ML092020393

Safety Evaluation for Amendment 165 to Release the Off-Shore Portions of the Circulating Water System from the License (TAC L605690)

ML092020393
Person / Time
Site:	San Onofre
Issue date:	02/24/2010
From:	James Shepherd NRC/FSME/DWMEP/DURLD/RDB
To:
Shepherd J 415-6712
Shared Package
ML093030400	List: ML092020393 ML093020580
References
TAC L60569
Download: ML092020393 (20)

Text

Field C SAFETY EVALUATION OFFICE OF FEDERAL AND STATE MATERIALS AND ENVIRONMENTAL MANAGEMENT PROGRAMS RELATED TO AMENDMENT NO. 165 TO FACILITY OPERATING LICENSE NO. DPR-13 SOUTHERN CALIFORNIA EDISON SAN ONOFRE NUCLEAR GENERATING STATION UNIT 1 DOCKET NO. 50-206

1. INTRODUCTION By letter dated December 19, 2007 (Ref.1), Southern California Edison (SCE or the licensee) submitted a request to amend Facility Operating License No. DPR-13, for the San Onofre Nuclear Generating Station Unit 1 (SONGS-1 or the facility). In accordance with the requirements of 10 CFR 50.83(d) (Ref. 2) the licensee has requested the addition of a new License Condition (126) to the SONGS-1 License to release a part of the site, the offshore cooling pipes, for unrestricted use. The proposed amendment would release for unrestricted use, a parcel of the ocean bottom that SCE leased from the California State Lands Commission, and the offshore portion of the San Onofre Unit 1 Circulating Water System, which is beneath that parcel of seabed floor. The structures comprising this portion of the system have been isolated from the plant. Following approval of this amendment, Southern California Edison will abandon these structures in place.

The lease agreement between the State of California, State Lands Commission and Southern California Edison Company and San Diego Gas and Electric Company defines the affected area. The lease agreement enacted on September 24, 1964, identified as Number 3193.1 in the [California] Public Resources Code Series, describes a piece of tidal and submerged land about 100 feet wide and 3310 feet long extending from the western boundary of the SCE site across the ocean floor in a southwesterly direction. This agreement now expires on September 24, 2013.

Because the Circulating Water System contained radiologically contaminated water, the licensee defines the system and the surrounding seabed as potentially contaminated (impacted) areas. As part of the license termination process, licensees submit a License Termination Plan (LTP) that includes planned residual radiological concentrations that have a calculated dose at or below the regulatory limit and As Low As Reasonable Achievable (ALARA). SCE does not plan to submit a License Termination Plan until after the other operating units on the site reach the end of licensed operation. Therefore, the licensee did not develop site-specific criteria for release of the site. Instead, the licensee conducted radiological sampling and surveying of the system and seabed to demonstrate compliance with the radiological criteria for unrestricted use as specified in Title 10 of the Code of Federal Regulations, Part 20, Section 1402. As part of its review process, NRC verified the licensees results by reviewing the procedures and independently evaluating split samples.

2. BACKGROUND San Onofre Nuclear Generating Station Unit 1 (SONGS-1) is located 3 miles (4.8 km) south of San Clemente on the Pacific Ocean coast, immediately south of the San Diego/Orange County border. It was a Westinghouse 450 megawatt (electric) pressurized water reactor, jointly owned by Southern California Edison (SCE) Company and San Diego Gas and Electric Company.

SCE operated SONGS-1 from initial criticality on June 14, 1967 until it was permanently shut down on November 30, 1992. Since its shutdown, SCE has moved the fuel to an onsite Independent Spent Fuel Storage Installation (ISFSI), removed and disposed of the components comprising Unit 1 and demolished the facility. Only the reactor vessel and the below-grade portions of some buildings remain on-site.

3. APPLICABLE REGULATORY REQUIREMENTS 10 CFR 50.83(d), Release of Impacted Areas, requires the licensee to submit an application for amendment of its license for the release of any impacted areas of its property. Such an application must include:

An evaluation of the effect of releasing the property to ensure that:

i) The dose to individual members of the public does not exceed the limits and standards of 10 CFR Part 20, Subpart D; (ii) There is no reduction in the effectiveness of emergency planning or physical security; (iii) Effluent releases remain within license conditions; (iv) The environmental monitoring program and offsite dose calculation manual are revised to account for the changes; (v) The siting criteria of 10 CFR Part 100 continues to be met; and (vi) All other applicable statutory and regulatory requirements continue to be met.

An application to release impacted areas must also include an historical site assessment of the part of the site to be released, including a description of such site and a schedule for its release. The application must further identify the methods used for, and results obtained from, the radiation surveys that were performed to demonstrate compliance with the radiological criteria for unrestricted use specified in 10 CFR 20.1402. The licensee must also supplement its environmental report, under 10 CFR 51.53, to describe any new information or significant environmental change associated with the licensee's proposed release of the impacted area.

4. SYSTEM EVALUATION SCE submitted its request on December 19, 2007 (Ref. 1) in accordance with 10 CFR 50.83(d).

The request describes SCEs approach for demonstrating compliance with radiological criteria

for unrestricted use for the proposed release of the offshore portion of the Circulating Water System from the SONGS-1 license.

4.1 System Description The Circulating Water System supplied seawater to condense the exhaust steam from the low-pressure turbines. In addition, the discharge conduit received waste water from the following systems:

on-site sewage treatment plant, radioactive liquid waste processing system, steam generator blowdown system, turbine plant oily waste / water separator and the condenser overboard (drawdown),

saltwater return from the Turbine Plant Cooling (TPCW) Water and Component Cooling Water (CCW) heat exchangers, and storm drain water via the yard drain sump.

During normal plant operation, seawater was drawn into the system at the intake terminal structure, pumped through the main condensers and other heat exchangers and returned to the discharge terminal structure. The Circulating Water System could also be configured to draw seawater in through the discharge conduit and discharge the heated water back through the intake conduit. This reverse tunnel evolution was performed periodically to minimize fouling of the intake conduit from the growth of marine organisms.

The components that SCE will abandon in place are within the piece of land described below, and include:

1. The intake terminal structure, 3200 feet southwest of the seawall,

2. The intake conduit running from the intake terminal structure to the southwestern edge of a concrete plug installed in the intake stop gate structure within the San Onofre Unit 1 area,

3. The discharge conduit running from the southwest edge of the concrete plug installed in the intake stop gate structure within the San Onofre Unit 1 area to the discharge terminal structure, and

4. The discharge terminal structure, 2600 feet southwest of the seawall.

The intake and discharge conduits are reinforced concrete pipes 12 feet (3.7 m) in diameter. At the point where they connect to the stop gate structures, the top of each conduit is 12 feet (3.7 m) below Mean Lower Low Water (MLLW) - the 19-year average of the lower of the two daily low water levels. The intake conduit extends out 3200 feet (975 m) to the intake terminal structure where the top of the conduit is approximately 32 (9.75 m) below MLLW. The discharge conduit extends out 2600 feet (792 m) to the discharge terminal structure where the top of the conduit is approximately 28 (8.5 m) below MLLW. The conduits are below the ocean floor and when constructed were covered by about 4 feet (1.2 m) of sand. They are within California lease P.R.C. 3193.1 that is a 100-foot wide parcel extending southwest from the mean high water level southwest of the SONGS Unit 1 site to approximately 3,300 feet offshore.

4.2 Current Condition of the Circulating Water System The main Circulating Water System pumps at San Onofre Unit 1 were secured shortly after plant shutdown in 1992. Smaller, auxiliary salt-water cooling system pumps circulated water through the offshore conduits to support spent fuel pool cooling requirements until all spent fuel was removed from the Unit 1 Spent Fuel Pool to the on site ISFSI.

The auxiliary salt-water cooling pumps were maintained in operation to support other Unit 1 decommissioning activities, including dilution water for permitted releases of liquid radioactive waste. At the completion of all radioactive liquid waste processing, a new system was constructed and placed in service to divert the storm drain system at Unit 1 to the San Onofre Unit 2 and 3 Circulating Water System. Radioactive releases via the Unit 1 Circulating Water

System were completed and all pumps circulating water through the San Onofre Unit 1 Circulating Water System were secured in November 2006.

4.3 Circulating Water System Surveys The structures and conduits comprising the offshore portion of the Circulating Water System at San Onofre Unit 1 and the associated parcel of the ocean floor are the subjects of this partial site release. Based on site operating history and the Historical Site Assessment (HSA), the offshore portion of the discharge conduit and the discharge terminal structure of San Onofre Unit 1 Circulating Water System are classified as an Impacted Area, Class 1. Based on site operating history and HSA the licensee also classified the offshore portion of the intake conduit and the intake terminal structure of San Onofre Unit 1 Circulating Water System as Impacted Areas, Class 1. The entire length of the offshore portion of the San Onofre Unit 1 Circulating Water System intake conduit and the intake terminal structure are included in a single survey unit. The entire length of the offshore portion of the discharge conduit and the discharge terminal structure are included in a single survey unit. SCE did not remediate these structures prior to sampling. There was no remediation of these structures as a result of these characterization / final status surveys.

The structures cannot be isolated from the Pacific Ocean. Therefore, all characterization and final surveys were performed underwater. In order to minimize risk to underwater sampling personnel, separate characterization and final status surveys (FSS) were not conducted.

Instead, divers collected a single set of samples as both the characterization and final status surveys.

SCE conducted radiological surveys at the onshore end of both intake and discharge conduits in December 2006 and January 2007. At the completion of these surveys, SCE permanently blocked the onshore end of the conduits with concrete. The results of these surveys show the calculated doses are less than five per cent (5%) of NRC criteria for release for unrestricted use.

The details are discussed in Section 6 of the submittal.

Surveys were conducted at the offshore end of both intake and discharge conduits and the local area surrounding the discharge terminal structure in May 2007. The results of these surveys show the calculated dose rates are less than five per cent (5%) of NRC criteria for release for unrestricted use. The details are also discussed in Section 6 of the submittal.

SCE conducted the sampling in accordance with procedures established for its Radiological Environmental Monitoring Program (REMP), including the Offsite Dose Calculation Manual, as stated in Defueled Technical Specifications 6.8.4b and 6.9.1.3. Quality assurance (QA) and quality control (QC) measures for the surveys included requirements for ensuring compliance with the REMP. SCE also conducted a thorough review of the results of ocean bottom sediment from the SONGS REMP. No sample results were above the reporting criteria. This is not sufficient, in and of itself, to conclude that the leased tract of ocean floor meets the acceptance criteria for unrestricted use. However, these data support a conclusion that any contaminants that might be present would be detectable at very low levels, or would be at levels below the minimum detectable activity (MDA) of the analysis process.

Because the survey methods defined in NUREG 1575, Rev. 1, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), do not apply to underwater areas, SCE consulted with the NRC staff to define a method for demonstrating compliance. In lieu of using Derived Concentration Guideline Limits (DCGLs) to demonstrate compliance with the dose limit of 25 millirem per year, SCE developed site-specific models for direct (external) and indirect (ingestion) dose. SCE used a direct dose model to calculate hypothetical annual exposure based on the actual measured concentrations of licensed radioactive material in samples collected during the conduct of the survey. SCEs indirect dose model follows applicable portions of the ingestion dose model in Regulatory Guide 1.109.

4.4 Circulating Water System Survey Results 4.4.1 Exposure Scenario The critical group for the exposure scenario for these site-specific acceptance criteria is a recreational lobster diver who enters the offshore Circulating Water System structures in the pursuit of lobster. SCE assumed the exposure time is a series of 30-minute dives into six of the eleven available openings into the conduit each day for the entire 173-day length of the lobster season. This hypothetical individual also ingests lobster and shellfish from within these structures at the average rate defined in Regulatory Guide 1.109.

4.4.2 Dose Calculations SCE developed site-specific dose models for both direct exposure and indirect exposure through ingestion. It used these models to derive site-specific acceptance criteria. The isotopes of interest considered for dose calculations included all isotopes identified in the evaluations conducted to comply with the requirements of 10 CFR Part 61. All gamma-emitting isotopes from the Part 61 analyses were considered in the direct dose calculations. Direct dose models considered radioactive material in sediment, imbedded in the concrete conduits, and materials both loosely and tightly adhered to the internal surface of the conduits. Sensitivity analysis demonstrated that, in all cases, the residual radioactive material in sediment dominated the dose rate. Site specific, underwater exposure rates were calculated using the Grove Engineering MicroShield software Version 5.03a.

Hypothetical radiation exposure from residual licensed radioactive material inside these structures, under the conditions proposed in the application, would result from two pathways:

external exposure to a diver who might enter these structures; and internal exposure by the ingestion of edible marine species containing residual licensed radioactive material.

Site-specific dose conversion models for these pathways were developed to demonstrate compliance with the dose criteria. Samples were collected from the subject structures,

analyzed, and the actual measured concentrations applied to the site-specific dose models.

The resulting hypothetical dose is then compared against the radiological criteria for unrestricted use of 25 mrem/yr.

The parcel of the ocean floor leased from the California State Lands Commission that SCE proposes to remove from licensee control also does not meet the assumptions in the dose models used to develop the soil acceptance criteria in MARSSIM. Therefore, site-specific occupancy factors for the ocean floor were not developed.

4.4.2.1 Internal Doses A representative sampling of lobsters was collected from the intake terminal structure and the southwestern end of the intake conduit. The edible portion of each lobster was removed and mixed into a composite sample. The analysis of this composite sample identified tritium at 5.92E-5 +/- 4.73E-5 microCuries per gram (Ci/g). Analysis of this composite sample of lobster flesh also identified Strontium-90 at 4.02E-7 +/- 3.31E-7 (Ci/g).

A representative sample of scallops was collected from the intake structure. These scallops were mixed into a composite sample. Analysis of this composite sample identified Calcium-45 and Actinium-227 at levels below the MDA, but neither of these is attributable to plant operations so they are not used in the dose calculations.

A representative sample of mussels was collected from the intake terminal structure. These mussels were mixed into a composite sample. Analysis of this composite sample identified Lead-210 that is a decay product of naturally occurring Uranium-238. Therefore, the dose due to Lead-210 resulting from the ingestion of mussels is not be included in this evaluation.

A representative sampling of lobsters was collected from the discharge terminal structure and the southwestern end of the discharge conduit. The edible portion of each lobster was removed and mixed into a composite sample. Analysis of this composite sample of lobster flesh identified tritium at 4.0E-5 +/- 4.51E-5 microCuries per gram. Ca-45 and U-234 were also

identified at levels below the MDA, but neither of these is attributable to plant operations so they are not used in the dose calculations.

A representative sample of scallops was collected from the discharge structure and mixed into a composite sample. Analysis of this composite sample identified tritium at 8.87E-5 +/- 5.77E-5 microCuries per gram. Analysis of this composite sample of scallops also identified Europium-154 at 6.03E-7 +/- 2.78E-7 microCuries per gram.

A representative sample of mussels was collected from the discharge terminal structure. These mussels were mixed into a composite sample. Analysis of this composite sample identified tritium at 7.26E-5 +/- 4.72E-5 microCuries per gram.

Applying the dose conversion factors from FGR-11 and the ingestion rates from NRC Regulatory Guide 1.109 for average consumption to the measured concentration yields the maximum credible dose due to the ingestion of lobster, scallops and mussels from reactor related isotopes is 7.96E-2 millirem per year, is in Table 6-1 of the submittal, shown below.

4.4.2.2 External Doses Dose models were developed for each identified gamma-emitting isotopes and the actual geometry of the conduit proposed to be abandoned below the ocean floor using the Grove Engineering MicroShield software.

Specific models were developed to evaluate dose from radioactive material deposited on the walls and top of the structures as well as radioactive material deposited in sediment on the bottom of the structure.

Divers from a marine biology company collected samples of sediment, wall scrapings and concrete from the surface of the conduits using industry standard collection methods. For diver safety reasons access was limited to the first 100 feet into the conduit from the onshore ends and the offshore ends of each conduit. Concentrations at the access points that will be opened during the preparations for abandonment along the length of the conduit are interpolated based on the results from the sampled locations. The average dose rate at each end of each tunnel is used as the endpoints for the interpolation. The distance used for end points in the interpolation is the midpoint of the sample area at each end (50 feet from the actual endpoints).

The dose at the intermediate points along the intake conduit was calculated by linear interpolation, and is in Table 6-9 of the submittal, shown below.

The dose rate at the intermediate points along the discharge conduit was calculated by linear interpolation, and is in Table 6-10 of the submittal, shown below.

The calculation for the annual Deep Dose Equivalent (DDE) to the hypothetical diver assumes entering six of the eleven openings into the two tunnels (six intermediate points and the terminal structure for the intake tunnel and five intermediate points and the terminal structure for the discharge tunnel). Assuming the diver stays for 30 minutes each dive, for each day of the 173 days of the lobster season, the DDE can be calculated using the average dose rate at these eleven points. The 50 ft points are not included in the DDE calculation because the onshore access to each pipe is plugged with concrete and is 650 feet from the nearest opening, which is too far for a lobster diver to go. Average dose rate is used because there is no reason for one location to be more attractive than another for lobster habitability.

The calculated annual DDE to the hypothetical diver is 4.14 E-1 millirem per year.

4.4.2.3 Total Doses Total Effective Dose Equivalent (TEDE) is calculated as the sum of internal and external exposure for all licensed isotopes identified by sample analysis using the following formula:

Where:

• TEDE is the annual Total Effective Dose Equivalent in millirem per year

• Ua is usage factor, i.e. the average annual consumption rate of fish and seafood

in kg per year from Tables E-4 in Regulatory Guide 1.109

• Ci is the specific activity of each isotope in the seafood in pCi/kg

• Di is the dose conversion factor from Table 2.2 of FGR-11 for isotope i

• EDE is the calculated external annual exposure in millirem per year As calculated in Table 6-1 above, the maximum Committed Effective Dose Equivalent (CEDE) internal exposure from ingestion of lobster, scallops and mussels taken from inside the tunnels is 7.96 E-2 millirem per year. The calculated annual DDE to the hypothetical diver is 4.14 E-1 millirem per year. The TEDE is the sum of the DDE and the CEDE, and is equal to 4.94 E-1 millirem per year from all pathways, is in Table 6-11 of the submittal, shown below.

This calculated TEDE of approximately 0.5 mrem/yr is far below the limit of 25 mrem/yr for release for unrestricted use, as stated in 10 CFR 20.1402.

5. NRC REVIEW OF CIRCULATING WATER SYSTEM SURVEYS The licensee conducted a series of sample analyses using media to represent the distribution of radionuclide contaminants, and their decay-corrected distribution, over the area planned for release. The isotopes of interest considered for dose calculations included all isotopes identified in the evaluations conducted to comply with the requirements of 10 CFR Part 61. All gamma-emitting isotopes from the Part 61 analyses were considered in the direct dose calculations. Direct dose models considered radioactive material in sediment, imbedded in the concrete conduits, and materials both loosely and tightly adhered to the internal surface of the conduits. Sensitivity analysis demonstrated that in all cases the residual radioactive material in sediment dominated the dose rate.

NRC staff evaluated the licensees analyses to demonstrate compliance with 10 CFR Part 20, Section 1402 using the guidance for evaluation of dose modeling in Draft NUREG-1836, Standard Review Plan for Releasing Part of a Reactor Facility or Site for Unrestricted Use Before Approval of the License Termination Plan, and NUREG-1757, Consolidated Decommissioning Guidance. In lieu of using Derived Concentration Guideline Limits that demonstrate compliance with the criteria for unrestricted release at 10 CFR Part 20, Section 1402, the licensee has developed site-specific models for external and internal exposures to the average member of a critical group. Per NUREG-1757, NRC staff reviewed the following information provided by the licensee: i) source term(s); (ii) exposure scenario(s); (iii) conceptual and mathematical model(s); (iv) uncertainty; and (v) ALARA.

The licensee used divers to collect samples from the intake and discharge structures. The samples were collected, in part, to demonstrate that the areas were sufficiently free of radioactive material for a partial site release. The samples included concrete, sediment, wall scrapings, and biological material from inside the structures. The primary radionuclides of concern were cobalt-60 and cesium-137.

During a routine inspection in March, 2007 (NRC Inspection Report 050-00206/07-007), NRC Field C conducted a confirmatory survey in the intake and outfall structures of the onshore portion of the Field C Unit 1 circulating water system to independently measure the radiological condition of the structures. In addition, the inspectors split nine concrete, sediment, and biological samples previously collected by the licensee in the offshore portions of the circulating water systems.

Both the licensees contract laboratory and Oak Ridge Institute analyzed the samples for Science and Education (ORISE) on behalf of the NRC. Two sets of samples were analyzed for gamma-emitting radionuclides. Selected samples were also analyzed for tritium (hydrogen-3) concentrations. Examples of the NRCs and licensees split sample results are presented in the table from the Inspection Report, shown below:

Table: IR Split Sampling Results Field C Sample Description NRCs Results (pCi/g) Licensees Results (pCi/g)

Intake-CL-09 cesium-137 0.16 +/- 0.04 cesium-137 0.133 +/- 0.026 Sediment cobalt-60 0.02 +/- 0.03 cobalt-60 0.015 +/- 0.013 tritium -1.5 +/- 2.8 tritium -0.5 +/- 1.0 Discharge-CC-06 cesium-137 0.07 +/- 0.04 cesium-137 0.056 +/- 0.015 Concrete cobalt-60 0.05 +/- 0.03 cobalt-60 0.086 +/- 0.012 tritium -1.5 +/- 2.7 tritium not measured Discharge-BIO-5 cesium-137 0.00 +/- 0.03 cesium-137 0.036 +/- 0.038 Biological cobalt-60 0.05 +/- 0.03 cobalt-60 0.012 +/- 0.033 tritium 2 +/- 19 tritium not measured The sample results indicate agreement between ORISE and the licensees laboratories. Field C Accordingly, the licensees laboratory was determined to be technically capable of accurately detecting and quantifying radioactive material in site samples.

The licensee reports that it has analyzed samples of sediment, wall scrapings, and concrete from both the internal and external conduits and the terminal structures. The licensees analyses indicate that only Cobalt-60, Cesium-134, Cesium-137, Europium-152, Europium-154, Manganese-54, Iridium-192, Sodium-22, and Niobium-94 are present at levels greater than the lower limit of detection and distinguishable from naturally occurring background or medical isotope concentrations.

Also, the licensee reports that it has analyzed samples of marine crustaceans and vertebrate fish collected within approximately the first 30 meters (100 feet) of conduit at both the onshore and offshore ends of the circulating water structures. It used this data to estimate the concentration of activity in these organisms that could result in internal ingestion exposures to the average member of the critical group. The licensees analyses indicate only tritium, Strontium-90, and Europium-154 are present at levels greater than the lower limit of detection and distinguishable from naturally occurring background or medical isotope concentrations.

NRC staff review of the licensees sample characterization data indicates that Cesium-137 is

also reported to be present in mussel samples collected in the onshore portion of the discharge conduit. The licensee did not provide a clear rationale for exclusion of this isotope from the source term. However, NRC staff does not expect the inclusion of Cesium-137 in ingestion exposure calculations to have a significant impact on the demonstration of compliance with the criteria specified in 10 CFR 20.1402.

NRC staff confirmation of the external dose using all reported residual radioactivity samples (i.e., sediment, scrapings, and concrete) collected from the conduit results in a dose of only 5.20 Sv/yr (0.520 mrem/yr). NRC staff concludes that this is a reasonable approach as concentrations would be expected to decrease exponentially due to removal processes (e.g.,

sorption to sediments, concrete) along the length of the conduit resulting in lower average concentrations along the length of conduit than those linearly interpolated by the licensee. NRC staff also considered an alternative analysis of the potential effect of re-suspended sediments within the conduits from potential diver disturbance. The alternative NRC staff analyses used MicroShield©, Version 5.05, to estimate external dose rates for approximately 3 cm to 15 cm (1 in. to 6 in.) of re-suspended sediments. The resultant dose rates are less than or approximately equal to the sediment dose rates calculated by the licensee. Therefore, NRC staff considers the licensees parameters and models for external exposures reasonable.

NRC staff note that the seafood ingestion rates reported by Regulatory Guide 1.109 are based on an U.S. Department of Agriculture Agricultural Economic Report 138, which estimated national per capita food consumption rates. The licensee did not provide a justification for the applicability of a nationally averaged seafood ingestion rate to the proposed lobster diver critical group. The licensee evaluated, though does not report, the effect of increased seafood ingestion rates on the estimated internal dose using a maximum exposed individual seafood ingestion rate from Regulatory Guide 1.109, Table E-5. Based on these assessments, the licensee estimated internal doses of approximately 4.15 Sv/yr (0.415 mrem/yr). The NRC staff does not expect larger consumption rates of contaminated seafood by the proposed critical group to have a significant impact on the demonstration of compliance with the criteria specified at 10 CFR Part 20, Section 1402. NRC staff considers the parameters, models, and calculations for internal exposures reasonable.

The licensee reports in Section 5 of the amendment application the results of its analysis that residual radioactivity has been reduced to levels that are as low as reasonably achievable.

NRC staff considers the licensees ALARA analysis reasonable.

The types of surveys and sampling methods described for the survey efforts are acceptable.

Based on its analyses, NRC staff considers that the licensee has provided reasonable assurance that the proposed action is protective of the public health and safety. The staff finds that the proposal to abandon in place the offshore subsurface structures of the San Onofre Nuclear Generating Station Unit 1 Circulating Water System, and release for unrestricted use the leased parcel of the ocean bottom, will comply with the radiological criteria specified at 10 CFR Part 20, Section 1402.

6. ENVIRONMENTAL REPORT NRC regulations require licensees to provide a supplement to the environmental report describing any new information or significant environmental changes associated with the licensees proposed license termination activities. Section 7 of the request updates the Environmental Report--Post Operating License Stage, San Onofre Nuclear Generating Station Unit 1, submitted on September 18, 2002 (Ref. 3). Therefore, Chapter 8 of the request constitutes a supplement to SONGS-1s Environmental Report, as required by 10 CFR 51.53(d) and 10 CFR 50.82(a)(9)(ii)(G). Based on the information in Chapter 8, the licensee concluded that the environmental impacts associated with changes in SONGS-1s decommissioning activities remain bounded by the previously issued Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, NUREG-0856 (Ref. 4). Under the provisions of 10 CFR 51.21, the staff prepared an environmental assessment (EA) (Ref. 5) to determine the impacts of the proposed action on the environment. In the EA, the staff found that approval of the request would not cause any significant impacts on the human environment and is protective of human health. Therefore, the staff concluded a Finding of No Significant Impact.

The staff reviewed the information in the request for SONGS-1, according to Section B.8 of NUREG-1700. Based on this review and the EA prepared by the staff, the staff concludes that the licensee met the regulatory requirements.

7. STATE CONSULTATION In accordance with NRC regulations, NRC notified the California State Land Commission (CSLC) of the proposed issuance of the amendment. The CSLC submitted comments to the EA on October 26, 2009. Briefly, the CSLC provided several editorial recommendations to clarify its requirements. NRC staff incorporated the CSLCs comments in the revised EA.

8. CONCLUSIONS The NRC staff has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that operation in the proposed manner will not endanger the health and safety of the public; (2) the licensee will conduct such activities in compliance with the Commissions regulations; and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

9. LIST OF CONTRIBUTORS C. Grossman, FSME/PAB J. Shepherd, FSME/RDB

10. LIST OF ACRONYMS ALARA As Low As Is Reasonable Achievable SONGS-1 San Onofre Nuclear Generating Station Unit 1 CEDE Committed Effective Dose Equivalent; internal exposure from ingestion CFR Code of Federal Regulations CSLC California State Land Commission

DCGL Derived Concentration Guideline Limit DDE Annual Deep Dose Equivalent; the dose equivalent at a tissue depth of 1 cm EA Environmental Assessment FR Federal Register FSME NRC Office of Federal and State Materials and Environmental Management Programs FSS Final Status Survey HSA Historical Site Assessment ISFSI Independent Spent Fuel Storage Installation MARSSIM Multi-Agency Radiation Survey And Site Investigation Manual MDA Minimum Detection Activity MDC Minimum Detectable Concentration MLLW Mean Lower Low Water - the 19 year average of the lower of the two daily low water levels mrem/hr millirem per hour mrem/yr millirem per year Sv/yr microSievert per year NRC Nuclear Regulatory Commission ORISE The Oak Ridge Institute for Science and Education

µCi/g microcurie per gram QA Quality Assurance QC Quality Control REMP Radiological Environmental Monitoring Program SCE Southern California Edison SER Safety Evaluation Report SONGS-1 San Onofre Nuclear Generating Station Unit 1 TEDE Total Effective Dose Equivalent

8.0 REFERENCES

1 Letter R. T. Ridenour (SCE) to NRC Amendment Application 222 to Facility License DPR-13, Request for Partial Site Release, December 19, 2007; ADAMS Accession No.:ML080580468 2 10 CFR 50.83(d) 3.Supplement to Environmental Report--Post Operating License Stage, San Onofre Nuclear Generating Station Unit 1, Facility License DPR-13, September 18, 2002, Southern California Edison, San Onofre, California 4.Nuclear Regulatory Commission, Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, NUREG-0856, U.S. Nuclear Regulatory Commission, Washington, D.C. (http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0586/)

5.Nuclear Regulatory Commission, Environmental Assessment. November 30, 2009, U.S.

Nuclear Regulatory Commission, Washington, D.C. (74 FR 62605) ADAMS Accession No.: ML093010071