Because Chernobyl is a work of fiction based on fact, it may be hard to tell what in it is to be taken as fact and what the license of the novelist.
To begin with, all of the characters who appear in the novel are fictitious. Some of the things done in the novel were in fact done by real people, as in the case of the three men who donned diving gear and entered into the flooded corridors under the reactor to open the drainage valves — the names of the three actual men are Alexei Ananenko, Valeriy Bezpalov and Boris Baranov — but the characters in the novel are not in any way modeled on them.
The nature and chronology of the explosion and its consequences correspond as closely to reality as has been possible, although I have taken a few minor liberties with timing. The accompanying events have also been drawn from actuality, although in a few cases it is at least arguable what the actuality is.
A special case of this is the "seventeen-page document." The document described does exist. It is a reasoned manifesto that pleads for quite drastic reforms in such areas as freedom of speech, industrial priorities, and political processes. The document has in fact been circulated surreptitiously within the USSR and, after Chernobyl, even abroad. What is not certain is whether this document emanates from high-placed officials, as it claims, or is a fabrication put together by Soviet emigres in the West. On the other hand, there is good evidence that many of the rather revolutionary changes the document proposes are in fact seriously contemplated by senior officials — though other high-ranking officials oppose them vigorously.
A particularly visible sign of such change is Mikhail Gorbachev's continuing sponsorship of a policy of "glasnost," or candor and honesty both in reporting the facts of Soviet life and in discussing what measures should be taken to deal with them. This policy did not begin with the Chernobyl event, but that disaster is what has made it possible for an outsider to understand the new policy. It was glasnost that permitted the publication of Lyubov Kovalevska's savagely critical article on the shortcomings of Chernobyl Nuclear Power Plant in the March 27, 1986, issue of Literaturna Ukraina, just a few weeks before the explosion. It was glasnost that resulted in the un-precedentedly complete and candid Soviet report on the Chernobyl accident submitted to the International Atomic Energy Authority in Vienna in September 1986 (from which much of the technical background of this novel was drawn). It was also glasnost that has since produced the reporting, in the Soviet press and abroad, of stories of riots, accidents, demonstrations, and other Soviet events that were almost never admitted previously — including stories of malfeasance of high Communist Party officials, and even of members of the KGB.
And, on a much smaller scale, I believe it was again because of glasnost that I received the great assistance and cooperation that was extended to me when I returned to the Soviet Union to complete my research for this novel. For this I must thank many Soviet officials, but in particular the leadership of the Union of Soviet Writers. They opened many doors for me, and imposed no restrictions on what I might write or whom I might see. With their help I was able to interview scores of people with direct knowledge of the Chernobyl accident, journalists, eyewitnesses, firemen who fought to control the damage, nuclear experts who were on the scene and many others. They did more to help me get this story than I could have hoped, and I am grateful.