ML052370381

Meeting Slides from Beaver Valley 8/24/05 Public Meeting

ML052370381
Person / Time
Site:	Beaver Valley
Issue date:	08/24/2005
From:	FirstEnergy Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation
References
Download: ML052370381 (34)

Text

BEAVER VALLEY POWER STATION Small Break LOCA Small Break LOCA Meeting

_____August 24, 2005

. -I .

Desired Outcome

.. ~~~~ ........ ,,....

Provide NRC with information on the Westinghouse NOTRUMP modeling considerations for SBLOCA Provide NRC with overview of BV plan to address SBLOCA issues Ensure NRC understanding with proposed approach and schedule Establish confidence in our proposed approach to support RSG installation 2

Agenda

.-Background

.Overview of SBLOCA issue

,'.Issue Description - specific to BV FENOC plans / schedule to address issue Preliminary NRC Questions

...Additional Questions / Comments 3

RSG Replacement

.. - ... o' .;

Critical Decision Points BV-1 Steam Generators are scheduled for replacement in 1R17 (Feb, 2006)

-. RSG fabrication complete *

--:N-stamp to be signed in September (to be shipped Sept. 3, 2005)

Steam Generators will be delivered to BV site in October 2005

• owners release at this point based upon ability to install 4

Current Submittal Background SBLOCA Modeling

Utilizes NOTRUMP Evaluation Model (EM)

'Integer' size breaks evaluated EPU/RSG submittal utilized loop seal clearing

• Both the intact and broken loops, down to [ ]aIc diameter N-loop model demonstrated all loop seals cleared Single analysis utilized for both EPU and RSG Is

NOTRUMP Evaluation Model (EM)

Comprised of two codes:

..-NOTRUMP

...System pressure, temperature, fluid level, fluid flow rate

.-Thermal-hydraulic transient in reactor coolant system and steam generators

• .SBLOCTA

.-Fuel rod heatup transient

Fuel cladding pressure, strain, temperature, burst, and transient oxidation 6

NOTRUMP Evaluation Model Input Geometric Data Thermal Hydraulic Intial Conditions Thermal Hydraulic Safety Injection Data > NOTRUMP Transient Technical Specifications Fuel Performance Data Fuel Performance Data Poak Clad Fuel Geometric Data SBLOCTA Temperature Core Power ~ and Fq, FAH, Pha Clad Oxidation

'I

NOTRUMP Code Features

• . . * <*S~t *; 4iI .k.;

.Bbo-;

.r. as;

.:.Meets requirements of Three Mile Island action plan (NUREG-0737)

General 1-D flow network, up to 200 nodes

Mixture level tracking in stacked nodes b Two-phase flow and drift flux models

Loop seal model 8

NOTRUMP Features cont.

t - m * :

S d9At 9{H i.-

Condensation heat transfer (Steam Generator)

..Core reflux model

..Flow regime mapping JCondensation of Safety Injection (COSI) condensation model 9

SBLOCTA Code Features

• ~ * .^' ; ,r4..:i Models 3 rods in hot assembly (hot, average, adjacent)

Radial and axial conduction [

]a

'Top-skewed power shape

..-Assembly blockage due to clad swell and rupture

..Zirc/water reaction - Baker/Just correlation

NOTRUMP WCAP History

'. .**--' A .

WCAP # SER Application WCAP-10054-P-A Letter from C. 0. Thomas (NRC) to Generic Over-all model E. P. Rahe (W), "Acceptance For application Referencing Of Licensing Topical Report WCAP 10079(P)

"NOTRUMP, A Nodal Transfer Small Break and General Network Code",

May, 1985.

WCAP-10079-P-A Letter from C. 0. Thomas (NRC) to Generic Code proper E. P. Rahe (W), "Acceptance For Referencing Of Licensing Topical Report WCAP 10054(P)

"Westinghouse Small Break ECCS Evaluation Model Using the NOTRUMP Code", May, 1985.

11

NOTRUMP WCAP History  ; - - ~. ~ ...-. -iir~.,.

WCAP # SER Application WCAP-11145-P-A Letter from C. E. Rossi (NRC) to L. Generic Forward-fit D. Butterfield (WOG), "Acceptance applicability for Referencing of Licensing Topical Report WCAP-11145", October 1986.

WCAP-10054-P-A, NRC Letter from R. C. Jones (NRC) Generic Addendum. 2, to N. J. Liparulo (W), "WCAP-Revision 1 10054-P, Addendum 2, Revision 1, COSI "NOTRUMP SBLOCA Using the COSI Steam Condensation Model," (TAC NO. M90784), August 1996.

12

NOTRUMP WCAP History

• ~~~~~ ;T>; - ;sA WCAP # SER Application WCAP-14710-P-A Letter from T. E. Collins (NRC) to N. Generic J. Liparulo (W), "Acceptance For Referencing Of The Topical Report WCAP-14710(P) "1-D Heat Conduction Model For Annular Pellets" (TAC NO. M96746), March 1998.

13

NOTRUMP EMI Application of NOTRUMP EM has remained unchanged since 1985 Code error corrections have been reported to NRC per Westinghouse 10 CFR 50.46 reporting process

.NSBU-NRC-O-5972, NRC Report for. NOTRUMP Version 38.0 Changes, June 30, 2000 EPU/RSG used Code Version 39

. V39.0 Reported in 2003 50.46 Annual Reporting Process 14

Non-integer Breaks

- . 5 -;._ .  ;

.,Staff questioned modeling of'integer' break sizes and requirements of 10 CFR 50.46 10 CFR 50.46 states in part, "number of postulated loss of coolant accidents of different sizes, locations, and other properties sufficient to provide assurance that the most severe postulated loss of coolant accidents are calculated" For Beaver Valley inclusion of non-integer size breaks produces limiting small break results 15

Non-integer Break Sizes

4. '-.

-0.25 inch increments used (25-27%

changes in break flow area per increment)

2 inch thru 3 inch This is considered adequate since Moody break flow model uncertainty is on the order of 30 to 40%

. -PCTcurve family is well characterized 16

Westinghouse Proprietary Class 2

\n1

Generic Methodology Considerations Loop seal clearing restriction NOTRUMP model nodalization Pre-transient oxidation Condensation modeling / considerations Modeling of break orientations

...:Consideration of breaks > 6 inch equiv diameter Transient termination considerations 18

Details of Beaver Valley Approach

• ,,*. . ,, . . ;_.S;.,... :_-,;.. . -,;

f *.:

Loop Ia,c seal clearing in broken loop only for break sizes less than [

] aC per WCAP-11145-P-A Maintain [ ]c NOTRUMP model 7.WCAP-10054-P-A Pre-transient oxidation addressed Non-integer size breaks addressed COSI Model application and break orientation addressed in WC-AP-10054-P-A Rev 1, Add 2 Document through RAI process Larger smaller breaks (0.5 and 1.0 ftA2 sizes) not limiting Transient extension after [ T in the NOTRUMP simulations since plant cooldown will occur per ES-1.2 It

EPU I RSG Plan Perform analysis at uprated thermal power I a,c

'..Possible credit extension of COSI condensation model

-t-Submit revised analysis / TS change to support RSG installation l0

Preliminary Results

,Revised analysis drafted for BV-1 Consideration of [SI Accumulator Pressure change]ac

-:PCT= 1920 F

.::Total Oxidation < 17%

21

Westinghouse Proprietary Class 2 Westinghouse Proprietary Class 2 a,c

Westinghouse Proprietary Class 2 a,c

EPU/AOR Comparison

--... . .. DiR u Differences in Unit 2 PCT EPU Results vs. AOR are mainly a trade-off between increased ECCS flow and [ Iac removal vs. core power

AOR: 3 inch break - 2,105OF

.;EPU: 3 inch break, no [ ]2C removal, AOR ECCS flows - 2,3260 F EPU: 3 inch break, no [ ]JC removal, EPU ECCS flows

- 1,996 0F

EPU: 3 inch break, [ ]aC removal, EPU ECCS flows -

1,6780 F

COSI Extension COSI

':.'..:Credits condensation of steam in RCS at safety injection points

. ..'rPart of Evaluation Model over pressure range of [

- atc psia (WCAP-10054-P-A, Rev 1 Add2)

Additional credit isjustified for pressure range down to [ ] psia I: Framatome studies

Safety Injection Condensation

_epic- i-o o f lo aters i t--eTstA.s.e Depiction of Flow Patterns in the COSI Test Assembly Si I

i Wr Cliffte- cumfnt TIAN41tri D 1av1Ir~

§1040 upstesaim flow Tct MLxLn%

butn.

DOWAeCOMI 27

COSI Extension Benefit a l~arc

Westinghouse Proprietary Class 2 a,c

• . -. - --;:- -.- Y' *...

9Lq

Westinghouse Proprietary Class 2 a,c j

30

Westinghouse Proprietary Class 2 a,c 31

Summary

• '%,Acceptable results obtained using approved NOTRUMP EM Break spectrum issue addressed Pre-transient oxidation included

- Loop seal clearing restrictions included

-. Generic methodology considerations are addressed by use of approved NOTRUMP EM.

32

Concluding Remarks T f B:

• Approach being taken in SBLOCA Analyses believed to address NRC issues Revised analyses are expected to support the established review schedule 33

Questions IAnswers 7e 34