05000366/LER-1981-052-03, /03L-0:on 810611,engineer Observed Core Max Fraction of Limiting Power Density to Be Greater than Frtp. Caused by Time Delays for Adjusting Rods,Running TIP Scans & Processing Time from Computer.Rod Pattern Adjusted

/03L-0:on 810611,engineer Observed Core Max Fraction of Limiting Power Density to Be Greater than Frtp. Caused by Time Delays for Adjusting Rods,Running TIP Scans & Processing Time from Computer.Rod Pattern Adjusted

ML19352B340
Person / Time
Site:	Hatch
Issue date:	06/25/1981
From:	Coggin C GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19352B339	List: 05000366/LER-1981-052, Forwards LER 81-052/03L-0 05000366/LER-1981-052-03, /03L-0:on 810611,engineer Observed Core Max Fraction of Limiting Power Density to Be Greater than Frtp. Caused by Time Delays for Adjusting Rods,Running TIP Scans & Processing Time from Computer.Rod Pattern Adjusted
References
LER-81-052-03L, LER-81-52-3L, NUDOCS 8107020400
Download: ML19352B340 (2)

LER-1981-052, /03L-0:on 810611,engineer Observed Core Max Fraction of Limiting Power Density to Be Greater than Frtp. Caused by Time Delays for Adjusting Rods,Running TIP Scans & Processing Time from Computer.Rod Pattern Adjusted

Event date:
Report date:
3661981052R03 - NRC Website

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sehtc, FORM 366 U. S. NUCLEAR REGULAT2;Y COMMISSION am LICENSEE EVENT REPORT CONTROL BLOCK: l l

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EVENT DATE 74 7b REPORT DATE 80 EVENT oESCRIPTioN AND pro 0ABLE CONSEQUENCES h LAt 0020 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> with mode switch in RUN during power increase following i

o 2 lo ial lB0P problems, the Rx engineer observed CMFLPD to be greater than FRTP.

I foTil (Attempts to reduce the relative power or adjust the APRMs within tha 1

trequired time limit were unsuccessful.

The shift foreman was notified, I o s oa land plans were made to be less than 25% oower within 4 hrs if not cor-J 10171 I rected.

Subsequently, adjusted pattern and APRMs at 0421.

There were

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i o is I i no efferts upon public health or safety.

Repetitive event - see LER 50-366/1981-03.

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33 34 35 36 31 4g el 42 43 44 47 CAUSE oESCRIPTION AND CORRECTIVE ACTIONS lilOllThe cause of the event has oeen attributed to time delays for adjusting I 11111Irods, running TIP scans, and processing time from the computer _.

The en-1 Igineer continued to adjust the rod patternvand improve the computer ac-I i 2 [TTTIl_ curacy until 0421 CDST when the APRMs were adjusted as required by Tech I ISpecs.

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50-366/1981-052 Licensee:

Georgia Power Company Facility Name:

Edwin I. Ilatch Docket #:

50-366

Narrative

Report for LER 50-366/1981-052 On 6-11-81, at 0020 with the mode switch in RUN during a power increase following BOP problems associated with condenser vacuum the reactor engineer observed the CMFLPD was greater than FRTP.

Attempts were made to char.ge the overall power with respect to local power in the crea of high peaking by changing recirc flow.

After updating the base distribution and obtaining a computer analysis the CMFLPD/FRTP ratio was still excessive; at this point the two-hour time limit required by Tech Specs 3.2.2 had expired.

Rod groups in the O'

region of high peaking were inserted to suppress the excessive peaks, TIP trnces were obtained in the adjacent and failed channels, and a computer analysis was demanded.

The computer analysis revealed the CMFLPD/FRTP ratio to be acceptable at 0421 hours0.00487 days <br />0.117 hours <br />6.960979e-4 weeks <br />1.601905e-4 months <br />.

There were no effects upon public health and safety due to this event.

This event is repetitive as last reported on LER 50-366/1981-003.

Adjusting core flow or the rod pattern to change core paramet-ers is an iterative process involving rod movements, TIP scans, and processing"of the data by the computer to calculate

'nc new values.

In some cases, as above, these changes are l

insufficient to allow APRM adjustments, and sufficient time to I

correct the problem does not exist.

All reactor engineers have been informed of the details of the event with suggestions to preclude further recurrence.

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