Information Notice No. 90-27: Clarification of the Recent Revisions to the Regulatory Requirements for Packaging of Uranium Hexafluoride (UF6) for Transportation
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR MATERIALS SAFETY AND SAFEGUARDS WASHINGTON, D.C. 20555 April 30, 1990 Information Notice No. 90-27: CLARIFICATION OF THE RECENT REVISIONS TO THE REGULATORY REQUIREMENTS FOR PACKAGING OF URANIUM HEXAFLUORIDE (UF6) FOR TRANSPORTATION Addressees: All Uranium Fuel Fabrication and Conversion Facilities. Purpose: This notice is being issued to review and clarify the significant features of two recent rulemaking actions which were completed by the U.S. Department of Transportation (DOT), relating to the regulatory requirements for the packaging of UF6 for transportation. It is suggested that recipients review the information here, and consider actions, if appropriate, to preclude possible problems in the transport of UF6. However, this information does not constitute new U.S. Nuclear Regulatory Commission (NRC) requirements, therefore no specific action or written response is required. Background: The routine transportation of UF6, both as a non-fissile radioactive material (depleted and natural uranium, a "low specific activity" [LSA] material) and as a fissile radioactive material (when containing "greater than" 1.0 weight percent U-235), constitutes a very significant volume of radioactive materials transportation in the nuclear fuel cycle, both within the USA and worldwide. UF6 is packaged for transport in cylinders which must meet certain inspection, testing and in-service requirements which are found in the 49 CFR DOT regulations and certain physical standards which are adopted by reference in those regulations. The primary type of packaging used are cylinders of steel, nickel, or monel in various diameters ranging from 1 inch to 48 inches. For shipments of the unenriched UF6 as an LSA, non-fissile radioactive material, the cylinders are normally shipped bare, without protective overpacks. Overpacks are used, however, for the shipment of enriched UF6, as a fissile material, when the U-235 content exceeds 1.0 weight percent. The overpacks used are either of the DOT Specifications 20PF or 21PF Series as prescribed in 49 CFR 178.120 and 178.121 of DOT regulations, or as authorized in several NRC Certificates of Compliance. (See Attachment 1.) Most shipments of UF6 are made in exclusive-use highway or rail vehicles, and in equivalent defined stowage areas or intermodal freight containers aboard seagoing vessels. 9004240313 . IN 90-27 April 30, 1990 Page 2 of 4 Before November 1986, the DOT regulations were not specific on the standards for the cylinders, but rather, referenced the need to use a "strong tight package" for exclusive-use shipments. For non-exclusive-use shipments, the cylinders were required to meet the requirements for DOT Specification 7A, Type A packaging. [The cylinders actually used, however, were in accordance with industry standards that exist in ANSI N14.1 and/or a Department of Energy (DOE) document, ORO-651]. On November 17, 1986, DOT issued a new regulation (49 CFR 173.420) specifying cylinder standards and other requirements for all shipments of UF6. Several supplemental notices and amendments were subsequently issued in the Docket HM-166V, with the last revision of the final rule having been issued on August 29, 1989. As for the protective overpacks for the cylinders, DOT originally issued its regulatory specifications for the DOT Specifications 20PF and 21PF series in 1974. Over the years, during the use of these overpacks, increasing difficulties have been experienced in their use, maintenance and quality control. The primary difficulty has been with the tendency of the packagings to collect and retain water within the phenolic foam insulating medium within the walls of the overpack. Although the presence of this water is not an immediate safety problem, the water does increase the gross weight of the packages significantly, and also accelerates corrosion of the metal and rotting of the wood components of the overpacks. It often tends to "slosh" out from the drain holes, and sometimes creates considerable alarm to the public and to carriers, when water (albeit non-radioactive water) is observed to be leaking from a package marked "RADIOACTIVE" in commerce. Accordingly, DOE petitioned DOT for rulemaking to amend the DOT 21PF series protective overpack specification, so as to authorize the use of an improved design that would correct the deficiencies. A notice of proposed rulemaking was issued in August 1984, with the final rule issued on September 20, 1988 (Docket HM-190). During the interim period, between the notice and final rule, several NRC-licensee shippers of UF6 in protective overpacks applied for and received NRC certificates of compliance authorizing use of non-DOT specification, improved overpacks. Discussion: Attachments 2 and 3 are chronological summaries of the two recently completed DOT rulemaking dockets relating to UF6 packaging and transportation. Attachment 2 summarizes the Docket HM-166V on cylinder requirements, and Attachment 3 summarizes the Docket HM-190 rule changes on the DOT Specification 21PF series of protective overpacks. Attachment 1 is a summary of the present status of several NRC certificates of compliance for overpacks that are similar to the DOT Specification 21PF overpacks. Discussion of each of these areas follows: CYLINDERS The net effect of the cylinder rulemaking imposed by the new 49 CFR 173.420 in Docket HM-166V has been to formalize, as regulatory requirements, the use of cylinders which have already been in use for many years, pursuant to certain industry standards, as well as other requirements (e.g., requirements for UF6 . IN 90-27 April 30, 1990 Page 3 of 4 to be in solid form and specified volumetric fill limits). In carrying out the rulemaking, however, several difficulties were observed (e.g., the method of cleaning for other than new cylinders, provisions for use of existing cylinders, etc.), as evidenced by the series of eight notices and amendments between April 1986 and April 1989. It is noted that the final rule also formalizes the use of the DOT Class 106A multiunit tank car tank (which is actually referred to in the industry as the Model 30A cylinder). However, both of the published industry standards -- ANSI N14.1-1987 and ORO-651, Rev. 5 -- have taken the position that the Model 30A cylinder is obsolete, and will be replaced by the Model 30B. In effect, therefore, DOE has stated that it will no longer fill Model 30A cylinders at its gaseous diffusion facilities after December 31, 1992. For any existing cylinder constructed before the new rules, continued use is authorized, provided that it was designed, inspected, tested, and marked in accordance with the 1987, 1982 or 1971 version of ANSI N14.1, in effect at the time of construction; or for cylinders manufactured before June 30, 1987, Section III, Div. I of the ASME Code. PROTECTIVE OVERPACKS The net result of the rulemaking in Docket HM-190 has been to upgrade the regulatory requirements for the fabrication, maintenance, and use of the DOT Specification 21PF-1 protective overpacks. The key dates for compliance with these new rules are: April 1, 1989--Construction of all new overpacks must be in accordance with DOT Specification 21PF-1B after this date, and these overpacks marked as such; and April 1, 1991--Refurbishment and conversion of all existing overpacks to the requirements of DOT Specification 21PF-1A must be accomplished and these overpacks marked as such. During the period between April 1, 1989 and April 1, 1991, therefore, the use of unmodified DOT Specification 21PF-1 overpacks continues to be authorized. However, both the owners of unmodified overpacks and the U.S. enrichment plants which fill the cylinders for subsequent loading into the overpacks are taking steps to perform quality control inspections of the overpacks to correct deficiencies, such as containing excessive water. (See Attachment 4). If such inspections reveal excessive water, measures are being taken to remove the overpack from service for drying, resealing, gasket replacement, or other necessary refurbishment, or if necessary, for disposal. The U.S. enrichment plants are also requesting the owners of unmodified overpacks to supply them with acceptance certifications stating that the quality control inspections and other maintenance procedures have been accomplished. . IN 90-27 April 30, 1990 Page 4 of 4 NRC CERTIFICATES OF COMPLIANCE During the period of the Docket HM-190 rulemaking, several U.S. owners of protective overpacks for 30" cylinders obtained certificates of compliance from the NRC to authorize the use of overpacks of improved design. These are summarized in Attachment 1. A comparison of the specifics of the DOT Specification 21PF-1A and 1B requirements with these certificates indicates that there will still remain a need for the certificates, in that there are substantial differences between, for example, the Model UX-30 (USA/9234/AF) and the NCI-21-PF-1 (USA/9196/AF) and the DOT specifications. Robert F. Burnett, Director Division of Safeguards and Transportation Office of Nuclear Materials Safety and Safeguards Technical Contact: A. W. Grella, NMSS (301) 492-3381 Attachments: 1. NRC Certificates of Compliance for UF6 Overpacks 2. Chronology of UF6 Cylinder Rulemaking (HM-166V) 3. Chronology of UF6 Overpack Rulemaking (HM-190) 4. "Interim Inspection and Sealing Procedures for DOT-21PF-1 Overpacks" 5. List of Recently Issued NMSS Information Notices 6. List of Recently Issued NRC Information Notices .ENDEND
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Page Last Reviewed/Updated Tuesday, March 09, 2021