ML24149A366

Cimarron Environmental Response Trust U-235 Enrichment in Environmental Media at the Cimarron Site

ML24149A366
Person / Time
Site:	07000925
Issue date:	05/28/2024
From:	Lux J Environmental Properties Management
To:	James Smith Office of Nuclear Material Safety and Safeguards, Document Control Desk
References
Download: ML24149A366 (1)

Text

May 28, 2024

Mr. James Smith U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738

Ms. Rachel Miller Oklahoma Department of Environmental Quality 707 North Robinson Oklahoma City, OK 73101

Re: Docket No. 07000925; License No. SNM-928 Cimarron Environmental Response Trust U-235 Enrichment in Environmental Media at the Cimarron Site

Dear Recipients:

Solely as Trustee for the Cimarron Environmental Response Trust (CERT), Environmental Properties Management LLC (EPM) submits herein a response to a May 23, 2024, email from the U. S. Nuclear Regulatory Commission (NRC) regarding the enrichment of uranium in environmental media. Section 6.2 of Facility Decommissioning Plan - Rev 3 (the DP) states, Because environmental media do not contain uranium exceeding 5% enrichment, decontamination cannot produce material exceeding 5% enrichment.

The May 23 email asked, Is there one document from the NRC or the CERT that states or implies that environmental media do not contain uranium exceeding 5% enrichment or is it conclusion from an amalgam of Final Status Surveys?

Section 3.5.3 of the DP describes the extent of uranium in groundwater at the Cimarron site.

Figures 3-5 and 3-6 from the DP (in ML22285A091) present maps delineating enrichment values for uranium in groundwater in all monitor wells in the western area (WA) and in Burial Area #1 (BA1), respectively. These enrichment values are based on isotopic mass concentration analysis of groundwater samples collected from 173 WA and BA1 monitor wells in 2017. Section 3.5.3 of the DP states that samples were collected from 197 monitor wells, but the data from those wells that were outside of any remediation area were not evaluated for enrichment. The analytical data upon which these maps are based is tabulated on Figures 3-5 and 3-6.

Enrichment values were calculated by dividing the U-235 concentration by the sum of the U-235 and U-238 concentrations (multiplying by 100 to obtain percent values). Groundwater samples were not analyzed for U-234, because 1) this would require analysis by another method, increasing the cost of analysis, and 2) the concentration of U-234 in low-enriched uranium is much less than 1% of the total mass - including the concentration of U-234 in the equation would have a negligible effect on the calculated enrichment value.

9400 Ward Parkway

• Kansas City, MO 64114 Tel: 405-642-5152

• jlux@envpm.com

In BA1, groundwater samples were collected from 68 monitor wells for analysis. Enrichment values do not vary greatly because there was only source of uranium to impact the groundwater -

the solid waste buried in the four trenches in BA1. The average enrichment for uranium in all monitor wells in BA1 is approximately 1.3%, and the highest enrichment value obtained was 2.3%, in groundwater collected from Monitor Well 02W47. Consequently, it is reasonable to assert that the enrichment of uranium in groundwater in BA1 does not exceed 5%.

In the WA, groundwater samples were collected from 105 monitor wells for analysis.

Enrichment values are variable, because there were multiple sources of uranium - liquid waste from the original impoundments (the source of the linear plume extending north in the Western Alluvial Area, a.k.a. the WAA), Uranium Ponds #1 and #2 (sources of contamination in Sandstones A and B as well as the WAA), and solid waste with still different waste characteristics in Burial Area #3. Enrichment values vary based on the source of groundwater impact. The average enrichment for all monitor wells is approximately 1.5%. The highest enrichment values are observed in the linear plume generated by a leaking pipeline carrying wastewater from the original sanitary lagoons. Even in this area, the highest enrichment obtained was 4.4%, in groundwater collected from Monitor Well T-75. Groundwater samples collected from only two monitor wells in the WA yielded an enrichment of 4% or greater. Consequently, it is safe to assert that the enrichment of uranium in groundwater in the WAA does not exceed 5%.

Section 6.2 asserts that the enrichment of uranium in environmental media (both soil and groundwater) does not exceed 5%. Whether licensed material in groundwater is adsorbed by soil, or whether licensed material desorbs from soil into groundwater, the chemical reaction does not vary by isotope. Consequently, U-234, U-235, and U-238 will sorb or desorb in the same isotopic proportions as are in the source.

In addition, because licensed material from multiple locations will be blended together in both the BA1 and the WA influent streams, the enrichment of the influent will be much closer to the average enrichment in the area than to the enrichment in any single location. EPM asserts that the licensed material that accumulates in ion exchange resin during groundwater treatment will be well below 5% in both waste streams.

License Condition 8 imposes a possession limit of 100 grams of contained U-235 if the enrichment exceeds 5.0 weight percent U-235. It refers to a note that states, If during the decontamination of the facilities and equipment at the Cimarron Plant, uranium solutions or compounds are generated that have a U-235 isotopic content greater than 5.0 wt. percent, prompt action shall be taken to degrade these materials to below 5.0 wt. percent U-235.

Section 6.2 requests the deletion of this possession limit (and the associated note) as unnecessary.

Page 2 of 3 EPM believes that Section 3.5.3 satisfactorily addresses the concern that licensed material exceeding 5% enrichment may be encountered during the extraction and treatment of groundwater at the Cimarron site.

If you have any questions or desire clarification, please contact me at (405) 642-5152 or at jlux@envpm.com.

Sincerely,

Jeff Lux Project Manager

cc: (electronic copies only)

Stephanie Anderson and Linda Gersey, NRC Region IV Paul Davis, Keisha Cornelius, Christopher Robinson, David Cates, and Jonathan Reid, DEQ NRC Public Document Room vcpsubmittals@deq.ok.gov

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