Sandia National Laboratories — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave.. S.E, Washington, DC 20590 OCT 1 9 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 ofa Class 7 (Radioactive) material under the HMR. The two methods ofcharacterization, 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 ofincoming 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 ofthe 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? AI: 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.#

Page 2Q2: Is it correct to sum the parent isotopic uranium values as shown in Table 3 ofthe 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. S(£'s;;:~ Ben Supko Acting Chief, Standards Development Standards and Rulemaking Division#

Page 3[&1 Sandia National Laboratories Operated for the U.S. Department of Energy by Sandia Corporation Michael W. Enghauser P.O. Box 5800 Principal Member of Technical Staff Albuquerque, NM 87185-1151 Radioactive and Mixed Waste Management Phone: (505) 284·6116 Fax: (505) 284-6166 Internet: mwengha@sandia.gov S I C.J1 tvt fa u.b ~ 173·fD3 May 19,2011 ~ I I 3. i..../:3~ -gAM U.S. DOT 11- 0 Ihlp PHMSA Office of Hazardous Materials Standards Attn: PHH-lO East Building 1200 New Jersey Avenue, SE. Washington, DC 20590--0001 SUbject: Activity Concentration Limit for Exempt Material (ACEM) and Activity Limit for Exempt Consignment (ALEC) Fraction Determinations for Depleted Uranium Dear Sir or Madam, For material containing depleted uranium (DU), meeting the 49 CFR 173.403 definition of DU, with the activity concentrations and activities in consignment presented in Table 1, is it necessary to regulate the material as radioactive material? Please review Table 2 and Table 3 which provide different determinations. In addition, is it correct to sum the parent isotopic uranium values as shown in Table 3 for comparison to the DU limits presented in 49 CFR 173.436? concentrations and activities in consignment. Summation 7.634 7634 Exceptional Service in the National Interest#

Page 4May 19,2011 Page 2 of2 Subject: ACEM and ALEC Fraction Detenninations for Depleted Uranium U-238 10 10000 U-235 0.031 31 10 10000 0.003 0.003 U-234 0.423 423 10 10000 0.042 0.042 Summation 2.837 2837 0.284 0.284 U-234 ACEM and ALEC conservatively set to minimum values. Parent nuclides and their progeny included in secular equilibrium per 49 CFR 173.436 are listed below: U-238 Th-234, Pa·234m U-235 Th-231 Table 3. Method showin DU 2837 1000 2.84 2.84 Please feel free to contact me at (505) 284-6116 if you have any questions. Sincerely, ~w~ Michael W. Enghauser cc: MS-1l51 Jeff Jarry, 04139 MS-1149 Howard Seeley, 04139 MS-1151 Beth Hanson, 04139 MS-1122 Robert P Rivera, 10261 MS-1122 Shawn Colborg, 10261#