Updated: August 28, 1996
STATUS REPORT ON AIR SHIPMENTS OF PLUTONIUMby Sharon Tanzer
The Board of Governors of the International Atomic Energy Agency (IAEA) is expected to adopt revised guidelines for the transport of radioactive material when the Board meets in Vienna, September 9-13. For the first time, the guidelines (known as Safety Series 6) will specify separate criteria for containers to be used for transporting radioactive material by air. At present, the same criteria apply to road, rail, sea and air transport---and the IAEA has acknowledged the current regulations offer less protection in the event of an air accident than they do for surface transport.1 A new IAEA Advisory Commission on Safety Standards (ACSS) reviewed the revised guidelines before forwarding them in June to the Board of Governors with a recommendation that the guidelines be approved.
Are the new guidelines strict enough? Representatives of international aviation organizations have been critical of the new IAEA standards. According to an expert study, the international test requirements for crash- and fire-resistance for the "black-box" flight data and voice recorders are much stricter than the IAEA's new test criteria for a plutonium shipment cask.2 A related report also points out that the IAEA sequence of crash and fire tests "did not replicate what was likely to happen in an aircraft accident."3
Agnes Bishop, president of Canada's Atomic Energy Control Board and chair of the IAEA's safety advisory commission, acknowledged "strong opposing views of some member states" regarding the new air transport guidelines in her letter transmitting the Commission's recommendation of approval to Dr. Hans Blix, Director General of the IAEA.4 The U.S. Government and three international aviation organizations have urged adoption of the stricter U.S. standards on several occasions during the review process. The United States also has "made it clear that, consistent with United States law, any plutonium air transport to, or over, the United States will be subject to the more rigorous United States packaging standards."5 Dr. Assad Kotaite, the head of the International Civil Aviation Organization (ICAO), acknowledged in a letter to Nuclear Control Institute, "There are issues which ICAO and IAEA have identified as requiring further study."6
The International Civil Aviation Organization still must review the IAEA Safety Series 6 to decide whether they should be incorporated in ICAO's "Technical Instructions for the Safe Transport of Dangerous Goods by Air"---the ICAO standards that signatories to the International Convention on Civil Aviation ("Chicago Convention") agree to follow. The first step in this two-year process will be a meeting at the IAEA of a Working Group of ICAO's Dangerous Goods Panel that will begin October 28.
The IAEA also will hold a meeting in November in Vienna on unresolved safety issues relating to air and other modes of transporting radioactive material, following its anticipated approval of the new guidelines in September.
Despite a decade-long effort to develop criteria for a separate air-transport ("Type C") cask for radioactive material, no such highly crash resistant cask has been successfully developed. It is significant, therefore, that the new Safety Series 6 guidelines allow an exemption from use of a Type C cask for air transport of plutonium when it is put in the form of mixed-oxide (MOX) fuel, thus allowing plutonium to continue to be flown in existing Type B casks---tested to withstand a crash of only 13 meters per second (m/s) or 30 mph. Because most plutonium is to be flown in this form, there will be no improvement whatever in safety requirements.
The United States has separate standards for domestic air shipments and international transshipments of plutonium, both far more severe than the proposed IAEA standard. The domestic standard, known as NUREG-0360, was developed to satisfy the requirements of the 1975 Scheuer Amendment, which barred the Nuclear Regulatory Commission from licensing any air shipments of plutonium until the NRC certified a cask capable of surviving "the crash and explosion of a high-flying aircraft." The key test criteria for NUREG-0360 are an impact test of 129 m/s (288 m.p.h.) and a one-hour fire test at 800 C.
The U.S. standard for international shipments overflying U.S. territory was designed to satisfy the 1987 Murkowski Amendment, which requires a cask to survive a "maximum, credible accident." The reference accident is the crash of a Pacific Southwest Airlines flight on December 7, 1987 at an impact speed of 282 m/s (630 mph).
The IAEA relies on the structural integrity of the container in which radioactive material is shipped to prevent a radioactive release in the event of an accident. The new guidelines designate criteria for a "Type C" air-transport cask. The new cask is intended to prevent release of intensely toxic plutonium in severe air crashes that existing casks could not survive.
The IAEA criteria for certifying the Type C air-shipment cask differ from U.S. licensing requirements in two key respects---impact speed and fire resistance. The U.S. test requires a cask to be propelled onto a hard target at a speed of 129 meters/second, as compared with the proposed IAEA test of 90 meters/second. The U.S. test requires the same cask to undergo both impact and fire tests in sequence, the latter defined as 800 C for 1 hour. The IAEA test uses the same fire standard but allows separate casks to be used for the impact and fire tests because "high speed impact and long duration fires are not expected to be encountered simultaneously . . . "7
The facts suggest otherwise. In 1992, an El Al cargo plane crashed into an apartment complex shortly after take off from Schiphol airport, near Amsterdam. According to FAA investigators, the plane's indicated speed at impact was 150 m/s (335 mph).8 The crash site burned for many hours.
A technical report prepared for ICAO's Dangerous Goods Panel found the impact test required by the IAEA for the new air-transport container to be far less rigorous than the international requirement for the so-called "black box" flight recorders.9 The test for the flight-recorder package corresponds to an impact speed of 138 meters/second (virtually identical to the U.S. impact standard), compared with the IAEA test of 90 meters/second. A report by an ICAO experts' working group also found that "the sequence of tests as presently proposed for Type C packagings did not replicate what was likely to happen in an aircraft accident." The report called for sequential impact and fire tests on the same cask rather than the separate impact and fire tests on different casks allowed by the IAEA. It also called for a fire test 300 C hotter than the 800 C test called for by the IAEA.10
At a September 1995 meeting in Vienna, an IAEA technical group (TRANSSAC) approved a German proposal to permit avoidance of the new air-transport packaging standard altogether when plutonium is shipped as fabricated fuel rather than in bulk form. Over objections by the U.S. government and international civil aviation associations, the German delegation won agreement to exempt plutonium-uranium, "mixed-oxide" (MOX) fuel from the Type C cask requirement as "low dispersible material." However, a U.S.-sponsored provision was also adopted requiring that the shipping and receiving countries, and any transit countries for a Type C cask as well as Type B packages containing exempted material like MOX fuel, must first approve use of the shipping containers.
German experts contend MOX fuel is a "very low dispersible material" and essentially self- containing. In an air crash, they insist, existing Type B casks are likely to remain sufficiently intact to limit releases of plutonium to an acceptable level. These casks "would only fail substantially in very severe accident conditions," according to a German working paper, which adds, "Serious aircraft accidents are quite rare." The German government justifies the exemption for MOX by claiming that the MOX fuel pellets themselves can withstand fire conditions more severe than the IAEA's air transport thermal test because of the way the fuel rods containing the pellets are manufactured, so that oxidation of the pellets and significant release of the plutonium would not take place even if the shipping cask were ruptured in a plane crash.
The U.S. government, in a position paper prepared for the Vienna meeting last September, warned that the proposed exemption "negates the original intent for developing [separate] air transport standards." The U.S. paper expressed concern that the allowable plutonium release proposed by the Germans "is not based on any defined model or rationale and that no risk analysis has been conducted on this proposal."11
A technical analysis by Nuclear Control Institute finds a number of mechanisms that could result in significant dispersal of plutonium in the event of a severe accident. A high-velocity impact that breached the fuel cladding, followed by a fire of moderate temperature that burned for several hours, could cause substantial releases of plutonium from oxidized fuel pellets, according to the NCI report.12
Air shipments pose environmental and public-health risks because of the possibility of a release of highly toxic plutonium in the event of an accident. Plutonium, if inhaled, is a deadly carcinogen. Releases of plutonium from weapons destroyed in two military aircraft accidents in the 1960s required massive, hazardous and costly cleanups.
Nonetheless, Britain has continued to fly plutonium in the form of MOX fuel, even in the face of a general warning by the IAEA that "a release of radioactive substances cannot be excluded in the case of a severe aircraft crash involving current package designs."13 The U.K. regularly flies MOX fuel to Switzerland for Swiss nuclear power reactors, and it has received several shipments of fresh MOX fuel from Belgium that had been originally intended for use in German research reactors.14 Britain may soon be flying MOX fuel to Germany for use in German power reactors. Recent cancellation of the Siemens fuel-fabrication facility in Hanau, Germany and construction of a MOX fuel-fabrication facility in England, make air shipments of MOX fuel from Britain to Germany more likely. The British have expressed a preference to the Germans for air shipment.15 And Japanese utilities may initiate air shipments of mixed-oxide fuel from Europe once the IAEA legitimates them by approving a new transport standard.16
In 1992, 82 fresh fuel elements from Germany's abandoned Kalkar breeder reactor were flown from Belgium to Scotland for storage. More recently, additional Kalkar fuel was sent to Belgium and then flown to Scotland. Germany had intended to fly 123 remaining Kalkar fuel assemblies from Frankfurt airport to Scotland in 1993. Nuclear Control Institute publicized the risks of these shipments at a joint press conference in Wiesbaden in April 1993 with Joschka Fischer, environment minister of Hesse. The shipments did not take place.
Under U.S. law, the Nuclear Regulatory Commission must certify that a container will not rupture under crash and blast-testing equivalent to the crash and explosion of a high-flying aircraft."17 There is an obvious economic explanation for the lesser IAEA testing criteria: no commercial plutonium air-shipment cask has ever been successfully tested to meet the strict U.S. standard. The authors of the weaker IAEA standard, conceding it "would be relatively simple" to devise a performance test for a package "which would guarantee that no package would ever fail in an accident situation," maintain such a test "would exact a tremendous economic toll from world economies."18 They anticipate a Type C package will fail "gracefully" and that it "will limit releases to accepted levels until the accident environments are well beyond those provided in the performance standards and then only gradually allow increased release as accident environments greatly exceed the performance test levels. . . "19 [Emphasis added.]
The experts concede, however, "there are only very limited data available on packagings tested to failure to see how release increases with severity of the accident environment."20
Germany has been the strongest advocate of exempting fresh MOX fuel elements from the pending air-transport requirements, thus allowing MOX to be transported by air in Type B casks. Recently, Germany trucked fresh MOX fuel assemblies from a shut-down research reactor to Belgium, where they were then flown to Scotland for storage. In this way, it was possible to circumvent opposition from German state governments to plutonium air shipments.
The IAEA's revision process got underway in the late 1980s. At that time, a number of European nations were embroiled in a controversial plan to send plutonium reprocessed in France to Japan by air. Because the cargo planes would refuel in Alaska, the shipping containers had to be licensed by the U.S. Nuclear Regulatory Commission. The plan was quashed when the shippers failed to design a cask that could meet U.S. standards. Nuclear Control Institute disclosed that a prototype package developed jointly by Japan's Power Reactor and Nuclear Fuel Development Corp. (PNC) and the U.S. Battelle-Columbus failed to survive a crash test at the U.S. Sandia National Laboratory.21 The impact of this disclosure was substantial. In December 1987, Congress effectively banned plutonium overflights22, and Japan was forced to ship plutonium by sea. In 1988, the U.K. Advisory Committee on the Transport of Radioactive Material (ACTRAM) asked the IAEA to initiate a review of the IAEA's transport package criteria "in view of the different requirements of the USA."23
Now, nearly a decade later, the IAEA is about to permit air shipments of plutonium over strong reservations by the U.S. and international aviation organizations. The alternative--- shipment of plutonium by sea---has turned out to be highly controversial. With tons of plutonium still to be returned from British and French reprocessors to Japanese, German, Swiss and Belgian utility companies, air shipments---once legitimated by the IAEA's new transport standards---once again appear to look attractive to the nuclear industry.
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End Notes1.IAEA TECDOC 702, "The air transport of radioactive material in large quantities or with high activity," p. 11. Back to document
2. Letter report, "Review of Crash Survival Specifications," from Michael R. Poole, chairman of the Flight Recorders Group, Transportation Safety Board of Canada, to M. Sastre, chairman, Ad Hoc Working Group of the Dangerous Goods Panel, International Civil Aviation Organization (ICAO). Back to document
3. "Report of the Ad Hoc Meeting on Type C Packages," (DGP/WG95-FL/32), ICAO, 8.8. Back to document
4. Letter from Agnes J. Bishop, M.D. to Dr. Hans Blix, IAEA Director General, June 27, 1996. Back to document
5. Letter to Agnes Bishop from James M. Taylor, executive director for operations, U.S. Nuclear Regulatory Commission, and U.S. representative to IAEA Advisory Commission on Safety Standards, May 31, 1996. Back to document
6. Letter from Dr. Assad Kotaite to Paul Leventhal and Dr. Edwin Lyman, Nuclear Control Institute, June 28, 1996. Back to document
7. IAEA TECDOC 702, p. 22. Back to document
8. Personal conversation with National Transportation Safety Board investigator. Back to document
9. Letter report (See footnote 2). Back to document
10. Report of Ad Hoc Working Group of the ICAO Dangerous Goods Panel, April 1995.Back to document
11. U.S. Position Paper, Research and Special Programs Administration, September 19, 1995.Back to document
12. Edwin S. Lyman, Ph.D, "Behavior of Mixed Oxide Fuels Under Transport Accident Conditions," Nuclear Control Institute, September 21, 1995. Also see technical note by Dr. Lyman attached to NCI letter to IAEA Director General Hans Blix, February 26, 1996. Back to document
13. "The Air Transport of Radioactive Materials in Large Quantities or With High Activity," IAEA TecDoc 702, Standing Advisory Group on Safe Transport of Radioactive Material, 1993. Back to document
14. In 1992, 82 fresh fuel elements from Germany's abandoned Kalkar breeder reactor were flown from Belgium to Scotland for storage. More recently, additional Kalkar fuel was sent to Belgium and then flown to Scotland. Germany had intended to fly 123 remaining Kalkar fuel assemblies from Frankfurt airport to Scotland in 1993. Nuclear Control Institute publicized the risks of these shipments at a joint press conference in Wiesbaden in April 1993 with Joschka Fischer, environment minister of Hesse. These shipments have not taken place. Back to document
15. German Bundestag Printed Matter 12/5448, July 19, 1993. Transmitted in a letter from the Federal Ministry for the Environment, Environmental Protection and Reactor Safety, dated July 14, 1993. Response to questions from delegates Dr. Klaus Kubler, et al. Back to document
16. Executives of Japan's largest utility, the Tokyo Electric Power Company (TEPCO) recently told a group of non-governmental organization representatives that it was considering air-lift as well as sea shipment of MOX fuel fabricated for TEPCO in Belgium. Citizens' Nuclear Information Center (Tokyo), "Memo of April 24 (1996) Meeting of Tokyo Based NGO Groups with TEPCO on the MOX Fabrication Contract." Back to document
17. Public Law 94-79, introduced by Rep. James Scheuer, banned air transport of plutonium into or out of the U.S. until a crashworthy cask had been developed and licensed. Back to document
18. IAEA TECDOC 702, p. 15.Back to document
19. TECDOC 702, p. 15. However, elastomer seals in use in many Type B package designs will not fail gracefully under thermal conditions only slightly more severe than the Type B thermal test, but may fail abruptly, resulting in increases in leak rates of many orders of magnitude. Dr. Edwin Lyman, Princeton University Center for Energy and Environmental Studies, "Questions/Comments Concerning the Air Transport of 'Very Low Dispersible' (VLD) Material," May 8, 1995. Dr. Lyman has since joined the Nuclear Control Institute as its Scientific Director.Back to document
20. Ibid., p. 15 Back to document
21. Paul Leventhal, Milton Hoenig and Alan Kuperman, "Air Transport of Plutonium Obtained by the Japanese from Nuclear Fuel Controlled by the United States," Nuclear Control Institute, March 3, 1987, p. 5. Back to document
22. Amendment No 1240 (Murkowski Amendment) to S. 9, Omnibus Veterans' Benefits and Services Act of 1987, Congressional Record, December 3, 1987, p. S.17177. The Nuclear Regulatory Commission was required to certify a cask that could survive a crash equivalent to a worst-case crash. The impact speed of the reference worst-case crash, as determined by the NRC, was 282 m/s (630 mph)---the Pacific Southwest Airlines Flight 1771, on December 7, 1987. Back to document
23. "The Transport of Civil Plutonium, by Air," Advisory Committee on the Safe Transport of Radioactive Material, May 1988, p. 2. Back to document