ML20127B247

Forwards Response to NRC 921229 Request for Addl Info Re Listing of Scrams Provided by New Ga Co Control Console That Are Not Part of TS & How New Control Console Provides Interlocks Required by TS

ML20127B247
Person / Time
Site:	University of Illinois
Issue date:	01/05/1993
From:	Holm R ILLINOIS, UNIV. OF, URBANA, IL
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9301120214
Download: ML20127B247 (4)

Text

.-

e Universitv of Illinois- Department of conese of Engineering Nuclor Enginening at Urbana-Champaign 214 Nuclear Engineering 217 133-2295 Lateratory 217 333-2906 far 103 South Goodwin Avenue Urbana, IL 61801-2984 January 5, 1992 Docket No. 50-151 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk M.S. PI-22 Washington, DC 20555

Dear Sir,

Please find enclosed the answers to your REQUEST FOR ADDITIONAL INFORMATION dated December ?9, 1992. If there are any further questions or questions concerning the information I have provided please call me at 217-333-7755.

Respectfully,

,f f4t ;L Richard L. Holm Reactor Supervisor Enc, cc: Regional Administrator, USiiRC, Region III Mr. Alexander Adams, Jr. , NRR, USNRC File 120027 9301120214 930105 ,\ /

PDR ADOCK 05000151 P PDR t d

l

13- L l y --

-l STATE OF ILLINOIS COUNTY OF CHAMPAIGN

. Richard L. Holm, being first. duly sworn on oath, deposes and says that he has affixed his signature to the letter above in his official-capacity as Reactor-Supervisor, University of Illinois Nuclear Reactor Laboratory; that in accordance with the provisions of Part 50 Chapter 1, Title 10 of.the Code of

. Federal Regulations, he is attaching this affidavit; that the facts set forth in the within letter are true to his best information and belief.

,7 - A. m.

~;Yh. fy R1 chard L. Holm' .

Reactor Supervisor Subscribed and sworn to before me, a Notary Public -in and for the County of Champaign, State of Illinois, this _6_ day of . January , A.D., 1993.

+-

/ 1-VI .a r

/O;~Ckh] (. p l  ;, i -f '7 W Notary Public n of. Illidols-f < Kl.-2 (b..f e_

v L

My Commission Expires

~ __-:_: _

" OFFICI AL SEAL "

K ATHLEEN M. DYSART NOTARY PUBUO, STATE OF ILLIN01S MY COMMisS!O'l EXPIRES 8A9/96

= . :: ::__  :: __

.{

i:

. . - . . = ., .-. . . . . . - , -.

,'t

J RESPONSE TO REQUEST FOR ADDITIONAL _INFORMATION UNIVERSITY OF ILLINOIS DOCKET No. 50-151 QUESTION: Please provide a listing of scrams provided by the new General Atomics control console that are not part of the Technical Speci fica tions.

ANSWER: The following scrams are provided by the General Atomics console that f

are not required by the Technical Specifications -

• NP-1000 liigh Voltage Low

• NPP-1000 High Voltage Low

• Key Switch in any position than "0N" (i.e. " RESET" or "0FF")

• A second power level scram (only one required by TS)

• Low Primary Flow when greater than 1 MW

• liigh TRIGA Tank Level

• Primary Outlet Temperature High

• 2 External Scram circuits

• Period Scram QUESTION: Discuss in general terms how the new control console provides the interlocks required by your TS.

ANSWER: Erevent Transient Rod Withdrawal when nower is greater than 250 Kw.

This interlock is operationally set at 1 Kw. The NM-1000 provides a power signal to the CSC software which determines whether or not the power is less than 1 Kw. The software then outputs to a relay _which will then allow the transient rod solenoids to energize to fire the=

rods if power is less than-l Kw.

Enevent control rod withdrawal when neutron count rate is less than 1 ner secgad t The NM-1000 provides a power signal to the CSC software which determines whether or not the power is greater than 1 cps. The software then outputs to a relay which will then allow the rods to be withdrawn if power is greater than 1 cps.

Prevent withdrawal of a transient rod when the slaJdard control rods are no_t fully insertad, (This does qct apply to the adiustable 1.tartsient rod if the movable _gylinder is fully _1.nserted when the air pr_ essure h applied.]

The CSC software prohibits firing the Fast Transient Rod unless all the manual rods are indicated to be on the bottom. The Adjustable Transient Rod may be fired if the movable cylinder is on the bottom.

1 i

i 1

NOTE; The following interlocks are provided by the control console that are not required by the Technical Specifications.

1) Software interlocks in the UP pushbutton circuit prohibit withdrawal of more than one rod at a time. ALL rod UP drive relays are inhibited anytime two or more UP pushbuttons are pressed.

2) Upward movement of the control rods is inhibited by the CSC software if all scrams are not reset.

3) Upward movement of the control rods is inhibited by the CSC software if control rod magnet current is not enabled.

QUNSTION: You proposed a change to the bases of TS 3.5 concerning power level scrams. Is il appropriate to state that the power lerel scram --

assure that the reactor operation sit.ys within the limits discussed in the Safety Analysis Report and approved by the NRC?

ANSWFR: Yes. The power 'evel scrama ensure that reactor operation will stay below the safety imit (fuel temperature) discussed in the safety Analysis Report and approved by the NRC.

_