ML20137M603

Proposed Change 85-11 to Tech Specs,Revising Section 3.3.8.3.a Allowing Substitution of Qualified Person for Rod Worth Minimizer at Power Levels Equal to or Less than 20% of Rated Thermal Power

ML20137M603
Person / Time
Site:	Pilgrim
Issue date:	09/09/1985
From:	BOSTON EDISON CO.
To:
Shared Package
ML20137M571	List: BECO-85-162, Application for Amend to License DPR-35 Consisting of Proposed Change 85-11,revising Section 3.3.8.3.a Allowing Substitution of Qualified Person for Rod Worth Minimizer at Power Levels Equal to or Less than 20%.Fee Paid ML20137M603
References
NUDOCS 8509130283
Download: ML20137M603 (3)

Text

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. LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT 3.2.B Control Rods 4.3.B Control Rods

2. The control rod drive housing support system shall be in b. When the rod is fully place during reactor power withdrawn the first time operation and when the subsequent to each reactor coolant system is refueling outage or pressurized above atmospheric. after maintenance, 3

pressure with fuel in the observe that the drive reactor vessel, unless all does not go to the control rods are fully overtravel position.

Inserted and Specification 3.3.A.1 is met. 2. The control rod drive housing' support system 3.a The rod worth minim

• 9r (RWM) shall be inspected after shall be operable during reassembly and the results power operation and startup,- of the. Inspection recorded.

4 when thermal power is less than or equal to 20% of 3. Prior to control rod rated thermal power. Entry withdrawal for startup or into startup mode and with- Insertion to reduce power i

drawal of selected control below 20% the operability rods is permitted for the of the Rod Worth Minimizer purpose of determining the (RWM) shall be verified by:

operability of the RWM prior to withdrawal of control rods a. verifying the for the purpose of bringing correctness of the the reactor to criticality. control rod withdrawal i sequence input to the Action: With the RWM inoper- RWM computer.

able, verify control rod movement and compliance with b. performing the RWM the prescribed control rod computer diagnostic test.

pattern by a second licensed operator or other technically c. verifying the qualified member of the opera- annunciation of the tional staff who is present at selection errors of at the reactor control console, least one Otherwise, control rod move-out-of-sequence control ment may be only by actuating rod in each distinct RWM the manual scram or placing group.

the reactor mode switch in the shutdown position. d. verifying the rod block function of an 3.b Control rod patterns and the out-of-sequence control sequence of withdrawal or rod which is withdrawn insertion shall be no more than three established such that: notches.

1. when the reactor is critical and below 20%

design power the maximum worth of any insequence control rod which is not electrically disarmed is

less than 0.010 delta k.

Amendment No. hDR D $5000293 82 P ppR q

, . . -.. LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENT

3.3.8 Control Rods 4.3.B Control Rods 3.b.2. and when the reactor is above 20% design power.the maximum worth of any control rod, including allowance for a single operator error, is less than 0.020 delta k.

4. Prior to control rod

4. Control rods 1shall not be withdrawal for startup or withdrawn for startup or during refueling, verify refueling unless at least two that at least two source source range channels have an range channels have an observed count rate equal to observed count rate of at or greater than three counts least three counts per per second. second.

5. During operation with limiting 5. When a limiting control rod control rod patterns, as pattern exists, an determined by the Reactor instrument functional test Engineer, either: of the RBM shall be performed prior to-

a. Both RBM channels shall be withdrawal of the operable: or designated rod (s) and daily thereafter.

b. Control rod withdrawal shall be blocked: or

c. The operating power level shall be limited so that the MCPR will remain above the Safety Limit MPCR

- assuming a single error that results in complete withdrawal of any single operable control rod. C. Scram Insertion Times C. Scram Insertion Times 1. Following each refueling outage, each operable

1. The average scram insertion control rod shall be time, based on the subjected to scram time deenergization of the scram tests from the fully pliot valve solenoids as time withdrawn position. If zero, of all operable control testing is not accomplished rods in the reactor power with the nuclear system operation condition shall be pressure above 950 psig, no greater than: the measured scram insertion time shall be '

% Inserted Average Scram extrapolated to reactor From Fully Insertion pressures above 950 psig Withdrawn Times (set) using previously determined correlations. Testing of 10 .55 all operable control rods 30 1.275 shall be completed prior to 50 2.00 exceeding 40% rated thermal 90 3.50 power.

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BASES:

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When THERMAL POWER is greater than 20% of RATED THERMAL POWER, t'here is no ,

-possible rod worth which. If dropped at the design rate of the velocity limiter, could result in a peak enthaley of 280 cal /gm. Thus requiring the RWM to be OPERASLE when THERMAL POWER is less than or equal to 20% of RATED. THERMAL.P0WER provides adequate-control.

.We are1therefore requiring as a limiting' condition of operation (LCO) that the-Rod Worth Minimizer (RWM) be operable when the reactor is critical and below 20% of design power in accordance with Specification 3.3.8.3a so that the.mavimum in-sequence control rod worth will be limitad to 0.010

-delta k as given in' Specification 3.3.8.3b(1) even assuming'c. single failure of the RWM or'an operator error. The RWM asslits &rd supplements the operator with'an effective backup control rod monitoring routine that enforces adherence'to pre-established startup, shutdown, and low power level control rod' procedures. The RWM computer prevents the operator from establishing control rod patterns that are not consistent with prestored RWM sequences by iinitiating appropriate rod select block, rod withdrawal block, and1 rod.)nsert block - interlock signals to the reactor manu'l ..

control systeps rod. block circuitry.

Reference:

FSAR Section 7.16.4.3. a The RWM sequences stored in the computer memory are based on control rod withdrawal procedures designed to limit the individual control rod worths to levels given in Specification 3.3.B.3.b.

Two exceptions to the requirement for RWM operability are permitted: (1)

The first exception permits the withdrawal of. selected control rods'tos ~

allow the determination of RWM operability prior to bringing the reactor to cr1tIcallty. (2) The second exceptton permits control rod movement with the RWM inoperable if the movement is verifled to be in compliance with the, prescribed control rod patterns by a second licensed. operator, or other quallfled member of the plant operational staff, who is 'present at the reactor, control console.

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