ML20129F640

Requests That Encl Handout for Nuclear Energy Inst/GPUN-OG/ NRC Conference Call on Nuclear Energy Inst/Epri Revised Source Term Task Force for Plant,Be Placed in Docket File 50-219

ML20129F640
Person / Time
Site:	Oyster Creek
Issue date:	10/25/1996
From:	Eaton R NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9610290178
Download: ML20129F640 (5)

Text

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@ RE:o g 4 UNITED STATES g

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C NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666-0001

$ o 4*....g October 25, 1996 MEMORANDUM T0: File i

FROM: Ronald B. Eaton, Senior Project Manager {

Project Directorate I-2  ;

Division of Reactor Projects I/II '

SUBJECT:

HANDOUT FOR NEI/GPUN-0C/NRC CONFERENCE CALL ON NEI/EPRI i REVISED SOURCE TERM TASK FORCE (0YSTER CREEK PILOT PLANT REQUEST)

Please place the attached subject correspondence received on October 9, 1996 in Docket File 50-219. i Docket Ho. 50-219 4

Attachment:

As stated 61STRIBUTION w/ attach.

Docket File PUBLIC REaton DISTRIBUTION w/o attach.

PDI-3 Memo CJamerson JStolz DOCUMENT NAME: G:\FATON\FILEMEMO.1 T2 esceive a copy of this documentllndcase in the boa: *C* = Copy without ettschment/ enclosure "E" = Copy with attachment / enclosure "N' = No copy 0FFICE PDl-2f PN h f PD3-3:LA lC PDl-2:Q l l l NAME REatori TTk CJamerson a b JStolz K DATE 10/7d/96' 10/23/96 "/ 10/11/96 OyICIALRECORDCOPY p:DI 'g[

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'8 ". n Nilt FILE DENTER COPY 9610290178 961025 PDR ADOCK 05000219 P PM ,

moteworthy Aspects megarding i-Application of the Revised DBA Source Term to Oyster Creek E

Aspect contrast with other Pilot Generic Value $

Annlications T

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1. Credit is being taken for of the two other BWR pilots, One can readily envision drywell sprays for the only Perry has taken credit that other small-containment n removal of airborne for sprays, and those sprays BWRs (i.e., Mark I and II $

radioactivity as well as for are in the con;ainment (Mark designs) may wish to apply the reduction of containment III design) rather than in drywell spray credit to the g pressure. the drywell (Mark I/II revised DBA source term. q design). Drywell sprays may be the 7 single most effective feature of small-containment {'

m BWRs for aerosol removal . B N

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2. GOTHIC-calculated In order to properly assess Use of an integrated g containment spray performance, pool analysis provides the nost thermal-hydraulics and scrubbing, and containment direct means of addressing Q a

containment atmosphere pressure vs. time, it is the containment E mixing rate (with DBA LOCA + necessary to use containment thermal-hydraulic issues and core-damage mass and energy thernal-hydraulics may be used in future y releases) are being consistent with the applications for that '

employed. core-damage nature of the reason.

event. In the case cf some other applications, adjustments were nade to the existing containment analysis thermal-hydraulics, ,

but for Oyster Creek an  !

integrated analysis is being performed. g:

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3. There is a significant Small BWR containments, in It is expected that the .' l 0i

potential for no engineered general, present the resvised DBA scurce term will pH control being needed smallest potential for require engineered pH based on negligible control in most -

substantial re-evolution of quantities of elemental iodine-from applications. The exact h chloride-bearing insulation containment water. This is nature, timing and maynitude within the containment and- apparent from the fact that of chemical addition, l7, the relatively small ratio in the Browns Ferry however, will vary from is of gas-space volume to water application acceptable dose plant to plant. The Oyster volume. results were obtained Creek application would y assuming a pH of 6.0 rather appear to present one end of -

than 7.0. However, use of a a spectrum of results; i.e.,

buffer will still be a plant where analysis may a required at Browns Ferry. show that supplementary d This may not be necessary chemical addition may not be  ;

for Oyster Creek. required at all.

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4. No Control Room charcoal Other applications have at While most plants have some ,

or particulate filtern are least credited particulate filtration for the control being credited (per the filters; some have credited roon (i.e., intake and/or {

original plant design). both, recirculation) , there is 2 always the potential for unfiltered in-lcakage during some portion of the 30-day h

dose calculation period. y The Oyster Creek original o' design presents a limiting case for consideration.

5.eReactor Building /SGTS Other BWR applications do Potential bypass flcwpaths bypass pathways are being no,t have isolation vary from plant to plant, considered including condensers. but this (or a similar) isolation condenser flowpath could crist at many non-condensable vents which BWRs. Radioactivity gl bypass the MSIVs. attenuation along such n:

bypass flewpaths has boon credited in the analyses of  ?.

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_. . ~ _ . -. ._ . . . -. .- . -.

some BWRs using TID-14844, but has not been developed fully for the revised DBA

• source tern. h a

6. Pressure-dependent MSIV Other BWR applications have While-not limited tc the y leak rates are being used not credited application of the revised (as credited in existing pressure-dependent MSIV leak DBA source te: m (witness the y analyses of record for Oyster Creek).

rates. existing credit in the case of Oyster Creek), the use of g

the revised DBA source term g changes the relationship d

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between drywell pressure and drywell activity  ;

concentration as credited. m Pressure-dependent MSIV B leakage has the potential W for broad application.

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7. No credit is being sought for the main condencer an a While Perry has made a cubmi-tal sccking no credit The Oycter Crcck geometry leven though it nakes use of

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mitigation feature. for the nain condenser, only two steam lines) is 4

Perry is a Mark III with a more typical of operating at third, safet.y-related manual Mark I and Mark II -

isolation valve outboard of containments which greatly the outboard MSIV in each of outnumber Mark III designs.

four steam lines. The  !

Oyster Creek plant has no such valve.

More generally, application of the revised DBA source term to Oyster Creek focuses at this time on demonstrating the adequacy of an original design in the face of additional 3, requirements rather than on increasing allowable MSIV Icak rates or other design o:

Jmprovements. While there is one other Mark I-containment BWR among currently agreed-upon pilots, that plant is not crediting drywell sprays (nor are that plant's  ?

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sprays independent of the ECCS) , that plant does not employ and isolation condenser (hence no MSIV bypass), and that plant is seeking to credit the main condenser for mitigation (and to increase the allowable MSIV leak rate). Therefore, the Oyster Creet work ~in progress constitutes a unique and-demonstrably useful pilot-application supporting MRC's ruleraking for the application of the revised DBA source term to operating plants. --

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