ML20072L474

Proposed Tech Specs Control Rod Exercising & Standby Liquid Control Pump Operability Testing

ML20072L474
Person / Time
Site:	Oyster Creek
Issue date:	08/19/1994
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20072L463	List: ML20072L459 ML20072L470 ML20072L474
References
NUDOCS 9408310311
Download: ML20072L474 (2)

Text

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+' 4.2 REACTIVITY CONTROL ,

1 Applicability: Applies to the surveillance requirements for reactivity control.

Qb.iective: To verify the capability for controlling reactivity.

Specificatign:

A. Following a reactor refueling when core alterations were performed, sufficient control rods shall be withdrawn to demonstrate with a i margin of 0.25% Ak that the core can be made subtritical at any time in the subsequent fuel cycle with the strongest operable l control rod fully withdrawn and all other operable rods fully i inserted.

B. The control rod drive housing support system shall be inspected after reassembly.

C. 1. After each major refueling outage and prior to resuming power operation, all operable control rods shall be scram time tested from the fully withdrawn position with reactor pressure above 800 psig.

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2. Following each reactor scram from rated pressure, the mean 90% insertion time shall be determined for eight selected rods. If the mean 90% insertion time of the selected control rod drives does not fall within the range of 2.4 to 3.1 seconds or the measured scram time of any one drive for 90% insertion does not fall within the range of 1.9 to 3.6 seconds, an evaluation shall be made to provide reasonable assurance that proper control rod drive performance is maintained.

3. Following any outage not initiated by a reactor scram, eight rods shall be scram tested with reactor pressure '

above 800 psig provided these have not been measured in six months. The same criteria of 4.2.C(2) shall apply.

D. Each partially or fully withdrawn control rod shall be exercised at least once each week. This test shall be performed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in the event power operation is continuing with two or more inoperable control rods or in the event power operation is continuing with one fully or partially withdrawn rod which cannot be moved and for which control rod drive mechanism damage has not been ruled out. The surveillance need not be completed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the number of inoperable rods has been reduced to less than two and if it has been demonstrated that control rod drive mechanism ,

collet housing failure is not the cause of an immovable control rod. 1 E. Surveillance of the standby liquid control system shall be as )

follows:

1. Pump operability Once/3 months

2. Boron concentration Once/ month determination Corrected: 12/24/84 OYSTER CREEK 4.2-1 Amendment No.: 13, 75, 144, 156 9408310311 940s19 PDR ADOCK 05000219 P pop

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that the reactor is sub-critical at that time by at least R + 0.25% delta k with the highest worth operable control

,. rod fully withdrawn.

The value of R is the difference between two calculated values of reactivity of the cold, xenon-free core with the strongest operable control rod fully withdrawn. The reactivity value at the beginning of life is subtracted from the maximum reactivity value anytime later in life to determine R, which must be a positive quantity or its value is conservatively taken as zero. The value of R shall include the potential shutdown margin loss assuming full B C settling in all possibly inverted tubes present 4

in the core. The value 0.25% delta k in the expression R

+ 0.25% delta k serves at the beginning of life as a finite, demonstrable shutdown margin. This margin is demonstrated by full withdrawal of the strongest rod and partial withdrawal of a diagonally adjacent rod to a position calculated to insert an R + 0.25% delta k reactivity. Observation of subcriticality in this condition assures subcriticality with not only the strongest rod fully withdrawn but at least an R + 0.25%

delta k margin beyond this.

The control rod drive housing support system

• is not subject to deterioration during operation. However, reassembly must be assured following a partial or complete removal.

The scram insertion times for all control rods" will be determined at the time of each refueling outage. The scram times generated at each refueling outage when compared to scram times previously recorded gives a measurement of the functional effects of deterioration for each control rod drive. The more frequent scram insertion time measurements of eight selectu rods are performed on a representative sample basis to monitor performance and give an early indication of possible deterioration and required maintenance. The times given for the eight-rod tests are based on the testing experience of control rod drives which were known to be in good condition.

The weekly control rod exercise test serves as a periodic check against deterioration of the control rod system.

Experience with this control rod system has indicated that weekly tests are adequate, and that rods which move by drive pressure will scrcm when-required as the pressure applied is much higher. ihe r0quirement to exercise the control rods within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of a condition with two or more control rods which are valved out of service or one fully or partially withdrawn control rod which can not be moved provides prompt assurance of the reliability of the remaining control rods.

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OYSTER CREEK 4.2-3 Amendment No.: 75, 124 l I

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