ML20206K744

Application for Amend to License R-103,changing Tech Specs 3.6.e That Would Authorize Movable & Unsecured Experiments in Ctr Test Hole as Allowed in All Other Experimental Regions of Reactor

ML20206K744
Person / Time
Site:	University of Missouri-Columbia
Issue date:	05/04/1999
From:	Mckibben J, Schoone A MISSOURI, UNIV. OF, ROLLA, MO
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20206K747	List: ML20206K744 ML20206K750
References
NUDOCS 9905130271
Download: ML20206K744 (2)

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REFERENCE:

l Docket 50-186

- University of Missouri Research Reactor E

, License R-103 '

SUBJECT:

Request s C' hange to Technical Specification 3.6.e Pursuant to 10 CFR50.59(c) .

and 10CFR50.90 De University of Missouri Research Reactor ' (MURR) requests a change to Technical Specification 3.6.e that would authorize movable and unsecured experiments in the center test hole as are allowed in all other

% experimental regions of the reactor. Technical Specification (T.S.) 1.6 defines Flux Trap as "Ihat portion of the reactor through the center of the core bounded by the 4.5 inch inside diameter tube and 15 inches above and below the core vertical center line." T.S.1.3 defines the center test hole as "The volume in the flux trap occupied by the removable experiment test tubes." His request is to expand the allowable experiments in the center test hole from secured experiments to include movable and unsecured experiments.

Movable, secured and unsecured experiments are defined in Technical Specifications as followc T.S.1.11 Movable Experiment "A movable experiment is one which is designed with the intent that it may be moved into and out of the reactor while the reactoris operating." ~ ' , .

T.S.1.24 Secured Expenment "A secured experiment is any experiment which is rigidly held in place by mechanical means with sufficient restraint to withstand any anticipated forces to which the experiment might be subjected."

T.S.1.25 Unsecured Expenment "An unsecured experiment is any experiment widch is not secured as defined in T.S.1.24, or the moving parts of secured experiments when they are in motion." ;

Technical Specifications 3.1.g through 3.1.k places limits on: the reactivity worth of each secured removable experiment, total for all experiments in the center test hole, each movable experiment, each unsecured experiment, and total for all unsecured experiments. No' change is requested to these limits. De limits for movable and unsecured experiments are based on Hazards Summary Report (HSR) Addendum 5 section 3-

" Step Reactivity insertion Analysis for Determination of Experiment Reactivity Limits."

Technical Specification 3.6.c currently stateithat " experiments in the center test hole shall be removed or installed only with the reactor shutdown and shall be rigidly held in place during reactor operation." Original HSR (July 1; 1%5) in section 8.2, Flux Tran. imposed this " , , ; high degree of administrative control to minimize me possibility ofinserting or removing a sample which would result in increased reactivity . . ."

and to eliminate the possibility of imerting or removing a sample which could result in a large reactivity.

effect. This section of the HSR also recognized that at some point in time adequate information would be obtained, which would allow removing this restriction on use of the center test hole. Page 8-3 of Original HSR states:-

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"It is feh that alternate'means for usage of this facility should be provided only after operational . .~

. experience has provided complete data on reactivity value. ' At some future date, after the acquiring x of suitable information pertaining to the flux trap' worth, a request will be made to the AEC [NRC) ? ' '

fs . for license amendment to permit insertion and removal of samples during reactor operation."

< The Original HSR under Accident Analysis also states on page 13-2:; 4

$ a4 d j.*The initial use of the center test hole will be limited to ' xperiments e Ehich can be moved or altered -

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q( '+'  ; only aAer reactor shutdownc It is intended however that at some future date techniques for an 2

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p, , W;[ . alternate method of use of this facility will be installed.W Only aRer adequate data is in hand will a a 0 -m

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4 request be submitted to the Atomic Energy Commission [NRC] for an addendum to the operating -i license to alter the mode of sample entry into the flux trap position."

he basis for T.S. 3.6.e states: "Although the reactivity worth of experiments in the center test hole is restricted to less than the reactivity insertion which could cause fuel element failure, this specification .

climinates a potential rnechanism for uncontrolled addition of reactivity "

It is requested to revise the Technical Specification 3.6.e to read as:

Only movable experiments in the center test hole shall be removed or installed with the reactor operating. All other experiments in the center test hole shall be removed or installed only with the reactor shut down. Secured experirnents in the center test hole shall be rigidly held in place during reactor operation.

During the intervening years since the Original HSR was written we have refined our rneasurements and our methods to characterize the reactivity of samples at specific heights in the center test hole. The experiments --

in the center test hole are run in aluminum cans. Approximately 20,000 different sample cans have been irradiated in the center test hole accumulating 50,000 can-weeks of experience. The target material has varied from large neutron absorbers like boron and iridium to small absorbers like aluminum and sulfur.

After 30 years of this operating experience, there no longer is the uncertainty about reactivity worth of experiments in the flux trap as there was before the reactor was taken critical. ne uncertainty, which created the need to impose the limitation, is no longer valid so we are requesting the unnecessary limitation be removed.

The safety evaluation in liSR Addendum 5 shows that movable experiments with reactivity worth not to exceed 0.001 Ak and unsecured experiments with reactivity worth not to exceed 0.0025 Ak do not create a safety problem. It is based on the affect of a step insertion of reactivity and thercibre limits the reactivity worth for these two classes of experiments. His analysis is applicable for any location of the sample.

It is requested to change the basis for T.S. 3.6.e to: q

'i Specification 3.6.e is intended to limit the experiments that can be moved in the center test hole j while the reactor is operating, to those that will not introduce reactivity transients more severe than one that can be controlled without initiating safety system action (Ref. Add. 5 to HSR).

Attached for your reference are revised Technical Specification pages with this change incorporated. If there are any further questions, please contact me at (573) 882 52% or Charlie McKibben at (573) 882-5204.

Sincerely, Reviewedand Approved:

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Anthony Schoone J. Charles McKibben Reactor Manager Associate Director attachments

• xc: Mr. Al Adams. USNRC M Mr. Tom Burdick, USNRC, Region til Dr. Edward Deutsch CHRISTINE M.ERRANTE Notary Public-State of Missotsi countyor soon.

My Commission Expires 04/142003