It was some night, wrote Windscales general manager to his UKAEA boss shortly after the October 1957 fire still Britains most serious nuclear incident.
He was summing up two days and one night of frantic, but later highly praised, activity which prevented a serious fire with limited radioactive release from becoming a major meltdown with doubtless catastrophic results.
A central section of the core involving about 150 fuel channels caught fire while the reactor was deliberately allowed to heat up for a routine annealing operation. As temperatures rose to 1,200C, large quantities of water, and the brave decision to turn off cooling fans, eventually extinguished the fire.
Surrounding fuel had been hastily pushed out of the core into the water duct beneath. Some of these rods, plus all the fuel in the second unaffected pile, were retrieved before both reactors were closed down and virtually abandoned for 30 years.
In the late 1980s, at the start of the current dismantling scheme, it was established that some 7,000 fuel rods remained in and around the core in a largely unknown condition. Some 300 of these rods were retrieved last year from the water duct.