ML20037A325
| ML20037A325 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/16/1977 |
| From: | Abraham P NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| References | |
| NUDOCS 7912130904 | |
| Download: ML20037A325 (1) | |
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l SU3JICT: Cconee Euclear Statide Error in Incore Detector Sig=al Processing At 4:45 p.m., De$esber 15,1977, M'4 called to report the disecvery cf an error in the cceputs: progras used for processicg the incere detector signal, which could potentially af f ect the axial isbsisnee celeviation by the plant cen uter. Participating in this centerence call vere I. J. Coppola, Ed Kane, Cary Hansen, and Charley Resbe cf MW and K. S. Canady, P. M. Abrahan, G. B. Sviedlehurst, R. L. Cill.
L. J. Bare, N. A. Rutherford, Bill McCollum, and Dick Clark of Duke.
MW reported that is the esisting plant cceter sof tvare the back-grov:d correction is cade cc the depletion corrected signal instead of the rav signal. This rathcdology could cause the online computer positive 1 balance to be less the, the a;tual positive i=balscce than the detector depletion is large. This error vas discovered by MV while revieving tha 21 imbalance data against predicted labslance.
The ef fect of this error en Ocense 2 is e.all at the prasent time
@; e. 31 incore detecter strito b. Ocence 1 are rev. In the case O.
of C<cnte 2 and 3 the =Asi_ um bias on the indicated intore positive i= balance could be 2.51.
Since the out-of-core i= balance is periodi-cally calibrated against the incore imbalance, ES*d re:c:2wnded that the US positive inhalance trip serpoints for Oconee 2 and 3 be re-duced by 2.5% until a sof twre change to correct this error ec~.ild be itglemented.
For the LCCA 1:balacce limits to adjusteents are required since the esisting 1 bits have adequate rargins to offset this error.
In the case of C<cuee 1 na adjust:ents are required on either the US imbahtee lini:s or the LCG i+., dance.11 its since the existing li=1ts have sufficient u.argin and since the i= pact on Unit 1 is s: mall.
PEJ agreed to provide a report ce thds ::.atter to be sulcitted to the
- GC by December 22, 1977.
P. M. Abraham inferned 3. T. Send att Ccones of this narter at 6 p.s.,
Dece2Eer 15, 1977, and further advised him to reduce the RPS positive 1 balance trip setpoints by 2.5 cn Ccceet 2 and J.
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M P. M. Abtaham F"C: ge cc:
K. 5. Canady H. T. Snead O. S. Bradhan D. C. Holt M. S. Tucknan W. A. Coley R. L. Cill L. J. T>are
- 5. A. Rutherford G. B. Swindlehurst R. 5. Tucker Dick C1stk
,q Bill McCollt:m P. H. Barton J. E. Smith R. 7. knd 3
R. M. Koehler T. S. Ear:
E. J. Co pola 4 g j
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