ML17265A270

Provides Response to Request for Addl Info on Radiation Effects Aspects of Spent Fuel Pool Mod at Plant

ML17265A270
Person / Time
Site:	Ginna
Issue date:	04/23/1998
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	Vissing G NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M95759, NUDOCS 9805150072
Download: ML17265A270 (8)

Text

CATEGORY 1 REGULA Y INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9805150072

.DOC.DATE: 98/04/23 NOTARIZED: YES DOCKET

.FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G

05000244 AUTH.NAME,,

AUTHOR AFFILIATION MECREDY,R.C.

Rochester Gas E Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION VISSING,G.S.

SIZE:

SUBJECT:

Provides response to request for addi info on 'radiation effects aspects of spent fuel pool mod at plant.

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4ND ROCHESTER GASANDElECTRIC CORPORATION ~ 89 FASTAVENUE, ROCHESTER N. Y 1dbf9-0001 ARFA CODE716 Sf6-270D ROBERT C. MECREDY Vice President Hvcteor Oryerotions April 23, 1998 U. S. Nuclear Regulatory Commission Document Control Desk Attn:

Guy ST Vissing Project Directorate I-1 Washington, D.C.

20555

Subject:

Response

to Request for Additional Information on the Radiation Effects Aspects of the Spent Fuel Pool Storage Rack Modification at R.

E. Ginna Nuclear Power Plant (TAC No.

M95759)

Docket No. 50-244 Ref. (1):

Letter from G.

S. Vissing (NRC) to R.

C. Mecredy (RGEE),

Subject:

Request for Additional Information on the Radiation Effects Aspects of the Spent Fuel Pool Storage Rack Modification at R.

E. Ginna Nuclear Power Plant (TAC No. M95759), dated March 2, 1998.

Dear Mr. Vissing:

By Reference 1,

the NRC staff requested additional information regarding the Radiati'on Effects Aspects of the Spent Fuel Pool Modification at R.

E. Ginna Nuclear Power Plant.

Attachment 1 of this letter provides the requested information.

Ver ruly

ours, Robert C. Mecre y Attachment JPOi500 Subscribed and sworn to before me on this 23rd day of April, 1998 Notary Public MARtE 'C. Vtt.LENEUVE Notary Public, State of New York Illonroe Connry

~gr Commission Expires October 31, 19

'tt805i50072 980423 V PDR ADQCK 05000244 p

e I'

PDR

xc:

Mr. Guy S. Vissing (Mail Stop 14B2)

Senior Project Manager Project Directorate 1-1 Washington, D.C.

20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Xnspector Mr. Paul D. Eddy State of New York Department of Public Service 3 Empire State

Plaza, Tenth Floor

Albany, NY 12223-1350 Mr. F. William Valentino, President New York State

Energy, Research, and Development Authority Corporate Plaza West 286 Washington Ave. Extension

Albany, NY 12203-6399,

U.S.

NRC G.S. Vissing A-1 April 17, 1998 Res onse oRe ues orAddiionailnforma lono eRadia io EffectsAs ectsof eS en ue oo S ora e Rack Modification a R E G nna Nuclear Power Plan In Chapter 6.0, Radiological Evaluation ofthe Spent Fuel Pool Re-Racking Licensing Report (February 1997),

you address the offsite dose consequences at the EAB and LPZ forboth a fuel handling and tornado missile accident.

For, these same two accidents, provide a discussion of the thyroid and whole body dose consequences to the control room operator.

These dose consequences should be within the acceptance criteria of30 rem thyroid and 5 rem whole body.

Res onse to ues o

o RG8 E has performed control room dose calculations for both fuel handling accident in the auxiliary building, and the tornado missile accident.

The results of the limiting analyses are presented below.

In both cases, the dose limits of General Design Criterion 19 were met.

A.

Introduction The offsite dose consequences were determined for the limiting, hypothetical fuel handling and tornado missile accidents.

Airborne fission product releases resulting from the hypothetical fuel handling accident (FHA) or tornado missile accident (TMA)would result in the introduction of some noble gas and iodine activity into the control room atmosphere.

Conservative calculations have been performed that estimate the resulting absorbed thyroid and whole body doses to a receptor assumed to be present in the control room for the assumed accident duration of two hours.

The fuel handling accident was performed with the control room assumed to be in the normal operating configuration.

This is assumed to result in 2000 CFM of unfiltered air being taken into the control room for the first 30 seconds following the fuel handling accident, until the control room is isolated and the system switches to the emergency recirculation mode with the air being forced through a charcoal filter system. The tornado missile analysis was analyzed with the control room ventilation system isolated.

This is consistent with Ginna Station procedure ER-SC.1, which requires that the system be placed in this configuration in the event a tornado is in the vicinityof the site.

Fuel Handling Accident Analysis The total isotopic activity available for release was determined using isotopic and release assumptions published in Section 15.7.3.2 of the UFSAR. Key assumptions are one assembly damaged having'100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> decay pool decontamination factor of 100 filtration system efficiency of 90% for inorganic and 70% for organic species of iodines no credit for decay until isotopes were introduced to the control room atmosphere The atmospheric dispersion factor (X/Q) was calculated using the bounding-value algorithm:

XiQ = [C'A'u]'secim')

where C=building shape factor A=area of perturbing building (m')

u=average wind speed (m/s)

U.S.

NRC G.S. Vissing A-2 April 17, 1998 The assumptions used to determine the X/Q were:

Building shape factor is an increasing function of aerodynamic "smoothness";

it varies between 0.5 for a "streamlined" building to 2.0 for a "bluff'uilding. The pertinent buildings at Ginna are much closer to the latter than the former, thus it could be argued that C would be closer to 2 than to 0.5. But for conservatism, and to account for the subjective nature of the definition of C, a value of 1.0 was assumed for C.

Exhausted effluents homogeneously mix with the air between the containment/intermediate building and the control building.

The activity concentration at the control room intake (on top of the control building) is assumed to be equal to the concentration in the cavity between the buildings.

Wind speed is assumed to be 1.0 m/sec.

This is in agreement with Regulatory Guide 1.25 assumption for a ground level release.

These assumptions resulted in a X/Q value of 6.95 x 10~ sec/m'or the area between the spent fuel pool ventilation exhaust point and the intake to the control room ventilation system.

Control room configuration assumptions:

The concrete shielding around the control building is assumed to be sufficient to reduce contributions to the gamma dose inside the building from sources outside the building to negligible levels.

Control Room intake is unfiltered. For the first 30 seconds, the intake rate is 2000 CFM. Design inleakage is assumed for the time period 30 sec < T < 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

Control room exhaust flow is assumed to be 0.0 CFM for the first 30 sec.

Control room exhaust flow is assumed to be equal to intake flow for 30 sec < T < 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

Filtered recirculation of control room air volume is started at t = 30 sec.

Recirculation filterefficiency is assumed to be 90% for inorganic and 70% for organic species of iodines.

Recirculation rate is 2000 CFM.

The thyroid dose was calculated as follows:

Determined integrated activity in the control room (Ci-sec) for 0 - 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, under the above assumptions.

Calculated the integrated dose using the above assumptions and the ICRP-30 dose conversion factors.

The whole body dose was calculated as follows:

Determined the integrated activity (Ci-sec) in the control room for 0 - 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, using the appropriate assumptions.

Converted the integrated activity source to an energy dependent time-integrated'amma source (y/cc).

Determined the integrated gamma dose at the center of the control room using a closed-form solution to the gamma flux integral equation and applied energy-dependent flux-to-dose conversion factors.

The resulting FHA doses for a two hour period were:

2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> thyroid dose ~ 23 Rem 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> whole body dose ~ 0.09 Rem Both of these values are less than the acceptance criteria of 30 rem to the thyroid and 5 rem to the whole body and are therefore acceptable.

f

U.S.

NRC G.S. Vissing C.

tornado Missile Accident A-3 ApZil 17 I 1998 The total isotopic activity available for release was determined as described in Section 6.2.6 of the February 1997 SFP Rerack Licensing Report.

Key assumptions are nine assemblies damaged - five with 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> of decay and four with 60 days of decay.

conservative radial peaking factor of 1.2 for all assemblies damaged.

pool decontamination factor of 100.

no filtration of iodines.

The atmospheric dispersion factor (X/Q)was calculated using the bounding-value algorithm described in Section B above.

For conservatism, the same X/Q value of 6.95 x 10~ sec/m'as used (extremely conservative since tornado conditions exist):

Control room configuration assumptions:

The concrete shielding around the control building is assumed to be sufficient to reduce contributions to the gamma dose inside the building from sources outside the building to negligible levels.

The release occurs through a hypothetical hole in the auxiliary building roof (i.e. no filtercredit)

Control Room is operated in the recirculation mode throughout the event.

Filtered recirculation of control room air volume is at a rate of 2000 CFM, with recirculation filter efficiency assumed to be 90% for inorganic and 70% for organic species of iodines.

This scenario resulted in control room doses of:

2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> thyroid dose s 11.9 Rem 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> whole body dose ~ 0.3 Rem Both of these values are less than the acceptance criteria of 30 rem to the thyroid and 5 rem to the whole body and are therefore acceptable.

U.s.

NRG G.S. Vissing A-4 April 17, 1998 In Table 6.5-1 ofyour February 1997 SFP re-racking report, you list the auxiliary building gaseous releases for 1994 and 1995.

This table does not show any contribution from Kr-85, which has been identified as one of the radionuclides released from other plants.

Provide your reasoning for not seeing any Kr-85 in the auxiliary building releases.

Res onse to uestion

o. 2:

A review of the 1994 and 1995 effluent reports indicates that there was no measurable Kr-85 released from the plant other than from batch releases from the gas decay tanks.

The Kr noble gases are not normally released from the AuxiliaryBuilding on a continuous basis.

Preliminary data for 1997 shows a small amount of Kr-85 released during the third and fourth quarters.

This release is attributed to the refueling outage and the failed fuel that occurred during the 1997 operating cycle.