ML093430933

SAMA Meteorological Anomaly Related to the Cooper Nuclear Station License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46

ML093430933
Person / Time
Site:	Cooper
Issue date:	12/07/2009
From:	Minahan S B Nebraska Public Power District (NPPD)
To:	Document Control Desk, Division of License Renewal
Brady B NRR/DLR/RPB1, 415-2981
References
NLS2009099
Download: ML093430933 (7)

Text

H Nebraska Public Power District NLS2009099 December 7 , 2009 U.S. Nuclear Regulatory Commission Attention:

Document Control Desk Washington , D.C. 20555-0001 "Always there wh e n you n e ed ItS" 54.17

Subject:

SAMA Meteorological Anomaly Related to the Cooper Nuclear Station License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46

References:

Letter from Stewart B. Minahan , Nebraska Public Power District , to U.S. Nuclear Regulatory Commission, dated September 24, 2008, "License Renewal App li cation" (NLS2008071).

Dear Sir or Madam:

The purpose of this letter is for the Nebraska Public Power District (NPPD) to address an error in Appendix E , Attachment E (Severe Accident Mitigation Alternatives (SAMA) Analysis) of the referenced Cooper Nuclear Station License Renewal Application (LRA). The error relates to the numerical averaging of wind direction, which is used for determining the radiological deposition and cost damage values from postulated severe events used in the cost/benefit evaluation of the SAMA Analysis.

The Nuclear Regulatory Commission (NRC) was initially made aware of this on November 16,2009. Subsequent conference calls were conducted on November 18 , 2009 and December 2, 2009 with the NRC Staff. A sensitivity analysis has been performed using the corrected meteorological data. A description of this analysis and the results are provided in Attachment I. The analysi s demonstrate s that the error was conservative relative to the average population dose and offsite economic cost , and that no SAMAs were inappropriately excluded from consideration in the LRA as a result of the error in wind direction.

According l y , no changes to the SAMA Analysis results as originally submitted in the LRA are necessary.

During the course of investigation into the meteorological anomaly, NPPD identified the need for corrections to Table E.I-12 of the SAM A Analysis and related text. This is discussed in Attachment I, and the LRA changes are provided in Attachment

2. NPPD understands from discussions with the NRC that this issue may affect the scheduled issuance of the draft Supplemental Environmental Impact Statement.

Should you have any questions regarding this submittal , please contact David Bremer , License Renewa l Project Manager , at (402) 825-5673. COOPER NUCLEAR STATION P.D. Bo x 98/ Brownvill e. NE 68321*0098 Tel e phone: (402) 825-3 8 11/ Fa" (402) 825-5211 wwwnppd corn NLS2009099 Page 2 of2 I declare under penalty of perjury that the foregoing is true and correct. Executed on 2 Oe c () t::J (Date) Sincerely, Vice President

-Nuclear and Chief Nuclear Officer Iwv Attachments cc: Regional Administrator wi attachments USNRC -Region IV Cooper Project Manager wi attachments USNRC -NRR Project Directorate IV-1 Senior Resident Inspector wi attachments USNRC -CNS Nebraska Health and Human Services wi attachments Department of Regulation and Licensure NPG Distribution wi attachments CNS Records wi attachments NLS2009099 Attachment 1 Page 1 of2 Attachment 1 Severe Accident Mitigation Alternatives Sensitivity Analysis As described in Section E.l.5.2.6 of the Cooper Nuclear Station (CNS) License Renewal Application (LRA) Environmental Report (ER), site specific meteorological data (wind speed, wind direction, atmospheric stability, and accumulated precipitation) were obtained from the onsite meteorological monitoring system. In particular, five recent years of data were averaged and used for the CNS LRA Severe Accident Mitigation Alternatives (SAMA) Analysis.

The data included 43,824 (one leap year) consecutive hourly values of wind speed, wind direction, precipitation, and temperature recorded at the CNS meteorological tower from January 2002 to December 2006. It has been determined that the method used to average the wind direction data was faulty because it indicated winds blowing toward the nOith that actually blew toward the south. Since a majority of the population around CNS is in the northern semicircle of the 50-mile radius (as shown in ER Table E.1-12), skewing the wind to the north should indicate a larger population dose and a larger offsite economic cost risk than would actually be experienced.

To demonstrate that the meteorological data used in the SAMA Analysis provided conservatively bounding results, sensitivity cases were run using MACCS2 to determine the mean population dose risk (PDR) and offsite economic cost risk (OECR) for each release mode using each of the single years of meteorological data. The results of the five one-year sensitivity analyses were averaged and compared with the values in ER Table E.1-14. This is consistent with the intent of the ER and showed that the values used in the ER are larger than if the error had not occurred.

The following table presents the averaged PDR and OECR results from the five sensitivity analyses along with the values from Table E.1-14 of the ER. Release Frequency Mode (lyr) Sensitivity Population Dose (person-sv)*

• I sv 100 rem Sensitivity Offsite Economic Cost ER Table E.I-14 ER Table E.I-14 PDR OECR (person-rem/yr)

($/yr) Sensitivity PDR (person-rem/yr)

• • 1.44E+00 (person-rem/yr) 2.46E-06 (lyr) x 5.87E+03 (person-sv) x 100 (rem/sv) Sensitivity OECR ($/yr)

NLS2009099 Attachment I Page 2 of2 Conclusion Since the PDR and OECR used in the ER are larger than the sensitivity values for all release modes, the baseline benefit reported in the ER is larger than what would have been reported had the error not occurred.

Similarly, the potential benefit reported in the ER for each of the SAMAs is conservative.

Therefore, the conclusions ofthe SAMA Analysis reported in ER Section 4.21.6 remain valid. Additional Clarification Table E.I-12 of the LRA ER provided the estimated population distribution within a 50-mile radius of the plant for the year 2034. Text accompanying the table indicates that for counties with a declining population trend, projected population in 2014 was used for the 2034 estimate.

For these declining population counties, the actual year 2000 population was used as the 2034 estimated population for input to the MACCS2 model both for the SAMA Analysis documented in the ER and for the sensitivity analysis discussed above, as an added conservatism.

Attachment 2 provides the correct 2034 population estimates within a 50-mile radius, and related text. As previously stated, the correct values shown in this table were the values actually used as inputs to the MACCS2 model in the original SAMA Analysis and the sensitivity analysis.

Accordingly, the corrections merely reflect the actual inputs used in the analysis and do not impact the results of these analyses.

NLS2009099 Attachment 2 Page 1 of2 Attachment 2 Changes to the License Renewal Application Cooper Nuclear Station, Docket No. 50-298, DPR-46 This attachment provides changes to the License Renewal Application as described in Attachment

1. The changes are presented in underline/strikeout format. 1. Section E.1.5.2.1 of the Environmental Report is revised to read: "The total population within a 50-mile radius of CNS was estimated for the year 2034, the end of the proposed license renewal period, for each spatial element by combining total resident population projections with transient populations.

The 2034 permanent population values are based on the county-level projections obtained from the University of Nebraska Bureau of Business Research from 2000-2020, Woods & Poole Economics, Inc. for Iowa from 2000-2030, Darrel Eklund et al. for Kansas from 2000-2040, and the Missouri Census Data Center from 2000-2025

[References E.l-ll, E.I-12, E.1-13 and E.I-14]. Regression methods were used to extrapolate population projections to 2034. For the counties with population in decline, the population value for;wM 2000 was used as the 2034 estimate.

Table E.I-12 shows the estimated population distribution.

2. Replace Table E.I-12 of the Environmental Report with the following revised table: Table E.1-12 Estimated Population Distribution within a 50-mile Radius Wind o to 11 to 2Ito 31 to 41to Total Direction 10 miles 20 miles 30 miles 40 miles 50 miles N 160 1,667 2,057 2,856 14,885 21,625 NNE 88 200 1,448 7,743 5,805 15,284 NE 247 265 1024 1,097 7,154 9,787 ENE 1,600 2,245 640 1,610 2,145 8,240 E 111 872 299 5,146 11,217 17,645 ESE 54 274 510 1,354 2,591 4,783 SE 10 540 1,810 1,987 3,179 7,526 SSE 44 321 886 1,911 2,165 5,327 S 67 555 5,565 5,141 3,706 15,034 SSW 342 584 458 3,885 2,643 7,912 SW 255 699 1,325 972 2,542 5,793 WSW 116 248 729 1,618 878 3,589 W 95 2,155 2,459 656 1,723 7,088 WNW 112 2,822 1,283 1,603 3,611 9,431 NLS2009099 Attachment 2 Page 2 of2 Wind Direction NW NNW Totals o to 11 to 10 miles 20 miles 151 526 1,261 240 4,713 14,213 21 to 31 to 41 to Total 30 miles 40 miles 50 miles 1,360 5,388 5,851 13,276 10,479 2,766 19,887 34,633 32,332 45,733 89,982 186,973 ATTACHMENT 3 LIST OF REGULATORY COMMITMENTS©4 ATTACHMENT 3 LlST OF REGULATORY COMMITMENTSCd Correspondence Number: NLS2009099 The following table identifies those actions committed to by Nebraska Public Power District (NPPD) in this document.

Any other actions discussed in the submittal represent intended or planned actions by NPPD. They are described for information only and are not regulatory commitments.

Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.

COMMITMENT COMMITTED DATE COMMITMENT NUMBER OR OUTAGE None PROCEDURE 0.42 REVISION 24 PAGE 19 OF 26