ML18113A277

LER 1977-004-00 for St. Lucie Unit 1, Possible Error in Indicated Power from Digital Data Processing System Calorimetric Program Was Noted

ML18113A277
Person / Time
Site:	Saint Lucie
Issue date:	02/18/1977
From:	Schmidt A Florida Power & Light Co
To:	Moseley N NRC/IE, NRC/RGN-II
References
PRN-LI-77-37 LER 1977-004-00
Download: ML18113A277 (6)

Text

P. O. BOX 013100, MIAMI, FL 33101

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FLORIDA POWER & LIGHT COMPANY February 18, 1977 PRN-LI-77-37 Mr. Norman C. Moseley, Director, Region II Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 230 Peachtree Street, N. W., Suite 1217 Atlanta, Georgia 30303

Dear Mr. Moseley:

REPORTABLE OCCURRENCE 335-77-4 ST. LUCIE UNIT 1 DATE OF OCCURRENCE: JANUARY 20, 1977 DDPS CALORIMETRIC The attached Licensee Event, Report is being submitted in accordance with Technical Specification 6.9 to provide 30-day notification of the subject occurrence.

Very truly yours, A. D. Schmidt Vice President Power Resources MAS/cpc Attachment cc: Robert Lowenstein, Esquire Director, Office of Inspection and Enforcement (30)

Director, Office of Management Information and Program Control (3)

PEOPLE... SERVING PEOPLE

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LICENSEE EVENT REPORT CONTROL BLOCK: fPLEASE PAINT ALL AMUIAEDINFORMATION) 01 89 F L UCENSEE NAME S L S 1 0 0 0 UCENSE NUMBEA 0 0 0 0 0 0 4 1 1

'0 UCENSE TYPE 1 1 EVENT

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7 14 15 25 26 31 32 AEPOAT REPORT CATEGORY TYPE SOURCE OOCKET NUMBER ~ EVENT OATE REPORT OATE

~01 CON'T L L 0 5 0 0 3 3 5 0 1 2 0 7 7 0 2 1 8 7 7 7 8 57 58 59 60 61 68 69 74 75 80 EVENT

'wer OESCRIPTION'o 2 While reviewin ascension test data from before and after the 89 80 Qg 5-month fuel reconstitution shutdown See LER 335-76-35 dated 7 23 76 a 7 8 9 80 I0D4) ossible error in indicated ower from the Di ital Data Processin S stem 7 8 9 80 toOI DDPS calorimetric rimar heat balance) ro ram was noted. ~An'nten-7 8 9 80 Qo 6 sive investi ation confirmed that the calorimetric ro ram was in error 7 8 9 FAME 80 SYSTKM CAUSC CQMPONB4T COMPONENT COOK COOK COMPONENT COOE SUPPUER MANUFACTURER VICLATCN foals]

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~0 1 N S T R U N F 112 0 N 11 12 17 43 47 48 CAUSE OESCRIPTION t00g There are two methods in the calorimetric ro ram for convertin analo 7 8 9 80 tOOI feedwat r flow si nals to di ital en ineerin units. One method involves 7 8 9 80 a direct 4'to 20 ma linearization while the other method allows for a

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t110 7 89 80 FACIUTY METHOO OF 7 8 STATUS

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~oo 10 POWER 12 13 OTHER STATUS NA 44 OISCOVEAY 45 46 OISCOVEAY OESCAIPTIQN NA 80 FORM OF ACTIVITY COATENT RELEASEO OF RELEASE AMOUNT OF ACTIVITY LOCATION OF AKLEASE Q~g NA NA 7 8,9 PERSONNFL EXPOSURES 10 11 44 45 NUMBER TYPE OESCAIPTIQN

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'3 NA 7 89 11 12 80 PERS'ONNEL INJURIES NUMBER QESCRIPTIQN

~~4 0 0 0 NA 7 8 9 11 12 80 PROBABLE CONSEQUENCES Qg8 NA 7 9 LOSS OP OAMAGE TO FACILITY TYPE OESCAIPTION z NA 7 89 10 80 PUBLICITY NA 7 8 9 80 AOOITIONAL FACTORS

~18 7S 9 o for continuation of Event Descri tion and Cause Descri tion.

80 7 89 M. A. Scho man PHPNEI305 552-3779 GPO GII1 ~ GOT

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LICENSEE EVENT REPORT REPORTABLE OCCURRENCE 335-77-4 PAGE TWO EVENT DESCRIPTION (Continued) and'ndicated 2.57% below actual power (at nominal 80%). The program was corrected and,now functions properly. This is the first occurrence involving software problems with the DDPS.

(335-77-4).

CAUSE DESCRIPTION '(Continued) special linearization curve for each flow transmitter. The second method will allow for non-linear behavior of different transmitters. During initial power ascension, the direct 4 to 20 ma linearization method was used.

Following fuel reconstitution, the program and data base were reloaded into the DDPS and the second method of converting analog signals to engineering units was used. However, the program contained an erroneous scaling factor for the range of the flow transmitted. This error caused the indicated feedwater flow and reactor power to be lower than actual. The program has been corrected and all calorimetric inputs reviewed to verify that no further errors are present in the special linearization method.

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