ML20125A499

Discusses Telcon Review of Monticello Plant SGTS Schematic Drawings

ML20125A499
Person / Time
Site:	Monticello
Issue date:	12/04/1969
From:	Danielle Sullivan US ATOMIC ENERGY COMMISSION (AEC)
To:	Moore V US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212080369
Download: ML20125A499 (2)

Text

DEC 4 BS9

/

Files T11RU V. Moore, Chief, Instrumentation & Power Technology Branch, DEL TE140N REVIEW OF )OfTICKLIA F1. ANT SCTS SCREMATIC DRAWING 88 DOCEIT f50-263 As stated in my memo to files dated November 14, 1969 (RT-857A), the applicant had agreed at our Wovember 4 meeting to provide some addi-tional independence between the redundant Standby Gas Treatment Systems and to submit the details of the modification to us for review. CVI Dwgs #A511-3203, Sheets 1-3 (Chg. 3) were subsequently sent to us, i

To assist us in the review we arranged a conference call with the applicant and his representatives on December 2. Participating in the call were UI.

C. Ross 9A.-E G. L. Davis J. W. Lingsfelter L. Wolf M. Clinton 6E,,ff, D. Vassallo T. Ippolito D. Sullivan Functionally, the SCT8 has not been changeds the " preferred" system (System A) is selected initially and, if it fatis, System B is selected after a time delay of 50 seconds. The modifications relate to the manner in which this is accomplished.

In the original design the control circuits of System A also controlled certain portions of system B. For example, the starting relays of System B were deenergised by the relays in System A which were actuated when System A was successful. In summary, the two control circuits were not independent.

In the modified design there is complete electrical independence between the two systems. There are two independent flowmeters in the common duct (we can call them 'A' and 'B') which control only their respective systems. For example, if system A fails to start, this condition would omce> . . . . . . . . .

$URNAME > .

O*W >. ====.======------.=~:.-=n - - --- - - - - - . . .

Wrrn AIX'-318 (lut. D-53) g 9212080369 691204 PDR ADOCK 05000263 p Pun

1w DEC 4 1959 Telcon 2 be sensed by flowmeter 'B' which would then start System B independently of the System A controllers. Thus, the only lack of independence arises from the process itself. This does have at least one potential commen failure mode 1 a useless flow via a broken duct in System A which would appear to System 2 as successful operation.

We were able to complete our review of the SCTS drawings during the course of the telcon.

/

!)

D. F. Sullivan Instrumentation & Fower RT-902A Technology Branch DRL11&FTB8DFS Division of Reactor Licensing ces F. Schroeder Distribution S. Levine N- Muppl.

R. Boyd DRL Reading

1. Detoung AD/RT Reading D. W 11er I&PTB Reading D. Vassallo T. Ippolito

! bec V. Moore l

D. Sullivan 1

omet > . .. D RL IIAUB... ....D RL 11 IB .. . . . . . . . . . . . . . . . .. ... . . . . . . . . . . ..

Sumuc > DS s e., . .. . .. , . . . . _ , .

om>

nirm ac.m<n,...e

.12 L ../69.. 12L h/6L .

. . = . . ... . . . . . . . . . . . . . .. .

,,,,,,,,,,,,,,,m,_,,,,

. .__