Scientist supports denials over atoll

Press, 5 April 1988, Page 8

Scientist supports denials over atoll

Special correspondent Auckland A leading New Zealand scientish has backed French denials that Mururoa Atoll is breaking up because of repeated nuclear explosions. Dr j Andrew McEwan, director of the New Zealand National Radiation Laboratory, said, “Some fracturing of volcanic rock takes place with each detonation, but there is no • way the atoll is going to break up.” Recent press reports quoted Vice-Admiral Pierre Thireaut, commander of French naval forces in the Pacific, as saying nuclear tests would be carried out on Fangataufa Atoll because Mururoa was in danger of breaking up. But the French Minister in charge of South Pacific issues, Mr Flosse, yesterday accused the New Zealand and Australian press of “lying” about, French nuclear testing in the Pacific. The controversy over the alleged resiting of the nuclear test centre was part of a campaign by “enemies” of France. He said the French Pacific nuclear test sites had always included both

Mururoa and Fangataufa atolls. Dr McEwan was one of five New Zealand and Australian scientists who surveyed Mururoa in 1983 and reported no significant radiation which could cause a health hazard. Various aspects of how the survey was done were later criticised. Dr McEwan said the atoll was sitting on a substantial area of volcanic rock. “There is no way it is suddenly going to collapse into the sea,” he said. The French had stopped testing at sites round the rim of the atoll when they ran out of suitable locations because of possible overlapping, and started in the lagoon itself. “It is clearly not as convenient as it was to operate round the rim where they could! simply drive to the site,” Dr McEwan said. ( “One of the reasons given for the move to Fangataufa was that it gave them better flexibility.” Not only did the French have to drill over water, but they had to return

with their rig to collect samples, which was fairly laborious. Dr McEwan said the more fracturing, the greater the movement of radioactive water through the volcanic rock. But it was a slow process. I But a model recently produced by scientists at Auckland University (predicted contaminated water was moving through fractures at 100 m a year. Dr McEwan said | the total yield of all underground explosions I was less than one of : the earlier atmospheric detonations. “.What that means is that making some worst case assumptions, the concentration in the lagoon would still not get to! the level where it would constitute a hazard ... someone could get their food there with no harmful effect, if anyone lived there.” It was clear, I Dr McEwan said, that over a very long period there would be some leak of radioactive material. But he said, "Detection and the health risk problem relate to very different levels of concentration.”