ML20210G861
| ML20210G861 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 09/22/1986 |
| From: | Sears P Office of Nuclear Reactor Regulation |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8609250483 | |
| Download: ML20210G861 (16) | |
Text
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September 22, 1986 Docket No. 50-309 MEMORANDUM FOR:
Ashok C. Thadani, Director PWR Prcject Directorate #8 Division of PWR Licensing-B FROM:
Patrick M. Sears, Project Manager PWR Project Directorate #8 Division of PWR Licensing-B
SUBJECT:
SUMMARY
OF MEETING HELD ON SEPTEMBER 9, 1986 CONCERNING MAINE YANKEE LARGE BREAK LOCA ANALYSIS AXIAL POWER SHAPE The meeting was held in Bethesda, Maryland.
Those attending are listed in.
Maine Yankee described in more detail information previously given the staff in a telecon on September 2, 1986.
Yankee Atomic, which performs Maine Yankee's fuel reload analyses, discovered that the highly peaked axial power distribution used in Maine Yankee's Large Break LOCA Analyses since 1977 is not the bounding shape.
The bounding shape is a flattened shape which gives higher peak clad temperatures especially later in the life of the reload.
New interim administrative procedures on peaking factors are being implemented to assure compliance with 10 CFR 50.46.
Since Maine Yankee's Cycle 10 reload submittal is in preparation, Maine Yankee personnel outlined a course of action which would facilitate review.
They 3
would do the following:
l 1.
Modify the injection p penalty and the power level used in the reflood hydraulics calculation.
These changes are relatively straight forward and also similar to changes made previously for other ECCS analyses.
This will be done in time for the first half of Cycle 10.
2.
Modify the reflood steam cooling model for the second half of Cycle 10 at a later date.
8609250483 860922 PDR ADOCK 05000309 P
PDR i
l.
These actions are outlined briefly in Enclosure 2.
Maine Yankee requested another meeting in approximately 3 weeks to present a more " fleshed out" plan of action for RSB comment.
/S/
Patrick M. Sears, Project Manager PWR Project Directorate #8 Division of PWR Licensing-B
Enclosure:
As stated 2
cc w/ enclosure:
See next page i{ $ K zer a :Jch d ni CJ'$$ 9 /86 9/t?/86 9// 86 9// 9 86
F-Mr. J. B. Randazza Maine Yankee Atomic Power Company Maine Yankee Atomic Power Station cc: Charles E. Monty, President Maine Yankee Atomic Power Company Mr. P. L. Anderson, Project Manager Yankee Atomic Electric Company 83 Edison Drive 1671 Worchester Road Augusta, Maine 04336 Framingham, Massachusetts 07101 Mr. Charles B. Brinkman Mr. G. D. Whittier Manager - Washington Nuclear Licensing Section Head Operations Maine Yankee Atomic Power Company Combustion Engineering, Inc. 83 Edison Drive 7910 Woodmont Avenue Augusta, Maine 04336 Bethesda, Maryland 20814 John A. Ritsher, Esquire Ropes & Gray 225 Franklin Street Boston, Massachusetts 02110 State Planning Officer Executive Department 189 State Street Augusta, Maine 04330 Mr. John H. Garrity, Plant Manager Maine Yankee Atomic Power Company P. O. Box 408 Wiscasset, Maine 04578 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 First Selectman of Wiscasset Municipal Building U.S. Route 1 Wiscasset, Maine 04578 Mr. Cornelius F. Holden Resident Inspector c/o U.S. Nuclear Regulatory Commission P. O. Box E Wiscasset, Maine 04578
r -- September 9,1986 -Name Organization P.M. Sears NRR, Maine Yankee Project Manager Cecil Thomas NRR, RSB Robert Jones NRR, RSB N. Lauben NRR, PBRS G. Douglas Whittier George Solan Maine Yankee, Manager, Nuclear Engineering & License Yankee Atomic Ausaf Husain Yankee Atomic Jamal Ghaus Yankee Atomic William J. Metevia Yankee Atomic / Maine Yankee Project Howard F. Jones, Jr. Maine Yankee Atomic Power Co. I l l
MY LOCA ANALYSIS AT YAEC (BACKGROUND) YAEC METHOD WAS FIRST USED FOR MY CYCLE 5 ANALYSIS CE ANALYSIS HAD IDENTIFIED TOP SKEW POWER SHAPE CONSERVATIVE MY SYMMETRIC 0FFSET LIMITS WERE USED TO DEFINE TOP SKEW POWER SHAPES I TOP SKEW POWER SHAPE USED FOR LHGR FOR PEAK ABOVE CORE MID PLANE l CH0PPED COSINE USED FOR LHGR FOR PEAK BELOW CORE MID PLANE l VERIFIED THAT LOCA DESIGN SHAPE IS VALID EACH CYCLE BY REEXAMINING POWER SHAPES RECENT STUDIES WITH YR SHOWED FLATTER POWER PROFILES MORE LIMITING. EXAMINATION OF MY CYCLE 10 SHAPES REVEALED FLATTER POWER PROFILES DO EXIST t CYCLE 9 LIMITS WERE RE-ANALYZED WITH FLATTER POWER SHAPES AND ADMIN. LIMITS IMPOSED ON PLANT OPERATION AH: SEPT. 9, 1986
I Figure 1 Maine Yankee Design Power Distributions 2.0 FSAR Design 1.68 l.41 1.5 l LOCA Design Normalized 1.0 Axial Power Distribution Design --Symnetric Offset-- LCO Shape Assembly Peripheral Power 0.5 Case Shape w/ Uncertainty Level FSAR +0. 315 +0.30 0-100% LOCA +0.23 +0.11 100% 9 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Fraction of Core Height
l, e ~ A Figure Maine Yankee Cycle 5 LOCA Axial Power Distributions compared to 3 liighest Core lleight Peaking Case (Steady-State) 20 00 i i i i i i i 10.00__ LOCA 16.0 kw/ft 16.00-- ~ Presumed LOCA Limit Core Height 14 00~~ Dependence ~ LOCA ,4 ~~ 14.0 kw/ft, # 12 00__
- a. /
N s- / Q It0 00__ / liighest Core Height ~- / o- / Peaking, Steady-State S 9.00_ 11.3 kw/ft a S 30__ .t.00__ / i / 2.00a I, 0 00 e i i i 0.JD , l' O .d0 , :;0 20 40 50 .iG 50 50 ' 1.bc REL ATIVE CORE HE!GHT
Figure Maine Yankee Cycles 5-9 T,0CA Axial Power Distributions compared to Tech. Spdc. Limit 4 and Envelope of Measured Plant Operation with Uncertainties 20 00 i i i t i i i i i I I I 3 I I i 1 19.00__ Tech. Spec. 16 kw/ft 16 00 Tech. Spec. 14 kw/ft 14 00__ ,x / / 12.00__ ,.2 n w Envelope of Measured N (10 00__ Operation with Uncertainties f (includes controlled power e / reductions, coastdown and $ 3 0g__ full power operation) a S-00__ / .t.00__ / 2.00a i. 0 00 i i i i i 0-JD 1' O .d0 .i0 .t0 . d> 0 .d0 .IO . '. O 50 1.b0 REL ATIVE CORE HE!GHT
FIGURE 5 COMPARISON OF ACCEPTABLE LHGR TO EXPECTED LHGR g-k- T.s 3.10.c.1 Eih:- - 0 's, %g % 's,, %g % g z-N~~c a C %g' kUh 2 N M ENVELOPE OF PROPOSED ADMIN. s ~ EXPECTED MRX. LNGR'S 'N / LIMIT en CD * - ~, 1 %g h \\ \\ \\ \\ e-i, f \\ j \\ h m-m- A i i a 0 20 40 60 80 100 CORE HEIGHT (%)
F MY CYCLE 10 LOCA ANALYSIS WANT Av0!D POWER DERATE Av0!D UNWARRANTED OPERATING RESTRICTIONS HIGHER LOCA LIMITS EfD FOLLOWING MODEL CHANGES APPROVED INJECTION AP PENALTY AVERAGE CORE REPRESENTATION FOR FLOODING CALC. REVISED STEAM COOLING CALCULATION AH/ SEPT. 9, 1986
INJECTION 6P PENALTY CURRENT MY MODEL (BASED ON XN-75-41) AP PENALTY ANGLE OF INJECTION WITH WITHOUT Act Ann 0 90 1.8 0.8 75 1.5 0.35 60 0.4 0.35 45 0.6 0.30 XN-NF-78-30 MODEL o BASED ON EPRI-294 " MIXING 0F ECC WATER WITH STEAM" 1/148 1/3 SCALE TESTS o AP = 0.15 PSID FOR PUMPED FLOW o GENERIC APPROVAL SER 3/30/79 YANKEE R0WE o AP = 0.15 FOR PUMPED FLOW SER 11/27/85 PROPOSE FOR MY APPLICATION o AP =~0.15 FOR PUMPED FLOW AH/ SEPT. 9, 1986 ?
e REVISED CORE MODEL DURING REFLOOD CURRENT MODEL HYDRAULICS: ALL ASSEMBLIES CONSIDERED HOT ASSEMBLY POWER = 1.02 x POWER x F ASS. TEMPERATURE OF CORE AT HOT ASSEMBLY CONDITIONS HEAT-UP: H0T R0D WITH T00DEE2-EM PROPOSED MODEL HYDRAULICS: CORE MODELLED WITH REPRESEN-TATIVE ASSEMBLIES POWER = 1.02 x POWER TEMP 0F CORE WITH REPRESEN-TATIVE ASSEMBLY HEAT-UP: HOT R0D WITH T00DEE2-EM AH/ SEPT. 9,, 1986
m l ~ STEAM COOLING FLECHT-SEASET TEST RESULTS SHOW NO DISCONTINUITY IN HEAT TRANSFER OCCURS o AT 1 IN/SEC CORE HEAT TRANSFER ENHANCED UNDER BLOCKAGE o SITUATION STEAM COOLING MODEL WILL BE REVISED LITERATURE ON REFLOOD HEAT TRANSFER WITH o BLOCKAGE WILL RE REVIEWED T00DEE2-EM MODEL WILL BE REVISED o REVISED MODEL WILL BE BENCHMARKED AGAINST o EXPERIMENTAL DATA AH/ SEPT. 9, 1986
CYCLE 10 ANALYSIS (PHASE I) CURRENT METHOD WITH FOLLOWING CHANGES WILL BE UTILIZED o AP PENALTY OF 0.15 PSID ( ALREADY USED FOR YR) o REFLOOD WITH AVG. CORE CONDITIONS (PHYSICAL REPRESENTATION) BREAK SPECTRUM SENSITIVITY WILL BE PERFORMED o CYCLE 5 RESULTS WILL BE USED FOR THE BLOW-DOWN PERIOD o MODIFIED REFLOOD MODEL WILL BE USED FOR THE REFLOOD PERIOD. o WORST BREAK SIZE WILL BE IDENTIFIED B0UNDARY CONDITIONS FOR WORST BREAK SIZE WILL BE USED TO GENERATE LHGR FOR VARIOUS POWER SHAPES RESULTS WILL BE SUBMITTED WITH THE CPAR 90 DAYS BEFORE CORE STARTUP 't AH/ SEPT. 9, 1986 i
CYCLE 10 hNALYSIS (PHASE II) CYCLE 10 ANALYSIS WILL BE REDONE WITH A REVISED STEAM COOLING MODEL MODEL CHANGE SUBMITTED 2/1/87 TO NRC SER FROM NRC 5/1/87 SUBMITTAL OF ANALYSIS 10/1/87 SCOPE SIMILAR T0 (PHASE I) SER ON SUBMITTAL 12/1/87 AH/ SEPT. 9, 1986
~ MEETING
SUMMARY
DISTRIBUTION Licensee: Maine Yankee Atomic Power Company Distribution [DN5eNil$1,][' 4 NRC PDR Local PDR PBD-8 Reading FMiraglia 0GC-Bethesda EJordan i i JPartlow BGrimes ACRS(10) Gray File 3.4c NRC Participants PM5 ears CThomas RJones NLauben cc: Licensee and Plant Service List i 1 4 i 4 I i . -.-...~...-...-...-..------r - - - - - - - - - - - - - - - - ~ ~ ~ - - - - - - ~ ~ - - - - ~ ~ ~ - - - - - -}}