ML19347E236
| ML19347E236 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe, Maine Yankee |
| Issue date: | 04/17/1981 |
| From: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| To: | Check P Office of Nuclear Reactor Regulation |
| References | |
| FYR-81-62, NUDOCS 8104240335 | |
| Download: ML19347E236 (3) | |
Text
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- YANKEE AT0 10 ELECTRIC C0 PANY 1671 Worcester Road, Framingham, Massachusetts 01701 2.C.2.1 g
FYR 81-62 e
sn April 17, 1981 4
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United States Nuclear Regulatory Commission 3
Washington, D. C.
20555 22 APR 2 4 ggg w u.s. g,T,.#
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Attenton:
Mr. Paul S. Check
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Assistant Director for Plant Systems
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jj \\ *D Division of System Integration q
Reference:
(a) License No. DPR-3 (Dockt No. 50-29)
(b) License No. DPR-36 (Docket No. 50-309)
(c) USNRC Letter to YAEC Dated March 18, 1981 (d) YAEC Letter to USNRC dated December 5, 1980 (WYR 80-129)
Subject:
Additional Data on RELAP 4/ MOD 3 Prediction of LOFT Test L3-6
Dear Sir:
This letter is in response to your request for additional information on Yankee Atomic Electric Company's prediction of LOFT test L3-6 [ Reference (c)). Attached you will find a list of model and input changes which were l
incorporated into the pre-test prediction model transmitted to you as an attachment to Reference (d).
If you have any questions, or desire additional information, please contact us.
I Very truly yours, l
YANKEE ATOMIC ELECTRIC COMPANY l
I J. A. Kay I
l Senior Engineer - Licensing
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8104240 W9 l
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RELAP4/ MOD 3 Model Changes Modifications were made to the special LOFT steam valve model. The modifications were made to alter the relief valve setpoints specified before the test to values which reflected the valve's behavior during the actual test. A testing of the LOFT steam valve model is given below and the changes made to the post-test predictions are underlined.
- C COMZ
- ID LS7227 1
- I CDC1.31
- C COML 3
,DADT,VAVPDS
- ID LS7228
- D COML.175 LE NGT H( J ) = ( 5 *MAXJU N+3 )
- NLFLT+8 *MAXJU N* NLI NT
- ID BHLS
- I FLOS.339 IF(I.NE.44) GO TO 85 DADTO = 0.05 C
C IN THE FOLLOWING CARDS THE LOGIC TO TRIP THE SPECIAL STEAM C
VALVE IS IMPLEMENTED C
IF(TRIP (5,XXXX)) GO TO 999 GO TO 886 999 IF(D ADT.LT.0.0. AND.P(K).GE.963.) DADT*0.0 IF(P(K).LE.953.0) DADT = -DADIO IF(P(K).GE.1010.5) DADT = DADTO IF(P(K).LE.1000.5. AND.DADT.GT.O.0) DADT = 0.0 VAVPOS = VAVPOS+DADT*DT IF(VAVPOS.LT.0.0) VAVPOS = 0.0 j
IF(VAVPOS.GT.1.0) VAVPOS = 1.0
~
886 VAVC0F =.366455*VAVPLS**3.286043*VAVPOS**2+1.51757*VAVPOS*
.00047633
-IF(VAVPOS.LT.O.1) VALC0F =.00643*VAVPOS+.01157 IF(VAVPOS.LT.O.016) VALCOF =.72938*VAVPOS IF(VAVPOS.LE.0.0) VALC0F = 0.0 IF(P(K).GE.400. ) WP(I) = VALC0F*P(K) 4 IF(P(K).LT.400. ) WP(I) = 1.149*VALC0F*SQRT(P(K)**2-(200. )** 2)
ESUBK(I) = ZERO FSUBK(I) = -ONEEX7 GO TO 270 85 CONTINUE
- I RJW1.237 3
,DADT,VAVPOS
- I INJU.257 D ADT= 0. 0 VAVPOS=0.646934 I
i
h Second change to the model is included in the Update IDENT RCH, listed below. This change allows the user ta - specify separate contraction coefficients for the _ subcooled and che two phase critical flow.
- C FLOS
- IDENT RCH
- I FLOS. 4 34 LAAl - 1.0
- B FLOS.440 AAl = Al
- D FLOS.441,FLOS.442 WTHMIN = -AAl*AJ* LEAK (H,PLL,I, DER,ICHOK,ITPL)
WT h..
AAl*AJ* LEAK (H,PLK,1, DER,1CHOK,ITPK)
Changes Made to the LOFT test L3-6 Input The following changes were made to.the LOFT test L3-6 input documented with the Staff through YAEC letter to USNRC, dated December 5,1980, (WYR-80-129).
1.
Wilson bubble rise model was removed.from volumes 8,13, la,15,16, 23, 24, 26 6 27.
2.
Volume #33 was removed. Volume 38 was relabeled as Volume 33.
3.
The pump two phase head and torque characteristics were replaced with a new table. This table is based on experimental data presented by EG6G at the NRC Meeting on January 15, 1981 (RELAPS calculations of L3-5 and L3-6).
4.
Following modifications to the junction input were made:
Junction 40 becomes 38 Junction 47 becomes 40 Junction 47 was added to represent primary pumps coolant injection flow.
5.
Fill table representing the leak through the steam generator relief valve was modified. The modification was made to reflect the secondary steam generator behavior encountered during the test.
The modification involved the use of five additional FILL junctions (48 through 52). They represent 50%, 40%, 30%, 20% and 10% of the initial leak flow through the valve and may be combined to obtain diff erent values of the leak' flow through the valve.
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