August 24, 2007

Mr. James Woolford, Director

Office of Superfund Remediation 

 and Technology Innovation

U.S. Environmental Protection Agency

Ariel Rios Building 

1200 Pennsylvania Avenue, N. W.

Mail Code: 5201P 

Washington, DC 20460 

SUBJECT: CONSULTATION ON THE DECOMMISSIONING OF THE RANCHO SECO

NUCLEAR GENERATING STATION IN HERALD, CALIFORNIA

Dear Mr. Woolford:

This letter notifies you of the decommissioning oversight actions that the U.S. Nuclear

Regulatory Commission (NRC) has taken and intends to take, for the Rancho Seco Nuclear

Generating Station in Herald, California.

On October 9, 2002, the NRC and the U.S. Environmental Protection Agency (EPA) entered

into a Memorandum of Understanding (MOU) on “Consultation and Finality on

Decommissioning and Decontamination of Contaminated Sites.” Under the MOU, EPA agreed

to continue its Comprehensive Environmental Response, Compensation, and Liability Act

deferral policy of not listing sites on the National Priorities List that are subject to NRC’s

licensing authority. The MOU provides that, unless an NRC-licensed site exceeds any of three

trigger criteria contained in the MOU, EPA agrees to a policy of deferral to NRC decisionmaking on decommissioning without the need for consultation.

For sites that trigger the criteria in the MOU, NRC will consult with EPA at two points in the

decommissioning process: (1) prior to NRC approval of the license termination plan (LTP) or

decommissioning plan, which NRC terms Level 1 consultation; and (2) following completion of

the Final Status Survey (FSS), which NRC terms Level 2 consultation.

We are sending this letter as our Level 1 consultation for the Rancho Seco site, because the

licensee’s proposed derived concentration guideline levels (DCGLs) for certain radionuclides for

this site exceed the soil concentration values in Table 1 of the MOU.

Rancho Seco has a deactivated pressurized-water nuclear reactor and is located on a 2480-

acre Sacramento Municipal Utility District (SMUD) site in Sacramento County at 14440 Twin

Cities Road, Herald, California. Rancho Seco was constructed between 1968 and 1974, and in

August 1974, the NRC licensed the reactor to operate commercially at 2772 megawatts

thermal. After passage of a nonbinding referendum by the voters of Sacramento County in

1989, SMUD decided to permanently shut down Rancho Seco. In an August 1989 public

meeting, SMUD formally informed the NRC that the plant was shut down permanently and

notified the NRC of its intent to seek amendments to the Rancho Seco operating license and

decommission the facility. In February 1997, SMUD began active decommissioning of the site. 
J.Woolford -2-

In August 2002, SMUD completed the transfer of all spent nuclear fuel to its independent spent

fuel storage installation (ISFSI) licensed under 10 CFR Part 72, “Licensing Requirements for

the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and ReactorRelated Greater Than Class C Waste.” In April 2006, SMUD submitted its LTP.

SMUD is proposing to decontaminate the Rancho Seco site to meet the requirements in 

Title 10 of the Code of Federal Regulations (CFR), Part 20.1402 for unrestricted use under an

industrial use scenario. The licensee chose an industrial use scenario since gas fired and solar

generating facilities exist on two sides of the former nuclear generating station. Bounding

calculations performed by the licensee indicated that the 10 CFR 20.1402 requirements for a

resident farmer would be met by July 2038. SMUD currently plans to leave in place at the site

multiple permanent buildings and structures, as well as paved areas and 11 concrete pads of

removed structures in place at the site after license termination.

No plant-generated radionuclides have been observed in the groundwater beneath the Rancho

Seco site. Also, no plant-generated radionuclides have been observed in the soil or rock

materials beneath the industrial area at a depth greater than 25 feet. The shallowest waterbearing unit is the water table at approximately 165 feet below ground surface. Therefore, it is

unlikely that plant-generated radionuclides will reach the groundwater or migrate offsite in the

future.

The DCGLs, which the staff plans to approve, are provided in the enclosure. Five of the six

radionuclides exceed the MOU soil concentration levels for the industrial land use scenario. 

Before the NRC license is terminated, the dose to the average member of the critical group at

the Rancho Seco site will be in compliance with NRC’s criteria in 10 CFR Part 20, Subpart E

that provides an all-pathways dose criteria of 0.25 millisieverts per year (25 millirem per year to

an average member of the critical group) and are as low as is reasonably achievable (ALARA). 

The dose criteria in 10 CFR Part 20, Subpart E are fully protective of the public health and

safety, and were the result of a comprehensive rulemaking, including an accompanying generic

environmental impact statement. Individuals at a decommissioned site are expected to receive

doses substantially below the constraint level because of the application of the ALARA

principal, conservative dose modeling assumptions, and the nature of the cleanup process

itself, which often reduces residual contamination levels significantly below site DCGLs. 

Additionally, the residual radioactivity at the site is expected to be much lower than the

approved DCGL values because meeting the 25 millirem per year criteria must be

demonstrated using an all pathways, sum of the fractions approach. The DCGLs in the LTP

represent the maximum levels for each radionuclide without considering the existence of other

radionuclides. Thus, in applying the sum of the fraction requirement, the actual cleanup values

will be reduced to ensure that the potential dose from all residual radioactivity at the site from all

media is less than 25 millirem per year.

However, in view of the extent to which the proposed cleanup values exceed the MOU trigger

levels, and based on NRC’s decommissioning experience, a Level 2 consultation may be

necessary because the levels of residual radioactivity remaining after remediation may still

exceed the MOU trigger levels. If this is the case, NRC will consult with the EPA in accordance

with the MOU.

As part of the LTP review and approval process, the NRC staff will prepare an environmental

assessment (EA) to document how the remediation at the Rancho Seco site would ensure 
J.Woolford -3-

protection of the public health and safety and the environment. The EA will be published in the

Federal Register.

Following your staff’s review of Enclosure 1 and other relevant information, as specified in

Section V.D.1 of the MOU, please send us your views on the Rancho Seco site within 90 days

of receiving this notification.

The staff anticipates approving the LTP at the conclusion of the consultation process. 

Following site remediation activities, the site will submit a FSS. NRC staff will review

information contained in this survey report and will compare the remaining levels of residual

radioactivity to the MOU trigger levels. If the FSS measurements trigger the MOU, a

consultation between the agencies will occur under the MOU to identify and resolve any

remaining issues. In the meantime, if you have any questions regarding this letter or the

remediation activities at the Rancho Seco site please contact Mr. Keith I. McConnell, Deputy

Director, Decommissioning and Uranium Recovery Licensing Directorate, at (301) 415-7295.

Sincerely, 

/RA/

Larry W. Camper, Director

Division of Waste Management 

 and Environmental Protection

Office of Federal and State Materials

 and Environmental Management Programs

Enclosure: 

Rancho Seco Proposed Cleanup Values

cc: Rancho Seco Service List

Docket No.: 50-312

License No.: DPR-54
J.Woolford -3-

protection of the public health and safety and the environment. The EA will be published in the

Federal Register.

Following your staff’s review of Enclosure 1 and other relevant information, as specified in

Section V.D.1 of the MOU, please send us your views on the Rancho Seco site within 90 days

of receiving this notification.

The staff plans to approve the LTP at the conclusion of the consultation process. Following site

remediation activities, the site will submit a FSS. NRC staff will review information contained in

this survey report and will compare the remaining levels of residual radioactivity to the MOU

trigger levels. If the FSS measurements trigger the MOU, a consultation between the agencies

will occur under the MOU to identify and resolve any remaining issues. In the meantime, if you

have any questions regarding this letter or the remediation activities at the Rancho Seco site

please contact Mr. Keith I. McConnell, Deputy Director, Decommissioning and Uranium

Recovery Licensing Directorate, at (301) 415-7295.

Sincerely,

/RA/

Larry W. Camper, Director

Division of Waste Management 

 and Environmental Protection

Office of Federal and State Materials

 and Environmental Management Programs

Enclosure: 

Rancho Seco Proposed Cleanup Values

cc: Rancho Seco Service List

Docket No.: 50-312

License No.: DPR-54

DISTRIBUTION:

FSME r/f RidsFsmeOd RidsRgnIMailCenter 

ML072210206

OFFICE DURLD/PM DURLD/LA DURLD DURLD/BC(A)

NAME J. Hickman T. Mixon R. Rodriguez B. Watson

DATE 8/9/2007 8/9/2007 8/10/2007 8/10/2007

OFFICE DURLD/DD DWMEP:D

NAME K. McConnell L. Camper

DATE 8/21/2007 8/24/2007

OFFICIAL RECORD COPY
Enclosure

Rancho Seco Proposed Cleanup Values (pCi/g)

Radionuclide Cleanup Value EPA MOU*

C-14 833,0000 123,000

Co-60 12.6 6

Ni-63 15,200,000 555,000

Sr-90 6,490 1,070

Cs-134 22.4 26

Cs-137 52.8 11

*Industrial/Commercial land use scenario
Rancho Seco Nuclear Generating Station Service List

cc:

Mr. James Shetler

AGM, Energy Supply

Sacramento Municipal Utility District

6201 S Street

P.O. Box 15830

Sacramento, CA 95852

Mr. Jerry Delezenski

QA/Licensing Superintendent

Sacramento Municipal Utility District

Rancho Seco Nuclear Station

14440 Twin Cities Road

Herald, CA 95638-9799

Sacramento County

Board of Supervisors

700 H Street, Suite 2450

Sacramento, CA 95814

Arlen Orchard, General Counsel

Sacramento Municipal Utility District

6201 S Street

P. O. Box 15830

Sacramento, CA 95817-1899

Steve Cohn, Assistant General Counsel

Sacramento Municipal Utility District

6201 S Street

P. O. Box 15830

Sacramento, CA 95817-1899

Mr. Steve Hsu

Radiologic Health Branch

MS 7610

PO Box 997414

Sacramento, CA 95899-7414

Mr. Gary Butner

Acting Chief

Radiation Program Director

Radiologic Health Branch

MS 7610

PO Box 997414

Sacramento, CA 95899-7414

Commissioners’ Office

California Energy Commission

1516 Ninth Street (MS 34)

Sacramento, CA 95814-5512

Site Document Control Supervisor

Sacramento Municipal Utility District

Rancho Seco Nuclear Generating Station

14440 Twin Cities Road

Herald, CA 95638-9799

Regional Administrator, Region IV

U.S. Nuclear Regulatory Commission

611 Ryan Plaza Drive, Suite 400

Arlington, TX 76011-8064

Bill Potter, Coordinator (Radiological)

Governor's Office of Emergency Services

Radiological Preparedness Unit

P.O. Box 419047

Rancho Cordova CA 95741-9047