TXX-6951, Interim Deficiency Rept CP-87-58 Re Modeling Errors in Computer Code RELAP-3.Initially Reported on 870814. Reanalysis of Affected Pipe Whip Restraint Designs Using RELAP-5 in Progress.Next Rept Will Be Submitted by 880203
| ML20236Q469 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/16/1987 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-87-58, TXX-6951, NUDOCS 8711200079 | |
| Download: ML20236Q469 (2) | |
Text
{{#Wiki_filter:m - s- \ i e
=M Log # TXX-6951 -{
L
._, d File # 10110 !
r- = . . 903.6 7UELECTR/C Ref#'10CFR50.55(e)- ) November' 16', 1987: William G. Counsil Ew:utive We Prewknt ! U. S. Nuclear Regulatory Commission q Attn: Document' Control Desk i Washington, D. C. 20555 j
'I
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) 1 DOCKET NOS. 50-445 AND 50-446 ! COMPUTER MODELING ERROR: RELAP-3 1 SDAR CP-87-58 (INTERIM REPORT) I Gentlemen: On August 14, 1987, we verbally notified your Mr. H. S. Phillips.of a j potentially reportable. item involving modeling errors in the ceouter code,
']
RELAP-3. Our last interim report was logged TXX-6707 dated September 14, ) 1987. After further evaluation we have determined that this'. item is ) reportable under the provisions of 10CFR50.55(e) and the required information i follows. Description of Deficiency
. The computer code RELAP-3 was used in calculating pipe rupture blowdown in the.
design of pipe whip restraints. .A check of the RELAP-3 results for the main steam lines using RELAP-5 determined that the use of RELAP-3 resulted in 1 miscalculation of loads applied to pipe whip restraints. A detailed review of 1 the computer code identified a modeling error in RELAP-3. As a result, use of , the RELAP-3 values may have resulted in non-conservative pipe whip restraint- l designs. The cause of this deficiency is the modeling error in the RELAP-3 computer code. The deficiency extends to all pipe whip restraints designed using data provided by RELAP-3. ; Safety Implications Failure of pipe whip restraints could adversely affect the ability of safety-related systems to perform as required following post accident conditions, due to the effects from the increased pipe whip and jet r impingement zones of influence. 8711200079 871116 DR ADOCK 0500 5 J [ l k 400 hrth Olive Street LB 81 Da!!as, Texas 75201 ,
; . __ ._o
a
\
i i TXX-6951 I November 16, 1987 f Page 2 of 2 Corrective Action
)
l We are currently conducting a reanalysis of the affected pipe whip restraint designs using RELAP-5. Our corrective actions and schedule of completion for this deficiency will be submitted no later than February 3, 1988. Very truly yours, ) 69166 W. G. Counsil l HAM /grr j c - Mr. R. D. Martin, Region IV ' Resident Inspectors, CPSES (3) i I 1 1}}