Repair brigade received high exposure doses

Publish date: May 20, 1997

Written by: Thomas Nilsen

A repair brigade at the LNPP performing works at the operating fourth reactor (RBMK- 1000 type), received high exposure doses, reports local environmental group Green World.

Having received the highest dose (28 rem), the repair leader was dismissed from work which may expose him to dangers of radiative contamination on January 12, 1997. The accident was a result of violations of the safety rules and an absence of control. The repair brigade was working on a loading machine at the forth operating RBMK-1000 reactor. The machine is used to remove spent fuel from the reactor and install fresh fuel when necessary.

–According to an LNPP employee, who phoned our office and preferres to remain unknown, 6-8 members of the brigade received equivalent doses between 19 and 28 rem (190 – 28O mSv) from several hours of exposure, says Green World spokesman Oleg Bodrov. Russian standards defines the maximum permissible equivalent dose for npp employees as 2 rem during a year (20 mSv). A Dr. J. Gofman-method compliant assessment gives 79% probability for one of the brigade members to acquire radiation-induced cancer, according to a Green World radiation expert.

On March 4 1997, about 8 p.m., another accident took place at a spent nuclear fuel storage facility at the LNPP. The building is situated close to the Baltic sea. According to Sergey Kharitonov, an LNPP employee and member of Green World, an absorber rod was deformed and stuck during reloading in a special container. Later, it was found that one of the reasons for the accident was a mistake of the personnel, when a container already filled with a rod was driven up for loading instead of an empty one.

A similar accident during reloading of one of the 22,000 spent fuel assemblies (highly active wastes) stored in the building, could cause leakages from a fuel rod with activity of several hundred thousands Curie (several TBq). According to Sergey Kharitonov, the March 4 accident resulted from a combination of less than perfect technology and neglect of safety regulations. For example, the hall where reloading of spent fuel is carried out is poorly illuminated, and the reloading monitoring equipment is obsolete. –We wrote about this in our newsletter "Baltic Region – Our Habitat" more than a year ago. Now we see that the situation has not changed. Thus, similar accidents should be anticipated in the future, says Oleg Bodrov.

According to official information from the LNPP press-centre, the first, second and fourth RMBK-1000 reactors operated at close to 100% power during the first three months this year. The third power unit is under reconstruction. The operating reactors produced 5,944 GWh electrical power, which was supplied to customers at 133.77 roubles/kWh (0.024 $/kWh). In addition, the LNPP supplied the city of Sosnovy Bor with "nuclear heat" for heating of houses at the cost of 31,000 roubles/Gcal (1.32 $/GJ), and hot water at 3.743 roubles/m3 (0.67 $/m3). Sosnovy Bor citizens consumed 1,398,640 m3 of cold drinking water during the same three months, which means that each inhabitant of the nuclear city consumed 260 litres of drinking water daily.