ML19256C772
| ML19256C772 | |
| Person / Time | |
|---|---|
| Issue date: | 03/23/1979 |
| From: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-79-060, PNO-79-60, NUDOCS 7910120449 | |
| Download: ML19256C772 (1) | |
Text
PRELIMINARY NOTIFICATION M
March 23, 1979 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-79-60 (RES)
This preliminary notification constitutes EARLY notice of event of POSSIBLE safety or public interest significance.
The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
Subject:
ERRORS IN CALCULATIONS FOR FIRST LOFT NUCLEAR TEST Ouring the preparation for the pretest calculations of the second nuclear test.in LOFT (test L2-3),'INEL discovered that two errors had been ude in the input data for the RELAP code calculation of the first nuclear test L2-2 and LASL discovered an error in the input data for the TRAC code calculation of the L2-2 test.
The input data errors in the RELAP code are the following:
1.
A discharge coefficient (or break flow modifier) of 1.0 was used instead of the intended value of 0.8.
The effect of this error would be that the calculated flow out of the vessel through tne Quick Opening Blowdown Valves would be greater than is actually the case.
Correcting this error will result in a lower calculated peak clad temperature.
2.
The volume of the upper plenum of the vessel was specified to be 20 cu. ft. instead of the actual value of 33 cu. ft.
Correcting this error is expected to result in a lower peak clad temperature also.
The inpu; data error found by LASL was such that it resulted in a peak power density used in the TRAC calculation that was 10% higher than the peak power in the test.
Correction of this error is expected to reduce the calculated peak clad temperature.
RES has asked both labs to improve their Quality Assurance practices associated with preparing the input data for calculations of this type, and actions have been taken by both labs.
New calculations are under way using the correct input data for both RELAP and TRAC, and RES will inform the Commission of the results when they are completed.
Contact:
T. Murley, RES x74281 1452 345 Distribution:
Transmitted H St N
, h Chairman Hendrie Commissioner Bradford S. J. Chilk, SECY Commissioner Kennedy Commissioner Ahearne C. C. Kammerer, CA Commissioner Gilinsky (For Distribution)
Transmitted: MNBBM-P. Bldg k / b J.G. Davis,f.Ql IE L. V. Gossick, ED0 H. R. Dentoa, NRR Region I H. L. Ornstein, ED0 R. C. DeYoung, NRR II l 96 J. J. Fouchard, PA R. J. Mattson, NRR I II _(-4. @ )
N. M. Haller, MPA V. Stello, NRR IV A $1 R. G. Ryan, OSP R. S. Boyd, NRR V
4 Gl H. K. Shapar, ELD SS M dg Z-l ' l Cl W. J. Dircks, NMSS (MAIL)
S. Levine, RES J. J. Cumings, 0I A T. E. Murley, RES R. Minogue, SD PRELIMINARY NOTIFICATION 991012 W8
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