ML23221A397
| ML23221A397 | |
| Person / Time | |
|---|---|
| Site: | WM-00072 |
| Issue date: | 08/15/2023 |
| From: | Mary Johnson NRC/RGN-IV/DRSS/DIOR |
| To: | NRC/RGN-IV/DRSS/DIOR |
| Johnson T | |
| References | |
| Download: ML23221A397 (10) | |
Text
August 15, 2023 MEMORANDUM TO:
Docket File WM-00072 THROUGH:
Gregory G. Warnick, Chief Decommissioning, ISFSI, and Operating Reactor Branch Division of Radiological Safety and Security FROM:
M. Troy Johnson, Health Physicist Decommissioning, ISFSI, and Operating Reactor Branch Division of Radiological Safety and Security
SUBJECT:
OBSERVATIONAL SITE VISIT AT SPOOK DISPOSAL SITE On July 25, 2023, the U.S. Nuclear Regulatory Commissions (NRC) Region IV Office conducted an observational site visit at the U.S. Department of Energys (DOE) Spook Site in Converse County, Wyoming. This site visit was conducted in accordance with Inspection Procedure 89060 Department of Energy Observational Site Visits. The purpose of the site visit was to observe DOEs routine, annual inspection of the Spook disposal site. Enclosed to this memorandum is the NRCs trip report for this site visit.
In summary, DOE conducted the annual inspection in accordance with the requirements specified in the NRC-accepted Long-Term Surveillance Plan dated January 1993 (ADAMS Accession No. ML15217A677). The disposal cell and surrounding area observed by the inspectors appeared to be in acceptable condition. No significant regulatory issues or safety concerns were identified during the site visit.
Docket: WM-00072 License: General License Pursuant to 10 CFR 40.27
Enclosure:
NRC Trip Report cc: Charlee A. Boger, Site Manager, DOE CONTACT: M. Troy Johnson, DRSS/DIOR (817) 200-1596 Anderson, Stephanie signing on behalf of Warnick, Gregory on 08/15/23
Enclosure U.S. NUCLEAR REGULATORY COMMISSION REGION IV Docket:
WM-00072 License:
General License Pursuant to 10 CFR 40.27 Report:
WM-00072/2023-001 Licensee:
U.S. Department of Energy Facility:
Spook Disposal Site Location:
Converse County, Wyoming Date:
July 25, 2023 Inspectors:
Approved by:
M. Troy Johnson Health Physicist Decommissioning, ISFSI, and Operating Reactor Branch Division of Radiological Safety and Security Michael M. LaFranzo Senior Health Physicist Decommissioning, ISFSI, and Operating Reactor Branch Division of Radiological Safety and Security Gregory G. Warnick, Chief Decommissioning, ISFSI, and Operating Reactor Branch Division of Radiological Safety and Security
Attachment:
Photographs Taken at the Spook Disposal Site
2 NRC Report
1 Background
The Spook Uranium Mill Tailings Disposal Site is classified as a Title I site under the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 and is located in Converse County, Wyoming. The site is 48 miles northeast of Casper, Wyoming, in portions of Sections 27 and 28, Township 38 North, Range 73 West, 6th Principal Meridian. The surface site comprises 13.5 acres and includes an additional subsurface 89 acres including the 5 acres of site disposal cell. The disposal cell contains 440,000 dry tons of residual radioactive materials. These materials consist of tailings and mill site debris. Total activity within the cell is 125 curies of radium-226.
The DOE maintains long-term custody of the site under the U.S. Nuclear Regulatory Commissions (NRC) general license requirements of 10 CFR 40.27. The Long-Term Surveillance Plan (LTSP) explains how DOE will fulfill the general license requirements specified in 10 CFR 40.27. The final LTSP for the Spook disposal site was issued in January 1993 (ML15217A677). Records indicate that the NRC subsequently accepted the LTSP by letter dated September 21, 1993 (ML20057C442).
The following is an excerpt from the NRC observational site visit on July 8, 2015 (ML15224B596) included for continuity:
The Wyoming Mining and Milling Company operated a uranium ore upgrade facility at the Spook site in Converse County, Wyoming, from 1962-1965. The concentrated slurry precipitate that was produced at the Spook site was shipped to the Western Nuclear Split Rock mill in Jeffrey City, Wyoming, for further processing. The operation of the upgrade facility produced tailings material and waste solutions. The tailings were stored on the ground or within an open pit mine. The solutions were disposed in the tailings or an acid pond situated adjacent to the upgrade facility.
Prior to remediation, the Spook site consisted of an open pit mine containing tailings, mine overburden material, several small ore piles, an acid pond, and miscellaneous waste debris. The U.S. Department of Energy (DOE) and the State of Wyoming signed a cooperative agreement in 1984 to remediate the site. Surface remediation began in the spring of 1989 and was completed in the fall of 1989. The DOE stabilized all contaminated wastes at the bottom of the open pit. The State of Wyoming backfilled the pit with mine overburden material, contoured the surface, and reseeded all disturbed areas. The NRC subsequently concurred with the completion of the remedial action by letter dated March 4, 1992 (ML15217A677).
The acid pond, located adjacent to the Spook upgrade facility, was also remediated. This work was conducted as a vicinity property cleanup project, although the waste material was disposed in the open mine pit with the rest of the mill wastes. The acid pond remediation efforts included excavating the pond to a depth of about 20 feet and backfilling the pond with uncontaminated material. Approximately 41,202 cubic yards of excavated pond material was placed in the mine pit. The NRC subsequently approved the remedial action completion report by letter dated April 4, 1991 (ML15218A425).
3 The Spook disposal cell is unique because it is located entirely underground in a former open-pit uranium mine. The disposal cell footprint occupies approximately 5 acres of the 13.5-acre site. The mine was approximately 1,600-feet long, 500-feet wide, and 100-feet deep. The contaminated material was encapsulated in the south-central section of the pit. The disposal cell contains approximately 440,000 tons (315,000 cubic yards) of contaminated waste material containing 125 curies of radium-226.
The base of the disposal cell consists of a 3-foot thick layer of low-permeability material.
The maximum height of the waste material in the cell is 54 feet. The underground cover placed over the wastes included a 1.5-foot thick radon barrier and a 10-foot thick high permeability material layer to minimize water infiltration into the cell. Depending on location, the depth of the mine overburden ranges from 49-65 feet over the disposal cell.
Disturbed surface areas were contoured and reseeded to protect the site from erosion.
2 Site Status Site features include eight boundary monuments, three survey monuments, two site markers, ten perimeter warning signs, one site entrance sign, and one well that is no longer active. The DOE staff observe the status of these site features during each annual inspection. The LTSP section 6.1 states inspections of the Spook site will be conducted annually for 5 years, beginning with the year of licensing. At the end of the 5 years, the DOE will evaluate the necessity for subsequent inspections and propose a future site inspection schedule. At the time of the inspection, the DOE site inspections continue to be made at an annual frequency.
NRC accepted the DOEs groundwater compliance strategy by letter dated October 9, 1997 (ML15218A429) as no remediation with the application of supplemental standards as allowed by 40 CFR 192.21(g) and 40 CFR 192.11(e). In accordance with this chosen compliance strategy, groundwater monitoring is not required at the Spook disposal site.
The DOE conducted the last site inspection on July 19, 2022. In this inspection, perimeter sign P5 showed signs of weathering and delamination and was replaced, the phone numbers on signs P6 and P7 were updated, the cap for quality control monument QC-3 was stamped as QC-1 and scheduled to be corrected, and new minor gully erosion was noted north of the disposal site and flagged for additional monitoring. No maintenance or need for follow up or contingency inspections were identified.
3 Site Observations and Findings Detailed instructions for implementing the annual inspection are provided in Section 6 of the LTSP. The DOE staff conducted the annual inspection on July 25, 2023. The purpose of the annual inspection was to confirm the integrity of the visible features of the site, to identify changes in conditions that may affect site integrity, and to determine the need for maintenance or additional inspection and monitoring.
The LTSP section 2.2 gives a detailed description of the site including detailed drawings of the unique (entirely underground) construction of the disposal cell. The DOE staff and contractors divide the site into three areas called transects for inspection purposes. The transects are the disposal cell (the area immediately on top of the cell) the site perimeter (area between the disposal cell and boundary of the site), and the outlying area (area within 0.25 mile of the site).
4 Each transect inside the site is visually inspected by walking a series of traverses across each transect so that the entire transect surface is inspected. Within each transect, inspectors examine specific site surveillance features, such as survey and boundary monuments, signs, site markers, previously identified items from former inspections, as well as other items (success of previous maintenance, erosion, settling, slumping, plant or animal encroachment, human intrusion or vandalism, and other activity or phenomenon that might affect the safety, integrity, long-term performance, or institutional control of the site).
The inspectors walked the site with DOE staff and contractor personnel. The inspectors with DOE staff and contractor personnel observed the replaced perimeter sign P5 and updated signs P6 and P7 identified from the previous inspection and noted that the quality control monument cap for QC-3 had been corrected.
During the last NRC observational site visit it was noted that no erosion or slumping was observed on or around the area of the underground cell. Vegetation appeared indistinguishable from the surrounding areas. Stable surface erosion (gullies) existed in an area northeast of the disposal site, but these features did not have an observable impact on the disposal site itself. The inspectors observed the environmental conditions to be effectively unchanged from the last NRC observational site visit even with the new erosion gully noted in the DOE annual inspection on July 19, 2022. Additionally, while there is no fence around the site, there was no evidence of grazing or animal disturbance at the time of the inspection.
The checklist still includes a requirement to review the status of a water supply well adjacent to the property and the well is still under permit by the state of Wyoming (permit number U.W. 617). The wellhead was capped with no pump or operating equipment indicating to the inspectors that it was no longer in use at the time of the inspection.
The NRC inspectors conducted a radiological survey using a Thermo Scientific RadEye PRD survey meter (serial number 31893, calibrated to cesium-137 with a calibration due date of March 31, 2024). With a background of about 7 microRoentgen per hour (R/hr),
as measured on the access road to the site, measurements within the property ranged from 5-12 R/hr. In summary, the ambient gamma radiation measurements across the site were indistinguishable from background levels, indicating that no residual radioactivity or naturally occurring radioactivity was identified at the site.
4 Conclusions The DOE staff conducted the site inspection in accordance with the site-specific checklist, LTSP, and 10 CFR 40.27 requirements. Maintenance items are being identified and corrected in accordance with the LTSP with a focus on safety, integrity, long-term performance, or institutional control of the site.
5 Meeting Summary The NRC inspectors participated in a pre-planning meeting with the DOE site manager and DOE contractors prior to the site inspection. During this meeting, the NRC, DOE, and contractors discussed topics such as site status, inspection plan, and potential
5 physical hazards. The inspectors discussed the final site observations with DOE staff and its contractor at the conclusion of the onsite visit.
6 Persons Contacted Charlee Boger, Site Manager Jordan Cario, Contractor Lead Inspector Trisha Santonastaso, Contractor Justin Hugo, Contractor Mickey Guziak, Contractor
Attachment Figure 1: Spook Disposal Site arial view Figure 2: Southern Site Marker
2 Figure 3: Perimeter sign Figure 4: Quality Control Survey Monument 1
3 Figure 5: Site erosion gully in the north