WARSAW — Evidence has emerged in recent weeks that Soviet authorities at the highest level had at least a general understanding of the scope and gravity of the Chernobyl nuclear accident hours after it occurred, though they delayed notifying the Soviet people and other countries for two days.
"The Kremlin knew what was going on within an hour and a half" after an explosion shattered the reactor at the plant in the Ukraine early on April 26, sending a plume of radioactive fission wastes a mile into the atmosphere, according to a Western diplomat in Moscow who is familiar with the technical aspects of the accident.
The diplomat said that mounting evidence, some of it admittedly circumstantial, indicates that the country's top political leaders, not simply officials at the upper levels of government agencies, knew the gravity of the situation that early.
His view is supported by Soviet scientific sources, who say that the central government in Moscow was almost certainly aware on the day of the accident that radioactivity from the burning graphite reactor had spread far beyond Chernobyl, 400 miles southwest of Moscow. These sources said that within hours of the initial explosion, the radiation activated alarms and automatic shutdown systems at other Soviet nuclear plants north of Chernobyl.
They said the emergency shutdown of other nuclear plants within Soviet territory would have been immediately apparent to the central authorities in Moscow and could have left no doubt about the geographic scope of the contamination or the likelihood that it would spread beyond the Soviet borders. They said the plants apparently resumed operation when it became clear that the source of radiation was elsewhere.
The sources did not identify the other facilities by name, but only two other nuclear power plants lie north of Chernobyl in the path of the initial fallout plume. They are the Rovno nuclear plant, 220 miles northwest of Chernobyl and two-thirds of the way to the Polish border, and the Ignalina nuclear power plant, 350 miles to the north in Soviet Lithuania and halfway to Helsinki, the Finnish capital.
Even if duty officers at Rovno and Ignalina failed to notify Moscow promptly of radiation-related shutdowns, a sudden drop in generating capacity would have caused a disturbance in the country's unified electric power grid, which operates on a relatively thin margin of reserve capacity, and this would not have passed unnoticed in Moscow.
Also, Soviet sources said, the KGB security agency maintains officers at all nuclear facilities, with sophisticated and independent lines of communication to Moscow. These officers would have had no incentive to minimize or cover up an emergency situation.
Absence of Safety Feature
The four-unit Chernobyl plant itself was reportedly not equipped with an automatic shutdown system linked to radiation alarms. The absence of such a system is said to have been the result of a cost-cutting feature, one of several that made Chernobyl one of the Soviet Union's cheapest nuclear power plants.
According to the official report on the accident eventually released by the Politburo, a series of gross breaches of reactor operating regulations by workers at the plant led to a breakdown that resulted in a hydrogen gas explosion. The blast breached the No. 4 reactor at 1:23 a.m. on April 26. But it was not until the evening of April 28 that a four-sentence notice from the news agency Tass disclosed the accident, and it only hinted at casualties.
Even then the news came only hours after radiation alarms had sounded 750 miles to the north in Sweden and Finland, and the Swedish government had demanded an explanation.
Soviet officials have given a variety of reasons for failing to inform the world promptly. These tend to deflect blame from the Kremlin and center instead on bureaucratic confusion and incompetence at the scene of the accident.
A number of officials have said that local authorities initially underestimated the gravity of the accident and failed to fully inform the central leadership. The plant's director, its chief engineer and other senior officials at Chernobyl have since been fired or severely reprimanded. On Saturday, the official Tass news agency announced the firing of four senior state officials for serious errors and shortcomings in their work which led to the accident. Twenty-eight people have died as a result of the disaster.
In his first, and so far only, substantive comment on the accident, Soviet leader Mikhail S. Gorbachev appeared to blame local officials. On May 14, he said that "as soon as we received reliable information, it was made available to the Soviet people and sent through diplomatic channels to the governments of foreign countries."
But there is evidence, even in Soviet newspapers and in official accounts, that the central authorities understood the seriousness of the accident the very day it occurred.