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 a1 Iutepigeece (b) (1) (b) (3) Adw French Underground Nuclear Testing: Environmentally Safe and Likely To Continue F7 APPROVED  FOR RELEASE DATE:  FEB 2008 =811W" Copy                                                                344 1-6 0 of Dieectorate r1 Iateltitteoce ((] French Underground Nuclear Testing: Environmentally Safe and Likely To Continue This paper was prepared byl             Office of Scientific and Weapons Researc   omments and queries are welcome and may be directed to the OSWR. (REVERSE BLANK) French Underground Nuclear Testing: Environmentally Safe Key Judgments       The French have conducted over 70 underground nuclear tests at their test i fwewri"maiiaMr    sites on Mururoa and Fangataufa Atolls in the South Pacific since 1975. as d 17 J JIMW)' 1933 Antinuclear sentiments in the region are high, and there have been bitter hW Wtd in this tepm. protests and public outcries against the test program. These protests arc fueled, in part, by sensational press reports that Mururoa Atoll is breaking apart and leaking large amounts of radioactive debris to the environment. Recent studies by both independent French and Pacific Basin scientists have confirmed claims by French nuclear-testing authorities that their operations do not pose a radiological threat to either human or marine populations in the Pacific region. Although there is some evidence for short-term venting of gaseous and volatile fission products from the underground tests, these releases arc not of a magnitude to pose an off-site health hazard. The studies found no evidence of any leakage of particulate bomb debris into the environment. We believe the French will continue their nuclear test program through the 1990s, probably at the current rate of seven to 12 tests per year. Before 1987. the French almost certainly will reactivate their test site on the nearby Fangataufa Atoll, which was deactivated in 1976. They may conduct all their high-yield tests at Fangataufa and restrict tests at Mururoa to under 50 kilotons after 1986. Moving high-yield testing to Fangataufa would reduce the amount of future geological stress on Mururoa Atoll and, thus, would provide an additional measure of safety to the test program. Although there always is the possibility of an accident, we believe the French nuclear test program will continue to have an excellent safety record and a negligible effect on the South Pacific environment. There have been recurrent press reports that the French might move to a different test site. Such a move would be politically untenable for the French, and we consider such a move from the South Pacific to be very un- likely. It is even less likely that the French would return to atmospheric testing. Although they are not precluded by treaty from doing so, the political cost of such testing would almost certainly outweigh any technical advantage. (REVERSE BLANK) r~                                                                    iii et Sw  -/0066 May 183 Key Judgments Introduction Geology of Mururoa Atoll I Normal Containment Practice 2 Current Status of Mururoa Atoll 3 Environmental Status 4 Study by French Scientists 4 Study by Pacific Basin Scientists 4 Future Prospects 0 Appendix French Underground Nuclear Tests in the South Pacific Major Geological Structures of Mururoa Atoll             2 Major Geological Structures of Mururoa Lagoon            2 Figure I French Underground Nuclear Testing in the South Pacific SY French Underground Nuclear Testing: Ensironmentally Safe Antinuclear sentiment has been widespread in the South Pacific Basin nations since France exploded its first nuclear bomb in the South Pacific above Mur- uroa Atoll (figure I t in 1966. Between 1966 and 1974. the French conducted 41 nuclear tests in the atmo- sphere above Mururoa and the nearby Fangataufa Atoll, each explosion provoking a fresh round of bitter protests. There is little doubt that the radioactive debris generated b) these tests posed an environmen- The continuing public protests over the atmospheric tests-mainly from South Pacific Basin nations such as Australia. New Zealand. and Papua New Guinea Ibul sometimes from South American and European nations as well(--finally caused the French to shift their testing underground. They conducted two small underground tests at Fangataufa Atoll in 1975 and then deactivated that site, probably to reduce the cost of maintaining the test effort. The entire testing effort was shifted to Mururoa Atoll, and since 1975 over 70 underground explosions have been conducted there The shift to underground nuclear testing has done little to quell protests from the South Pacific nations. Antinuclear protests continue to be fueled b) sensa- tional press reports of widespread leakage of radioac- tive debris and extensive geologic damage to Mururoa Atoll. The environmental impact of French nuclear testing has been one of the major complaints of the South Pacific Forum, an organization of regional governments such as Australia, New Zealand, Papua New Guinea, and Fiji. The Forum wishes to have the South Pacific declared a "nuclear free zone." Such a declaration would ban not only nuclear testing but also the stationing of nuclear weapons in the region, even in the case of nuclear-armed warships-an issue of major concern to the United States. This paper assesses the technical validity of the claims of geologic damage and environmental contamination from re- cent French nuclear testing and the future of the test program.= The structures of Mururoa and Fangataufa Atolls arc extremely similar and differ mainly in the depth at which the various geologic zones are located. For simplicity, we will discuss only Mururoa, but the same geologic data apply to Fangataufa.' Tables I and 2 show the basic structure of Mururoa. 0 Mururoa is a coral atoll built upon a volcanic (basalt) base (figure 21. The French conduct their nuclear tests in the volcanic base. French geological studies indi- cate that the volcanics rise from a depth of roughly 3,000 to 4.000 meters to approximately 500 meters below the surface. Although the slope of the side of the base is generally gentle, rising at 15 to 40 degrees. certain portions are locally steep, rising at angles greater than 60 degrees. Both the side and the base tend to alternate compacted and fractured layers. Fracturing has severely limited the available testing space at Mururoa; safety precautions preclude testing near fractured layers. The central massif of the atoll-the section under the lagoon-although still slightly fractured, is more dense and homogeneous than the sides. This area has a higher safety factor and more available space.L1 A transition zone composed of welded conglomerates (pebbles adhering to each other) is atop the volcanics. This zone, thick on the sides of the atoll and thinner in the lagoon, has a large amount of void space and has produced numerous problems in drilling. The material is very crumbly, and the French usually stabilize the zone with cement when drilling through it.I       I t~. Table I Major Geological Structures of Mururos Atoll Approximate    Composition Depthinwlent O to 170       Detrital coral 110 to 760     Thick. massive dolomites 7M) to 420     Sand) gravel and coral debris 420 to $!0     Basaltic conglomerates with calcareous cement -514)          lavasand sukanic brcccias with alternating compact and scoriacious layers: aerial sukanies atop deep submarine sukanics The transition zone the none between the loose. corallinc rucks and the underlaying solanicst extends from roughly 400 to 500 meters in depth and is cstremel) inhomogeneous: it is quite treacherous from both a drilling and a safety prim of view. Fangaiaufa Atoll has a similar overall structure. although the individual Ia)ee' are at different depths. Layers of limestones and dolomites, the remains of coral. arc atop the transition zone. These layers arc extremely inhomogcncous. ranging in composition from hard and marbled tocnalky. Because the sides of the atoll are so steep. this limestone and dolomite zone tends to flake and crumble under shock. The zone gradually merges into dctrital coral on the sides of the atoll. The coral is poorly consolidated and contains voids which are, in many cases. open to the ocean. The limestones under the lagoon are covered by a thin layer of sand French nuclear tests now are conducted in shafts drilled vertically into the volcanic base of Mururoa Atoll.                            the shafts typi- cally are ouu to      me ers acep.                               ith the exact depth depending on the yield of the explosive device and the local geology. (As was noted in the previous section. safety constraints do not allow the explosion to be conducted in a fractured basaltic layer.t Table 2 Major Geological Structures of Mururoa Lagoon ., Appoatmate     Cumpwit Depth irrrrrrrit 40 to 170      Limestone Isorne circulation ta)enl 174) to 270    Dolomite' Isar) ins from crumbly to massiwcl 170 to 550     Aerial snkania 550            Compact submarine sotcanics Ilaias and volcanic brcccia t ? The transition zone Ithe ionic between the laze. coratline rocks and the underlaying tolanicst under the lagoon is thin in m ,%t plates and occurs at roughly 260? to 295?meter depth. Fangataufa Atoll has a similar overall structure. although the individual layers are at different depths. Because of the weak and crumbly nature of the transition zone and corallinc structures, the French have stated that they do not consider them to have an) ability to contain bomb debris. Thus, a depth of detonation is chosen that will not allow the cracks and fissures created by the explosion out of the transition zone. and preferably not out of the basalt. Although the saturated limestones and dolomites do provide overburden weight. they do not have suflicient struc- tural integrity to be an effective part of the containment mined and the device in place. the shaft is backfilled with stemming material and plugs of either cement or epoxy. All the materials used in the backfilling opera- tion are chosen to prevent the release of radioactive debris. At least two different types of stemming material are used, depending on the surrounding geologic zone. Reportedly. in the volcanic zone, a basalt/sand/gravel mixture is used; a mix of crushed coral, sand. and gravel is used in the corallinc struc- tures. Although these mixtures retard particulate Figure 2 Mumma C'rus Section 0 E3 debris, they do not stop the percolation of gases. The cement and epoxy plugs are used as gas blocks and effectively prevent the movement of radioactive gas up the holc. Gas blocks also are used to prevent the now of gas up the diagnostics and device-suspension cables.[ This con a"                ly is not completely effective                  he French do not put steel liners in their emplacement shafts, and some minor gas leakage into the surrounding geologic struc- tures is inevitable. Such leakage, however, will be minor because of slow percolation rates, and much of that leakage will be dispersed in the deep ocean Although Mururoa has sustained damage from nucle- ar testing, our analysis indicates that the damage has not been as extensive as reported in the regional press and has not impaired the overall structural integrity of the atoll. The extent of damage, however, has been a matter of concern to the French and was one of the reasons they began testing under the lagoon in 1981. The sedimentary material and chalky limestones on the sides of the atoll have received the most damage. This material tends to crack, crush, and slide when subjected to the shock from a nuclear explosion. This tendency is increased by the steep slope of the atoll and worsens in proportion to the yield of the explosion and its proximity to the edge of the atoll. For instance. a reliable source indicated that a 180-kiloton blast in 1979 caused a massive layer of limestone and coral to break off the edge of the atoll. The material fell into the lagoon and produced a large wave, which washed over the atoll. This event gave rise to sensational reports in both the Pacific Basin and French presses that the atoll was crumbling and breaking apart. The damage actually was localized and not significant. Geological studies have indicated that damage to the atoll has not been significant enough to pose either a long-term safety or radiological hazard. Damage to the surface and upper layers of the atoll has thus far been both localized and minimal and has not affected normal operations. Damage to the underlying volcan- ic also has been minimal, consisting of the normal fissures and voids caused by any nuclear explosion. Because the explosions arc laterally far from the sea. there is little chance of a breakout in that direction. The French have taken two steps to enhance the safety of the atoll. Since the beginning of 1981. they have conducted 14 tests under the lagoon, roughly alternating with tests under the atoll. Testing under the lagoon reduces the stress on the coralline atoll structure and makes use of a more compact and homogeneous volcanic structure than that available under the atoll proper. All of the higher yield (greater than 20 kilotons) tests since 1981 have been conducted under the lagoon. The French also have limited the size of the explosions they conduct at Mururoa. A reliable source reported in 1980 that the French would no longer conduct tests above 100 kilotons at Mururoa. Since 1980. there has been one test with a central-value yield of 100 kilotons: the rest have been less than 60 kilotons. Tests under the atoll proper have all been under 20- kiloton yield since that time. The South Pacific Basin countries have made almost continual protests about nuclear testing since the French effort was moved to the area in 1966. The antinuclear protests have centered on fears of both short- and long-term health hazards and on marine contamination. These protests seem to have little technical basis. The French repeatedly have denied claims of contamination and damage to the atolls and have stressed their excellent safety record. The Basin countries have countered with the argument that the French claims were based on French data and were not susceptible to independent verification. The French Government took two major steps in response to this criticism Study by French Scleutlsts According to a reliable source, a team of reputable French scientists, not connected with the nuclear- testing program, was invited to Mururoa in 1982. The team studied the geological integrity of the site, the possibility of widespread radioactive contamination. and the safety procedures of the test operations. Although the team expressed some minor concerns. they concluded that the Mururoa operations did not pose a risk to either the environment or the public safety. They said that the atoll was structurally sound and that there was no evidence that the underground tests were an off-site threat. They expressed a slight concern that earlier atmospheric tests contaminated the lagoon sediments but presented no data on radia- Study by Pacific Basin Scientists The French also invited a scientific team from the South Pacific Forum countries to visit the site in 1983. Although stressing that participation would not lessen their opposition to nuclear testing, the Govern- ments of New Zealand. Australia, and Papua New Guinea accepted the invitation. In October 1983. a team of six scientists from those countries toured Mururoa and examined both radiation monitoring and geophysical records. They also were allowed to collect extensive physical samples of sea life, vegeta- tion, soil, coral, and seawater for radiological exami- nation. The study conducted by this team probably is the most extensive independent study ever of another country's nuclear test site.0 Although the South Pacific team disagreed with some of the French claims and were not able to verify others, their report generally concluded that the cur- rent test program appears to pose no radiological threat to the environment or surrounding population. Radiation doses affecting the population in the area generally are well below those in other areas of the world, and any traces of fallout, even from the earlier atmospheric tests, are far below those levels posing any health hazards. There also was no evidence of increased rates of radiation-induced diseases in the French Polynesian population (and by analogy in the The South Pacific team studied geological and hydro- logical data on the atoll in detail, commenting on the wealth of material available. They also were provided drilling core samples for study. They concluded that the structural integrity of the atoll as a whole, and the underlying volcanic base in particular, had not been damaged seriously. They did estimate, however, that the transition zone was not as impermeable to leakage as the French had claimed and also concluded that there had been substantial localized damage to the coralline structures. Although not currently a prob- lem, the team noted that the creation of fissures in both the limestones and the volcanics could open a path for potential future leakage. The South Pacific team concluded that there was some evidence of short-term venting of gaseous and volatile fission products after a test. A review of this evidence, however, suggests that the amount of vent- ing is not significant from a radiological health or safety standpoint.- There was no geological evidence of any short-term leakage of nonvolatile debris. ^ The South Pacific team was unable to investigate completely the concern of the 1982 French survey group regarding the contamination of the sediments in Mururoa Lagoon. The French have estimated that there are 10 to 20 kilograms of plutonium in the sediments. This contamination apparently resulted from the atmospheric tests and from poor waste- handling procedures before 1981. Although the team was not allowed to sample the sediments or coral in certain portions of the lagoon, their estimates were in basic accord with the French claim. They also esti- mated that less than 10 grams of plutonium were transported from the lagoon to the ocean each year. This amount should not be a health hazard. The team similarly concluded that the uptake of the plutonium by local sea life would not be a health hazard= These two studies have not reduced the number or the intensity of the antinuclear protests in the South Pacific region, even though the results of the studies have been given worldwide distribution and have been extensively quoted in the press. The nuclear-testing issue has now become a very emotional one and probably can no longer be dealt with on a purely scientific basis. Despite the good safety record of the French operations, nuclear testing remains, and will likely remain, a rallying point for antinuclear forces in the region. The recent decision of New Zealand to ban nuclear- a?med or nuclear-powered warships from its waters is only another example of this regional feeling, albeit of a much higher profile than the periodic skirmishes with France. The two issues are not directly connect- ed, and resolution of one will not resolve the other.[ Although there always is a possibility that a nuclear test will result in a massive blowout of radioactive debris, the French emphasis on safety makes this extremely unlikely. The test site would be extremely difficult to evacuate in an emergency, so the degree of French precautions regarding test safety Iparticularl% emphasis on conducting explosions far from potential- ly hazardous geologic areas and the environment) arc quite understandable. The French also maintain a strict, continuing, on-site radiation-monitoring sys- tem. Data from this system indicate that individuals on Mururoa actually receive a smaller radiation dose The French are unlikely to stop nuclear testing in the near future. Four major, new French weapons systems currently are scheduled to be deployed during the 1990s. Although two of these systems-the M-S submarine-launched ballistic missile and the SX mobile ground-launched missile-reportedly will be based upon the I50-kiloton warhead currently in the M-4 SLBM, some testing still will be required to "custom tailor" the systems. The other two systems- the Hades missile and another reportedly using an enhanced radiation warhead-already are under de- velopment but will require further testing. These existing requirements for warheads for new systems indicate that testing will continue at least through the 1990s. even precluding any new weapons designs. The rate of testing probably will remain close to the present Icvel-roughly seven to 12 tests per year. We believe that all the tests will be conducted under- ground: political considerations almost certainly pre- The French are refurbishing the faciliti-s on Fanga- taufa Atoll. A test could be conducted there bs the end of 1986. but we do not know whether the entire testing effort will be moved from Mururoa to Fanga- taufa. Although more than 70 tests have been con- ducted at Mururoa. there seems to be room for additional emplacement shafts. The space problem on the atoll also has been cased by testing under the lagoon. We do not believe continued testing will pose a significantly greater safety or radiological risk than in the past. Mururoa probably is the most extensively studied coral atoll in the world, and we believe the risk associated with continued testing is low. Although the French may be preparing for an eventu- al move from Mururoa to Fangataufa. it is more likely that the latter site will be used solely for high- yield tests. Such a move would provide increased safety at both locations. The risk of venting or damage to the atoll would be lessened at Mururoa. because the shock and fissure radius from a low-yield test is less than from a high-yield test. High-yield tests at Fangataufa could be placed farther apart to assure that there would be less likelihood of induced collateral damage. There also would be very few tests at Fangataufa. possibly only one or two each year. The risk of venting, therefore, also would be de- creased. It is unclear, however, whether the French would accept the economic cost of maintaining two We discount the recurrent rumors that France has been exploring the possibility of opening a new test site. These rumors have focused on the French-held Kerguelen Islands in the Indian Ocean and have been denied repeatedly by French Defense Minister Charles Hernu. There are several reasons for the French not to move. Such a move probably would actually increase environmental and safety hazards. In the Kerguelen, the French do not have the considerable background in site geology, in drilling, and in test experience that they have at the current site. Further, weather would be less hospitable in the Kerguelen and possibly would limit the testing sea- son. Most important, the political problems would increase rather than decrease. Several countries have hinted that they would drop diplomatic recognition of France should nuclear testing be moved to the Kcrguclens. U c believe it is even less likely that the French would return to atmospheric testing, although there is no treaty prohibition against their doing so. Atmospheric testing would significantly raise the level of environ- mental hazard and would provide the basis for much increased-and highly justified-antinuclear protest. We believe that this political liability would far outweigh any technical advantage to be gained by atmospheric testing. Freaef, UsderFowld Nuclear Tests is the Soath Pacific Test Date Yield Location Test Date Yield Location Number i0o1o1"0? Number 4kilou>rut- 59 a S Jun 75 2.8 Atoll 97 6 Mar 81 3 Atoll 60 t 26 Nov 75 4.3 Atoll 98 28 Mar 8I 6 Atoll 61 11 Jul 76 12 Atoll 99 10 Apr 81 6 Lagoon 62 19 Feb 77 10 Atoll 100 8 Jul 81 14 Atoll 63 19 Mar 77 110 Atoll 101 11 Jul 8I I Atoll 64 6 Jul 77 10 Atoll 102 18 Jul 81 _ Atoll 65 12 Nov 77 6 Atoll 103 3 Aug 81 14 Atoll 66 24 Nov 77 100 Atoll 104 6 Nov $1 I Atoll 67 17 Dec 77 6 Atoll 105 11 Nov 81 6 :Moll 68 27 Feb 78 2 Atoll 106 5 Dec 81 4 Atoll 69 22 Mar 78 7 Atoll 107 8 Dec 81 13 lagoon 70 19 Jul 78 4 Atoll log 20 Feb 82 1 Atoll 71 26 Jul 18 2 Atoll 109 24 Feb 82 1 Atoll 72 2 Nov 78 3 Atoll 110 20 Mar 8'_ 7 Lagoon 73 30 Nov 78 120 Atoll III 23 Mar 8: O.5 Atoll 74 17 Dec 78 8 Atoll 112 27 Jun 82 I Atoll 75 19 Dec 78 10 Atoll 113 1 Jul 82 14 Atoll 76 I Mar 79 5 Atoll 114 21 Jul 82 3 Atoll 77 9 Mar 79 6 Atoll 115 25 Jul 82 48 lagoon 78 24 Mar 79 10 Atoll 116 27 Nov 82 0.5 Atoll 79 4 Apr 79 7 Atoll 117 16 Apr 83 57 Lagoon 80 I8 Jun 79 5 Atoll Its 25 Apr 83 0.25 Lagoon 81 29 Jun 79 IS Atoll 119 25 May 83 100 Lagoon 82 25 Jul 79 180 Atoll 120 18 Jun 83 I Atoll 83 28 Jul 79 5 Atoll 121 28 Jun 83 24 Lagoon 84 22 Nov 79 5 Atoll 122 20 Jul 93 4 Atoll 85 23 Feb 80 2 Atoll 123 4 .Aug 83 16 Lagoon 86 3 Mar 80 3 Atoll 124 3 Dec 83 2 Atoll 87 23 Mar 80 51 Atoll 125 7 Dec 83 8 Lagoon 88 I Apr 80 ' 15 Atoll 126 8 May 84 4 Atoll 89 4 Apr 80 5 Atoll 127 12 May 84 40 Lagoon 90 16 Jun 80 25 Atoll 128 12 Jun 84 6 Atoll 91 21 Jun 80 5 Atoll 129 16 Jun 84 20 Lagoon 92 6 Jul 80 4 Atoll 130 27 Oct 84 4 Atoll 93 19 Jul 80 74 Atoll 131 2 Nov 84 45 Lagoon 94 25 Nov 80 0.5 Atoll 132 1 Dec 84 <0.5 Atoll 95 3 Dec 80 43 Atoll 133 6 Dec 84 41 lagoon % 27 Feb 81 3 Atoll ? US Atomic Energy Detection System (AEDS) derived central- value yield. n All tests except 59 and 60 were conducted at Mururoa.