ML093020493

Lr Hearing - Weather Runs 10 29 09.doc

ML093020493
Person / Time
Site:	Indian Point
Issue date:	10/29/2009
From:	Office of Nuclear Reactor Regulation
To:	Division of License Renewal
References
Download: ML093020493 (4)

Text

IPRenewal NPEmails From: Palla, Robert Sent: Thursday, October 29, 2009 1:07 PM To: Stuyvenberg, Andrew Cc: IPRenewal NPEmails

Subject:

Weather Runs 10 29 09.doc Attachments: Weather Runs 10 29 09.doc FYI 1

Hearing Identifier: IndianPointUnits2and3NonPublic_EX Email Number: 1838 Mail Envelope Properties (8C658E9029C91D4D90C6960EF59FC0D60258F0F749)

Subject:

Weather Runs 10 29 09.doc Sent Date: 10/29/2009 1:07:29 PM Received Date: 10/29/2009 1:07:30 PM From: Palla, Robert Created By: Robert.Palla@nrc.gov Recipients:

"IPRenewal NPEmails" <IPRenewal.NPEmails@nrc.gov>

Tracking Status: None "Stuyvenberg, Andrew" <Andrew.Stuyvenberg@nrc.gov>

Tracking Status: None Post Office: HQCLSTR02.nrc.gov Files Size Date & Time MESSAGE 5 10/29/2009 1:07:30 PM Weather Runs 10 29 09.doc 224878 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Indian Point Weather Weather data were reviewed and are of interest because the consequences for a given release of radioactive material would be different if the release occurred at different times of the year and under different ambient weather conditions. Entergy averaged 5 years of meteorological data and used the 5 year average as input data in the MACCS2 analysis rather than using the standard approach of sampling over a year of data. The process used to average the data was provided in the MACCS2 Meteorological Input File Figure 1. Plot of Entergy 5 Year Averaged Weather from Generation Report the site 10 meter tower showing direction wind is blowing (IPEC00103877 thru toward.

IPEC00103889). The MACCS2 input file meti.inp includes 8,760 hourly weather samples (365 days x 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s/day) from the January 2000 to December 2004 IPEC 10 meter met tower data. The results of the averaged weather generate a wind rose predominantly in the northerly direction as shown in Figure

1. Review of the process describing how the weather was averaged did not provide insights into why the wind rose is predominantly northerly.

The averaged weather data Figure 2. Plot of Weather for Years 1999 - 2002 from the site 10 were compared meter tower showing direction wind is blowing toward. (percent by to the wind direction) speed/direction information provided in the Indian Point annual effluent reports for 1999 though 2002 (ML031220099, ML021260723, ML011240172, ML003714664), also for the 10 meter met tower. A wind rose was developed for each year from 1999 through 2002. Each of the weather files for the years 1999 thru 2002 are relatively similar, and the wind rose for each year of weather shows in Figure 2 that the northern and southern directions are October 29, 2009

dominant. Thus, the MACCS2 input of averaged weather used in the analysis does not appear to reflect the annual weather conditions. An analysis is needed using discrete years of weather data for each or at least some of the 5 years, without averaging weather, to understand the effects of weather on the SAMA conclusions.

Data Needs The inputs and assumptions regarding the weather input file were not described well enough to fully understand whether the application of these were appropriate for the analysis. In order to confirm the SAMA analysis is conservative and consistent with current industry practice and modeling techniques, additional information is needed including the following:

1. Additional information is needed in the form of consequence analyses using annual, rather than averaged, weather data. An analysis of at least one specific weather year should be conducted using the 10 meter weather information available from the site. Use of the 10 meter station may be expected to show a greater likelihood of wind in the northerly and southerly directions following the river. It may be beneficial to also perform an analysis using the weather data from the 120 meter station available from the site.

When performing the analysis using the specific weather year, it may be beneficial to revise some other parameters.

• NUREG 1150 values of 50 rem in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and 25 rem in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as the input criteria for Hotspot and Normal Relocation. These values lead to higher dose to individuals than current practice would indicate. Values used in current MACCS2 analyses are based on EPA protective action guides (PAGs) of 1 rem in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and 0.5 rem in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

• A single plume segment was modeled by Entergy which can limit the effect of weather changes. There may be a benefit to using the more current approach of multiple plume segments. Using hourly plume segments takes maximum advantage of wind shifts that occur in the weather data, but this would require using WinMACCS rather than the older MACCS2.

October 29, 2009