United States Nuclear Regulatory Commission - Protecting People and the Environment

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. 





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                                                            IN 90-27 
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                                                            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 
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                                                            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. 

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                                                            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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