The Ottawa Citizen from Ottawa, Ontario, Canada • 30

miii nryiiTri- The CITIZEN, OTTAWA SATURDAY, MAY 17, 1986 POOR QUALITY ORIGINAL Safety approach Disaster sparked new Soviet 'openness' 1 iii in a CANDU 'plus' (Ian Wilson is vice-president of the Canadian Nuclear Asso- "ciation, an association of 150 companies in the nuclear indus-'try in Canada, including Ontario Hydro and Atomic Energy of ('. Ltd.) By lan Wilson TORONTO iryniji iijTTrnr pummi p.i world By Tom Wicker New York Times an it happen here? Are we in immediate danger? When news of the nuclear accident at NEW YORK side from the death and miserv suffered bv so iinany Soviet citizens and perhaps other Europeans. liiia rce on the front pages of Canadian newspa-pw pers, these questions were posed over and over by reporters scrambling to talk to anyone to speculate on what had happened and to express concerns or opinions on these questions. i Qualified responses from nuclear industry representatives were headlined in absolute terms: It Can't Happen Here. In reaction to such broad assurances, critics -dismissed the difference between CANDU reac-i tors and those at Chernobyl as being irrelevant.

A disaster that the Russians had recently said was "unthinkable" had happened. Why believe the Canadian industry? And anyway, it is the similarities that are important, the critics claimed. The similarities are that both reactors use oxide fuel and niobiumzirconium alloy pressure tubes, and both are used to pro AP ohoto Damaged reactor at Chernobyl nuclear plant is below chimney at centre duce heat, which in turn produces electricity in "a turbinegenerator. Gorbachev suffers political meltdown By James Ferrabee Souiham Nows LONDON oviet leader Mikhail Gorbachev peoples living in and around Chernobyl were evacuated. Neighboring countries picked up high radiation levels days before the Soviet authorities in Moscow admitted there was anything wrong.

Gorbachev chastised the Western media for a "conglomerate of lies" about the seriousness of the explosion and its after-effects. Then, as if admitting they were slow was scrambling to limit the dam-age inside and outside the Soviet Union when he spoke to the peo 'k in releasing information themselves, he proposed a conference be held in Vienna to work out mechanisms for reporting future nuclear accidents. Gorbachev looked tired and his performance on TV lacked its usual ener around the plant during the first few days. He said nothing about current radiation levels at Chernobyl. The information he provided, in short, even 18 days after the event, was considerably less than full and frank.

The Chernobyl accident has hurt him outside his country, particularly in Western Europe, where the Soviets have long pitched their propaganda to the peace movements. The peace movements, in turn, traditionally have singled out the U.S., Britain and France rather than the Soviet Union as the greater danger in the nuclear age. Chernobyl is certain to cause many in the peace movements, as well as governments, to think again. There are obviously a great many lessons to be learned from what caused the explosion and what safety mechanisms and damage-control precautions were in place. The TV speech added little to the knowledge of those outside the Soviet Union about what happened April 26 at Chernobyl.

It will not substantially alter Western Europe's view that the accident was bungled. What could alter the view of Gorbachev in the next few weeks and months is if he decides to have an open and full investigation of what happened at Chernobyl and reveal the findings, however distasteful those may be. But that seems highly unlikely. Gorbachev ple in a 27-minute TV speech this week. He attempted to dress up the Chernobyl explosion at the nuclear power plant in the Ukraine as an exercise in heroics that averted catastrophe.

"Thanks to the effective measures taken, it is possible to say today that the worst has passed. The most serious consequences have been averted," he said. "Of course, the end is not yet. It is not time to rest." These last words clearly show that Chernobyl was a major human disaster as well as a serious political setback for the Soviets and Gorbachev. He had to admit that nine people had died and his speech conceded that there were nearly 300 other casualties an increase of more than 100 on what Soviet authorities had admitted until then.

How many of the casualties will die in the next weeks and months, and how many early deaths will be caused by Chernobyl won't be known for years. The major problem internally and externally is the length of time it took the Soviet authorities to inform their own people and those outside of what was going on. It was some 72 hours before the 40.000 gy and assurance. The Chernobyl accident is the worst crisis lie has had to face since coming to power 14 months ago. It showed safeguards at the Soviet nuclear power plants to be feeble, but even worse, that the political bureaucracy reacts very slowly.

It was 48 hours before the Soviet media admitted anything had happened. After it was reported, local party bosses in the Ukraine were blamed. In his TV speech, Gorbachev spent little time assessing blame, and a lot of time on the heroics of those who worked President Reagan and the Western allies have plenty of reason to take quiet satisfaction in the plight of the Soviet government following the Chernobyl nuclear disaster. For one thing, world public reaction has clearly forced Moscow to an unprecedented degree of openness with other nations and even its own people notably including Mikhail Gorbachev's remarkable (for a Soviet leader) televised report on the accident. For another, in his call for "an international regime" to supervise reactor safety and provide the world community with early warning of such accidents as that at Chernobyl, Gorbachev departed sharply from the Soviet Union's usual insistence on excluding the world from its internal affairs.

Finally, in an effort to recover from what has been a body blow to Soviet prestige and credibility, Gorbachev has been pushed to take a new risk for arms control renewing his previously-cancelled moratorium on nuclear testing, despite the fact that Moscow has conducted no tests at all since last Aug. 6, while Reagan has ordered 11 U.S. tests in the same period. All three of these developments, in effect, are substantial "victories" for the West and ought to be regarded as such, though without gloating or polemics. Unfortunately, Washington's reaction has mostly been critical the charge, for instance, that the original Soviet delay in reporting the accident to the world "proves" that Moscow is not to be trusted to observe an arms control agreement with the U.S.

That remains to be seen, but some other accusations against the Russians clearly were undeserved. There were not 2,000 dead buried in mass graves as a result of the accident; a second reactor was not involved; no complete "meltdown" occurred; and it's not even certain that the original Soviet delay in warning other countries was callous and deliberate. Nevertheless, international anger was justified by the initial Soviet secrecy, even if it was more nearly the result of bad judgment, human error and bureaucratic inertia than purposeful deception. But in a longer view, the West might profit by emphasizing, instead, the more forthcoming Soviet attitude resulting from the world's expressed anger and demonstrated in Gorbachev's televised speech. There was reason to believe before Chernobyl that the depressed state of the Soviet economy had led a new generation of leadership to question the cumbersome governing system it inherited.

And it has become a commonplace Western observation that Moscow's technological need to make computers and computer education far more widely available ultimately will conflict with its political need to maintain tight control of the information available to its citizens. Now Chernobyl and its aftermath have demonstrated further severe deficiencies on the part of the Soviet government. It was unable to protect its people from a nuclear accident and as a consequence has seen fit to call for international assistance in preventing such accidents in the future. The high tribute that Gorbachev paid to American physicians though one of them has suggested that no nation is sufficiently prepared to meet such a disaster was a concession that Moscow also needed outside help in caring for victims of the accident. To only one of these striking Soviet developments has Reagan so far responded favorably.

A White House statement welcomed Gorbachev's proposal for "an international regime," based on a strengthened International Atomic Energy Agency, to promote nuclear reactor safety and to provide "prompt warning and supply of information" in the event of a nuclear accident. A judiciously-worded and non-polemical statement by Reagan taking note of and implicitly encouraging further Soviet openness with the world and its own citizens also seems in order. If adversity forced Gorbachev more toward Western ways of responding to crisis, whv not credit him for it? Gamma-ray spectrometer tracing problem By Malcolm W. Browne New York Times a ragged paten ot lawn i Stockholm, behind an old brick 'building that once housed a vet The major differences are that CANDU reac- i use heavy water as a moderator the pressure tubes sit in a large vessel containing cool water. The Chernobyl reactors use graph-" ite, a form of carbon, as a moderator the pressure tubes are surrounded by this combustible material.

CANDU units are housed in a containment building the four-foot-thick reinforced concrete walls would not be penetrated by the direct impact of a jumbo jet. Chernobyl did not have such a containment building. And CANDU units have a dousing system to condense any radioactive steam released within the contain- ment building. But the most basic difference is the defence-in-depth approach that Canada brought to nuclear power development. Yes, we believe a core meltdown resulting in release of massive amounts of radiation is inconceivable in a CANDU reactor.

But what if it should happen through equipment failure or operator error that we are unable to imagine? There is not only the containment building around the reactor; there is a one-kilometre exclusion zone around the station. Yes, we are confident that people living near a CANDU will never have to be evacuted because of a leak of radiation from the station. But should evacuation be necessary, there is an emergency plan. And yes, given all of the differences in design and philosophical approach to safety, we believe the presence of a CANDU poses no life-threatening risk to people living near the plant. But complacent we're not.

There is no doubt that the Chernobyl accident will result in a careful review of the safety of nuclear power by many of the 27 countries now operating reactors. In fact, there was an immediate call by Sweden for a world conference on nuclear reactor safety. The Canadian nuclear industry welcomed the prompt assertion by the federal government that Canada would participate in any such international review. Since its inception in 1957, Canada has been an active member of the International Atomic Energy Agency, whose headquarters is in Vien- na. CANDU plants have been subject to inspection by the IAEA, and Canada has participated fully in the exchange of information on reactor operation.

The Soviet Union had very recently allowed IAEA inspection of some of their facilities, but these did not include the units at Chernobyl. There have been extensive public inquiries into the safety of the CANDU reactors, such as the hearings before the Ontario Select Committee on Hydro Affairs and the Ontario Royal Commission on Electric Power Planning. What could an international review accomplish that these more focused local inquiries could not? There can be liUle doubt that the massive news coverage on Chernobyl has been disquiet- ing, both for people who had previously been ambivalent about and for supporters of nuclear power development, i-ii It won't help to dwell on the opportunity that the news media around the world took to satis- fii fy our appetite for a good scare story. This dis- aster was an editor's dream rumor, terror, mystery, international politics and wild speculation, all served up with a heavy dose of radi- V-ation. Perhaps one concern associated with radiation may already be reduced by the news coverage: If there were any doubt before, there should be none now that radiation is easy to detect.

As we have all seen from the news coming out of Europe in the wake of Chernobyl, we may not be able to see it, feel it, or smell it but you can't hide it. There is undoubtedly, however, an urgent need for the Canadian public to be given the necessary assurances that not only are CAN-DUs safe but also U.S. nuclear plants just across the Great Lakes and elsewhere are safe. For any world review of nuclear reactor safety to be fully effective, the Soviets must agree to participate. There are hopeful signs that they are belatedly realizing their responsibility to their neighbors and the advantages of such international cooperation.

The need for exchange and provision of time- accurate information was one of the most, important lessons learned from the Three Mile Island accident in the U.S. by the Western nations. The Soviet people have our sympathy. But only complete openness and co-operation will temper the world's justifiable anger and indig-nation, and disperse the cloud of suspicion and uncertainty hanging over the nuclear power erinary hospital, a squat instru played key roles in deciphering the Chernobyl disaster was Dr. Ingemar Vin-tersved, a nuclear physicist with Sweden's National Defence Research Institute.

Vintersved once worked at the Chalk River reactor in Canada, and his papers on nuclear surveillance have been widely published by leading American scientific journals. "In a case like this, you have to work mainly with dirt," he told a visitor. "The Chernobyl reactor itself must be emitting radiation, but the intensity of that radiation falls off with the square of the distance it travels. Beyond a few hundred yards from the plant it would be practically undetectable. So in Sweden, hundreds of miles away, we must rely mainly on fallout in drawing our inferences." Radioactive fallout is intrinsically dangerous.

The gamma rays or other radiation emitted by a microscopic particle of dust or a droplet of aerosol mist travel only short distances. But when a radioactive particle settles on the skin or enters the body, the source of radiation is in direct contact with living tissue, and the local intensity of exposure may become dangerously high. For this reason, residents of the Chernobyl area are being advised to bathe frequently and to stay indoors. Certain kinds of fallout are especially dangerous because the body incorporates them into living tissue. Radioactive iodine 131 is particularly feared because it becomes concentrated in the thyroid gland, and by so doing it may irradiate surrounding tissues with gamma-ray doses high enough to cause cancer.

Radioactive cesium and strontium are assimilated into bone. But fallout is very useful to scientific investigators. The mix of radioactive isotopes in a microscopic particle of smoke can be distinctive, and may reveal a great deal about the source of the fallout. The presence of zirconium, for instance, implies that the source reached a very high temperature at some point, and that a meltdown may have occurred. The isotope zirconium 95 is one of about 20 isotopes that Swedish scientists have identified in the fallout coming from Chernobyl.

Looking for fallout is the first part of the analytical process. In Sweden the ground is now covered with it, and in places enough has accumulated to create agricultural problems. Since fallout drifts with the wind, it is deposited in irregular patterns; the ground around Stockholm, for instance, is contaminated only to a negligible extent, but 160 kilometres to the north is an extensive hot spot where the grazing of cattle has been temporarily banned. All European countries have been dusted with Chernobyl fallout, but the quirks of weather have produced a patchwork of widely ranging radiation intensities. Measuring overall levels of fallout in Sweden is a largely automated process.

Some 25 monitoring stations throughout the country record radiation levels using simple devices called ionization chambers. The sensing elements of these instruments are given electrical charges before measurements begin. When X-rays or gamma rays penetrate an instrument, they permit the charge to dissipate, and the decline in the charge is proportional to the amount of radiation it has received. Instruments relay their readings to Stockholm, and technicians supplement these data using portable manual instruments. But much more important in the interpretation of fallout is the gamma-ray spectrometer.

Gamma rays, which are more penetrating and more dangerous than X-rays, are produced by certain types of unstable atoms. When the nucleus of such an atom spontaneously flies apart in the process called fission, it gives off a packet of electromagnetic energy a gamma-ray photon. The energy of the photon, measured in thousands of electron volts (abbreviated as KeV), is as distinctive as a fingerprint, and can be used to identify the type of atom from which it was emitted. Since radioactive nuclei may split apart in several possible ways, several different energy levels may be associated with the photons they produce, and all these energy levels may serve as clues. To measure the energies of individual gamma-ray photons requires a large cylindrical crystal of pure, silvery germanium, chilled by liquid nitrogen to a temperature of minus 320 degrees Fahrenheit.

When a gamma-ray photon hits such a crystal it briefly permits a tiny pulse of electricity to flow. By measuring the duration of the pulse, a gamma-ray spectrometer can calculate the energy of the photon that caused it. ment perched on a wooden tripod peers straight down at the ground through its cylindrical metal snout. A passer-by would scarcely notice it, yet the gadget's importance to the world would be hard to exaggerate. The instrument, a portable gamma-ray spectrometer, is one of the key sensors used by Swedish science detectives in piecing together an accurate account of what really happened at the Chernobyl reactor plant.

The gamma-ray detector in the backyard of the former cattle clinic is one of many set up in the pastures, forests and towns of Sweden, all of them continuously looking at and analysing the fallout that drifts to the ground beneath them. The accident, occurred April 26 some 1,440 kilometres from Stockholm, came to world attention two days later because of the stringent safeguards that prevail at Sweden's four nuclear power reactors. An employee of the Forsmark reactor arriving for his shift on April 27 routinely scanned his feet with a radiation detector before entering the plant, and the detector sounded an alarm that was soon heard around the world. The radioactive dust on the worker's shoes had come not from inside the plant but from the distant Ukraine. But it was a long step from detecting radioactive dust on a man's feet to deducing that an accident had occurred at the Chernobyl reactor, and that the core had probably melted down.

To reach that conclusion took the co-ordinated analyses of nuclear physicists, meteorologists, reactor experts and even jet fighter pilots who flew through the radioactive cloud. Sweden's experts worked round the clock, and while other nations were still guessing, Stockholm was able to provide details based on hard scientific evidence. In the absence of information from the source, an accurate assessment of a nuclear explosion or power plant accident must be based on a host of scientific measurements, on powerful computer programs and on perceptive inferences from limited data. Among the Swedish investigators who.