ML14274A210
| ML14274A210 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/10/2014 |
| From: | Thomas Wengert Plant Licensing Branch IV |
| To: | Sterdis A Southern California Edison Co |
| References | |
| MF3835, MF3836, MF3837 | |
| Download: ML14274A210 (5) | |
Text
1 NRR-PMDAPEm Resource From:
Wengert, Thomas Sent:
Wednesday, September 10, 2014 3:22 PM To:
andrea.sterdis@sce.com Cc:
mark.morgan@sce.com; kenneth.r.wilson@sce.com; John.Brabec@sce.com; Broaddus, Doug
Subject:
SONGS - Draft RAI RE: Emergency Planning Exemption Request (TAC Nos. MF3835, MF3836, and MF3837)
Attachments:
SONGS - EP Exemption Draft RAI #2.pdf Ms. Sterdis, By letter dated March 31, 2014 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML14092A332), Southern California Edison (SCE) requested exemptions from portions of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50) for the San Onofre Nuclear Generating Station (SONGS) Units 1, 2 and 3 Radiological Emergency Response Plan. Specifically, SCE requested exemption from certain emergency plan (EP) requirements of 10 CFR 50.47(b), 10 CFR 50.47(c)(2), and Section IV to Appendix E of 10 CFR 50. The requested exemptions would allow SCE to reduce some emergency plan requirements and subsequently revise the SONGS Radiological Emergency Response Plan consistent with the permanently defueled condition of the reactors.
Based on the Nuclear Regulatory Commission (NRC) staffs review of SCEs EP exemption request, responses to the attached draft request for additional information (RAI) are required to facilitate completion of the staffs technical review. I am sending you this preliminary copy to give you an opportunity to ask clarifying questions if the request is not clear. These questions will be made publicly available following your review.
Please let me know if SCE would like to have a conference call with the NRC staff to clarify this request. Also, lets discuss the proposed timing for SCEs response.
Tom Wengert Senior Project Manager U.S. Nuclear Regulatory Commission NRR/DORL/LPL4-2 (301) 415-4037
Hearing Identifier:
NRR_PMDA Email Number:
1598 Mail Envelope Properties (Thomas.Wengert@nrc.gov20140910152200)
Subject:
SONGS - Draft RAI RE: Emergency Planning Exemption Request (TAC Nos.
MF3835, MF3836, and MF3837)
Sent Date:
9/10/2014 3:22:08 PM Received Date:
9/10/2014 3:22:00 PM From:
Wengert, Thomas Created By:
Thomas.Wengert@nrc.gov Recipients:
"mark.morgan@sce.com" <mark.morgan@sce.com>
Tracking Status: None "kenneth.r.wilson@sce.com" <kenneth.r.wilson@sce.com>
Tracking Status: None "John.Brabec@sce.com" <John.Brabec@sce.com>
Tracking Status: None "Broaddus, Doug" <Doug.Broaddus@nrc.gov>
Tracking Status: None "andrea.sterdis@sce.com" <andrea.sterdis@sce.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 1527 9/10/2014 3:22:00 PM SONGS - EP Exemption Draft RAI #2.pdf 113330 Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received:
REQUEST FOR ADDITIONAL INFORMATION EMERGENCY PLANNING EXEMPTION REQUEST SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 1, 2, AND 3 AND INDEPENDENT SPENT FUEL STORAGE INSTALLATION DOCKET NOS. 50-206, 50-361, 50-362 AND 72-041 By application, dated March 31, 2014 (Agencywide Documents Access and Management System Accession Number ML14092A332), Southern California Edison (SCE, the licensee) submitted a request for exemptions from certain emergency planning requirements of Title 10 of the Code of Federal Regulations (10 CFR) 50.47 and 10 CFR Part 50, Appendix E for San Onofre Nuclear Generating Station (SONGS) Units 1, 2, and 3, and the Independent Spent Fuel Storage Facility. This exemption request reflects the permanently defueled condition of SONGS and would allow the licensee to discontinue offsite emergency planning activities and reduce the scope of onsite emergency planning.
The Radiation Protection and Consequence Branch (ARCB) of the Nuclear Regulatory Commissions (NRC) Division of Risk Assessment have reviewed the information in the exemption request and determined additional information is required to complete its review.
ARCB-RAI-1, Section 3.0, page 3 of 22 of the exemption request states:
The remaining [UFSAR] Chapter 15 design basis accident scenarios that apply to a permanently defueled facility that have the potential to result in a radiological release are a fuel handling accident in the fuel handling building, a spent fuel cask drop accident, a spent fuel pool boiling accident, a liquid Radioactive Waste System leak or failure, a radioactive release due to liquid tank failures, and an accidental release of waste gas.
Furthermore, As described below, the remaining accident analyses for SONGS, calculated as of August, 2013, show that the dose consequences are within the relevant regulatory limits.
Please provide additional information for each of these remaining UFSAR Chapter 15 design basis accident (DBA) scenarios that apply to a permanently defueled facility that has the potential to result in a radiological release. Provide a table for each relevant DBA that lists: (1) the parameters used in the dose analysis, (2) the original modeled value for
2 each parameter listed in the SONGS Units 2 and 3 Updated Final Safety Analysis Report (UFSAR), (3) the new modeled value for each parameter in the revised DBAs, and (4) a description as to why the new modeled value for each parameter is justified (if changed).
ARCB-RAI-2, Section 4.2, of the exemption request proposes a beyond-design-basis event concerning a loss of water inventory from the SONGS spent fuel pools (SFPs) as of June 12, 2013, the date on which SCE certified permanent cession of power operations of SONGS Units 2 and 3. SCE stated that the purpose of this calculation is to determine the potential radiological impact due to loss of shielding to the public at the Exclusion Area Boundary (EAB) for the event in which the spent fuel assemblies are uncovered following drain down.
The licensee concluded, Based on calculated direct and scattered dose rates from spent fuel assemblies in a SONGS SFP following drain down, it is concluded that the maximum dose at the EAB would be well below the acceptance criteria.
Therefore, the U. S. Nuclear Regulatory Commission (NRC) staff needs additional information on the modeling assumptions for such an analysis and a Monte Carlo N-Particle Transport Code, version 5 (MCNP5) input deck. The purpose of this request is to confirm that these calculations are acceptable and that the estimated doses are well below the acceptance criterion for exemption from requiring offsite emergency planning zones is less than 1 rem projected dose for a four-day period.
ARCB-RAI-3, Section 4.2, page 13 of 22 of the exemption request states:
The source terms for neutron and gamma radiation in spent fuel pools were calculated with consideration of plant shutdown dates as outlined earlier.
Please provide both a summary of the source term analysis that calculated the neutron and gamma source terms for the spent fuel pools and the source term used to perform the MCNP5 calculation.
ARCB-RAI-4 The dose criteria specified in 10 CFR 50.67 is in terms of total effective dose equivalent (TEDE).
As such, confirmatory calculations are performed in terms of TEDE to compare against the dose acceptance criteria specified in NUREG-0800, Section 15.0.1. This analysis differs from the Environmental Protection Agency (EPA) Protective Action Guide [PAG] and Planning Guidance for Radiological Incidents (a.k.a the EPA PAG Manual) recommendation for a projected whole body dose of 1 to 5 rem total effective dose (TED) over four days. The TEDE is defined as the sum of the effective dose equivalent for external exposures and the committed effective dose equivalent for internal exposures. The projected whole body dose calculation for TED is defined as the sum of the effective dose from external radiation exposure (i.e., groundshine and cloudshine) and the committed effective dose from inhaled radioactive material. Dose conversion factors (DCF) applied in both analyses convert the estimated environmental exposure to dose in the units of concern. Dose conversion factors acceptable to the NRC staff are derived from data provided in International Commission on Radiological Protection Publication 30, Limits for Intakes of Radionuclides by Workers and can be found in Federal
3 Guidance Report 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion, and Ingestion, and Federal Guidance Report No. 12, External Exposure to Radionuclides in Air, Water, and Soil, for exposure to radionuclides in air, water, and soil.
While both TEDE and TED calculate dose for both external and internal exposure, the underlying dosimetry models used to develop the DCFs are not the same. Please provide a summary explaining why the use of the EPA PAG dose criteria TED is acceptable in addition to the dose criteria specified in 10 CFR 50.67, which is calculated in terms of TEDE.
ARCB-RAI-5 Section 3.0, Page 3 of 21 of Enclosure 1 to the exemption request states that the UFSAR has been updated accordingly in accordance with 10 CFR 50.71(e), to reflect the possible accident/transients scenarios pertinent to the reactor being permanently shut down and defueled.
Please provide the revised UFSAR descriptions of Chapter 15.