ML20155F124

Proposed Tech Spec 4.3.1.1,extending Monthly Surveillance Interval for Power Range Neutron Flux High Setpoint Addl 10 Days

ML20155F124
Person / Time
Site:	Braidwood
Issue date:	06/02/1988
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20155F072	List: ML20155F066 ML20155F124
References
NUDOCS 8806160293
Download: ML20155F124 (4)

Text

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'o$ oo TABLE 4.3-1 I$ $2

• U REACTOR TRIP SYSTEN INSTRUNENTATION SURVEILLANCE REQUIRENENTS

$$ 6 ffj E3 TRIP XW . ANALOG ACTUATING NODES FOR oco c: CilANNEL DEVICE WHICH CHANNEL CHANNEL OPERATIONAL OPERATIONAL ACTUATION SURVEILLANCE

$$ 25 FUNCTIONAL UNIT - CilECK CALIBRATION ow y TEST TEST LOGIC TEST IS REQUIRED SS$3 >a 1. Manual Reactor Trip N.A. N.A. N.A. R N.A. 1, 2, 3 * , 4 * , S*

U $ e-n2 2. Power Range, Neutron Flux

a. liigh Setpoint S D(2, 4), Q, N.A. N.A. 1, 2 N(3,47,14) 4 6),

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b. Low Setpoint 5 R(4)# Q N. A. N.A. 1###, 2

3. Power Range, Neutron Flux, N.A.

liigh Positive Rate R(4)# Q N.A. N.A. 1, 2 Y

• • 4 . Power Range, Neutron Flux, N.A. R(4)# Q N.A. N.A.

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liigh Negative Rate 1, 2 S. Intermediate Range, S R(4, Sa)# Q N.A. N.A.

Neutron Flux 1###, 2

6. Source Range, Neutron Flux 5 R(4, Sb, 12)# Q(9) N.A. N.A. 2##, 3, 4, S

7. Overtemperature AT S 2; R(13)# Q N.A. N.A. 1, 2 g; 8. Overpower AT S R#

S Q N.A. N.A. 1, 2 Sg 9. Pressurizer Pressure-Low S R# Q** N.A.

-1 (Above P-7) N.A. 1 o

10. Pressurizer Pressure-High 5 -

R# Q N.A. N.A. 1, 2

11. Pressurizer Water Level-High 5 R# Q N.A.

(Above P-7) N.A. 1

TABLE 4.3-1 (Continued) 1 TABLE NOTATIONS (12) At least once per 18 months during shutdown verify that on a simulated Boron Dilution Doubling test signal CVCS valves 112D and E open and 112B and C close within 30 seconds.

(13) CHANNEL CALIBRATION shall include the RTO bypass 1 cops flow rate.

( N) O n o. o n e. + i m e_ basis eh roy h Tu.n t. t r, tete, # he periaf.it.isy of this s arva tt a nce. Fu u n i+ .L c al y M o. y b e- EX bdt d -from 31 day J (men /bl y) 'o 91 dayJ.

BRAIDWOOD - UNITS 1 & 2 3/4 3-12a

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t commonwealthEdisonhasevaluatedthisproposedamendhn't and

' determined that it involveswb significant hazards considerations. According to 10 CFR 50.92(c), a proposed amendment to an operating license involves no significant hazards considerations if operation >of the facility in accordance with the proposed amendmeht would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new cr different kind of accident freni any accident previously evaluated; or (3) Involve a significant reduction in a eargin of safety.

r This proposed amen @nent requests a one' time only change (effective until June 15, 1988) for Unit 1, to Technical Specification 4.3.1.1 for the /

Reactor Trip System Instrumentation. .The change proposes, on a one time basis, to extend the monthly surveillance periodicity for the Power Range Neutron Flux High Setpoint from 31 days to 41 days.

The probability or consequences of accidents while the incore moveable detector system is degraded are not increased because extension of a surveillance interval does not significantly affect the probability for the occurrence of an accident. Shiffly and 18-month surveillances are performed on the equipment to demonst' rate Operability. Given that the equipment will still function, the consequences of an accident remain unaffected. ,

The possibility of a new or different kind of accident from any V accident previously evaluated is not created begsuse the ability of the moveable detector system to measure core powe." distributions is not significantly degraded. Also, the impact on' the ability to measure quandrant tilt and core average axial power shape p regligi.ble. Finally, no new equipment is introduced and no equipment is operated in a new or different manner. .

The margin of safety is not reduced because sufficient thimbles will 3e available to ensure that no queirant will be,unmonitored. The plugge.d tabes that necessitate this change are not concentrated in any qut6: ant or core region. A full core flux map 27, 1988 utilizing 42 thimbles indicated acceptable compa,tuupleted rison of ScoregAxial May Flux Difference.

Based upon the above, commeavealth EdYson believes th's '

amendment i involves no significant hazards consideration.

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, SAPETY EVALUATION J

l' The Movable Incore Detector System (MIDS) consists of 58 incore flux

-thimbles to permit measurement of the axial neutron flux distribution within the reactor core. Six movable neutron flux detectors are available to scan the length of the 5-8 selected fuel assemblies to provide remote reading of the axial flux distribution. The MIDS is used for confirmatory information and is  ;

not required for the day to day safe operation of the core. Daily core power performance is monitored by the excore detectors. ,

commonwealth Edison believes there is no safety significance in extending the monthly surveillance interval for the power Range Neutron Flux High Setpoint for ten (10) additional days, while the~ plant operates at 75%

power. There are other functional tests that are performed on a shiftly and 18 month basis which would detect degradation or inoperatifity of a channel or component so appropriate actions can be initiated. . These other types of t'esting include low and high voltage power supply adjustaents, detector current and full power meter checks, a flux difference amplifiar check, and p . power range rate circuit and bistable relay driver adjustments, performance of these unsures that the affected channels operate within specified limits.

In addition, the channel checks perform a qualitative assessment of 3 channel behavior. If one channel's indication deviates from its other associated channels, this can be readily detected and corrective actions would be taken.

( commenwealth Edison believes that the routine shiftly and 18 month surveillances that will continue to be performed during the extended 10 day

period will detect instrument failure mechanisms. Therefore, any failures can be corrected so the Unit will not operate in a degraded condition. Also, the probabili.ty of an accident occurring during this surveillance extension is minimal. .rypically there are redundant trip signals to respond to an accident scenario. It is highly unlikely these trip signals will not function as a result of this surveillance extension. Thus, Commonwealth Edison believes tr.is on-time extension re<;uest should not x '.gnificantly impact the safety of Braidwood Station. T o

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