ML20085F592

Telecopy AO AO-22-74:on 741010,low Flow Trip Setpoints for Three & Two Primary Coolant Pump Operation Found to Be Below Tech Spec Limit.Caused by Use of Incorrect Figures in Calculating Setpoints

ML20085F592
Person / Time
Site:	Palisades
Issue date:	10/11/1974
From:	Flynn J, Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20085F589	List: ML20085F586 ML20085F592
References
AO-22-74, NUDOCS 8308230036
Download: ML20085F592 (9)

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2. A. REPORT DATE 11- 74

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8. OCCURRENCE DATE 10-74 53

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4. IDENT[FICATION OF OCCURRENCE -

LOW FLOW TRIP SETPOINTS FOR 3 PCP AND 2 PCP OPERATION FOUND TO DE BELOW TECHNICAL SPECIFICATIONS LIMIT.

5. CONDITIONS PRIOR TO OCCURRENCE -

PLANT OPERATING IN 4 PCP CONFIGURATION AT POWER LEVEL OF X 30 PER- -

CENT.

6. DESCRIPTION OF OCCURRENCE -

, A. A PPOSSIBLE VIOLATION WAS DETECTED 10-3-74 WHEN P-CE-3962 sr.im <nne>WAS REVIEWED AND IT WAS FOUND THAT PRESENT SETPOINTS APPEARED -

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LESS CONSERVATIVE THAN THOSE RECOMMENDED IN P-CE-5962.

THIS INFORMATION WAS VERBALLY RELAYED TO RON COOK ON 10-4-74.

B. FURTHER ANALYSIS OF AVAILABLE INFORMATION VAS CONDUCTED BOTH AT THE PLANT AND IN THE GENERAL OFFICE AND ON 10-10-74 A PRC MEETING WAS HELD AT THE PLANI WITH FIVE MEMBERS OF THE GENERAL OFFICE STAFF PRESENT. AT THIS TIME IT WAS DETERMINED THAT THE SETPOINTS FOR 5 PUMP AND 2 PUMP OPERATION WERE BELOW IECHNICAL SPECIFICATION LIMITS.

7. APPARENT CAUSE -

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• Tele 9 ram ALL PUMP COMBINATIONS IT WAS ASSUMED THAT FLOW WAS EQUAL TO THE SQUARE ROOT OF DP - BASED ON A4 PUMP DP AS 100 PERCENT - FOR ALL PUMP CONFIGURATIONS.

IT HAS BEEN DETERMINED THAT THE SQUARE ROOT RELATIONSHIP IS ONLY A VALID ASSUMPTION WHEN THE FLOW CORRESPOND-ING TO EACH PUMP CONFIGURATION IS ASSUMED TO BE 100 PERCENT FLOW IN CALCULATING EACH IRIP SETPOINT AND THE PERCENT OF 4 PUMP FLOW CON-VERTED TO A PERCENT OF 5 PUMP - OR 2 PUMP - FLOW TO ESTABLISH THE MINIMUM TRIP SETPOINY.

ORIGINAL CALCULATIONS SHOWED THAT 90 PERCENT OF 5 PUMP FLOW - AND 2 PUMP - WAS MORE CONSERVATIVE THAN THE CALCULATED MINIMUM SETPOINT

, AND THIS VALUE WAS USED. THE TRIP SETPOINT BECAME --

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semOWIRIP/ EQUALS 0.9E2 X DP5 1 b - - - - -

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EQUALS 0.81 X DP5 HOWEVER, ASSUMING MEASURED 5 PsMP FLOW - F3 - EQUALS .758 0F MEASURED 4 PUMP FLOW - F4 - AND USING 71 PERCENT OF 4 PUMP FLOW TRIP AS A SETPOINT, THE PREVIOUSLY CALCULATED SETPOINT IS SHOWN TO BE IN ERROR.

E.G. F5 EQUALS .75dF4 F/THIP/ EQUALS .71F4 EQUALS .71 73

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DP5/ TRIP / EQUALS .71

--"-- E2 X DP5

,758 A SIMILAR ANAYYSIS ALSO SHOWS THAT THE 2 PUMP TRIP SETPOINT WAS AL SO BELOW TECHNICAL SPECIFICATIONS LIMITS.

6. ANALYSIS OF OCCURRENCE -

SINCE THE PLANT HAS NOT OPERATED IN THE 2 OR 5 PUMP CONFIGURATION AT POWER NO SAFETY LIMITS WERE VIOLATED. ALSO BECAUSE ALL INFORMA-TION USED TO DETERMINE THE TECHNICAL SPECIFICATION LIMITS IS NOT IMMEDIATELY AVAILABLE, THE DETERMINATION AS TO POSSIBLE SAFETY

' W PROBLEMS HAD THE PLANT OPERATED IN THESE MODES HAS NOT BEEN ANALY2ED

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9. CORRECTIVE ACTION-l CORRECTIVE ACTION RECOMMENDED BY THE PLAN )

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A. INITIATE ADMINISTRATIVE CONTROLS TO LIMIT REACTOR OPERATION j IN THE 2 PUMP MODE TO THE HOT STANDBY CONDITION UNTIL THE PROPER l l FLOW TRIP SETPOINTS ARE ESTABLISHED.

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B. SET THE HIGH POWER TRIP SETPOINT FOR 5 PUMP OPERATION AT 25 PERCENT POWER. THIS IS BASED ON THE FACT THAT NORMAL 2 PUMP OPERATION ALLOWS 25 PERCENT REACTOR POWER, AND THE 5 PUMP FLOW TRIP SETPOINT PRESENTLY ESTABLISHED I WELL ABOVE Tile 46 PERCENT

_ _ 4 ._. . r e c u core ifarT roR 9 PilMP FLOW. GIVEN THAT FLOW EXCEEDS THE t I

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MINIMUM ALLOWABLE FOR 25 PERCENT, THE POWER LEVEL OF 25 PER-CENT IS CONSERVATIVE. _

C.

CP C0 IS ALREADY ENGAGED IN DISCUSSIONS WITH COMBUSTION EN- -

GINEERING TO ESTABLISH JUSTIFICATION FOR NEW LOW FLOW IRIP SET-POINTS. WHEN THIS DATA BECOMES AVAILABLE, A TECH SPEC CHANGE WILL BE INITIATED TO ALLIEVIATE THE PRESENT SITUATION.

10. FAILURE DATA -

NOT APPLICABLE l....___-~_..___.. _ _ _ _ _ _ . _ . _ . - , _ . , _ _ . . _ . . _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ _ _

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