ML20056H025

Submits Comments on Draft Application Format & Content & Review Plan & Acceptance Criteria for Non-Power Reactors, Chapter 14

ML20056H025
Person / Time
Site:	University of Wisconsin
Issue date:	08/31/1993
From:	Cashwell R WISCONSIN, UNIV. OF, MADISON, WI
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 9309080089
Download: ML20056H025 (3)

Text

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e u emouco7 August 31, 1993 l

Director, Non-Power Reactors and Decommissioning Project l Directorate United States Nuclear Regulatory Commission M. S. ll-B-20 Washington, DC 20555

Dear Sir:

l Tha folleving cermente arc submitted on " Draft Application Format and Content Guidance and Review Plan and Acceptance Criteria for Non-power Reactors", Chapter 14.

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! Page 13 (2) Reactivity insertion rates.

For pulsing TRIGA-type reactors the maximum reactivity insertion i rate does not appear to be of any significance. For University l of Wisconsin cores, firing the transient rod gives a reactivity insertion rate in excess of 7%p/second ($10/second). This  ;

compares to a maximum instantaneous insertion rate of about O.2%p/second (SO.14/second) from simultaneously withdrawing all other control elements at maximum rate at the position of maximum differential control element worth. Reactivity insertion rate is a limiting parameter in analysis of a startup accident, and the rate has historically been limited to a value that will result in a power-level trip before prompt critical is reached, assuming l continuous control element withdrawal at maximum reactivity I insertion rate. This should not apply to a reactor which is J routinely made prompt critical in normal operation. Is thera l some other accident which requires limitation of reactivity 1 insertion rate? If not, then pulsing reactors should not have ]

such a limit stated in technical specifications. l l

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Page 13 (4) Scram Channels The second paragraph appears inconsistent. The first sentence indicates historical acceptance of power level scrams as high as ,

1.2 tines licensed maximum steady-state power, while the sixth i sentence states that power level scrams should be set below licensed power level. Maximum steady state power level does not appear to be a difficult term to define and enforce.

Deliberately operating above the licensed maximum but below the scram setpoint would appear to me to be operation outside the permitted envelope. You appear to be defining a concept of Maximum Analyzed Safe Power Level and insisting that the power i level setpoint be set below this level; but operation at such a 1

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e' power level would not be prudent, since it does not include any  !

margin. If it does include a margin, whether it be for  ;

calibration errors, instrument malfunctions, or for any other reason, it certainly should legal to operate at that level.

For clarification, I would suggest that a statement be made that the safety analysis should show safe operation at the power level scram point, but that maximum licensed steady state power level will be below this level to incorporate margins for error.

i The statements in this section seem to neglect the purpose of l safety limits and limiting safety system settings as defined  !

elsewhere in the document. The basis for such settings should be ,

"to avoid failure of the fuel". The maximum licensed power  :

level, in most facilities, really does not have this basis, but t is based instead on heat removal capability, radiation shielding j capability, or some other limitation. l t

Page 18 (5) Detection of fission product activity The second paragraph indicates that the specified fission product l monitor should be able to initiate an action, such as scram or ,

isolation. An alarm would provide indication of a problem and I initiation of appropriate diagnostic and remedial procedures: '

requiring a, scram will likely result in a much higher setpoint to prevent spurious scrams. Therefore, an alarm is likely to provide safer operation and earlier attention to the problem.

f Page 19  !

(8) Secondary and Primary Coolant Radioactivity Limits  ;

The requirement for weekly gross radioactivity determination might be met by some other means that might be superior. For instance, a continuous reading fission product monitor or a ,

radiation monitor continuously viewing a cleanup demineralizer i could provide even earlier detection of a fission product leak of l significant size. Periodic grab sanple monitoring might not be needed as often under this situation.

Page 24 3.8.2 Materials

! The second paragraph indicates double encapsulation should be required for liquid, gas, and potentially corrosive materials. i Many facilities irradiate material in liquid form (for neutron activation analysis) that is so dilute that it would not add significant activity to the reactor coolant if the capsule were to-open during irradiation. Such samples should not require double encapsulation. Further, all samples irradiated will contain air or some other cover gas in addition to the sample, and many gas samples will have insignificant effect on the activity of the coolant or the air in the vicinity of the reactor even if they rupture during irradiation. The statement requiring

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,s 1 double encapsulation should apply to liquid or gaseous samples which can produce significant quantities of radioactivity o- j samples of naterials corrosive to reactor' components in the  ;

environment of the irradiation facility or reactor pool. i l

Thank you for the opportunity to comment on this document.

Very truly yours, l y Y l R. J. Ca'shwell Reactor Director l W A $ S o - t s te X'

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