The England Syndrome

The Overlook

By Tom Clavin

“The Overlook” appears every Thursday at tomclavin.substack.com. An overlook is usually a place from which one can see in many if not all directions, including where one has been and where one is going. If you enjoy the column, please "like" it and let me know what you think by commenting (check out previous ones while you're at it).  Likes, comments, and shares help with author discoverability on Substack.com, and all support is appreciated. Don't forget to hit the ‘Subscribe’ button – it’s free!

          For good reasons, in the annals of nuclear plant disasters Chernobyl and Three Mile Island have received the most attention. But flying under the radioactive radar since it occurred 64 years ago this month has been the Windscale fire. It was the worst nuclear accident in the United Kingdom's history, and one of the worst in the world, ranked in severity at level 5 out of a possible 7 on the International Nuclear Event Scale. 

The fire took place at the Windscale facility on the northwest coast of England in Cumberland. The two graphite-moderated reactors, referred to at the time as "piles,” had been built as part of the British post-war atomic bomb project. The fire burned for three days and released radioactive fallout which spread across the UK and the rest of Europe. The radioactive isotope iodine-131, which may lead to cancer of the thyroid, was particularly concerning at the time. It has since come to light that small but significant amounts of the highly dangerous radioactive isotope polonium-210 were also released.

On October 7, 1957, operators of Pile 1 noticed that the reactor was heating up more than normal, and a “Wigner release” was ordered. This had been carried out eight times in the past, and it was known that the cycle would cause the entire reactor core to heat up evenly. But during this attempt the temperatures began falling across the reactor core, except in channel 2053, where the temperature was rising. Concluding that 2053 was releasing energy but none of the others were, on the following morning the decision was made to try a second Wigner release. This attempt caused the temperature of the entire reactor to rise, indicating a successful release.

However: Early in the morning of October 10 it was suspected that something unusual was going on. The temperature in the core was supposed to gradually fall as the Wigner energy release ended, but the monitoring equipment showed that the core temperature was instead rising. As this process continued, the temperature continued to increase and eventually reached 400 °C. Cooling fans were sped up and airflow was increased. Radiation detectors in the chimney then indicated a release, and it was assumed that a cartridge had burst. This had happened in the past, but unknown to the operators, the cartridge had not just burst, it had caught fire.

Speeding up the fans increased the airflow in the channel, fanning the flames. The fire spread to surrounding fuel channels, and soon the radioactivity in the chimney was rapidly increasing. A foreman arriving for work noticed smoke coming out of the chimney. The core temperature continued to rise and the operators began to suspect the core was on fire. They tried to examine the pile with a remote scanner but it jammed. Tom Hughes, second in command to the reactor manager, Tom Tuohy, suggested examining the reactor personally. He and another operator went to the charge face of the reactor, clad in protective gear. A fuel channel inspection plug was taken out close to a thermocouple registering high temperatures and it was then they saw four channels of fuel glowing bright cherry red.

There was now no doubt that the reactor was on fire and had been for almost 48 hours. Tuohy then donned full protective equipment and breathing apparatus and scaled the 80-foot ladder to the top of the reactor building, where he stood atop the reactor lid to examine the rear of the reactor -- exposing himself to a large amount of radiation. Red-hot fuel cartridges were glowing in the fuel channels on the discharge face. Tuohy returned to the reactor upper containment several times throughout the incident, at the height of which a fierce conflagration was raging.

Operators tried to blow the flames out by running the fans at maximum speed, but this fed the flames. Hughes and his colleague had already created a fire break by ejecting some undamaged fuel cartridges from around the blaze. Tuohy suggested trying to eject some from the heart of the fire by bludgeoning the melted cartridges through the reactor and into the cooling pond behind it with scaffolding poles. This proved impossible and the fuel rods refused to budge, no matter how much force was applied. The poles were withdrawn with their ends red hot. One returned dripping molten metal.

The fire was at its worst on October 11, with 11 tons of uranium ablaze. Temperatures were becoming extreme -- one thermocouple registered 1300° C -- and the biological shield around the stricken reactor was now in severe danger of collapse. Tuohy suggested using water. This was risky, as molten metal oxidizes in contact with water, stripping oxygen from the water molecules and leaving free hydrogen, which could mix with incoming air and explode, tearing open the weakened containment. But with no other options, the operators decided to go ahead with the plan.

About a dozen fire hoses were hauled to the charge face of the reactor. Their nozzles were cut off and the lines themselves connected to scaffolding poles and fed into fuel channels about three feet above the heart of the fire. Tuohy once again hauled himself onto the reactor shielding and ordered the water to be turned on, listening carefully at the inspection holes for any sign of a hydrogen reaction as the pressure was increased. Alas, this effort also failed.

Tuohy then ordered everyone out of the reactor building except himself and the fire chief in order to shut off all cooling and ventilating air entering the reactor. By this time, an evacuation of the local area was being considered. Tuohy climbed up several times and reported watching the flames leaping from the discharge face slowly dying away. During one of the inspections, he found that the inspection plates—which were removed with a metal hook to facilitate viewing of the discharge face of the core—were stuck fast. This was due to the fire trying to suck air in from wherever it could. He managed to pull an inspection plate away and was greeted with the sight of the fire dying.

Finally, some hope. Water was kept flowing through the pile for a further 24 hours until it was completely cold. The bad news was there had been a release into atmosphere of radioactive material that spread across the UK and Europe. The UK government under Harold Macmillan ordered original reports into the fire to be heavily censored and information about the incident to be kept largely secret. Later reworking of contamination data has shown national and international contamination may have been higher than previously estimated.

In the you-can’t-be-too-careful department: The presence of chimney scrubbers at the Windscale plant was credited with maintaining partial containment and thus minimizing the radioactive content of the smoke that poured from the chimney during the fire. These scrubbers were installed at great expense on the insistence of John Cockcroft and were known as Cockcroft's Folly . . . until the 1957 fire.

Because of the release of radioactive isotope iodine-131, it was decided that consumption of milk from the surrounding area should be stopped. Eventually restrictions were put in place on the consumption of milk from the 200-square-mile area surrounding the plant. Milk from farms was destroyed and dumped in the Irish Sea.

The release of the highly dangerous radioactive isotope polonium-210, which had been covered up at the time, was not factored into government reports until 1983, when it was estimated that the fallout had caused 33 cancer fatalities in the long-term. These deaths were attributed not only to thyroid cancer but also to lung cancer. An updated 1988 UK government report estimated that 100 fatalities "probably" resulted from cancers. The government report also estimated that 90 non-fatal cancers were caused by the incident, as well as 10 hereditary defects. 

The Windscale reactor tank itself has remained sealed since the accident and still contains about 15 tons of uranium fuel. The pile is not scheduled for final decommissioning until 2037. By the way, the courageous Tom Tuohy, who had exposed himself to high levels of radiation, lived to be 90.

Tom Clavin is the bestselling author/co-author of 18 books, including the forthcoming Lightning Down: A World War II Story of Survival, to be published by St. Martin’s Press on November 2. To pre-order, please go to your local bookstore or to Bookshop.org, Amazon.com, or BN.com.