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Nebraska

Hallam Nuclear Power Facility

Long-Term Stewardship Site Highlights

Hallam Nuclear Power Facility (page 3) Major Activities- groundwater monitoring Site Size -7.3 hectares (18 acres) Start/End Years- 1998/past 2070 Estimated Average Annual Cost FY 2006- $46,000

Table of Contents

Table of Contents

Hallam Nuclear Power Facility ............................................................. 3

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National Defense Authorization Act (NDAA) Long-Term Stewardship Report

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Hallam Nuclem· Powe1· Facility

HALLAM NUCLEAR POWER FACILITY 1.0 1.1
SITE SUMMARY

Site Description and Mission
LONG-TERM STEWARDSHIP HIGHLIGHTS Major Long-Term Stewardship Activities -

The Hallam Nuclear Power Facility is a former sodiumcooled, graphite-moderated nuclear reactor. It was built and operated by the U.S. Atomic Energy Commission (AEC), the predecessor agency of the U.S. Department of Energy (DOE), between 1962 and 1964. The reactor was decommissioned and dismantled in 1969. The facility is located on a small portion of the 260-hectare (640-acre) site of the Sheldon Power Station in Lancaster County, Nebraska, approximately 30 kilometers ( 19 miles) south of Lincoln, on land owned by the Nebraska Public Power District.

groundwater monitoring Total Site Area- 7.3 hectares (18 acres)
Estimated Volume of Residual Contaminants-

facilities unknown
Long-Term Stewardship Start-End Years- 1998-past 2070 Average Annual Long-Term Stewardship Cost FY 2000-2006-$46,000 Landlord- U.S. Department of Energy, Grand

Junction Office The current mission of the Hallam Nuclear Power Facility is to perform long-term stewardship activities, including monitoring of the groundwater. The AEC operated the 240-megawatt thermal reactor as a demonstration facility from 1962 until 1964. In 1965, the ABC terminated its agreement with the Nebraska Public Power District (then known as Consumers Public Power District) to operate the reactor facility. The Nebraska Public Power District dismantled and decommissioned the reactor from 1967 through 1969. In 1971, the AEC retired the facility.

1.2

Site Cleanup and Accomplishments

The Nebraska Public Power District dismantled and decommissioned the reactor core and removed most of the radioactive materials from the site; however, some radioactive materials were entombed in place. All potential contaminants at the site are contained within the entombment structure in Area 1 (reactor vessel and vessel containment structures), Area 2 (Fuel Storage Pit 3 thimbles), or Area 3 (moderator element storage cells). These contaminants include nickel-63, cobalt-60, iron-55, manganese-54, samarium-151, cesium-137, strontium-90, and tritium. The contaminants within the structure consist of activation products in the stainless steel reactor vessel and its internals. Lesser amounts of activation products are dispersed in the carbon steel thermal shield and guard vessel surrounding the reactor vessel and in the compartment liner itself. The core and most of the radioactive materials, including all of the bulk sodium, were removed from the site. The residual sodium reacted with steam to form sodium hydroxide, removing the potential for hydrogen formation at a later date should water leak into the facility. The reactor vessel and surrounding guard vessel, which use double-walled piping, as well as most of the reactor vessel internals, remain within the compartment. Fuel Storage Pit 3 contains a number of stainless steel thimbles formerly used to store spent fuel elements. The storage pool was drained, and the thimbles now contain process tubes, control rod tubes, dummy elements, and a spent neutron source. To prevent leaks, closures and dust covers for each thimble have been welded in place and the interspace has been filled with expanding concrete. Storage Area 3 consists of 12 storage cells containing three canistered moderator elements that experienced cladding failures during reactor operation. A number of parts such as pumps, valves, and segments of piping are stored in these cells. The moderator cells were sealed by welding the plug casings to the cell liners and filling
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National Defense Authorization Act (NDAA) Long-Term Stewardship Report

@ Groundwater Monitoring Well 0.05

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the space above the plugs with expanding concrete. The basement level of the facility contained radioactive waste disposal equipment, all of which has either been removed or decontaminated, as appropriate. All reactor compartments have been sealed, and the surface of the below-grade concrete structure was covered with sand, a waterproof polyvinyl membrane, and a covering of earth. The cover was sloped for proper drainage, and drain tile was installed at the periphery. Above-grade structures have been weatherproofed by a layer of polyvinyl and a protective cover of concrete. All that remains above ground is the sealed concrete intermediate heat exchanger building. Total radioactivity was 300,000 curies at the time of closure. By 2000, the activity level will have decayed to approximately 15,000 curies. There is no known soil or groundwater contamination at the Hallam Nuclear Power Facility and no evidence of contamination being released from the site.

2.0

SITE-WIDE LONG-TERM STEWARDSHIP

2.1

Long-Term Stewardship Activities

Although the Nebraska Public Power District owns the property, DOE currently has the responsibility to perform long-term stewardship activities for the entombed reactor structure at the Hallam Nuclear Power Facility. Longterm stewardship responsibility was transferred to the DOE Grand Junction Office in 1998. The former reactor site is now a 0.6 hectare (1.4 acre) grass-covered mound with a heat exchanger building. The installation of a shallow groundwater monitoring system was completed in 1995 and is used as part of the surveillance program for the entombed reactor. Groundwater monitoring is conducted annually and will continue indefinitely. Site records are kept in permanent storage at the DOE Grand Junction Office in Colorado. The types of records kept include characterization data, decommissioning design information, decommissioning report, annual inspection
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Hallam Nuclear Power Facility

reports, and groundwater monitoring results. In addition, the Nebraska Public Power District will control access to the site due to contaminated buried materials.

2.2

Specific Long-Term Stewardship Activities

STAKEHOLDER INTERACTION

Groundwater

Although there is no known groundwater contamination at the site, groundwater monitoring is conducted annually to ensure the stability of the entombed reactor. Water level measurements are obtained from all19 DOE wells. Samples for analysis are obtained from 17 of the DOE wells. The samples are analyzed for gross alpha, gross beta, tritium, gamma spectrometry, and nickel-63. The annual monitoring and surveillance report discusses the results of the groundwater monitoring and summarizes the physical condition of the site. This report also discusses the need for follow-up inspections, monitoring, or maintenance actions, should any be necessary.

Community interaction at the site has been minimal to date. DOE sends a copy of the site's annual inspection report to the State of Nebraska and the Nebraska Public Power District.

Facilities
The reactor is entombed onsite. Access to the property is restricted, as entry can only be made through the secured property of an operating power plant where the site is located. Potential contaminants remain within the entombed reactor; however, DOE does not conduct any active monitoring of this area.

2.3

Regulatory Regime

Long-term stewardship activities at the Hallam Nuclear Power Facility is governed by several requirements in the following regulations: the Atomic Energy Act of 1954, as amended; EPA Groundwater Protection Standards; and the National Environmental Policy Act of 1969, as amended.

2.4

ASSUMPTIONS AND UNCERTAINTIES

DOE's Grand Junction Office plans to evaluate the monitoring program and may decrease the sampling frequency and the number of sampling locations. However, for the purpose of this report, groundwater monitoring is assumed to continue indefinitely. Because the site is already performing long-term stewardship activities, these activities are well known and are not expected to change dramatically. Site surveillance and maintenance will be required past 2070. 3.0
ESTIMATED LONG-TERM STEWARDSHIP COSTS

The following table shows the estimated costs of long-term stewardship activities for the Hallam Nuclear Power Facility. Because the site is already conducting long-term stewardship activities, costs are based on actual costs. The costs below include repairs to the roof and walls of the concrete structure in fiscal year (FY) 2001. These cost estimates reflect the current site agreements and monitoring frequencies. Thus, if the frequency and the number of sampling locations decrease, the costs will decrease.

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National Defense Authorization Act (NOAA) Long-Term Stewardship Report

Site Long-Term Stewardship Costs (Constant Year 2000 Dollars) Year(s)
FY 2000 FY2001 FY2002 FY 2003 FY 2004 FY 2005 FY2006 FY 2007

Amo.unt
$44,000 $125,700 $30,700 $29,600 $30,000 $30,300 $30,700 $30,500

Year(s)
FY 2008 FY2009 FY 2010 FY 2011-2015 FY 2016-2020 FY 2021-2025 FY 2026-2030 FY 2031-2035

Amount
$30,500 $30,500 $30,500 $146,100 $187,700 $149,700 $158,400 $160,000

Year(s)
FY 2036-2040 FY 2041-2045 FY 2046-2050 FY 2051-2055 FY 2056-2060 FY 2061-2065 FY 2066-2070

Amount
$208,100 $160,000 $160,100 $160,000 $208,100 $160,000 $160,100

4.0

FUTURE USES

The site is within an electrical generating power station owned by Nebraska Public Power District, which maintains security for the site. The facility will remain under controlled access due to contaminated materials. No drilling or other intrusive activities are allowed on the property. For any future inquiries, county land title records have been annotated regarding the presence of the decommissioned facility.

For more information about the Hallam Nuclear Power Facility, contact:
Art Kleinrath, Long-Term Surveillance and Maintenance Program Manager U.S. Department of Energy, Grand Junction Office 2597 B3/4 Road, Grand Junction, CO 81503 Phone: 970-248-6037 or visit the Internet website at http://www.doegjpo.com

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