The third reactor was shut down “on August 27th at around 6:30 pm when it was discovered that there was a crack in the reactor’s discharge accumulator," the plant’s press service said.
“In order to avoid disorders, (we) began to discharge the energy block, and at 7:40 pm it was shut down,” the statement from the Leningrad plant read.
“A crack in the accumulator of the feed pump is nothing short of an accident, which could have radiological consequences,” said Alexander Nikitin, head of Bellona’s Russia offices.
According to an official with the International Atomic Energy Agency (IAEA) who Bellona Web contacted about the circumstances, the agency maintains a 24-hour communication system devoted to receiving nuclear event and emergency notifications worldwide.
The IAEA official said in an email interview that the incident at the Leningrad Nuclear Power Plant did not warrant the activation of this communications system, as the IAEA received notice of the mishap directly from its Russian counterpart, and information about the hole in the feed pump system had been published on the site of Russia’s nuclear corporation, Rosatom, where it was described as a “non-incident.”
The IAEA maintains the seven-point International Nuclear Event Scale (INES). In order for a nuclear event to be classified as an “accident,” it must be ranked a four or higher. The IAEA official wrote that, based on information received from Russia regarding the feed pump, the event is considered to be a zero, or a “non-incident” on the INES scale.
But that may not be the end of the story. The IAEA official wrote that the IAEA may get more detailed information about the event from Russia later this week. Bellona Web and the IAEA will remain in contact over further developments.
The safe ranking that the IAEA is currently inclined to give the August 27th incident notwithstanding, Bellona and a host of other Russian and international environmental groups and nuclear regulators have long called for the closure of the aged Leningrad plant for its repeated safety breaches, the bulk of which are catalogued in a major Bellona report.
The Leningrad Nuclear Power Plant is located 80 kilometres west of St. Petersburg and its 5 million residents on the shores of the Baltic Sea. Each of its four first-generation fatally flawed Chernobyl-type RBMK-1000 reactors are capable of generating 1000 megawatts of power.
RBMK-1000s, which came into wide use in the Soviet Union in the 1960’s, are graphite moderated – a heat management system that was later revealed to be grossly insufficient, as evidenced by the Chernobyl disaster of 1986.
The plant’s history has been characterised by leaky and overfilled wet storage units for spend nuclear fuel assemblies, take-over strikes held by workers, inebriated workers behind the controls, human errors during reactor repairs that have resulted in shut downs, waste seepage into the Baltic Sea, and, on one occasion, a worker sneaking a gun through the plant’s poor security.
Nonetheless, the plant remains a Potemkin Village for foreign nuclear officials and a source of power for Finland, which has alternatively decried the plant’s shortcomings and shielded it from critics as a result of its contribution to the Finnish electrical grid.
Three years ago, however, Finnish authorities took an unequivocal stance against the plant. Heikki Reponen, an expert with STUK, Finland’s official Radiation and Nuclear Safety Authority, called the reactors at the Leningrad Nuclear Power Plant unsafe for use, and Finnish Member of European Parliament called for the plants closure.
The new incident at one of Russia’s oldest nuclear power plants dovetails with a groundswell of popular Russian opinion against nuclear power and its potential expansion, recent polls commissioned by environmental groups have shown.
As a result of a crack or aperture in the feed pump circuit, contaminated water could leak from the closed system of the feed circuit into the technological zone of a nuclear power plan – that the area in which reactor workers are located, Nikitin added.
The feed pump, Nikitin explained, pours water into a reactor’s separator drums in which it is mixed with the water of the circuits of the multiple forced circulation system. Water in the circuit of the multiple forced circulation system is highly radioactive, as it comes into contact with the heat generating elements of the reactor.
As a result of a crack or aperture in the feed pump circuit, contaminated water could leak from the closed system of the feed circuit into the technological zone of a nuclear power plan ¬– that the area in which reactor workers are located, Nikitin added.
“The main question is where the crack is located and if (plant officials) have managed to localise the spilled water within a safe zone,” said Nikitin.
Additional confirmation of how serious the situation was is indicated by the shut down and cooling of the reactor itself, which indicated that a serious technical error occurred that made operating the reactor at a lower power level impossible, thus requiring its full stoppage.
As to possible irradiation of plant workers, Nikitin said that “here, everything depends on the concrete situation. The feed pumps are located in very protected areas typically inaccessible to people, and such a malfunction has to be diagnosed using automated equipment, but we unfortunately do not have full information about the events.”
As to speculations on how the hole would have appeared, Nikitin said that, as a rule, such accidents are a result of worn out technology and production mistakes.
The Leningrad Nuclear Power Plant’s No.3 Reactor came online in 1979 with an engineered life expectancy of 30 years, meaning it should be taken out of service this year.
“Despite the fact that extending the engineered life expectancy of such reactors is sufficiently adventurous, we expect that (Russian state nuclear corporation) Rosatom’s plans to use the nuclear power plant beyond its engineered basis remain the same,” said Nikitin.
The most serious accident experienced by the Leningrad Nuclear Power Plant happened in 1975 when an aqueduct in reactor No 1 malfunctioned, causing a large number of dangerous radionuclides to be released into the atmosphere through a ventilation shaft.
The details of the circumstances surrounding the accident – which at the time resulted in radio and television announcement to St. Petersburg and area residents not to go outside – remain classified.
Charles Digges and the staff of Bellona’s St. Petersburg co-wrote this report.