ML25196A439
| ML25196A439 | |
| Person / Time | |
|---|---|
| Issue date: | 11/18/1976 |
| From: | Moeller D Advisory Committee on Reactor Safeguards |
| To: | Rowden M NRC/Chairman |
| References | |
| Download: ML25196A439 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 November 18, 1976 Honorable Marcus A.. Rowden Chairman U. s. Nuclear Regulatory Conmission Washington, OC 20555 SUBJECl':
REJ?ORr 00 PROPOSED QOALIFICATIOO CRITERIA '10 CERTIFY PACKAGES FOR AIR TRANSPORl' OF P~IUM
Dear Mr. Rowden:
At its 199th meeting, November 11-13, 1976, the Advisory Comnittee on Reactor Safeguards (ACRS) completed its review of the qualification cri-teria proposed by the Nuclear Regulatory Conmission (NRC) Staff for the certification of packages for air transport of plutonium. This matter was considered by a working Group of the ACRS at meetings in Washington, D. c.,.
on October 23, 1975, and February 12, 1976, and in Chicago, Illinois, on August 28, 1975, April 20, 1976, and November 5, 1976. During this review the working Group and the ACRS had the benefit of discussions with repre-sentatives of the NRC Staff, the Energy Research and Developnent Admin-istration, and their consultants and contractors. The Comnittee also had the benefit of the documents listed.
'lbese criteria were developed in response to the requirements of Public Law 94-79 which requires, in part, that the NRC not license shipnents by air of plutonium in any form until it "has certified to the Joint Conmittee on Atomic Energy of the Congress that a safe container has been developed and tested which will not rupture under crash and blast-testing equivalent to the crash and explosion of a high-flying aircraft.*
'lbe proposed criteria require that a package for the shipnent of plutonium by air meet certain rigorous qualification criteria in addition to those now required by 10 CFR 71. These additional criteria define a set of conditions representing those to which a shipping package would be subjected during and following various kinds of aircraft crashes; they require tests and, in sane cases, analytical assessments, to deoonstrate that the package can undergo these oonditions without rupture and without developing leakage that could lead to more than a negligible release of plutonimn to the enviromnent.
3606
Honorable Marcus November 18, 1976 The criteria require a sequential series of tests involving impact, crushing, puncture, exposure to fire, and subsequent inmersion in water, after which leak tightness must be demonstrated. In addition, individual nonsequential tests are required to simulate the conditions of impact following free-fall of the package from a high;,..flying aircraft and of subnersion in a deep body of water.
The approach, followed by the NRC Staff in defining the crash environment and the required tests, has been to select deterministic upper bound values corresponding to a maximlDD credible accident. The one exception to this is the requirement of the impact test, which involves impact at a velocity of 422 ft/sec at a right angle onto a flat, essentially unyielding surface.
The NRC Staff believes that this test is an upper bound for all crashes likely to occur during aircraft landing or take-off or in the vicinity of an airport. Although it cannot be established with certainty that impacts.
at higher velocities cannot occur, the requirements of impact at a right angle and onto an essentially unyielding surface represent extreme condi-tions that are very unlikely to occur and thus provide a degree of conserv-atism that is expected to oompensate for possible higher impact velocities.
Further conservatism is provided by the requirement of a sequence of five tests, each representing the -worst condition to be expected.
The NRC Staff has considered other possible threats to a shipping package, including the possibility of its being struck by high-velocity fragments from a failed jet engine. The NRC Staff has eliminated this threat from consideration on probabilistic grounds. The Conmittee believes that the combination of low probability and the inherent resistance of a package designed to these criteria to excessive damage frau a jet-engine fragment, leads to an acceptably safe situation.
The Conmittee notes the imposition of operational controls, to assure stowage of plutonilDD shipping packages in the aft-most cargo carrying area of the aircraft, as a means of reducing the hazard from longitudi-nal crushing by other cargo. The Conmittee agrees that this is a suitable solution to this particular problem but believes that requirements for tie-down of the packages to resist movement under normal conditions and under accident conditions less severe than those considered in the pro-posed criteria are desirable.
The acceptance standards for survivability require oot only that the containment vessel not be ruptured following the various sequential and individual tests but also that it must still provide a sufficient degree of contaimnent to restrict leakage to a very small amount, in accordance with the International Atomic Energy Agency Regulations for the Safe Trans-port of Radioactive Materials.
3607
Honorable Marcus November 18 *. 1976
'lbe Ccmmittee notes that the Sandia Laboratories, acting as contractor to the NBC, have designed, fabricated, and tested a package that meets all of the proposed criteria. It should be noted, however, that although the proposed test and acceptance criteria are of such a nature that they are applicable to packages containing plutonium in any form, the Sandia Laboratories' package has been tested and its acceptability has been demn-strated only for the shipnent of plutoni\\DD oxide. If plutonium is to be shipped in other forms, further demnstration of the acceptability of this design will have to be made.
ibe Ccmnittee believes that the qualification criteria proposed by the me Staff are properly responsive to the requirements of Public Law 94-79, and that there is reasonable assurance that a package meeting these criteria, properly assembled and suitably stowed in the aft-most portion of an aircraft, will be capable of maintaining its integrity in the event of a crash without leakage of plutonium to the environment in amounts that would represent an undue hazard to the health and safety of the public.
References:
Sincerely :yours, Dade w. Moeller Qiairman
- 1. Nuclear Regulatory Ccmmission Staff working Paper on Proposed Qualification Criteria for Plutonimn Package Certification, dated September 27, 1976
- 2. Letter, A. Snyder, Sandia Laboratories, to IC. Qiapnan, Nuclear Regulatory Conmission, concerning Plutonium Package Certifi-cation Program, dated September 10, 1976
- 3. IDckbeed-Georgia Company Report on Determination of Crash Impact Conditions Pertaining to Multi-Engine Transport Aircraft, dated November 1970 3608