ML20011E690

Provides Util Interpretation of Plant Tech Spec Section 6.2.2 Re Control Rod Withdrawal Interlock Operability.To Permit Drive Movement,Temporary Jumper Placed in Control Rod Withdrawal Permissive Circuit to Inhibit Rod Block

ML20011E690
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	02/13/1990
From:	Eddy J CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9002220195
Download: ML20011E690 (3)

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e Consumers Power rewsamos MKJNEAW5 PROENs55 oonoral officos: 1945 West Parnell Road, Jackson, MI 49201 * (517) 7s8 0650 February 13, 1990 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

TECHNICAL SPECIFICATION SECTION 6.2.2 INTERPRETATION The purpose of this letter is to provide the NRC with Consumers Power Company's interpretation of Big Rock Point Technical Specification Section 6.2.2 which deals with control rod withdrawal interlock operability.

Recently, some questions have been raised with respect to the applicability of Section 6.2.2 during cold shutdown with all the fuel bundles removed from the reactor. The following interpretation has been reviewed by the Big Rock Point Plant Review Committee and submittal of this letter was considered prudent.

Big Rock Point Technical Specification 6.2.1 describes the Control Rod Interlocks as follows:

6.2.1 Interlocks Interlocks shall prevent control rod withdrawal when any of the following conditions exist:

(a) When any two of the thirty-two scram accumulators are at pressure below 700 psig.

(b) When any one of the three sover range monitor channels reads:

(1) Less than 1 x 10~ % poser, when reactor power is above the operating range of the source range monitoring

channels, (2) Creater than 105% power or (3) A reactor period less than 15 seconds.

(c) When the scram dump tank is bypassed, g0 oC0190-0013-NLO2 9002220195 900213

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I Big Rock Point Plant TS Section 6.2.2 Interpretation February 13, 1990 t

(d) When the mode selector switch is in the shutdown position.

Section 6.2.2 also states the following operability requirements:

6.2.2 Operating Requirements t

The control rod withdrawal permissive interlocks shall always be OPERABLE. No further withdrawal of control rods will be permitted if one of these circuits is found to be inoperable.

In interpreting the constraints of "always be operable" in Section 6.2.2, the Big Rock Point Plant Review Committee concludes that these interlocks must be operable when fuel bundles are in the reactor. Having the control rod drive interlocks operable with no fuel in the reactor provides no safety benefit and conflicts with Technical Specification 6.1.5 which only requires the nuclear instrumentation to be operable in the power operation, shutdown, and refueling modes.

During refueling outages with no fuel in the reactor, it is necessary to move control rod drives for the following reasens o

To uncouple a control blade to perform control rod drive maintenance o

Following removal of a control blade and fuel channels, it is necessary to withdraw the control rod drive to protect against damage to the index tube and spud.

To perform Technical Specification control rod drive testing o

prior to reloading the fuel into the reactor.

With no fuel in the reactor, the neutron monitors, if placed in service, will have a downscale indication.

This causes a " rod block" which inhibits the performance of control rod drive testing.

A review was also performed of the Standard Technical Specifications for BWRs.

Section 3/4.3.6 describes the Limiting Condition for Operation for the Control Rod Withdrawal Block Instrumentation.

In reviewing Table 3.3.6-1 of the Standard Technical Specifications, none of the " rod blocks" are required to be operable for cold shutdown mode.

This conclusion supports the Big Rock Point

Position, To permit drive movement under these circumstances, a temporary jumper is

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placed in the control rod withdrawal permissive circuit to inhibit the rod block. The installation and removal of the jumper is administratively controlled by procedure and can only be used with all fuel bundles removed from the core.

This concern and position have been discussed with Region III personnel in the OC0190-0013-NLO2

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