ML041970383

Response to Request for Additional Information (RAI) Dated June 9, 2004, Regarding Proposed Control Room Emergency Air Treatment System (Creats) Modification and Change in Dose Calculation Methodology to Alternate Source Term

ML041970383
Person / Time
Site:	Ginna
Issue date:	07/08/2004
From:	Korsnick M Constellation Energy Group
To:	Clark R Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML041970383 (10)

Text

I, Maria Korsnick 1503 Lake Road Vice President Ontario, New York 14519-9364 585.771.3494 585.771.3943 Fax maria.korsnick@constellation.com Constellation Energy R.E. Ginna Nuclear Power Plant July 8, 2004 Mr. Robert L. Clark Office of Nuclear Regulatory Regulation U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001

Subject:

Response to Request for Additional Information (RAI) dated June 9, 2004, Regarding Proposed Control Room Emergency Air Treatment System (CREATS)

Modification and Change in Dose Calculation Methodology to Alternate Source Term R.E. Ginna Nuclear Power Plant Docket No. 50-244

References:

1. Letter from Robert C. Mecredy (RG&E) to Robert L. Clark (NRC) dated May 21, 2003, License Amendment Request Regarding Revision of Ginna Technical Specification Sections 1.1, 3.3.6, 3.4.16, 3.6.6, 3.7.9, 5.5.10, 5.5.16, and 5.6.7 Resulting From Modification of the Control Room Emergency Air Treatment System and Change in Dose Calculation Methodology to Alternate Source Term.

2. Letter from Robert L Clark (NRC) to Robert C. Mecredy (RG&E) dated June 9, 2004, Request for Additional Information Regarding R.E. Ginna Nuclear Power Plant License Amendment Request Relating to the Control Room Emergency Air Treatment System Modification (TAC No. MB9123).

Dear Mr. Clark:

The attachments to this letter provide a response to the Request for Additional Information (RAIs) contained in Reference 2 and related items discussed during a conference call between RG&E and your staff on May 20, 2004. Specifically, Attachment 2 discusses assumptions included in the Tornado Missile Accident (TMA) dose calculations. This information should be docketed as an addendum to Reference 1. If you have questions regarding the content of this correspondence, please contact Mr. Mike Ruby at (585) 771-3572 or Mr. George Wrobel at (585) 771-3535.

Very truly yours, JQ Mary G. Korsni 100 7 I

STATE OF NEWYORK  :

TO WIT:

COUNTY OF WAYNE I, Mary G. Korsnick, being duly sworn, state that I am Vice President - R.E. Ginna Nuclear Power Plant, LLC (Ginna LLC), and that I am duly authorized to execute and file this response on behalf of Ginna LLC. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Ginna LLC employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.

16ZF/vk $ z Subscribed and sworn before me, a Notary Public in and for the State of New York and County of this 8 day of @LdAft . 2004.

WITNESS my Hand and Notarial Seal: )&/trC Notary Public My Commission Expires: / -oT/-O'-o Date SHARON LMUER NTV PJ*K S* el Hew York Fat hN0.01M16017755 Attachments: Cl NesD ork

1. Response to RAls

2. May 20, 2004 Conference Call with NRC Cc: Mr. Robert L. Clark (Mail Stop 0-8-C2)

Project Directorate I Division of Licensing Project Management Office of Nuclear Regulatory Regulation U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852 Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 U.S. NRC Ginna Senior Resident Inspector

Mr. Peter R. Smith New York State Energy, Research, and Development Authority Corporate Plaza West 286 Washington Avenue Extension Albany, NY 12203-6399 Mr. Paul Eddy NYS Department of Public Service 3 Empire State Plaza, 10 th Floor Albany, NY 12223 James M. Petro Jr., Esquire Counsel Constellation Energy 750 East Pratt Street, 5th Floor Baltimore, MD 21202 Daniel F. Stenger Ballard Spahr Andrews & Ingersoll, LLP 601 13'h Street, N.W., Suite 1000 South Washington, DC 20005

Attachment I Response to RAls

REQUEST FOR ADDITIONAL INFORMATION R.E. GINNA NUCLEAR POWER PLANT CONTROL ROOM EMERGENCY AIR TREATMENT SYSTEM R.E. Ginna Nuclear Power Plant's (formerly Rochester Gas and Electric Corporation's) proposed design modifications to the Control Room Emergency Air Treatment System, the Control Room Emergency Cooling System, and the Containment Post Accident Charcoal Filters are based on the full scope implementation of the alternate source term. The Nuclear Regulatory Commission staff has determined that the following additional information is needed to complete its review.

Meteorological Data

1. There are apparently a number of day-of-the-year and hour-of-the-day labeling discrepancies in the ARCON96 1999-2003 hourly meteorological data set. Examples of these day and hour labeling discrepancies for the year 1999 are provided in Table 1.

Similar abnormalities exist for each of the other years in the data set. A precursory review of the data base also indicates that the data capture rate for each year is less than 100% (e.g., there are less than 8,760 hourly values for each year); yet, there are no hours in the data set that have been identified as having invalid data.

The day and hour labeling discrepancies should not have an impact on the ARCON96 results. However, in order to properly implement ARCON96's intended technical approach, the ARCON96 meteorological data input file should have one record for every hour in the year, even for those hours where there are no valid data. As explained in Subsection 3.8 of Revision I to NUREG/CR-6331, "Atmospheric Relative Concentrations in Building Wakes,"ARCON96 uses time series of hourly meteorological data to properly account for the effects on wind direction persistence in reducing average relative concentrations for periods longer than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> in duration. Missing data are treated by deleting hours with missing data from the calculation of the average relative concentrations used in determining the cumulative frequency distributions.

Missing data tolerance criteria are used to determine when the number of hours of missing data make a specific average relative concentration unacceptable. The criterion for averaging 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or less is zero missing data; for longer duration averages, up to 10% missing data are acceptable. Averages are not calculated for periods in which the number of hours of missing data exceed tolerance criteria.

Response

The day-of-the-year and hour-of-the-day labeling discrepancies have been addressed and data labels no longer repeat.

556 missing hours have been added (coded as 999) as follows:

1999 - 180 hours0.00208 days <br />0.05 hours <br />2.97619e-4 weeks <br />6.849e-5 months <br /> 2000- 117 2001 - 248 2002 - 8 2003 - 3 The total hours per year are as follows:

Page 1 of 4

1999, 2001, 2003 and 2003: 8,760 hours0.0088 days <br />0.211 hours <br />0.00126 weeks <br />2.8918e-4 months <br /> 2000 (leap year): 8,784 hours0.00907 days <br />0.218 hours <br />0.0013 weeks <br />2.98312e-4 months <br />

2. There are nearly 700 consecutive hours in the 2003 data base (from day 197 hour0.00228 days <br />0.0547 hours <br />3.257275e-4 weeks <br />7.49585e-5 months <br /> 11 through day 227 hour0.00263 days <br />0.0631 hours <br />3.753307e-4 weeks <br />8.63735e-5 months <br /> 08) where nearly all of the lower level wind direction values are reported as "002" Likewise, there are 144 consecutive hours in the 2002 data base (from day 253 hour0.00293 days <br />0.0703 hours <br />4.183201e-4 weeks <br />9.62665e-5 months <br /> 08 through day 259 hour0.003 days <br />0.0719 hours <br />4.282407e-4 weeks <br />9.85495e-5 months <br /> 07) where nearly all of the lower level wind direction values are also reported as "002". These are most likely invalid data values which should be reset to "999."

Response

There are 835 hours0.00966 days <br />0.232 hours <br />0.00138 weeks <br />3.177175e-4 months <br /> identified with invalid lower-level data. All of these were judged invalid as a result of consecutive, identical lower-level wind direction, and were reset to 999. The corresponding upper-level direction values were all judged to be valid. When either the lower-level speed or direction data is invalid, ARCON96 substitutes valid upper-level data for the corresponding hour. As such, ARCON96 considers this information to be valid.

Control Room Atmospheric Dispersion Factors

3. There are apparently three ARCON96 files (CASEIA.log, CASE2A.log, and CASE2TA.log) related to determining control room CHI/Q values for a containment leakage release. Which one of these three runs is being considered for use in the dose assessment analyses and why?

Response

The Radiological Basis Case (Case 2a) is being used in the dose assessment analysis.

Two sensitivity cases were run in addition to the Radiological Basis Case. The sensitivity cases were included for information. Casela (sensitivity case) , evaluated the effect of a reduced initial diffusion coefficient, in the vertical direction. The 70 was based on a source height equal to the distance from grade to the containment springline. Case 2a (Radiological Basis) used a a,. based on a source height from grade to the top of the containment dome. Case 2T(sensitivity case) increased the wake area from the calculated containment vertical area of 1071 M2, to 2000 M2 . The results show little benefit to increasing the wake area.

4. There are apparently two ARCON96 files (CASE4A.log and CASE4TA.log) related to determining control room CHI/Q values for atmospheric relief valve releases. Which one of these two runs is being considered for use in the dose assessment analyses and why?

Response

Page 2 of 4

The Radiological Base Case (Case 4a) is being used in the dose assessment analysis.

A sensitivity case was run in addition to the Radiological Basis Case. The sensitivity case was included for information. Case 4a, used the calculated containment vertical area; Case 4aT (sensitivity case) used 2000 M2. The results show little benefit to increasing the wake area.

5. There are apparently two ARCON96 files (CASE5A.log and CASE6A.log) related to determining control room CHI/Q values for plant releases. Which one of these two runs is being considered for use in the dose assessment analyses and why?

Response

The Case 5a x/Qs are for Plant Vent releases. The Case 6A values are for Containment Vent releases. The Plant Vent source is used in the dose analysis of the Fuel Handling Accident (FHA) in the spent fuel pool because the ventilation system is required by Tech Specs and assumed to be running during the event. The Containment Vent is not used for any dose calculations. Bounding releases from an open containment (FHA in containment) are via the Equipment Hatch roll-up door (Case 3).

6. There are apparently five ARCON96 files (Case7.log, Case7a.log, Case7b.log, Case7cc.log, and Case7dd.Iog) related to determining control room CHI/Q values for auxiliary building leakage releases. Which one of these five runs is being considered for use in the dose assessment analyses and why? Please also justify using the containment building area (1071 m 2 ) as the basis for determining wake diffusion for this release point.

Response

The five cases represent the leakage areas, from the Auxiliary Building to the environment that are identified as closest to the CR air intake. Case 7a is limiting and will be used in the control room dose assessment.

The building areas, used for wake diffusion, were re-evaluated for each source, rather than assuming that all releases are into the containment wake. The revised area, assumed for Case 7a, is 553 M2.

Site Boundary Atmospheric Dispersion Factors

7. Is it still your intent to use the current CHI/Q values presented in the Ginna UFSAR for

-allthe EAB and LPZ dose calculations, except for the tornado missile and locked rotor accidents?

Response

Both the EAB and LPZ x/Qs have been assessed using the KRPavan code. The joint cumulative distribution used for these calculations is based on the same meteorological data set used for the updated ARCON96 assessment (except for missing and invalid hours, which were removed). For consistency, the new CHI/Q values will be used in all of the updated dose analysis.

Page 3 of 4

TABLE I Day-of-the-year and Hour-of-the-day Labeling Discrepancies For 1999 Range of Data Labels Missing Data Labels Repeated Data Labels Date of First Date of Last Date of First Date of Last Date of First Date of Last Data Record Data Record Data Record Data Record Data Record Data Record Day Hour Day Hour Day Hour Day Hour Day Hour Day Hour 001 00 353 23 008 10 008 10 031 00 031 23 056 01 056 04 058 00 058 23 069 22 070 07 087 00 087 23 072 15 072 15 116 00 116 23 075 07 075 08 146 00 146 23 088 07 088 08 175 00 175 23 090 02 090 02 205 00 205 23 090 06 091 06 235 00 235 23 092 19 092 19 264 00 264 23 093 11 093 13 294 07 294 09 153 08 154 15 323 00 323 23 267 04 267 04 295 12 295 12 317 18 317 18 323 10 323 12 327 05 327 06 329 12 329 12 329 16 329 16 343 23 344 06 345 02 345 06 345 08 345 13 _ _I Page 4 of 4

Attachment 2 May 20, 2004 Conference Call With NRC

May 20, 2004 Conference call with NRC Call participants: M. Ruby - RG&E K. Rubin - RG&E Consultant for Dose Analysis Bob Clark - NRC Project Manager Brad Harvey - NRC Meteorologist Jay Lee - NRC Analysis Item 1 - The draft RAls from Brad Harvey, Control Room Emergency Air Treatment System Modifications Draft Meteorology RAls, Revision 1, 4/26/04, were reviewed.

Questions 1 through 6 were discussed and agreed to by RG&E. The comments have already been incorporated into the latest revision of the calculations. The answer to question 7 is yes, the new x/Q for off site doses will be used in the analysis going forward. It was agreed that Bob Clark will issue the questions as official RAls to document the issues and responses.

Item 2 - Unlike ARCON96, The PAVAN methodology does not account for missing or invalid data. Consideration was given to writing the PAVAN joint cumulative frequency distribution with upper level data substituted for invalid lower level data, similar to the ARCON96 process. We concluded that data substitution is not consistent with the PAVAN methodology, and NRC agreed. The PAVAN meteorological data set is considered to be valid if it captures at least 90% of the possible hours. Ginna's data set exceeds the minimum capture.

Item 3 - The Tornado Missile Accident (TMA) - The NRC stated that since Ginna was quite unique in postulating a TMA, there is no branch position on the assumptions that go into the analysis. However they agreed that the following approach is reasonable and acceptable.

• This accident was previously modeled similar to the Fuel Handling Accident (FHA), in that building remained in tact and the release duration was assumed to occur over a two-hour period. However, the nature of the accident dictates that the Auxiliary Building would be damaged in the TMA scenario, and that assuming a "puff" release was acceptable.

• Since the release would occur in extremely unsettled atmospheric conditions, it is also reasonable to assume a "tornado xIQ" based on recorded meteorological conditions using Mr. Rubin's described methods (-22 m/s wind speed) was acceptable. The NRC further added that this could be extracted from ARCON96 using a single hour of recorded data.

• It is acceptable to use a diffused area source based on the surface area of the Spent Fuel Pool (SFP) in place of a point source.

• A one minute tornado duration assumption is appropriate.

The above points were reviewed and the call ended without further discussion.