ML20087D311

Proposed Tech Specs,Relocating Heat Flux Hot Channel Factor F (Z),Penalty of Two Percent in SR 4.2.2.2.e.1 to COLR to Allow for burnup-dependent Values of Penalty in Excess of Two Percent

ML20087D311
Person / Time
Site:	Sequoyah
Issue date:	08/07/1995
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20087D307	List: ML20087D304 ML20087D311
References
NUDOCS 9508100272
Download: ML20087D311 (9)

Text

- , . . . _ _ .

4 - .

. POWER DISTR.IBUTION LIMITS e

-SURVEILLANCE REQUIREMENTS (Continued)

e. 'With measurements indicating .

g4 Fwr oR.

K spec.u= M m TWd 00A maximum' l over z K(z) i has increased since the previous determinatin of F M e of the following actions shall be taken: 9 (z) either

1. F M(z) shall .be increased [irf/Vsafr/pfftl over that specified in q

4.2.2.2.c & -

M

2. Fq (z) shall be measured at least once per 7 effective full A power days until 2 successive maps indicate that

~

maximum (Z) is not increasing.

over z , K(z)

f. With the' relationships specified in 4.2.2.2.c above not being satisfied:

1.

Calculate the percent F expression: g (z) exceeds its limit by the following r

N Fg (z) x W(z)

\ w maximum ) -1 x 100

-( _for P > 0.5 p tTP

'over 2 >,

x g(7) R159-r s N

maximum Fg (z) x W(z) -1 x 100 4 over z for P < 0.5 p ETP x g(2) > R159 I

0.5 ,

_,, f.

2. Either of the following actions shall be taken:

a. Place the core in an equilibrium condition where the~

limit in 4.2.2.2.c-is satisfied. Power level may then be increased provided the AFD limits of Specifi-cation 3.2.1 are reduced 1% AFD for each percent F (z) lR159 exceeded its lioit, or q

.j

b. Comply with the r*quirements of Specification 3.2.2.for Fq (z) exceeding its limit by the percent calculated above.

9508100272 950007 7 R144 l PDR ADOCK 0500 SEQUOYAH - UNIT 1 3/4 2-7 Amendment No. 19, 95, 140, 155 ,l October 23, 1991-

.l

- ~ - , ,- ,

e n - - , ., , ,,..m- , e.

ADMINISTRATIVE CONTROLS HOMTHLY REACTOR OPERATING REPORT 6.9.1.10 Routine reports of operating statistics and shutdown experience, including documentation of all challenges to the PORVs or Safety Valves, shall be submitted on a R76 monthly basis no later than the 15th of each month following the calendar month covered by the report.

CORE OPERATING LIMITS REPORT 6.9.1.14 Core operating limits shall be established and documented in the CORE OPERATING LIMITS REPORT before each reload cycle or any remining part of a reload cycle for the following:

1. Moderator Temperature Coefficient BOL and E0L limits and 300 ppm surveillance limit for Specification 3/4.1.1.3, R159

2. Shutdown Bank Insertion Limit for Specification 3/4.1.3.5,

3. Control Bank Insertion Limits for Specification 3/4.1.3.6, f}e t9

4. Axial Flux Difference Limits for Specification 3/4.2.1,

[

5. Heat Flux Hot Channel Factor, K(z), @W(z)ffor Specification 3/4.2.2, and p

6. Nuclear Enthalpy Hot Channel Factor and Power Factor Multiplier for A Specification 3/4.2.3.

6.9.1.14.a The analytical methods used to determine the core operating limits shall be those previously reviewed and approved by NRC in:

i

@$ A I

h 1 ie l

1. WCAP 9272 P A, ' WESTINGHOUSE RELOAD SAFETY EVALUATION I Ph i HETH000 LOGY", July 1985 (W Proprietary).

(Methodology for Specifications 3.1.1.3 Moderator Temperature I I4Ls Coefficient, 3.1.3.5 Shutdown Bank Insertion Limit. 3.1.3.6 Control '$ig Bank Insertion Limits, 3.2.1 Axial Flux Difference, 3.2.2 Heat Flux 1 i

2.

Hot Chann WCAP 10216 P.

L VIStars p

.3 - Nuclear Enthalpy Hot Channel Factor.)

"RELAXATIOb 0F CONSTANT AXIAL OFFSET CONTROL F, SURVEILLANCE e[

3 TECHNICAL SPECIFICATION",((UN719@i(W Proprietary). >

(Methodology for Speci ication 3.2.1 Axial Flux Difference (Relaxed h pggu M I N Axial Offset Control) nd 3.2.2 - Heat Flux Hot Channel Factor (W(z) f2 i surveillance require nts for F Methodology).)

a tA

3. WCAP 10266 P A Rev. 2. "THE 1981 REVISION OF WESTINGHOUSE EVALUATION H00EL USING BASH CODE", March 1987, (W Proprietary).

k (Hethodology for Specification 3.2.2 Heat Flux Hot Channel Factor).

4. WCAP 13631 P A, " SAFETY EVALUATION SUPPORTING A MORE NEGATIVE E0L H00ERATOR TEMPERATURE COEFFICIENT TECHNICAL SPECIFICATION FOR THE SEQUOYAH NUCLEAR R175 PLANTS," HARCH 1993 (W Proprietary).

(Hethodology for Specification 3.1.1.3 Moderator Temperature Coefficient)

SEQUOYAH UNIT 1 6-21 Amendment Nos. 52. 58. 72, 74 October 26, 1993 117, 152, 155, 156, 171

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued)

e. With measurements indicating

~~ ~

By rwc- Moto t*2 8 MY=-

pae.7 aa sg%s-eeoa-o t ^'

maximum Ff(z) ng COL.A.

over z K(z) A has of increased the followingsince theshall actions previous determinatin of Fq (z) either be taken:

1 N

1. Fq (z) shall be increased /y/24e/cp6)d over that specified 4.2.2.2.c N

2. Fq (z) shall be measured at least once per 7 effective full R21 power days until 2 successive maps indicate that maximum FM (z) is not increasing.

over z K(z) f.

With the relationships specified in 4.2.2.2.c above not being satisfied: i i

1. Calculate the percent qF (z) exceeds its limit by the following '

expression:

N maximum Fn (z) x W(z) -l x 100 for P > 0.5 4I over z >

~

x g(7) l R146 A p:RTP

/ .

l maximum (*)

• N(Z) -1 x 100 for P < 0.5 4 over z p RTP >

x K(z) R146

_,.5 .g

2. Either of the following actions shall be taken:

g

a. Place the core in an equilibrium condition where the limit in 4.2.2.2.c is satisfied. Power level may then be increased provided the AFD limits of Specifi- R146 cation 3.2.1 are reduced 1% AFD for each percent Fq (z) exceeded its limit, or

b. Comply with the requirements of Specification 3.2.2 for RT Fq (z) exceeding its limit by the percent calculated above.

SEQUOYAH - UNIT 2 3/4 2-6 Amendment No. 21, 95, 131, 146 March 30, 1992

l l

-ADMINISTRATIVE CONTROLS MONTHLY REACTOR OPERATING REPORT- j 1

6.9.1.10 Routine reports of operating statistics and shutdown experience, including )

documentation of all challenges to the PORVs or Safety Valves, shall be submitted on a R64 1

. monthly basis no later than the 15th of eacn month following the calendar month covered 1 by the report. I l

CORE OPERATING LIMITS REPORT j

-6.9.1.14 Core operating limits shall be established and documented in the CORE l OPERATING LIMITS REPORT before each reload cycle or any remaining part of a rt: load cycle i for the following:

R146

1. Moderator Temperature Coefficient BOL and E0L limits and 300 ppm surveillance limit for Specification 3/4.1.1.3,

2. Shutdown Bank Insertion Limit for Specification 3/4.1.3.5, v ),l j g} g

3. Control Bank Insertion Limits for Specification 3/4.1.3.6, #

fj

4. Axial Flux Difference Limits for Specification 4.2.1, .

fU

5. Heat Flux Hot Channel Factor K(z),QW(z)vfor Specification 3/4.2.2, and h

6. Nuclear Enthalpy Hot Channel Factor and Power Factor Multiplier for Specification 3/4.2.3. k(

m i

h i 6.9.1.14.a The analytical methods used to determine the core operating limits shall be P , i those previously reviewed and approved by NRC in: j c! -

1.

-3 WCAP 9272 P A. " WESTINGHOUSE RELOAD SAFETY EVALUATION METH000 LOGY", July 1985 (W Proprietary). j, '4 (Methodology for Specifications 3.1.1.3 Moderator Temperature Coefficient 3.1.3.5 Shutdown Bank Insertion Limit. 3.1.3.6 Control

( f o4 Bank Insertion Limits, 3.2.1 Axial Flux Difference, 3.2.2 Heat Flux f I!

g Hot Channel Factor, and 3.2.3 Nuclear Enthalpy Hot Channel Factor.) g[q j WCAP 10216 P A) "RELAXATIOi 0F CONS" ANT AXIAL OFFSET o CONTROL F$ SURV l TECHNICAL SPECIFICATION",lAOK)9&T (WProprietary).

(Methodology for Spec ication 3.2.1 Axial Flux Difference (Relaxed cn0 -i -

F444uiq l'l'l Axial Offset Control) and 3.2.2 Heat Flux Hot Channel Factor (W(z) 'E D-i

=

q veillance requir nts for F aMethodology).) /

3. WCAP 10266 P A Rev. 2, "THE 1981 REVISION OF WESTINGHOUSI EVALUATION MODEL bl USING BASH CODE" March 1987, (W Proprietary). '

(Methodology for Specification 3.2.2 Heat Flux Pot Channel Factor).

4. WCAP 13631 P A. " SAFETY EVALUATION SUPPORTING A MORE NEGATIVE EOL MODERATOR TEMPERATURE COEFFICIENT TECHNICAL SPECIFICATION FOR THE SEQUOYAH NUCLEAR PLANTS," HARCH 1993 (W Proprietary).

(Methodology for Specification 3.1.1.3 Moderator Temperature Coefficient) 6.9.1.14.b The core operating limits shall be determined so that all applicable limits (e.g., fuel thermal mechanical limits, core thermal hydraulic limits, ECCS limits. R146 nuclear limits such as shutdown margin, and transient and accident analysis limits) of the safety analysis are met.

SEQUOYAH UNIT 2 6 22 Amendment Nos- 44, 50, 64 Ocotber 26, 199366, 107, 134, 146, 161

o : 7 ':

!* l W

J ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE SEQUOYAH NUCLEAR PLANT (SON) UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SON-TS-95-17)

DESCRIPTION AND JUSTIFICATION FOR HEAT FLUX HOT CHANNEL FACTOR SURVElLLANCE AND CORE OPERATING LIMITS REPORT REVISION

Descriotion of Chanae TVA proposes to modify the Sequoyah Nuclear Plant (SON) Units 1 and 2 technical specifications (TSs) by transferring the two percent penalty in Surveillance Requirement (SR) 4.2.2.2.e.1 to the Core Operating Limits Report (COLR).

Accordingly, the following changes are being proposed:

1. SR 4.2.2.2.e.1 will have the phrase "by 2 percent" deleted and the phrase '~by the appropriate factor specified in the COLR" added.

2. TS 6.9.1.14.5 will have a reference to the penalty term that was deleted from SR 4.2.2.2.e.1 added.

3. TS 6.9.1.14.a.2 will be revised to reference Revision 1 A of Westinghouse Commercial Atomic Power (WCAP) 10216-P-A," Relaxation of Constant Axial Of fset Control - Fo Surveillance Technical Specification," dated February 1994.

Reason for Chanae Recently, some Westinghouse Electric Corporation designed cores have experienced increases in the measured value of the heat flux hot channel factor, Fo(Z), as high as five to six percent between monthly measurements over certain burnup ranges.

Therefore, the assumption that Fo(Z) will not increase by more than two percent over a burnup interval of 31 effective full power days (EFPD) is not conservative. To address this issue, Westinghouse submitted to NRC Revision 1 of WCAP 10216-P, which was approved by NRC on November 26,1993. The revised WCAP incorporates minor methodology changes to account for Fo(Z) increases of greater than two percent between monthly surveillances.

Justification for Chanaes During normal operation, Fo(Z) is shown to be within its limit by performing periodic measurements. Since Fo(Z) surveillance is required when power has been increased by 10 percent of rated thermal power from the previous surveillance, or at least every 31 EFPD, the TSs take into account the possibility that Fo(Z) may increase between surveillances. The TS requires that when performing the surveillanco, the resulting maximum Fo(Z) value must be compared to the maximum Fo(Z) determined from the previous measurement. H the maximum Fo(Z) has increased since the previous determination of Fo(Z), the TS allows two options. Either the current Fo(Z) must be increased by an additional two percent to account for further increases in Fo(Z) before the next surveillance, or the surveillance period must be reduced to every seven EFPD.

. 2-The Fo(Z) penalty of two percent was based on the Westinghouse assumption that Fo(Z) would change by no more than two percent between monthly flux maps. This assumption was based on calculations for previous core designs that predate the low-leakage loading patterns, high amounts of burnable poisons, and 18-month cycles typical of recent cores. Recently, some Westinghouse-designed cores experienced increases in the measured Fo(Z) as high as five to six percent between monthly flux maps over certain burnup ranges. Therefore, for those cores that are predicted to have larger increases in Fo(Z) over certain burnup ranges, a larger penalty will be provided on a cycle-specific basis. The penalties will be calculated using NRC-approved methods.

The burnup-dependent penalty will be included in the cycle-specific COLR as a replacement to the standard value of two percent in the current TS. The penalty will be presented in tabular form specifying the values, at specific burnups, that are in excess of two percent. At all other burnups, the COLR willindicate that the standard l two percent penalty will still apply.

The staff has determined that the above-described method for accounting for the additional Fo(Z) penalty, including the relocation of the penalty to the COLR, is acceptable. The staff's conclusiens are documented and have been included in the approved topical report WCAP 10216-P-A, Revision 1 A.

Environmental Imoa_qt Eveluation The proposed change does not involve an unreviewed environmental question because operation of SON Units 1 and 2 in accordance with this change would not:

1. Result in a significant increase in any adverse environmentalimpact previously evaluated in the Final Environmental Statement (FES) as modified by NRC's testimony to the Atomic Safety and Licensing Board, supplements to the FES, environmentalimpact appraisals, or decisions of the Atomic Safety and Licensing Board.

2. Result in a significant change in effluents or power levels.

3. Result in matters not previously reviewed in the licensing basis for SON that may have a significant environmentalimpact.

I

_m_._,.___..___.____ . _ _ . _ . _ __ _ _ _ _ . . . _ _ _ _ . _ . . _ _ _ _ . _ _ _ _ _ _ , _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

c' * ..

ENCLOSURE 3 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT (SON) UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SON-TS-95-17)

DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION FOR THE HEAT FLUX HOT CHANNEL FACTOR AND CORE OPERATING LIMITS REPORT REVISION I

1 l

d 1

a .

A Significant Hazards Evaluation TVA has evaluated the proposed technical specification (TS) change and has determined that it does not represent a significant hazards consideration based on criteria established in 10 CFR 50.92(c). Operation of Sequoyah Nuclear Plant (SON) in accordance with the proposed amendment will not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change involves only the manner in which the penalty factors for Fo(Z) would be specified (i.e., a burnup-dependent factor specified in the Core Operating Limits Report [COLR) versus a constant factor specified in the TS).

This is simply used to account for the fact that Fo(Z) may increase between surveillance intervals. These penalty factors are not assumed in any of the initiating events for the accident analyses. Therefore, the proposed change will havo no effect on the probability of any accidents previously evaluated. The penalty factors specified in the COLR will be calculated using NRC-approved methodology and will therefore continue to provide an equivalent level of protection as the existing TS requirement. Therefore, the proposed change will not affect the consequences of any accident previously evaluated.

2. Create the possibility of a new or different kind of accident from any previously analyzed.

The proposed change does not involve a physical alteration to the plant (no new or different kind of equipment will be installed) or alter the manner in which the plant would be operated. Thus, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Involve a significant reduction in a margin of safety.

The proposed change will continue to ensure that potentialincreases in Fo(Z) over a surveillance interval will be properly accounted for. The penalty factors will be calculated using NRC-approved methodology. Therefore, the proposed change will not involve a reduction in margin of safety.