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Interpretation Response #11-0126 ([Sandia National Laboratories] [Mr. Michael W. Enghauser])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Sandia National Laboratories

Individual Name: Mr. Michael W. Enghauser

Location State: NM Country: US

View the Interpretation Document

Response text:

October 19, 2011

 

 

Mr. Michael W. Enghauser

Sandia National Laboratories

P.O. Box 5800 MS 1151

Albuquerque, NM 87185

Ref. No. 11-0126

Dear Mr. Enghauser:

This responds to your May 19, 2011 request for clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to characterization of material containing depleted uranium. In your letter, you provide the activity concentration and consignment activity values for each radionuclide contained in the mixture. You provide two methods for determining whether the material in question meets the definition of a Class 7 (Radioactive) material under the HMR. The two methods of characterization, your questions, and PHMSA"s response are summarized as follows:

Method 1: The actual activity concentration and consignment activity of the material using the parent radionuclides (U-238, U-235, U-234; see Table 2 of incoming letter) were compared to the activity concentration for exempt material and the activity limit for exempt consignment values in § 173.436. The result of the calculation showed that both the activity concentration and the consignment activity of the material in question are below the exempt thresholds specified in § 173.436.

Method 2: The actual activity concentration and consignment activity of the material using the value for depleted uranium (see Table 3 of incoming letter) were compared to the activity concentration for exempt material and the activity limit for exempt consignment values in § 173.436. The result of the calculation showed that the material in question exceeds the thresholds specified in § 173.436 for depleted uranium.

Q1: Should the material in question be regulated as a Class 7 material based on the calculation methods summarized above and outlined in the incoming letter?

A1: The shipper may ship the material in accordance with the result of either characterization method under the HMR. Method 2 is the more conservative method and results in the material meeting the definition of a Class 7 material. Method 1 is a more detailed calculation that results in the material being exempt from Class 7 regulations.



Q2: Is it correct to sum the parent isotopic uranium values as shown in Table 3 of the incoming letter for comparison to the depleted uranium limits specified in § 173.436?

A2: Yes.

I hope this answers your inquiry. If you need additional assistance, please contact this office at (202) 366-8553.

Sincerely,

Ben Supko

Acting Chief, Standards Development

Standards and Rulemaking Division

173.436

Regulation Sections

Section Subject
173.436 Exempt material activity concentrations and exempt consignment activity limits for radionuclides