NL-08-0109, License Renewal Application, Follow Up to Severe Accident Mitigation Alternatives Request for Additional Information Review Questions
| ML080360158 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 02/01/2008 |
| From: | Tynan T Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-08-0109 | |
| Download: ML080360158 (6) | |
Text
Tom Tynan Vice President -Vogtle Southern Nuclear Operating Company, Inc.
7821 River Road Waynesboro, Georgia 30830 Tel 706.826.3151 Fax 706.826.3321 SOUTHERN COMPANY Energy to Serve Your WorldSM February 1, 2008 Docket Nos. 50-424 & 50-425 NL-08-0109 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001 Southern Nuclear Operating Company Vogtle License Renewal Application Follow Up to Severe Accident Mitigation Alternatives Request for Additional Information Review Questions Ladies and Gentlemen:
By letter NL-07-2255, dated December 20, 2007, Southern Nuclear Operating Company (SNC) provided responses to the U.S. Nuclear Regulatory Commission (NRC) Requests for Additional Information (RAIs) concerning the Severe Accident Mitigation Alternative (SAMA) analysis.
Subsequently, NRC informally provided three (3) follow-up questions on the SAMA response.
In a conference call on January 22, 2008, NRC and SNC discussed the proposed responses to the three follow up questions and NRC concurred with the responses proposed by SNC. Please find enclosed the SNC response to the referenced follow-up questions.
If you have any questions, please contact D. L. Fulton at 205-992-7536 or T. C. Moorer at 205-992-5807.
4/21
U.S. Nuclear Regulatory Commission NL-08-0109 Page 2 of 3 Mr. T. E. Tynan states he is a Vice President of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and to the best of his knowledge and belief, the facts set forth in this letter are true.
Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY Tom E. Tynan TET/DLF/dmw Sworn to and subscripted before me this day of -
Y1 lJ.Y\\
2008 U Notary Public
.".Notary Public, Burke County, Georgia SMM commission expires." MYCommission Expires November 11, 2011
Enclosure:
- 1. Response to Follow Up Questions to SAMA RALs on the Vogtle Units 1 and 2 License Renewal Application Environmental Report.
U.S. Nuclear Regulatory Commission NL-08-0109 Page 3 of 3 cc:
Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, Vice President - Vogtle Mr. D. H. Jones, Vice President - Engineering Ms. M. M. Caston, Vice President and Corporate Counsel Mr. B. J. George, Manager - Nuclear Licensing Mr. N. J. Stringfellow, Licensing Supervisor - Vogtle Mr. S. M. Blanton, Balch and Bingham LLP Mr. C. R. Myer, Project Manager - License Renewal Mr. T. C. Moorer, Project Manager - Environmental Document Services RTYPE: CVC7000 Nuclear Regulatory Commission Mr. J. P. Leous, Environmental Project Manager - Vogtle Mr. D. J. Ashley, License Renewal Project Manager - Vogtle Dr. W. D. Travers, Regional Administrator Mr. S. P. Lingam, NRR Project Manager - Vogtle Mr. G. J. McCoy, Senior Resident Inspector - Vogtle State of Georgia Mr. N. Holcomb, Commissioner - Dept. of Natural Resources Tetra Tech NUS. Inc.
Ms. K. K. Patterson, Project Manager w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/o Enclosures w/ Enclosures w/ Enclosures w/ Enclosures w/ Enclosures w/ Enclosures w/o Enclosures w/o Enclosures
NL-08-0109 Follow Up RAI Responses Southern Nuclear Operating Company NL-08-0109 Response to Follow Up Questions to SAMA RAI Responses On Vogtle License Renewal Application Environmental Report
NL-08-0109 Enclosure I Follow Up RAI Responses NRC Follow Up Questions from the Review of SNC's SAMA Analysis Request for Additional Information response for the Vogtle Electric Generating Plant, Units 1 and 2 License Renewal Application Based on the Nuclear Regulatory Commission's (NRC's) review of the December 20, 2007, Severe Accident Mitigation Alternatives (SAMA) Request for Additional Information (RAI)
Response submitted by Southern Nuclear Operating Company (SNC) under letter NL 2255, the NRC has informally issued three (3) follow-up questions.
- 1. The response to RAI 4c only provided revised benefit results for a 3% discount rate. The environmental report (ER) also includes a 7% discount rate. Please provide the 7% calculations.
Response
The original real discount rate (RDR) of 3 percent has been changed to 7 percent and the modified maximum averted cost-risk was re-calculated using the methodology outlined in Section F.4 of the ER and summarized in the RAI 4c response. Implementation of the 7 percent RDR reduced the modified maximum averted cost risk (MMACR) by almost 20 percent compared with the case where a 3 percent RDR was used. This corresponds to a decrease in the MMACR from
$1,014,000 to $820,000.
The Phase I SAMA list was reviewed to determine if such a decrease in the MMACR would impact the disposition of any SAMAs.
Similar to the original assessment in the ER, it was determined that SAMA 7 (installation of enhanced RCP seals) would have more readily screened out in the Phase I analysis using a RDR of 7 percent, in place of the 3 percent value.
Additionally, similar to the original assessment, the determination of cost effectiveness does not change for any of the Phase II SAMAs when the 7 percent RDR was used in lieu of 3 percent. As shown below, SAMAs 2 and 4 are still shown to be cost beneficial, and the remaining SAMAs are not cost beneficial in the base case assessment.
VEGP 7% RDR Sensitivity SAMA ID Cost of Averted Cost-Net Value Implementation Risk SAMA 1
$2,700,000
$347,502
-$2,352,498 SAMA 2
$25,000
$336,164
$311,164 SAMA 3
$4,114,000
$299,712
-$3,814,288 SAMA 4
$25,000
$171,026
$146,026 SAMA 5
$1,760,000
$93,680
-$1,666,320 SAMA 6
$525,000
$240,682
-$284,318 SAMA.7
$1,050,000
$384,026
-$665,974 SAMA 8
$13,045,000
$322,470
-$12,722,530 SAMA 9
$250,000
$20,780
-$229,220 SAMA 10
$25,000
$4,850
-$20,150 SAMA 11
$520,000
$74,410
-$445,590 SAMA 12
$100,000
$14,458
-$85,542 SAMA 13
$100,000
$14,402
-$85,598 SAMA 14
$425,000
$14,458
-$410,542 SAMA 15
$900,000
$347,502 1-$552,498 SAMA 16
$25,000 I $14,458
-$10,542
NL-08-0109 Enclosure I Follow Up RAI Responses
- 2.
The ER only indicates that the cost estimates conservatively did not include the cost of replacement power during extended outages required to implement the modifications.
No mention of contingency costs associated with unforseen implementation obstacles in either the ER or the RAI responses. Please provide verification if these costs were included in the evaluation.
Response
A review of the VEGP specific implementation costs revealed that the implementation costs do not include any replacement power costs that may be incurred due to consequential shutdown time.
Additionally, the VEGP specific implementation costs in general do not include contingency costs for unforeseen difficulties.
However, it was noted that the larger efforts (SAMAs 3, 5, and 8), with greater potential for unknown implementation obstacles, did include an approximate 20% contingency based on the anticipated magnitude of those efforts (i.e. in excess of a million dollars). The incorporation of this contingency would not impact the results of the SAMA assessment, since SAMAs 3 and 8 would still screen out in the Phase I analysis without incorporating the contingency and SAMA 5 would still not be cost beneficial in the Phase II assessment.
- 3. The ER does not provide the sources for the year 2000 population census data and the county-level census data used to estimate the annual population growth rate.
What sources were used?
Response
The year 2000 population census information was from the SECPOP2000 code. That population was distributed by distance and direction according to the code's output.
The population estimates for years 2010 onward were projected by calculating an annualized growth rate using 1980 and 2000 census data (by county) as the base. County-level census data from 1980 was taken from "1990 Census of Population and Housing, Population and Housing Unit Counts, United States, 1990 CPH-2-1."
Table 30 of that document, "Population and Housing Units: 1940 to 1990," presents populations by state and county during the indicated 50-year period.
That document was accessed for this analysis on June 1, 2005 at http://www.census.gov/population/www/censusdata/hiscendata.html and was still available as of 1/20/2008 at http://www.census.gov/prod/cen 1990/cph2/cph-2-1-1.pdf. County-level census data from 2000 was taken from "Ranking Tables for Counties: Population in 2000 and Population Change from 1990 to 2000 (PHC-T-4)." That document was originally accessed on June 2, 2005 from http://www.census.gov.
Table 1 of that document (available on 1/20/08 at http://www.census.gov/population!cen2000/phc-t4/tab0l.pdf) presents populations by state and county for 1990 and 2000.
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