ML20217G683

Forwards Comments on Draft 11 of Ansi/Ans 15.20, Control & Safety Sys for Research Reactors

ML20217G683
Person / Time
Site:	University of California-Davis
Issue date:	10/08/1997
From:	Alexander Adams NRC (Affiliation Not Assigned)
To:	Richards W AIR FORCE, DEPT. OF
References
NUDOCS 9710140151
Download: ML20217G683 (5)

Text

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• 0:tober 8, 1997 Dr. Wade J. Richards Chairman, ANS 15 SM ALC/TIR 5335 Price Avenue McClellan AFB, California 95652 2504-

SUBJECT:

COMMENTS ON ANS 15.20

Dear Dr. Richards:

Please find enclosed comments on Draft 11 of ANSl/ANS 15.20, ' Control and Safett Systems for Research Reactors " These comments were developed by the Instrumentation and Controls Branch in the Office of Nuclear Re.: tor Regulation. If you have any questions-concerning thest, comments, please contact me at 301 415 1127.-

Sincerely, I

l

' Alexander Adams, Jr., Senior Project Manager Non Power Reactors and Decommissioning Project Directorate Division of Reactor Program Management i j- Office of Nuclear Reactor Regulation Docket No. 50-607 i

Enclosure:

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%, .....# October 8, 1997 Dr. Wade J. Richards Chairman, ANS 15 SM ALC/TIR 5335 Price Avenue McClellan AFB, California 95652 2504

SUBJECT:

COMMENTS ON ANS 15.20

Dear Dr. Ric'tards:

Please find enclosed comments on Draft 11 of ANSI /ANS 15.20, " Control and Safety

, Systems for Research Reactors." These comments were developed by the Instrumentation and Controls Branch in the Office of Nuclear Reactor Hegulation, if you have any questions concerning these comments, please contact me at 301-415 1127.

Sincerely, h WCCY ,

Alexander Adams, Jr., Seni r ject Manager Non-Power Reactors and Decommissioning Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No. 50-607

Enclosure:

As stated cc w/ enclosure:

See next page -

i

E' McClellan AFB TRIGA REACTOR Docket No. 50-607 cc:

Dr. Wade J. Richards SM-ALC/TI-l 5335 Price Avenue, Bldg. 258 McClellan AFB, California 95652-2504 Lt. Col. Marcia Thornton HQ AFSC/ SEW 9570 Avenue G., Bldg. 24499 Kirtland AFB, New Mexico 87117-5670 Col. Robert Capell HQ AFMC/SGC i 4225 Logistics Avenue, Suite 23 Wright-Patterson AFB, 0his 45433-5762 l

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ENCLOSURE NRC Comments on Draft 11 of ANSI /ANS 15.20

" Control and Safety Systems for Research Reactors"

1. Page 5, Line 7. Add " minimum" beinre " criteria."

2. Page 5, Line 12. Add " minimum" before " criteria."

3. Page 6, Line 5. Change " presence" to " interaction" or " intervention."

4. Page 6. Line 8. We recommend changing the example to use a built in test setup. We discourage the use of jumpers and lifted leads due to tne number of cases where the system was not restored properly to its originct condition.

5, Page 6, Line 18. The phrase " infinitesimal that there is virtually no chance that it will l occur"in connection with " probability of occurrence" seems to state that there must l be a probability numoer that must be calculated and a threshold assigned. In practice f it might be better to eliminate the probability requirement and make reference to a safety analysis for the credibility determination it is also standard practice to accept different thresholds for the credibility based upon the possible consequences.

6. Page 11, Line 23. Add "and manually" following " automatically."

7. Page 12, Line 13. Change item 4 to read:

The RSS shall be designed such that a single f ailure can not cause the loss of the proper protective action when required.

8. Page 12, Line 14. Add a new item after item 4:

The RSS shall be designed such that, in the presence of a postulated common mode / common-cause failure of software, a diverse means to shut down the reactor shall be provided.

9. Page 13, Line 28. Af ter " covers)" add "and administrative controls."

10. Page 14, Line 23. Revise item 1:

(1) Environmental and seismic conditions in the area should not prevent the RSS from performing its safety function.

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11. - Page 14, Line 26. Revise item 2i

_ (2) Electromagnetic interference should not prevent the RSS from performing its safety function, j 12.~ Page 16, Line 19. Typo integrate.

L: 13. L Page 16,~ Line 19. Add " including hardware" after " functions."'

L .14. Page-19, Line 10. Add a new item after item 1:

The RSS and RCS shall be designed such that, in the presence of a postulated common cause failure of software in the RSS, a diverse means to shut down the reactor shall be provided.

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