Information Notice No. 97-57: Leak Testing of Packaging Used in the Transport of Radioactive Material
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555-0001
July 30, 1997
NRC INFORMATION NOTICE 97-57: LEAK TESTING OF PACKAGING USED IN THE
TRANSPORT OF RADIOACTIVE MATERIAL
Addressees
Suppliers and users of packaging for the transportation of radioactive
material required to perform packaging leak tests.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to observed shortcomings in leak testing of
packaging used in the transport of radioactive material. It is expected that
recipients will review the information for applicability to their operations
and consider actions, as appropriate, to avoid similar problems. However,
suggestions contained in this information notice are not NRC requirements;
therefore, no specific action or written response is required.
Description of Circumstances
As part of the fabrication, operation, and maintenance of transportation
packaging, leak testing may be used to verify the integrity of a packaging�s
containment. NRC, through its transportation inspection program, has noted
shortcomings in the performance of packaging leak tests. Specifically, NRC
has found that purging, used to remove packaging cavity air and establish a
known representative tracer mixture at the containment boundary being tested,
has been performed inadequately and that gas used in tests has not been
controlled to ensure its quality (e.g., tracer gas concentration). These
findings introduce uncertainties that could lead to the acceptance of
erroneous test results.
Discussion
To obtain accurate leak test data, measures must be taken to ensure that a
known representative tracer mixture reaches the containment boundary being
tested. However, NRC has found that leak tests have been performed without
using the appropriate level of control. American National Standard Institute
(ANSI) N14.5-1987, "Leakage Tests on Packages for Shipment of Radioactive
Materials," Appendix A, Section A2.2, states: "Tracer materials are to be
clean and free of contaminants that might affect test results. Care must be
taken to ensure that a known representative tracer mixture reaches the
boundary being tested." It should be noted that NRC finds ANSI N14.5
generally acceptable, as described in NRC Regulatory Guide 7.4, "Leakage Tests
on Packages for Shipment of Radioactive Materials."
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NRC inspections have identified two factors that may not allow a known
representative tracer mixture to exist at the boundary being tested; (1)
incomplete purging of the packaging cavity, and (2) lack of objective evidence
documenting critical characteristics of gas used in testing (e.g., tracer gas
concentration). Each factor is described in further detail below.
(1) Packaging design and configuration during testing have been identified
as contributing factors to incomplete packaging purging. NRC has
observed purging operations and identified the following inappropriate
coincident conditions: (a) adjacent vent and drain ports located at
same end of the packaging, (b) small packaging diameter-to-length ratio,
(c) absence of an internal purge path, and (d) port orientation incom-
patible with tracer gas characteristics (i.e., specific gravity). It
was not evident to NRC that the purge operations observed during leak
tests would produce a known concentration of tracer gas or a uniform gas
mixture throughout the packaging cavity. Evaluation of the effects of
packaging design and configuration on purge operations can be used to
improve purge results. Other methods of establishing a known repre-
sentative tracer mixture, such as evacuation and fill, have been found
to be effective.
(2) In order to ensure that a known representative tracer mixture exists at
the boundary being tested, objective evidence about critical
characteristics of the tracer gas must be known before the gas is
introduced into the packaging cavity for testing. The required level of
objective evidence depends on a material�s safety-related application.
In the case of leak testing, tracer gas is used to verify the integrity
of a packaging's containment, which is typically classified as "critical
to safe operations." NUREG/ CR-6407, "Classification of Transportation
Packaging and Dry Spent Fuel Storage System Components According to
Importance to Safety," provides guidance on component classification and
required quality assurance records. NUREG/CR-6407 also addresses
quality assurance records for the dedication of safety-related
commercial-grade items, such as a tracer gas.
Further guidance on procurement of commercial-grade items for safety-
related applications can be found in NRC Generic Letter 89-02, "Actions
to Improve the Detection of Counterfeit and Fraudulently Marked
Products." This generic letter conditionally endorses the guidelines
contained in Electric Power Research Institute Group NP-5652, "Guidance
for the Utilization of Commercial-Grade Items in Nuclear Safety-Related
Applications (NCIG-07)." The guidance provides examples of commercial-
grade items (e.g., fuel oil, lubricating grease/oil, materials, etc.)
and potential critical characteristics in terms of product
identification (e.g., color coding, industry standard markings, part
number/unique identifier, etc.) and physical characteristics (e.g.,
concentration, purity, etc.). The guidance further provides four
acceptance methods: (a) special tests and inspections, (b) commercial
grade survey of supplier, (c) source verification, and (d) acceptable
supplier/item performance record.
It should be noted that industry practice such as in American Society
for Testing and Materials, Designation E 1212-92, "Standard Practice for
Quality Control Systems for Nondestructive Testing Agencies," requires
that the quality control system include . IN 97-57
July 30, 1997
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procedures to assure effective supplier quality for all purchased
materials and that requirements for quality shall be established in the
purchase agreement. It further requires that quality records include
product identification to allow traceability of what was tested and
what materials and equipment were used.
This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
one of the technical contacts listed below.
William F. Kane, Director
Spent Fuel Project Office
Office of Nuclear Material
Safety and Safeguards
Technical contacts: James E. Spets, NMSS
301-415-8553
E-mail: jes2@nrc.gov
Alternate:
Nancy L. Osgood, NMSS
301-415-8513
E-mail: nlo@nrc.gov
Attachments:
1. Referenced Codes and Standards
2. List of Recently Issued NMSS Information Notices
3. List of Recently Issued NRC Information Notices. Attachment 1
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REFERENCES
1. American National Standard Institute N14.5-1987, "Leakage Tests on
Packages for Shipment of Radioactive Materials."
2. American Society for Testing and Materials, Designation E 1212-92,
"Standard Practice for Quality Control Systems for Nondestructive
Testing Agencies."
3. Electric Power Research Institute Group NP-5652, "Guidance for the
Utilization of Commercial-Grade Items in Nuclear Safety-Related
Applications (NCIG-07)."
4. NUREG/CR-6407, "Classification of Transportation Packaging and Dry Spent
Fuel Storage System Components According to Importance to Safety."
5. Regulatory Guide 7.4, "Leakage Tests on Packages for Shipment of
Radioactive Material."
6. U.S. Code of Federal Regulations, 10 CFR Part 71, "Packaging and
Transportation of Radioactive Material."
7. U.S. Nuclear Regulatory Commission, Generic Letter 89-02, "Actions to
Improve the Detection of Counterfeit and Fraudulently Marked Products."
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