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Interpretation Response #18-0014

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

Interpretation Response Details

Response Publish Date:

Company Name: Nuclear Energy Institute

Individual Name: Janet Schlueter

Location State: DC Country: US

View the Interpretation Document

Response text:

August 21, 2018

Janet Schlueter
Senior Director
Nuclear Energy Institute
1201 F Street NW, Suite 1100
Washington, DC  20004

Reference No. 18-0014

Dear Ms. Schlueter:

This letter is in response to your January 18, 2018, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to non-radioactive solid objects with surface radioactive contamination.  Specifically, you ask about amendments made in the HM-250 Final Rule (79 FR 40590; July 11, 2014).

We have paraphrased and answered your questions as follows:

Q1. You ask if the threshold for low toxicity alpha emitters—0.4 Bq/cm2—applies for uranium-234 (U-234) when determining levels of contamination.

A1. The answer is no.  The definition of low toxicity alpha emitters includes natural uranium, depleted uranium, uranium-235, and uranium-238.  It specifically excludes enriched uranium, including uranium-234.  Therefore, the more stringent contamination limit for other alpha emitters would apply, 0.04 Bq/cm2.

Q2.  You note that the HM-250 Final Rule added § 173.401(b)(5) to except non radioactive solid objects with low levels of surface contamination from the HMR requirements for radioactive substances.  You ask whether this amendment invalidates a letter of interpretation previously issued by this Office under Reference No. 06-0274.

A2. The answer is no.  The addition of § 173.401(b)(5) excludes certain materials from the requirements of 49 CFR 173 Subpart I, in addition to the exemptions found in § 173.436.  PHMSA addressed Reference No. 06-0274 in the HM-250 Final Rule, stating that § 173.401(b)(5) was added to clarify that non-radioactive solid objects with radioactive substances present on any surfaces in quantities not exceeding the limits cited in the definition of contamination in § 173.403 are not subject to the Class 7 (radioactive) material requirements of the HMR. 

HM-250 also explains that radioactive contaminated items below the consignment exemption limits in § 173.436 are not regulated as radioactive materials.  Thus, while uranium-234 may not be excepted from the HMR based on § 173.401(b)(5), it is possible that it would not be regulated as a radioactive material based on exempted material activity concentrations in § 173.436.

I hope this information is helpful.  Please contact us if we can be of further assistance.



Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

173.401(b)(5), 173, 173.403, 173.436,

Regulation Sections

Section Subject
173.401 Scope
173.403 Definitions
173.436 Exempt material activity concentrations and exempt consignment activity limits for radionuclides