ML20134B551

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Proposed Tech Specs 3.1.3.5 Re Control Rod Scram Accumulators
ML20134B551
Person / Time
Site: Hope Creek PSEG icon.png
Issue date: 01/24/1997
From:
Public Service Enterprise Group
To:
Shared Package
ML20134B546 List:
References
LCR-H96-08, LCR-H96-8, LR-N97041, NUDOCS 9701300195
Download: ML20134B551 (8)
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Text

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. Document Control Desk LR-N97041 Attachment 3 LCR H96-08 t

i HOPE CREEK GENERATING STATION i FACILITY OPERATING LICENSES NPF-57

DOCKET NO. 50-354 CHANGE TO TECHNICAL SPECIFICATIONS l IMPROVEMENT TO TECHNICAL SPECIFICATION SECTION 3.1.3.5, CONTROL
ROD SCRAM ACCUMULATORS 1

TECHNICAL SPECIFICATION PAGES WITH PROPOSED CHANGES l l The following Technical Specifications for Facility Operating 4

License No. NPF-57 are affected by this change request: )

j Technical Specification Pages i 3/4.1.3.5 3/4 1-9

} 3/4 1-10 BASES 3/4.1.3 B 3/4 1-2 i

i B 3/4 1-2a B 3/4 1-2b l B 3/4 1-2c B 3/4 1-3 1

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l 9701300195 970124 t Page 1 of 1 PDR ADOCK 05000354 P PDR ,

REACTIVITY CONTROL SYSTEMS CONTROL ROD SCRAM ACCUMULATORS LIMITING CONDITION FCR OPERATION 3.1.3.5 Each control rod scram accumulator shall be OPERABLE.

APPLICABILITY: OPERATIONAL CONDITIONS 1, 2 and 5*.

ACTION:

NOTE--------------------------------

Separate condition entry is allowed for each control rod

a. In OPERATIONAL CONDITIONS 1 or 2:
1. With one control rod scram accumulator inoperable and reactor pressure 2 900 psig, within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, a) Restore the inoperable accumulator to OPERABLE status, or I

b) Insert the associated control rod, declare the associated control rod inoperable and disarm the associated control valves either electrically or hydraulically by closing the drive water and exhaust water isolation valves.

Otherwise, be in at least HOT SHUTDOWN with the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

2. With two or more control rod scram accumulators inoperable and reactor pressure 2 900 psig, a) Within 20 minutes of discovery of this condition concurrent with charging water i pressure < 940 osig, restore charging water  !

header pressure to 2 940 psig otherwise place I the mode switch in the shutdown position **,

and b) Within one hour insert the associated control rods, declare the associated control rods inoperable and disarm the associated control valves either electrically or hydraulically by closing the drive water and exhaust water isolation valves.

Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

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HOPE CREEK 3/4 1-9 Amendment No. l

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i j REACTIVITY CONTROL SYSTEMS j LIMITING CONDITION FOR OPERATION (Continued) i

! ACTION (Continued) l

. 3. With one or more control rod scram accumulators inoperable l and reactor pressure < 900 psig, 1

i a) Immediately upon discovery of charging water header 1 pressure < 940 psig, verify all control rods i associaced with inoperable accumulators are fully

{ inserted otherwise place the mode switch in the

{ shutdown position **, and i

j b) Within one hour insert the associated control rod (s),

j declare the associated control rod (s) inoperable and a

disarm the associated contro.'. valves either I

electrically or hydraulically by closing the drive .

1 water and exhaust water isolation valves.

Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. l 1

b. In OPERATIONAL CONDITION 5*: l l
1. With one or more withdrawn control rods I inoperable, upon discovery immediately initiate )

action to fully insert inoperable withdrawn i control rods, i

c. The. provisions of Specification 3.0.4 are not applicable.

SURVEILLANCE REOUIREMENTS 4.1.3.5 Each control rod scram accumulator shall be determined OPERABLE:

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a. At least once per 7 days by verifying that the indicated pressure l is greater than or equal to 940 psig unless the control rod is I' inserted and disarmed or scrammed.

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  • At least the accumulator associated with each withdrawn control rod. Not' applicable to control rode removed per Specification 3.9.10.1 or 3.9.10.2.

HOPE CREEK 3/4 1-10 Amendment No.

1 j REACTIVITY CONTROL SYSTEMS BASES

, 3/4.1.3 CONTROL RODS i

The specifications of this section ensure that (1) the minimum SHUTDOWN MARGIN is maintained, (2) the control rod insertion times are consistent with those used in the accident analysis, and (3) limit the potential effects of 3

' the rod drop accident. The ACTION statements permit variations from the basic requirements but at the same time impose more restrictive criteria for continued operation. A limitation on inoperable rods is set such that the resultant effect on total rod worth and scram shape will be kept to a minimum.

The requirements for the various scram time measurements ensure that any i

indication of systematic problems with rod drives will be investigated on a timely basis.

The operability of an individual control rod is based on a combination of factors, primarily, the scram insertion times, the control rod coupling 1

integrity, and the ability to determine the control rod position. Accumulator i operability is addressed by LCO 3.1.3.5. The associated scram accumulator status for a control rod only affects the scram insertion times; therefore, an j inoperable accumulator does not immediately require declaring a control rod i

inoperable. Although not all control rods are required to be operable to satisfy the intended reactivity control requirements, control over the number l- of inoperable control rods is required.

j control rod insertion capability is demonstrated by surveillance 4.1.3.1.2 inserting each partially or fully withdrawn control rod at least one

notch and observing that the control rod moves. The control rod may then be 1

returned to its original position. This ensures the control rod is not stuck and is free to insert on a scram signal. At any time, a control rod is

' immovable for reasons not associated with the control rod drive mechanism, a determination of that control rod's trippability (Operability) must be made and appropriate actions taken. As an example, if the control rod can be scrammed, but can not be moved due to a RMCS failure, the rod (s) may continue to be considered OPERABLE provided all other related surveillances are 1

current. '

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Damage within the control rod drive mechanism could be a generic problem, therefore with a withdrawn control rod immovable because of excessive friction or mechanical interference, operation of the reactor is limited to a 4 time period which is reasonable to determine the cause of the inoperability l

. and at the same time prevent operation with a large number of inoperable l

, control rods.

l Control rods that are inoperable for other reasons are permitted to be j taken out of service provided that those in the nonfully-inserted position are consistent with the SHUTDOWN MARGIN requirements.

The number of control rods permitted to be inoperable could be more than the eight allowed by the specification, but the occurrence of eight inoperable rods could be indicative of a generie problem and the reactor must be shutdown for investigation and resolution of the problem.

HOPE CREEK B 3/4 1-2 Amendment No.

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REACTIVITY CONTROL SYSTEMS BASES ,

CONTROL RODS (Continued)

The control rod system is designed to bring the reactor suberitical at a l rate fast enough to prevent the MCPR from becoming less than the fuel cladding l Safety Limit during the limiting power transient analyzed in section 15.4 of the FSAR. This analysis shows that the negative reactivity rates resulting from the scram with the average response of all the drives as given in the j specifications, provide the required protection and MCPR remains greater than j the fuel cladding Safety Limit. The occurrence of scram times longer then  ;

those specified should be viewed as an indication of a systematic problem with i the rod drives and therefore the surveillance interval is reduced in order to prevent operation of the reactor for long periods of time with a potentially serious problem.

The scram discharge volume is required to be OPERABLE so that it will be available when needed to accept discharge water from the control rods during a reactor scram and will isolate the reactor coolant system from the containment when required.

Control rods with inoperable accumulators are declared inoperable and Specification 3.1.3.1 then applies. -This prevents a pattern of inopsrable accumulators that would result in less reactivity insertion on a scram than has been analyzed. The OPERABILITY of the control rod scram accumulators is required to ensure that adequate scram insertion capability exists when needed over the entire range of reactor pressures. The OPERABILITY of the scram accumulators is based on maintaining adequate accumulator pressure.

In OPCON 1 and 2, the scram function is required for mitigation of DBAs and transients, and therefore the scram accumulators must be OPERABLE to support the scram function. In OPCON 3 and 4, control rods are only allowed to be withdrawn under limits imposed by the reactor mode switch being in shutdown and by the control rod block being applied. This provides adequate

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requirements for control rod scram accumulator OPERABILITY during thesa conditions. In OPCON 5, withdrawn control rods are required to have OPERABLE accumulators.

The actions of Specification 3.1.3.5 are modified by a note indicating that a separate Condition entry is allowed for each control rod scram accumulator. This is acceptable since the required Actions for each condition provide appropriate compensatory actions for each affected accumulator.

Complying with the Required Actions may allow for continued operation and subsequent affected accumulators governed by subsequent condition entry and application of associated Required Actions.

With two or more control red scram accumulators inoperable and reactor pressure > 900 psig, adequate pre ssure must be supplied to the charging water header. With inadequate charging water pressure, the accumulators could HOPE CREEK B 3/4 1-2a Amendment No.

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REACTIVITY CONTROL SYSTEMS l BASES i

CONTROL RODS (Continued) l become inoperable, resulting in a potential degradation of the scram l

performance. Therefore, within 20 minutes from discovery of charging water header pressure < 940 psig concurrent with conditions in Action 3.1.3.5.a.2, adequate charging water header pressure must be restored. The allowed j completion Time of 20 minutes is reasonable, to place a CRD pump into service I I

to restore the charging header pressure, if required. This completion Time is based on the ability of the reactor pressure alone to fully insert all control

rods.

With one or more control rod scram accumulators inoperable and the ,

i reactor pressure < 900 psig, the pressure supplied to the charging water I header must be adequate to ensure that accumulators remain charged. With the

]' reactor pressure < 900 psig, the function of the accumulators in providing the acram force becomes much more important since the scram function could become

, degraded during a depressurization event or at low reactor pressures.

Therefore, immediately upon discovery of charging water header pressure < 940 peig, concurrent with conditions in Action 3.1.3.5.a.3, all control rods associated with inoperable accumulators must be verified to be fully inserted.

Withdrawn control rods with inoperable accumulators may fail to scram under these low pressure conditions. The associated control rods must also be j inserted, declared inoperable, and disarmed within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The allowed

, Completion Time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> is reasonable considering the low probability of DBA or transient occurring during the time that the accumulator is inoperable.

The reactor mode switch must be immediately placed in the shutdown position if either Required Action and associated Completion Time associated with loss of the CRD charging pump (Required Actions 3.1.3.5.a.2.a or 3.1.3.5.a.3.a) cannot be met. This ensures that all insertable control rods are inserted and that the reactor is in condition that does not require the active function (i.e., scram) of the control rods. This Required Action is modified by a note stating that the action is not applicable if all control rods associated with the inoperable scram accumulators are fully inserted, since the function of the control rods has been performed.

Surveillance Requirement 4.1.3.5 requires that the accumulator pressure be checked every 7 days to ensure adequate accumulator pressure exists to provide sufficient scram force. The primary indicator of accumulator OPERABILITY is the accumulator pressure. A minimum accumulator pressure is specified, below which the capability of the accumulator to perform its intended function becomes degraded and the accumulator is considered inoperable. Declaring the accumulator inoperable when the minimum pressure is not maintained ensures that significant degradation in scram times does not occur. The 7 day frequency has been shown to be acceptable through operating experience and takes into account indications available in the control room.

Control rod coupling integrity is required to ensure compliance with the analysis of the rod drop accident in the FSAR. The overtravel position HOPE CREEK B 3/4 1-2b Artndment No.

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l REACTIVITY CONTROL SYSTEMS l

j BASES CONTROL RODS (Continued) feature provides the only positive means of determining that a rod is properly coupled and therefore this check must be performed prior to achieving i criticality after completing CORE ALTERATIONS that could have affected the control rod coupling integr't ,y. The subsequent check is performed as a backup to the initial demonstration.

In order to ensure that the control rod patterns can be followed and therefore that other parameters are within their limits, the control rod ,

position indication system must be OPERABLE. i i

The control rod housing support restricts the outward movement of a control rod to less than 6 inches in the event of a housing failure. The amount of rod reactivity which could be added by this small amount of rod withdrawal is less than a normal withdrawal increment and will not contribute to any damage to the primary coolant system. The support is not required when there is no pressure to act as a driving force to rapidly eject a drive l housing.

l The required surveillance intervals are adequate to determine that the rods are OPERABLE and not so frequent as to cause wear on the system components.

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l HOPE CREEK B 3/4 1-2c Amendment No.

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REACTIVITY CONTROL SYSTEMS l l l l BASES

I 3/4.2.4 CONTROL ROD PROGRAM CONTROLS Control rod withdrawal and insertion sequences are established to assure

) that the maximum insequence individual control rod or control rod segments

{ which are withdrawn at any time during the fuel cycle could not be worth

{ enough to result in peak fuel enthalpy greater than 280 cal /gm in the event of f

a control rod drop accident. The specified sequences are characterized by j homogeneous, scattered patterns of control rod withdrawal. When THERMAL POWER f is greater than 20% of RATED THERMAL POWER, there is no possible rod worth j which, if dropped at the design rate of the velocity limiter, could result in l a peak enthalpy of 280 cal /gm. Thus requiring the RSCS and/or RWM to be OPERABLE when THERMAL POWER is less than or equal to 20% of RATED THERMAL j POWER provides adequate control.

t l The RSCS and RWM provide automatic supervision to assure that out-of-

} sequence rods will not be withdrawn or inserted. I I The analysis of the rod drop accident is presented in Section 15.4.9 of j the FSAR and the techniques of the analysis are presented in a topical report, l Reference 1, and two supplements, References 2 and 3. l The RBM is designed to automatically prevent fuel damage in the event of erroneous rod withdrawal from locations of high power density during nigh I power operation. Two channels are provided. Tripping one of the channels j will block erroneous rod withdrawal soon enough to prevent fuel damage. This l system backs up the written sequence used by the operator for withdrawal of control rods. i l

i B 3/4 1-3 Amendment No.

HOPE CREEK l

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