ML20011F257

Advises That 891003 Request for Appropriate Tech Specs for Chlorine Detection Re Control Room Habitability,Not Warranted

ML20011F257
Person / Time
Site:	Oyster Creek
Issue date:	02/21/1990
From:	Devine J GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
5000-90-1892, NUDOCS 9003020255
Download: ML20011F257 (4)

Text

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, GPU Nuclear Corporation g e gn '

One Upper Pond Road

'e {G;s i wEBB Parsippany, New Jersey 07054 201 316 7000-TELEX 1316-482 Writer's Direct Dial Number:

February 21, 1990

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LU.S. Nuclear Regulatory Commission Attentions- Document Control Desk Mail' Station P1-137 o Washington, D.C. '20555 i

, Gentlemen:

Subject Oyster Creek Nuclear Generating Station (OCNGS) 1 Docket No. 50-219

,i Control Room Habitability References (1) NRC Ltr. dated 30/3/89 (2) GPUN Ltr. dated 5/16/89 (3) GPUN Ltr. dated 10/18/89 In a recent letter (Ref. 1), the staff requested appropriate technical specifications for chlorine detection and minimum air flow requirements to the  ;

control room envelopc. The staff based this request on the fact that Oyster Creek removed only the 1-ton liquid chlorine cylinders in 1987 and retained a  :

150.lb. cylinder to treat the new radwaste service water system.

'In lieu'of an additional-TS (Ref. 3), GPUN is providing our technical

-justification for our present operating' philosophy. By procedure, the control j room HVAC system-is in full recirculation (minimum outside air) for chlorine system maintenance, tank delivery and handling. Since these activities j

represent the greatest potential for an inadvertent onsite chlorine release, we negate the importance of chlorine detection to initiate immediate operator l action. Therefore,.a separate TS for chlorine detection is not warranted, in I that the system would already be in full recirculation for1the most probable _

accidental release.

Secondly, the-toxic transport analysis (Ref. 2) is very conservative for assessing the potential hazard to the control room. The analysis assumes: the centerline of-the chlorine plume blows directly toward the control room air intakes with no credit fore the mixing of the chlorine plume due to building wake, or for the enclosure that houses the 150 lb. cylinder. With these assumptions, the. analysis calculates for the most limiting event (3/8" line break), a maximum allowable outside air flow of 1750 CFM-for a wind speed of 0.5 MPS and wind stability' class C. The maximum outside air flow represents the infiltration rate during full recirculation whereby a toxic limit is not reached in the control room envelope. The following description provides more details on the conservatisms associated with this analysis, and our position 9003020255 900221- r PDR ADOCK 05000219

.P PDC C32035389 gDh GPU Nuclear Corporation is a subsidiary of General Pubhc Utilities Corporation  :

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.q 'In-summary,.GPUN dpos*not believe a new TS.is necessary for the issue of.

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c control room habitat.ility.for'two reasons. One, procedures are in place to

! minimizelthe effects of a chlorine release during.the most probable scenarios.

E .Second,~the transport analysis'is conservative by its inherent-assumptions such b,

as no credit for site structure dispersion of the chlorine plume. If you have any additional. questions on this issue, please contact Mr. Michael Laggart, I Manager, BWR Licensing, at (201) 316-7968.

Very truly yours, 8W&

J. C. DeVine, Jr.

Director Technical

Functions 0- JCD/cjg.

Attachments:

ect Mr. William T. Russell, Administrator Region I

.U.S. Nuclear Regulatory Commission 475.Allendale Road King of Prussia, PA 19406 NRC Resident Inspector

~ Oyster Creek fluelear Generating Station

. Forked River, N.J. 08731 l

Mr. Alex Dromerick  :

U.S.: Nuclear Regulatory Commission .)

Mail Station'P1-137 Washington,-D.C. 20555' ],

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L ?cn th3 tTCting'r;quir:mento forTtha OyctOr Crook control room: I

1. No credit was.taken for building wakes or other dispersive phenomena Y resulting1 f rom the intervening topology of site structures.

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.The. analysis' conservatively assumes the wind direction is such that the

. centerline of the. chlorine plume at ground level blows directly toward the control room air intake. Actually, the 150 lb. cylinder is housed within an enclosure, and there are local structures such as tanks and buildings that provide obstructions between the source of the plume and the control room outside air intakes.

The enclosure which houser the cylinder is located at ground level, 380 ft. j northwest of the control room air intake (See attached sketch). The control room air intakes are located on the roof of the office building at a elevations 64and 73'. Between the cylinder enclosure and the control room air intakes there are tanks and buildings with heights up to.100 ft

-(Turbine Generator Building). A chlorine plume driven by a wind from NW through W of:the cylinder. enclosure does not have a straight line path to.

the control room air intake. The presence of these local obstructions produces a large scale turbulence that alters the wind path and reduces the probability of the plume reaching the control room air intake, which is located at the opposite side of the turbine building (east of the Turbine Building). Likewise,.a chlorine plume driven by a wind from N, NE, E, SW, S, or SE of the cylinder enclosure would have no impact on the control room air intake. .The cylinder is located northwest of the control room air

. intakes and the wind direction would drive the chlorine plume away from.

the control room outside air intakes. .{

'2. .The Oyster Creek control room has provisions for detecting a chlorine

. release and minimizing outside air (full recirculation) to the control room. . Even with these design features, GPUN does not take credit for a

" tight" controlEroom (Type A or B) per Regulatory Guide 1.78.

[ A comparison between the data /results of this analysis and Reg. Guide 1.78 indicates that for an' infiltration rate of 1750 CFM and a total control room free volume of 27500 cu. ft., the air exchange rate is 3.8 per hour.

As per Reg. Guide 1.78 Appendix A, verification by periodic. field testing

-is only required for control rooms vith an air exchange rates of less than

• 0.015 per hour (Type A) and 0.06 per hour (Type B). As per Table C-2 of the same Reg. Guide, the type C control room (air exchange rate of 1.2 per.

hour) does not require verification by field testing. Since GPUN classifies the oyster Creek control room as " Type C", the need for periodic infiltration testing is not required.

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