ML040570889
| ML040570889 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/24/2004 |
| From: | Kenyon T NRC/NRR/DRIP/RLEP |
| To: | Forbes J Entergy Operations |
| Kenyon TJ, NRR/DRIP/RLEP, 415-1120 | |
| References | |
| Download: ML040570889 (10) | |
Text
February 24, 2004 Mr. Jeff Forbes, Vice President Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, Arkansas 72802
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING SEVERE ACCIDENT MITIGATION ALTERNATIVES FOR ANO-2
Dear Mr. Forbes:
The staff has reviewed Entergys analysis of severe accident mitigation alternatives (SAMAs) submitted in support of its application for license renewal for ANO-2, and has identified areas where additional information is needed to complete its review. Enclosed is the staff's request for additional information.
As discussed with your staff, we request that you provide your responses to these RAIs within 60 days of the date of this letter. If you have any questions, please contact me at (301) 415-1120.
Sincerely,
/RA/
Thomas J. Kenyon, Sr. Environmental Project Manager License Renewal and Environmental Impacts Branch Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket No.: 50-368
Enclosure:
As stated cc w/encl: See next page
February 24, 2004 Mr. Jeff Forbes, Vice President Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 Russellville, Arkansas 72802
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING SEVERE ACCIDENT MITIGATION ALTERNATIVES FOR ANO-2
Dear Mr. Forbes:
The staff has reviewed Entergys analysis of severe accident mitigation alternatives (SAMAs) submitted in support of its application for license renewal for ANO-2, and has identified areas where additional information is needed to complete its review. Enclosed is the staff's request for additional information.
As discussed with your staff, we request that you provide your responses to these RAIs within 60 days of the date of this letter. If you have any questions, please contact me at (301) 415-1120.
Sincerely,
/RA/
Thomas J. Kenyon, Sr. Environmental Project Manager License Renewal and Environmental Impacts Branch Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation Docket No.: 50-368
Enclosure:
As stated cc w/encl: See next page Distribution:
D. Matthews/F. Gillespie P. T. Kuo T. Kenyon J. Tappert M. Masnik S. Imboden G. Suber T. Alexion L. Smith, RIV R. Deese, RIV E. Crowe, RIV J. Dixon, RIV M. Lemoncelli D. Neitzel (PNNL)
K. Leigh (PNNL)
R. Palla ACRS/ACNW RIDSRgn4MailCenter RidsOgcMailCenter Accession No: ML040570889 Document Name: G:\\RLEP\\Environmental Section\\ANO-2\\Letters\\SAMA RAI ltr.wpd OFFICE LA:RLEP PM:RLEP SC:RLEP PD:RLEP NAME M. Jenkins T. Kenyon J. Tappert P.T. Kuo DATE 2/19/04 2/24/04 2/24/04 2/24/04 OFFICIAL RECORD COPY
Enclosure Request for Additional Information Regarding the Analysis of Severe Accident Mitigation Alternatives (SAMAs) for Arkansas Nuclear One, Unit 2 1.
The SAMA analysis is based on the most recent version of the ANO-2 Probabilistic Safety Assessment (PSA) for internal events, i.e., Revision 3p2, which is a modification to the IPE submittal transmitted to the NRC in March 1994. Please provide the following information regarding this PSA model:
a.
A description of the internal and external peer reviews of the level 1 and 2 portions of the PSA that have been performed since the IPE.
b.
A description of the overall findings of the owners group peer review (by element), and discussion of any findings/observations (e.g., A and B Facts and Observations) that could potentially affect the SAMA identification and evaluation process, and how Entergy has addressed these findings for this application (including, for example, sensitivity studies of the impacts of alternative assumptions).
c.
A breakdown of the internal events core damage frequency (CDF) by major contributors, initiators or accident classes, such as loss of offsite power (LOOP),
station blackout (SBO), transients, anticipated transient without scram (ATWS),
loss-of-coolant accident (LOCA), interfacing systems LOCA (ISLOCA), steam generator tube rupture (SGTR), internal floods, etc. According to ER Table 4-4, the staff has calculated the following:
Transients 3.90E-6 Small Break LOCA 1.52E-6 ISLOCA 3.27E-7 Vessel Rupture 2.70E-7 Medium Break LOCA 1.66E-7 Large Break LOCA 2.25E-7 SGTR 1.03E-7 Total CDF 6.51E-6 The total CDF calculated by the staff does not equate to the CDF of 7.17E-06/year calculated and used by Entergy in the SAMA analysis. It appears that ATWS and internal flooding are not included in the CDF results displayed in Environmental Report (ER) Table 4-4. This might explain the difference in CDF values given by Entergy and calculated by the staff. Please update/revise the numbers as appropriate, and explain any differences. If ATWS and internal floods are not included, provide justification for their exclusion.
d.
The approximate CDF and large early release frequency (LERF) for each revision to the PSA model, and a description of the major reasons for the changes from the prior version, i.e., a brief statement about major hardware and/or modeling changes that resulted in the new CDF.
e.
The changes in the level 2 methodology since the IPE submittal, including major modeling assumptions, containment event tree (CET) structure, and binning of end states.
f.
A description of the mapping of Level 1 results into the various containment end states/release categories. If this remains unchanged since the IPE, please indicate so.
g.
Table E.1-2 lists the release category frequencies and fission product release fractions used in the level 3 analysis. These appear to be unchanged since the IPE submittal. If this is the case, explain why the current CDF was not used in the SAMA analysis. If not, please provide the updated values used in the level 3 analysis.
h.
A breakdown of the population dose (person-rem per year within 50 miles) by containment release mode, such as steam generator tube rupture (SGTR),
ISLOCA, early containment failure, late containment failure, and no containment failure.
2.
Discuss the RCP seal LOCA model utilized in the ANO-2 PSA and why it is judged to provide an appropriate representation of RCP seal LOCA events. Also, indicate the current percent contribution to the CDF for RCP seal LOCA.
3.
Based on the accident sequence descriptions provided in the ER, it does not appear that thermally-induced SGTR is included in the level 1 PSA model. Discuss the impact including thermally-induced SGTR events on the SAMA analysis.
4.
Relative to the MACCS2 input and results, please provide the following:
a.
A brief discussion on how the releases were modeled, e.g., at ground level with a thermal content the same as ambient, and b.
Clarification of whether the replacement power costs were scaled relative to the 910 MWe reference plant since ANO-2 is rated at 1023 MWe.
5.
According to the ER, Entergy evaluated 192 SAMA candidates and eliminated 99 SAMAs during the initial screening. In this regard, please provide the following:
a.
A description of how the dominant risk contributors at ANO-2, including dominant sequences and equipment failures and operator actions identified through importance analyses (e.g., Fussell-Vesely, Risk Reduction Worth, etc.) were used to identify potential plant-specific SAMAs.
b.
The percentage of the total CDF represented by the top 100 cut sets that were evaluated.
c.
A listing of equipment failures and human actions that have greatest potential for reducing risk at ANO-2 based on importance analysis and cut set screening.
d.
For each dominant contributor identified in the current PSA, a cross-reference to the SAMA(s) evaluated in the ER that address that contributor. If a SAMA was not evaluated for a dominant risk contributor, justify why SAMAs to further reduce these contributors would not be cost beneficial.
e.
A list of the 99 SAMAs that were screened out in the initial screening and the basis for excluding each of these SAMAs.
f.
The status of each of the SAMA candidates obtained from the IPEEE (SAMAs IPEEE-01 through IPEEE-11), and g.
By letter dated October 5, 1995, Entergy indicated that SAMA FW-17 was implemented in 1993. In addition, the staff understood that SAMA CB-23 was implemented. However, these enhancements are evaluated in the SAMA analysis and found to not be cost beneficial. Confirm whether these enhancements were actually implemented.
6.
The SAMA analysis did not include an assessment of SAMAs for external events. The ANO-2 IPE for External Events (IPEEE) SER reports that the CDF due to internal fire initiated events is about 3.8x10-5 per reactor year which is substantially greater than the internal events CDF on which the SAMA evaluation is based. The risk analyses at other commercial nuclear power plants also indicate that external events could be large contributors to CDF and the overall risk to the public. In this regard, the following additional information is requested:
a.
NUREG-1742 (Perspectives Gained From the IPEEE Program, Final Report, 4/02), lists the significant fire area CDFs for ANO-2 (page 3-8 of Volume 2).
While these fire-related CDF estimates may be conservative, they are still large relative to the ANO-2 internal events CDF. For each fire area, please explain what measures were taken to further reduce risk, and explain why these CDFs can not be further reduced in a cost effective manner.
b.
NUREG-1742 lists seismic outliers and improvements for ANO-2 (page 2-25 of Volume 2). Indicate whether the Plant improvements that address the outliers have been implemented for all outliers. If not, please explain why within the context of this SAMA study.
7.
Entergy has opted to double the estimated benefits (for internal events) to accommodate any contributions for external events. This is acceptable when sound reasons exist to support such a numerical adjustment. However, based on the information in the ER and in the ANO-2 IPEEE report, the fire CDF is approximately a factor five greater than the internal events CDF, which suggests that the estimated benefit for the SAMAs should be increased by at least a factor of six to account for external events (in contrast to the factor of two used in the SAMA analysis). In order to determine if external events have been satisfactorily accounted for, please provide the following information:
a.
The current CDF for fire-initiated events, and justification that doubling the estimated benefits for internal events will bound the risk from fire events.
b.
An assessment of the impact on the initial and the final screenings if the internal events risk reduction estimates are increased by a factor that would bound the risk from fire and seismic events, and c.
Justification for why the following SAMAs would not be cost beneficial when the risk reduction associated with external events is reflected in the baseline estimates, given that the implementation costs are within a factor of 3 of the estimated benefits: AC/DC-16, AT-02, CB-10, CB-26, CC-07, CW-06, CW-21, CW-23, CW-27, EV-02, FW-13, FW-17, HV-03, HV-05, and OT-06.
8.
The SAMA analysis did not include an assessment of the impact of PSA uncertainties.
On that basis, please provide the following information to address these concerns:
a.
An estimate of the uncertainties associated with the calculated core damage frequency (e.g., the mean and median internal events CDF estimates and the 5th and 95th percentile values of the uncertainty distribution), and b.
An assessment of the impact on the final screening if risk reduction estimates are increased to account for uncertainties in the risk assessment. Please consider the uncertainties due to both the averted cost-risk and the cost of implementation to determine changes in the net value for these SAMAs.
9.
Based on a review of Table E.2-1 of the ER, cost estimates for implementation are provided only when a previous cost estimate was available, or when the candidate SAMA involves a modification to a procedure. For the remaining SAMAs, only a generic statement is provided that the cost of implementing the SAMA is judged to exceed the attainable benefit. Please provide justification, supported by a more detailed analysis or cost estimate, for eliminating the following SAMA candidates, particularly when the risk reduction associated with external events is reflected in the baseline estimates: CB-03, CB-14, CC-01, CC-20, CW-01, CW-09, CW-13, CW-24, CW-26, EV-31, and FW-01.
Arkansas Nuclear One, Unit 2 cc:
Executive Vice President
& Chief Operating Officer Entergy Operations, Inc.
P. O. Box 31995 Jackson, Mississippi 39286-1995 Division of Radiation Control and Emergency Management Arkansas Department of Health 4815 West Markham, Mail Slot #30 Little Rock, Arkansas 72205-3867 Winston & Strawn 1400 L Street, N.W.
Washington, DC 20005-3502 Mr. Mike Schoppman Framatome ANP, Richland, Inc.
Suite 705 1911 North Fort Myer Drive Rosslyn, VA 22209 Senior Resident Inspector U.S. Nuclear Regulatory Commission P. O. Box 310 London, Arkansas 72847 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 County Judge of Pope County Pope County Courthouse Russellville, Arkansas 72801 Vice President, Operations Support Entergy Operations, Inc.
P. O. Box 31995 Jackson, Mississippi 39286-1995 Wise, Carter, Child & Caraway P. O. Box 651 Jackson, Mississippi 39205 Mr. Garry Young Entergy Operations, Inc.
Arkansas Nuclear One 1448 SR 333 GSB-2E Russellville, Arkansas 72802 Russellville Resident Office U.S. Army Corp of Engineers PO Box 1087 Russellville, Arkansas 72811 Director Arkansas Natural Heritage Commission 1500 Tower Building 323 Center Street Little Rock, Arkansas 72201 Mr. Craig Uyeda Arkansas Game and Fish Commission 2 Natural Resources Drive Little Rock, Arkansas 72205 George McCluskey, Senior Archeologist Arkansas State Historic Preservation Office 323 Center Street, Suite 1500 Little Rock, Arkansas 72201 Director Arkansas Department of Environmental Quality PO Box 8913 Little Rock, Arkansas 72219-8913 Director Arkansas Soil and Water Conservation Commission 101 E. Capitol Ave, Suite 350 Little Rock, Arkansas 72201 Chairman Arkansas Public Service Commission 1000 Center Building Little Rock, Arkansas 72201
Arkansas Nuclear One, Unit 2 2
cc:
Raye Turner Mayor, City of Russellville PO Box 428 Russellville, Arkansas 72801 Edwin Price Mayor, City of London PO Box 130 London, Arkansas 72847 Mayor, City of Dardanelle PO Box V Dardanelle, Arkansas 72834 Logan County Judge Courthouse, Room 22 Paris, Arkansas 72855 Johnson County Judge P.O. Box 278 Clarksville, Arkansas 72830 Yell County Judge P.O. Box 236 Dardanelle, Arkansas 72834 Conway County Judge Courthouse Morrillton, Arkansas 72110 LaRue Parker, Chairwoman Caddo Indian Tribe of Oklahoma P.O. Box 487 Binger, Oklahoma 73009 Chadwick Smith, Principal Chief Cherokee Nation of Oklahoma P.O. Box 948 Tahlequah, Oklahoma 74465 Gregory E. Pyle, Chief Choctaw Nation of Oklahoma P.O. Drawer 1210 16th and Locust Streets Durant, Oklahoma 74702-1210 R. Perry Beaver, Principal Chief Muscogee (Creek) Nation of Oklahoma P.O. Box 580 Okmulgee, Oklahoma 74447 Jim R. Gray, Principal Chief Osage Tribal Council P.O. Box 799 Pawhuska, Oklahoma 74056 John Berrey, Chairman Quapaw Tribal Business Committee P.O. Box 765 Quapaw, Oklahoma 74363 Jerry G. Haney, Principal Chief Seminole Nation of Oklahoma P.O. Box 1498 Wewoka, Oklahoma 74884 Dallas Proctor, Chief United Keetoowah Band of Cherokee Indians PO Box 746 Tahlequah, OK 74465 Rick Buckley Entergy Operations, Inc.
PO Box 31995 Jackson, Mississippi 39286 Jager Smith Entergy Operations, Inc.
PO Box 651 Jackson, Mississippi 39205 Bernard Bevill Arkansas Department of Health 4815 West Markham Street Little Rock, Arkansas 72205 Chris Meyer Arkansas Department of Health P. O. Box 1749 Russellville, Arkansas 72811
Arkansas Nuclear One, Unit 2 3
cc:
Dennis Calloway Entergy Operations, Inc.
1448 SR 333 Russellville, Arkansas 72801 Grant Merrill KARV Radio 201 West Second Street Russellville, Arkansas 72801 Kate Sullivan KATV Main Street Little Rock, Arkansas 72211 Tom McChesney Arkansas Department of Health P.O. Box 1749 Russellville, Arkansas 72811 Ms. Francis Hager Ross Pendergraft Library Arkansas Tech University 305 West Q Street Russellville, Arkansas 72801 U.S. EPA, Region 6 1445 Ross Avenue Suite 1200 Dallas, TX 75202 Mr. Craig G. Anderson Vice President Operations, ANO Entergy Operations, Inc.
1448 S. R. 333 Russellville, AR 72801