Interpretation Response #06-0100 ([Department of Energy] [Mr. James M. Shuler])

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

Interpretation Response Details

Response Publish Date: 10/13/2006

Company Name: Department of Energy

Individual Name: Mr. James M. Shuler

Location State: DC Country: US

View the Interpretation Document

Response text:

Oct 13, 2006

Mr. James M. Shuler                 Reference No. 06-0100
Department of Energy
Washington, D.C. 20585

Dear Mr. Shuler:

This is in response to your April 20, 2006 letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to radioactive materials. Specifically, you request clarification of the exception in § 173.453(f) for fissile material. You request additional clarification of a response we provided to Dennis Ashworth in a letter of interpretation issued on January 17, 2006 (Ref. No. 05-0254) regarding this topic. Your questions are summarized and answered as follows:

Q1. How is a shipment of plutonium defined?

Al. For the purposes of the exception in § 173.453(f), a “shipment of plutonium” is the shipment of a material where plutonium is the primary radionuclide present, with only trace amounts of other radionuclides.

Q2. How much plutonium must be present for the exception to apply?

A2. The exception in § 173.453(f) applies to packages containing, individually, a total plutonium mass of not more than 1000 grams. The exception does not specify a minimum amount of plutonium; however, only trace amounts of other radionuclides may be present to qualify for the exception.

Q3. How much plutonium must be fissile plutonium for the exception?

A3. None of the plutonium “must” be fissile, but not more than 20 percent by mass may consist of plutonium-239, plutonium-241, or any combination of these.

Q4. The January 17, 2006 letter of interpretation issued to Dennis Ashworth stated that the exception in § 173.453(f) is not intended to apply to shipments of large quantities of uranium with some plutonium present. How much uranium is considered to be “large quantities”?

A4.      As you noted in your letter, it is not possible to have fissile plutonium without some fissile uranium present. The scenario you presented of 1E-06 grams of plutonium-238 and 100 kg of uranium-235 as package contents is not the type of shipment that is intended to be covered by the exception. To satisfy the exception in § 173.453(f) only
trace amounts of uranium may be present; we interpret a trace amount of uranium to be less than or equal to 1% of the mass of the fissile plutonium present in the package.
Q5.How much fissile uranium may be included in a shipment to qualify for the exception?

A5.An acceptable level of uranium is less than or equal to 1% of the mass of the fCould 850 g of plutonium-238 and 100 g of uranium-235 in a single package qualify for the exception?

A6. The answer is no. The exception is intended to apply to those shipments of plutonium that contain only trace quantities of uranium. See A4 and A5.

Note that our January 17 letter referenced a proposal before the International Atomic Energy Agency to expand the scope of the exception to permit 20% of fissile nuclides by mass; however, the current exception in § 173.453(f) applies specifically to plutonium.

I hope this information is helpful. If you have further questions, please do not hesitate to contact this office.

Sincerely,

John A. Gale
Chief, Standards Development
Office of Hazardous Materials Standards

173.453

Regulation Sections