ML19269D816

Requests Special Attention to Util 790411 Response to IE Bulletin 79-05,Item 6.Sump Drain Design at Plant Should Be Changed for Safety Purposes

ML19269D816
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/06/1979
From:	Richardson C ARKANSAS, UNIV. OF, FAYETTEVILLE, AR
To:	Harold Denton Office of Nuclear Reactor Regulation
References
IEB-79-05, IEB-79-5, NUDOCS 7906140435
Download: ML19269D816 (2)

Text

DEPARTMENT OF PHYslCS 104 Physics Building Fayetteville, Arkansas 72701 (501) 575-2506

@ UNIVERSITY OF ARKANSAS College of Arts and Sciences June 6, 1979 Mr. Harold R. Denton Director, Office of Nuclear Reactor Regulation Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20555 Dear Mr. Denton; I am a member of a Task Force appointed by the Governor of Arkansas, the Honorable Bill Clinton, to study the accident a'; Three Mile Island and to consider its consequences to the stata because of the operation of Arkansas Nuclear One, Unit One, a reactor of similar design. The purpose of this letter is to request that special attention and review be given to the response of the licensee, Arkansas Power and Light Company, to item 6 in IE Bulletin 79-05 dated April 1,1979:

" Review your operating modes and procedures for all systems designed to transfer potentially radioactive gases and liquids out of the containment to assure undesired pumping of radioactive liquids and gases will not occur inadvertently."

On April ll, Mr. David C. Trimble, AP&L responded: "The drain line from the ANO-1 Reactor Building Sump to the Reactor Auxiliary Building Sump is a normally closed gravity flow line which does not use a pump and requires manual operation to transfer liquids." He explains that there are two valves on the line receiving safety-grade power and a Reactor Building Isolation signal. In a letter of April 16, Mr. Trimble explains that not later than the next fuel outage, these valves will be provided with signals to isolate on low RCS pressure.

Finally Mr. Trimble states that " procedure modifications will be made to verify termination of any manual draining operation in the event of an accident."

My concern with this drain design is caused by the feature " gravity flow." The containment building is, of course, the last line of defense against exposure of the public to radiation. It would seem to me that this defense would be much stronger if the gravity flow line were not present. A drain line with outlet above the level of water in the sump in the worst case and fitted with the two valves with all the safety features now present and to-be-fitted at ANO-1 s 9 1o i i Be Univmay of Arnansas is an Eaual OccortuniN Emciover 7006140 h [ G

Mr. Harold R. Denton Page 2 June 6,1979 would appear to be much safer. The necessity of lifting the water out of the sump would make it much less likely that a transfer happen inadvertently. Of course, the pump to do this must not be started automatically.

I request that the staff give special attention to the design of the sump drain at Atl0-1 with consideration given to changes for improved safety.

Sincerely yours, 0l, $:us -

C. B. Richardson, Professor CBR/bkd cc: Mr. David C. Trimble, AP&L

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