D.C. Cook Unit 1 is analyzed with maximum safeguards because the current Appendix K models give more limiting results assuming the maximum possible ECCS flow delivery. In that case, maximum safeguards which assume minimum infection line .resistances, enhanced ECCS pump performance, and no single failure, result in the highest amount of flow delivered to the RCS. Westinghouse ECCS analyses currently performed for some other Westinghouse plants assune minimum safeguards because that assumption is more limiting for those plants than the maximum safeguards assumption.

Based on previous LOCA sensitivity studies, the limiting large break was found to be the double ended cold leg guillotine (DECLG). Therefore, only the DECLG break is considered in the large break ECCS performance analysis. Calculations were performed for a range of Moody break discharge coefficients.

Current LOCA analysis for the D.C. Cook Unit 1 has denanstrated that maximum safeguards assumptions result in the highest peak clad temperature. Therefore, the worst break for D.C. Cook (CD-0.6) was re-analyzed, assuming maximum safeguards.

The results of the analyses presented in Attachment D show that 1) the maximum clad temperature calculated for a large break is 2163 F, 2) the maximum local metal-water reaction is 9.65 percent, and 3) the total core metal-water reaction is less than 0.3 percent. The clad temperature tr ansient is terminated at a time when the core geometry is still amenable to cooling. As a result, the core temperature will continue to drop and the ability to remove decay heat generated in the fuel for an extended period of time will be provided. These calculations were performed at 102$ of the Design Thermal Power of 3411 MWT and a peaking factor of 2. 10.

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Mr. Harold R. Denton C-2 AEP: NRC: 0745M On the basis of the above evaluations, where the only differences from previously analyzed results are the change in the power level from 3250 MWt to 3411 Wt and an increased peaking factor F from 1.97 to 2. 10, which is based upon a change in the methods used to perform the analysis; and since the results of such analysis are within the guidelines specified in 10 CFR 50.46, we conclude that the change will not involve a significant hazards considerations as defined by 10 CFR 50.92.

Also since the accidents analyzed will not result in an increase in the radiological source term, we believe this change will not have an adverse effect to the environment.