ML020650564

Reduction in Requested Effective Full Power Years (EFPY) for Technical Specifications (TS) Change No. 414 - Pressure - Temperature (P-T) Curve Update, Response to Request for Additional Information

ML020650564
Person / Time
Site:	Browns Ferry
Issue date:	02/06/2002
From:	Abney T Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TVA-BFN-TS-414, Suppl 2
Download: ML020650564 (11)

Text

Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 February 6, 2002 TVA-BFN-TS-414 Supplement 2 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN:

Document Control Desk Washington, D.C.

20555-0001 Gentlemen:

In the Matter of

)

Docket Nos.

50-260 Tennessee Valley Authority

)

50-296 BROWNS FERRY NUCLEAR PLANT (BFN)

REDUCTION IN REQUESTED EFFECTIVE FULL POWER YEARS (EFPY)

FOR TECHNICAL SPECIFICATIONS (TS)

CHANGE NO.

414 -

PRESSURE TEMPERATURE (P-T)

CURVE UPDATE By letter dated August 17,

2001, TVA submitted a license amendment request for NRC approval of updated P-T curves for BFN Unit 2 and Unit 3.

Subsequent to the submittal of that request, the proposed changes to the P-T curves were discussed in teleconferences between members of the NRC staff and TVA personnel on October 18,

2001, on October 31,

2001, and again on November 26, 2001.

On December 14,

2001, BFN submitted TS-414 Supplement 1 to provide TVA's response to the issues raised by the NRC staff in these discussions.

Subsequent to the submittal of TS-414 Supplement 1, NRC raised additional questions regarding the conservatism of the neutron fluence values used in the calculation of the P-T curves.

This Supplement 2 addresses these questions.

The calculations supporting the revised P-T curves are based on an analytically established 32 EFPY neutron fluence of 1.12xlO3 n/cm2.

The license amendment request was for curves effective until 19.5 EFPY, therefore the proportional fluence value used in calculating the curves was 6.83x10 17 n/cm2. Subsequent to the December 14,2001, submittal of Supplement 1, the NRC staff took the technical position that these fluence values did not provide a margin of conservatism sufficient for this application.

While TVA differs with the NRC staff on this technical position, we are amending our q')

Printed on recycled paper

U.S. Nuclear Regulatory Commission Page 2 February 6, 2002 original request as follows in order to add further conservatism.

TVA requests that the P-T curves be approved using the same fluence value, but for a period of 17.2 EFPY for Unit 2 and 13.1 EFPY for Unit 3.

This reduces the original requested period by 2.3 EFPY for Unit 2 and 6.4 EFPY for Unit 3, and would extend the current, approved curves by only 1.2 EFPY for Unit 2.

The current, approved P-T curves for Unit 3 are valid for 20 EFPY.

The following conservatism margins are inherent in using the requested curves for the 17.2 EFPY and 13.1 EFPY intervals.

"* BFN Unit 2 and Unit 3 have both undergone thermal power uprates of 5% since they were initially licensed. General Electric (GE) has stated that it is reasonable to assume a fluence increase proportional to the power uprate for uprates of this magnitude.

TVA compensated the analytical fluence value used in the P-T curve calculations for the effects of the power uprate by adding 5% to it.

"* The analytical flux value increased by the factor of 5%

was assumed to have existed over the entire 32 EFPY period of interest for the BFN reactors.

In actuality the first 12.2 EFPY of Unit 2 operation and the first 7.4 EFPY of Unit 3 operation occurred at the originally licensed power level with the original, lower flux.

As of the date of this letter, Unit 2 has operated for 2.7 EFPY and Unit 3 for 3.4 EFPY at power uprate conditions. Attributing the higher, post-uprate fluence values to the period before uprate implementation provides additional conservatism in the fluence value used in the calculations.

"* Analysis of the surveillance capsule removed from Unit 2 during its 1994 refueling outage provided evidence that the actual neutron fluence was substantially lower than the analytical value.

Data from this sample, pulled after 8 EFPY of operation, indicated that the 32 EFPY fluence would be on the order of 6.05xi017 n/cm2, well below the 1.12x10'8 n/cm2 analytical value used in the calculations.

U.S. Nuclear Regulatory Commission Page 3 February 6, 2002 eThe requested P-T curves are calculated using a fluence value of 6.83xi01 7 n/cm2.

The actual predicted fluence value for Unit 2 at 17.2 EFPY is 5.83x1017 n/cm2, and the actual predicted fluence value for Unit 3 at 13.1 EFPY is 4.47xi01 7 n/cm2.

The higher value used in the calculations relative to the actual predicted fluence provides further conservatism in the analysis.

Taken in their totality, the above conservatism factors provide an adequate margin to compensate for any fluence uncertainties resulting from analytical methods used.

TVA is actively preparing a submittal to request extended power uprates for Unit 2 and Unit 3.

As part of this work, a fluence calculation using the recently approved Regulatory Guide 1.190 methodology will be performed to establish P-T curves appropriate for extended power uprate operation.

The newly calculated curves will be submitted by mid-2003 for NRC approval by early 2004.

Approval of the currently requested P-T curves for 17.2 and 13.1 EFPY for Unit 2 and Unit 3, respectively, will cover plant operation until that time.

Use of the requested P-T curves in the upcoming Unit 3 refueling outage will provide substantial industrial safety benefits to workers.

This is because the requested curves incorporate relief provided by ASME Code Case N-640 which removes unnecessary restrictions to the pressure-temperature operating window.

These restrictions challenge the operations staff during pressure tests to maintain a high temperature within a limited operating window, and the higher temperatures result in greater physical stress on the inspection personnel working in the vicinity of the piping.

For these reasons BFN requests approval of the P-T curves by March 1, 2002. to this letter contains the updated, marked up pages of the appropriate TS for Unit 2 and for Unit 3.

contains the updated copies of the revised pages as they would appear following approval of this request.

TVA has determined that the proposed finding of no significant hazards considerations and environmental impact consideration as submitted in the August 17, 2001 letter remain valid.

The technical details of the license amendment request as described in the December 14, 2001 Supplement 1 submittal have not been

U.S.

Nuclear Regulatory Commission Page 4 February 6, 2002 changed, therefore no additional review by the BFN Plant Operations Review Committee or the BFN Nuclear Safety Review Board was required.

Their previous reviews determined that operation of BFN Units 2 and 3 in accordance with the proposed change will not endanger the health and safety of the public.

TVA's request for exemption from the requirements of 10 CFR 50, Appendix G, which was submitted in conjunction with TS-414 to allow the use of ASME Code Case N-640 as a basis for the revised

curves, is not affected by this supplemental submittal.

There are no new commitments contained in this letter.

If you have any questions about this change, please telephone me at (256) 729-2636.

S ceree T. E.

./

Man r of Licensing d Industry Aff irs Subs

'bed and orn to before me on this t

day of February 2002.

Notary Public My Commission Expires 09/22/02

U.S.

Nuclear Regulatory Commission Page 5 February 6, 2002 Enclosures cc (Enclosures):

State Health Officer Alabama Department of Public Health RSA Tower - Administration Suite 1552 P.O.

Box 303017 Montgomery, Alabama 36130-3017 (Via NRC Electronic Distribution)

Mr.

Paul Fredrickson, Branch Chief U.S. Nuclear Regulatory Commission Sam Nunn Atlanta Federal Center Region II 61 Forsyth Street, S.

W.,

Suite 23T85 Atlanta, Georgia 30303-8931 Mr.

Kahtan N.

Jabbour, Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident Inspector Browns Ferry Nuclear Plant P.O.

Box 149 Athens, Alabama 35611

ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)

UNITS 2 AND 3 PROPOSED TECHNICAL SPECIFICATION (TS)

CHANGE TS-414 SUPPLEMENT 2 MARKED PAGES I.

AFFECTED PAGE LIST Unit 2 -

page 3.4-29 Unit 3 -

page 3.4-29 I I.

MARKE D PAGE S See attached.

Added "ASME" for additio clarity in this note.

BROWNS FERRY UNIT 2 1 2 3

These curve6h avee el e e d RCS P/T Limits 3.4.9 nal SCurve No. 1 Minimum temperat r pressure tests such as required by ASME Section XI.

Curve No. 2 Minimum temperature for mechanical heatup or cooldown following nuclear shutdown.

Curve No. 3 Minimum temperature for core operation (criticality).

1500 1400 1300

-* 1200 C.

1100 0

=

9 1000 0

6-5900 C,)

a, 800 3700

.c 600 Em

" 500 a,S400 a,.

300 Figure 3.4.9-1 Pressure/Temperature Limits BFN-UNIT 2 3.4-29 Amendment No. 257 January 15, 1999 1600 ow in En los r 2 bel v Notes SThese curves include sufficient margin to provide protection against feedwater nozzle

____degradation.

The curves allow for shifts in RTNDT of the Reactor vessel beltline materials, in accordance with Reg. Guide 1.99,

__Rev.

2, to compensate for radiation embrittlement for-46 17.2 EFPY.

CURVES 1, 2, & 3 ARE VALID FOR

/

46-17.2 EFPY OF OPERATION 100 150 200 250 300 350 400 mum Reactor Vessel Metal Temperature (OF)

The period of valid use f these curves has been changed from 16 to 17.2 EFPY.

200 100 0

312 PSIG BOLTUP 820F I

I 0

50 Mini

RCS P/T Limits 3.4.9 Added "ASME" for additional clarity in this note.

Curve No. 1 Minimum tempeture for pressure tests such as required by ASMESection Xl.

Curve No. 2 Minimum temperature for mechanical heatup or cooldown following nuclear shutdown.

Curve No. 3 Minimum temperature for core operation (criticality).

Notes These curves include sufficient margin to provide protection against feedwater nozzle degradation. The curves allow for shifts in RTNDT of the Reactor vessel beltline materials, in accordance with Reg. Guide 1 99, Rev. 2, to compensate for radiation embrittlement for 13.1 EFPY.

1600 1600 1400 1300 The period of valid use of these curves has been changed from 20 to 13.1 EFPY Figure 3.4.9-1 Pressure/Temperature Limits BFN-UNIT 3 3.4-29 Amendment No. 217 January 15, 1999 1

2 3

I fese turves ave ee deleted ad re Laced ith

'e curvs s own in Elosjr6 2 elow 312 PSIG CURVES 1, 2, & 3 ARE VALID 70'U FOR 1EFY OF 70 0 F OPERATION 1200 U 1100 0

S1000 U,

(n 900 LU.

0 800 LU 700 600 W 500 Ct) 400 W

U.'

300 200 100 0

BROWNS FERRY UNIT 3

• 00 0

50 100 150 200 250 300 350 4

MINIMUM REACT-. OR*

U VI:bb,,L MEl I/,L I I::VlIr"I*U" I UIE 1rp -

ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)

Units 2 and 3 PROPOSED TECHNICAL SPECIFICATION (TS)

CHANGE TS-414 SUPPLEMENT 2 REVISED PAGES I.

AFFECTED PAGE LIST Unit 2 Page 3.4-29 Unit 3 Page 3.4-29 II.

REVISED PAGES See attached.

RCS P/T Limits 3.4.9 I I I I I I I I I I I I I I I I I I I BROWNS FERRY LNIT2 CLRVES 1, 2, &3AFE VAUD FOR 17.2EFPY OF OPERA11ON 1 -

2 3l i t J/

.1/u 11.'

I I

I 4

I U

S W

W1

..1

.211 200 --

0 BOLTUP 82OcF I

I I

r r *

=f I, /

L 312 PSIG f I I A If r.

50 100 150 200 1600 1500 1400 1300-250 MIiMUM I

ECTORVESSEL METAL TEv¶PBATLE(°F)

Figure 3.4.9-1 Pressure/Temperature Limits BFN-UNIT 2 3.4-29 Amendment No.

(approval date)

Curve No. 1 Minimum temperature for pressure tests such as required by ASME Section X1.

Curve No. 2 Minimum temperature for mechanical heatup or cooldown following nuclear shutdown.

Curve No. 3 Minimum temperature for core operation (criticality).

Notes These curves include sufficient margin to provide protection against feedwater nozzle degradation. The curves allow for shifts in RTNDT of the Reactor vessel beltline materials, in accordance with Reg. Guide 1.99, Rev. 2, to compensate for radiation embrittlement for 17.2 EFPY.

.- 1200 U)

< 1100 LU D.

O1000

-J w

U)

U) 900 w

o 800 I

w W 700 z

I,-.

LU W

,I)

CO 0.

100 0

I 400 I

II r

RCS P/T Limits 3.4.9 1500 1400 1300 1200

-1100 0

LU x

CL 1000 0

-J W

(n 900 W

LUJ o

800 W

W 700 j

600 W

W 400 300 200 100 0

50 100 150 200 MINIMUM REACTOR VESSEL METAL TEMPERATURE ('F)

I I

I I

I I

2 BROWNS FERRY UNIT3 3' 1

CURVES 1, 2, & 3 ARE VALID FOR 13.1 EFPY OF OPERATION PI I

r BOLTUP 70 OF

000, 250 Figure 3.4.9-1 Pressure/Temperature Limits BFN-UNIT 3 3.4-29 Amendment No.

(approval date) 1600 Curve No. 1 Minimum temperature for pressure tests such as required by ASME Section XI.

Curve No. 2 Minimum temperature for mechanical heatup or cooldown following nuclear shutdown.

Curve No. 3 Minimum temperature for core operation (criticality).

Notes These curves include sufficient margin to provide protection against feedwater nozzle degradation. The curves allow for shifts in RTNDT of the Reactor vessel beltline materials, in accordance with Reg. Guide 1.99, Rev. 2, to compensate for radiation embrittlement for 13.1 EFPY.

0