ML20203C273

Forwards Response to NRC 990105 Telcon Request for Addl Info Re LAR 276,revised Accident Analysis Atmospheric Dispersion Factors

ML20203C273
Person / Time
Site:	Crane
Issue date:	02/03/1999
From:	Langenbach J GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1920-99-20002, NUDOCS 9902110325
Download: ML20203C273 (7)

Text

.

_- -,.. ~.

~..-_

l a

l l

GPU Nuclear,Inc.

(

Route 441 South NUCLEAR Post Office Box 480 Middletown, PA 17057-0480 Tel 717 944-7621 February 03, 1999 1920-99-20002 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington,DC 20555 Gentlemen:

Subject:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 AdditionalInformation-License Amendment Request No. 276 - Revised Accident Analysis Atmospheric Dispersion Factors As discussed in a conference call on January 5,1999, this letter provides the additional information requested by the NRC.

If any additional information is needed, please contact Mr. David J. Distel, Nuclear Uceasing and Regulatory Affairs, at (973) 316-7955.

Sincerely,

/

l James W. Langenbach Vice President and Director, TMI k

mJD Attachment I - Itemized Question Responses s

l Attachment II-Meteorological Data 4

cc:

Admini:trator, Region I TMI Senior Resident Inspector TMI-l Senior Project Manager 11004,3

/

/

File No. 9816;

,lf[)0 q.

(jfEg'yA

/}

C 99o2itosas 99o203 p) l PDR ADOCK 05o00289 p

PDR fp

1920-99-20002 Attachment I l

Page 1 of 6 ATTACHMENTI

1. NRC Ouestion I

The licensee has provided the meteorological data they used to calculate their revised X/Q i

l values, but it is not in the attached standard NRC format (Appendix A to Section 2.7, i

l Meteorology and Air Quality, of draft NUREG-1555, Environmental Standard Review Plan).

i l

Response

l Attachment II provides the previously submitted meteorological data reformatted to the standard NRC format and corrected as discussed. However, the previously submitted meteorological data that was based on the TMI meteorological tower 150 ft level wind speed l

l and direction instrumentation has been deleted since this instrumentation is not routinely calibrated and is not relied upon for regulatory required monitoring purposes. Deletion of this i

data does not affect the atmospheric dispersion factors developed in License Amendment j

l Request No. 276.

i L

i I

i l

l l

L i

i t

i i

i 1920-99-20002 Attachment I Page 2 of 6

2. NRC Ouestion Is the period of meteorological data the only change from prior calculations in the licensee's analysis? In reading Parsgraph III, Safety Evaluation Justification Change, ofEnclosure I to the October 15,1998 letter regarding License Amendment Request No. 276, rnention is made i

of the methodology used to calculate the distances that appear in Table 2 of Enclosure 1.

Was there also a change in the distances at which the X/Q values were calculated, although l

the Exclusion Area Boundary itself may have remained uncharged?

Resnonse This license amendment request updates the accident analysis atmospheric dispeision factors i

(X/Q) for the TMI-I Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) to incorporate recent and accurate meteorological data. The calculation of the X/Q values is l

performed using NRC Regulatory Guide 1.145 methodology and are determined on a directional dependent basis with a fixed EAB and LPZ boundary as defined in the existing TMI-l Technical Specifications. The distances to the existing TMI-I Technical Specification defined EAB in each direction sector are shown in Table 1 of License Amendment Request No. 276 (GPUN letter to the NRC 1920-98-20526, dated October 15,1998), These distances represent tla " stretched circle" depicted in TMI-I Technical Specification Section 5.1.1.

The EAB X/Q values presently used in the TMI-1 Updated Final Safety Analysis Report (UFSAR) Chapter 14 accident analyses are based on earlier meteorological data and were developed using Regulatory Guide 1.145 methodology with a variable boundary based on the actual site property boundary. The actual site property distances exceed the EAB distances shown in Table I referenced above. The proposed license amendment achieves consistency between the Technical Specification defined EAB distances and the distances used to determine the accident analysis X/Q for the EAB.

j Therefore, there is a change in the distances at which the UFSAR accident analysis X/Q values are being calculated to be consistent with the Technical Specification defined EAB, in addition to the use of an updated meteorological database The actual EAB as currently defined in the TMI-l Technical Specifications remains unchanged.

1920-99-20002 Attachnunt I Page 4 of 6 l

^ 4. NRC Ouestion i

The data were measured at the 100 foot level. What power law relationship was used to extrapolate the wind speeds to the 10 meter level?

' Response l

Meteorological data for wind speed and direction is collected at the 100-Ft. level.

Temperature data is collected at 150-Ft and 33-Ft levels. In correcting wind speed to the 10 meter level the following power law relationship was used:

U33Ft. = UnooFt. ( H33Ft. / H ooFt.)"

t j

U = wind speed l

H = height ofmeasurement l

l N = 0.25 for Pasquill Stability A, B, and C 0.33 for Pasquill Stability D l

0.50 for Pasquill Stability E, F, and G This relationship is presented in and used in the following references:

1. Reommended Guide for the Prediction of the Dispersion of Airborne Effluents, ASME, Third edition 1979

2. NUREG/CR-2858 PAVAN: An Atmospheric Dispersion Program for Evaluating Design Basis Accidental Releases ofRadioactive Materials from Nuclear Power Stations, Bander m

i 4

1920-99-20002 At*=durwat I Page 5 of 6

5. NRC Ouestion Was a cross sectional building wake correction assumed in the calculations? Ifso, what value l

was used?

Response

The containment cross-sectional area was utilized for wake correction. A containment projected area of 2000 square meters is used.

1 s

i i

1920-99-20002 Attachment I Page 6 of 6

6. NRC Ouestion Will the FSAR be updated to show the revised X/Q values for the LPZ and explain that the largest ratio of the current FSAR and revised X/Q values (9.75) was used to calculate the revised doses at the LPZ?

Response

The TMI-1 Updated Final Safety Analysis Repon (UFSAR) Chapter 14 will be revised to j

reflect the new licensing basis X/Q values and resulting radiological dose consequences as shown in License Amendment Request No. 276, GPU Nuclear letter to the NRC dated October 15,1998 (1920-98-20526). Additionally, TMI-l UFSAR Chapter 2 will be updated l

-to reflect the revised meteorological data and the methodology used to develop the new EAB and LPZ X/Q values and their application in the development of the revised UFSAR Chapter 14 dose consequences. These UFSAR updates will be provided in the next scheduled update to be published in April 2000.

i 1

i*

!~

4 I

l.

e

- -. -...-.. -. -... ~

i l

ATTACHMENT II i

Reformatted 1992,1993,1995,1996 Meteorological Data 1

(via Magnetic Media Electronic Diskette) i L

?

l I

I l

l l

k i

4 l

j i

I l

f f

4 4

4 I