ML20215E293

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Proposes Alternate Method for Insp & Repair of Transient Rod Drive Assembly.Semiannual Removal of Transient Rod Shock Absorber & Visual Insp Recommended.Maint & Repairs Will Be Conducted W/O Removal of Fuel
ML20215E293
Person / Time
Site: Berkeley Research Reactor
Issue date: 04/09/1969
From: Mark H
CALIFORNIA, UNIV. OF, BERKELEY, CA
To: Skovholt D
US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20215E220 List:
References
FOIA-86-811 1468, NUDOCS 8612220029
Download: ML20215E293 (2)
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UNIVERSITY OF CALIFORNIA, BEBrELEY s

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SANTA BARBARA

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BEHutELEY. DAVIS

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COLLECE OF ENCINEERING BERKELEY, CALIFORNZA 94720

- DEPARDIENT OF NUCLEAR ENCINEEMNG g

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go W k-8h Mr. Donald J. Skovholt gh Assistant Director for Reactor Operatiopsf UVEO'

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Division of Reactor Licensing cy MAY 7 1569 d:p:ypg U. S. Atomic Energy Commission J

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Dear Mr. Skovholt:

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Your proposed amendment to our license coircerning maintenance work on the transient rod drive assembly has been carefully considered by the staff of this facility.

I would like to submit an alternate method of accomplishing these inspections and repairs.

I will also describe the inspections we have incorporated into our operating procedures to minimize any malfunctions of the transient rod drive which could affect reactor safety.

On February 27, 1968 I corresponded with you concerning sticking of the transient rod piston in the cylinder due to rust on the cylinder wall.

As a result of that experience we have instituted a monthly inspection of the cylinder.

This is a

accomplished by removing the shock' absorber and visually inspect-ing the cylinder for rust, dirt, excessive wear and proper lubrication.

This inspection is logged in our monthly checklist.

At unscheduled times the inspection plate.on the transient rod gear box is removed and an inspection made for rust, dirt and oxcessive wear.

I do not feel this inspection has any significance regarding reactor safety since complete failure of this gearing system would not prevent the transient rod from falling into the I feel that further disassembly of the transient rod drive core.

would create the possibility,of f ailures of components due to excessive manipulation.

Just following initial criticality of the reactor we installed an air pressure regulator and pressure gauge 'and an air line filter

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and water trap.

Each day the reactor is operated the pressure is y

0-recorded on the Daily Startup Checklist. - We also cycle the transient rod solenoid valve and the preset timer which drops the rod in following withdrawal in the pulse mode. 'This operation of' E

the solenoid valve and timer is also recorded in the Daily Start-p.g up Checklist and satisfies section E-10 of our Technical Specifi-cations.

In our reactor the solenoid valvo is physically located oom M

under the reactor bridge which is made of five inch thick steel

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Disassembling the solenoid valv,e I

would be extremely difficult without complete removal because of cow its location.

Removal would involve disassembling it from the plumbing system and disconnecting the electrical hook-p which ~

is in conduit.

This job would require as much as n' da,and our fGD2237).7/

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experiences.with:,the solenoid; valves in our ventilation system is that disassembly creates malfunctions rather.than prevents them.

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My recommendations for incorporating a procedure'into our license which would help ' prevent failure of the: transient rod drive would be as follows:

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~ Semi-annually, but at intervals of not more than e'ight 1.

months, remove the transient rod shock absorber and visually inspect the cylinder and piston for signs of rust, dirt, excessive wear and proper lubrication.

Make necessary repairs and re-assemble.

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Maintain an air pressure regulater (set at not greater than 80 pounds per square inch, gauge),and an air line filter and water trap in the air,line between the air source and the transient rod solenoid valve.

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Each~ day the reactor is operated.the transient rod solenoid valve and preset timer.shall be cycled to insure proper operation (This point is probably already covered by section E-10~of our Technical Specifications).

All of the above maintenance.and repa' irs will be done without any fuel removed from the core to reduce the reactivity.

The transient rod will be considered an operable rod when the shock absorber is removed for calculating reactivity as required by cection E-5 of our Technical Specifications.

I feel that the above items will help to prevent. transient rod drive malfunction.

I would appreciate hearing from you when a decision has been made on what should be incorporated into our license.

Sincerely, Hans Mark Reactor Administrator HM:Ib State of California)

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County of Alameda' )

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Before me personally appeared Hans Mark, to me known to be the ' person who signed the foregoing instrument in my presence, and made. cath before me to the. allegations set forth therein, on the ninth day of April, 1969 Witnessed my hand and seal Margaret A. Hardy Notary public

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