The storage building was constructed in concrete and consists of two rectangular pools in which the inward walls are lined with steel plate. Each pool is 60 metres long, three metres wide and six metres deep with a total volume of about 1,000 m³. The volume of water in the oldest part of the facility is 600 m³ whereas the area built in 1973 has a capacity of 1,400 m³. The entire building itself is 70 metres long and 18 metres high. The facility was taken into use with the understanding that the spent nuclear fuel was to be stored in the water in the storage pools. The level of water in the pools was to be monitored from the neighbouring building in which the purification facility for liquid radioactive waste was located. Any eventual adjustments would also be made here. However, since the purification facility was not in operation, monitoring of the water level and other measurements had to be done manually. The fuel assemblies were placed alongside each other in rows of five or six and stored in containers. Each container of nuclear fuel weighed up to 350 kilograms. Up until 1973, the facility had a storage capacity corresponding to 550 of these containers. Upon the completion of the second building stage, the capacity had increased by 2 000 for a total of 2,550 containers. These had between 12,750 and 17,850 fuel assemblies, corresponding to 54 to 76 reactor cores. Later, as the Northern Fleet faced storage capacity problems for its spent fuel, the possibility of placing the containers closer together in the pools was considered. This idea was rejected for reasons of radiation safety.

Spent nuclear fuel assemblies from all of the Northern Fleet shipyards were sent to Building 5. The containers were transported aboard Northern Fleet service ships of type 326 M and type 2020 to a special pier in Andreeva Bay. Here the derricks of the service ships lifted the holding containers up from the storage compartments and transferred them into a larger transport container. The transport container was then hoisted over to a dumper of the type BeLAZ-450 and driven up the 350 m long road up the hill and into Building 5. Unloading from the dumper took place inside Building 5 using a crane with a lifting capacity of 15 tonnes. The containers full of spent fuel were then removed from the transport container into an unloading room and transferred into a pool of water. Here it was attached to a chain hook beneath a special crane on rollers mounted in the roof of the building. This crane was driven to the designated location inside the building where the containers holding the fuel assemblies were to hang.

The containers of spent nuclear fuel were suspended so that they were covered by four metres of water. This was to protect the facility’s employees from receiving dangerously high doses of radiation, as well as to cool the heat producing fuel assemblies. One of the earliest problems at the storage facility was that water penetrated the containers, resulting in direct contact between fuel and water.

In February 1982, the personnel of Building 5 discovered that the level of water in the second pool had dropped and a dangerous leak had developed (see the section below). It soon became apparent that the storage facility could no longer be used, and measures were taken to remove the fuel assemblies from the building.

The accident at the storage facility for spent nuclear fuel
In February 1982, it was discovered that the water level of the pools in Building 5 had fallen dramatically. Upon closer inspection it was learned that there was a serious leak of highly radioactive water from the pools. The first open information about the accident came to light in March 1993 through the environmental foundation Bellona. The first official Russian confirmation of a leak of radioactivity in Andreeva Bay did not come until later in the same year when Russia’s environmental advisor, Aleksey Yablokov, issued an official report on the practice of dumping radioactive waste at sea. A detailed description of the incident follows below:

The location of the leak in the second pool was in the lower parts of a concrete wall which had been covered on the inside with steel plate. These steel plates had cracked, and ice had formed on the outside of the building as the water continued to leak out. A commission of specialists from the Northern Fleet was formed to investigate the accident. Their calculations showed that the pool was leaking at a rate of about 30 litres a day. The commission worked with the builders of Building 5 to develop a plan of action. In the meantime, the leak grew worse. By April 1982, it was calculated that water was leaking from the pool at a rate of 100 litres a day. Measuring equipment mounted on the outside of the wall in the vicinity of the leak indicated radiation levels of 15 mGy/h (1.5 R/h). The level of radioactivity at the bottom of the pool was about 150 MBq/l (4 x 10^-3 Ci/l). The radioactivity of the water which had leaked out was measured at 110 MBq/l (3 x 10^-3 Ci/l). In August 1982, work was started on covering the lower parts of the walls and floor of the pool with concrete. About 600 m³ of concrete was poured. Simultaneously, an attempt was made to filter the water that was leaking on the outside of the building with the aim of preventing the flow of contaminated water into the sea and the subsequent contamination of the area. The distance from Building 5 to the sea is 350 m, and the attempt to filter the water proved to be ineffectual, as were the efforts to stop the leaks. Towards the end of September 1982, the leak had increased and was now calculated to be up to 30 tonnes of water a day. The water in the pool had sunk to such a low level that there was a risk that the containers of fuel assemblies would no longer be covered. This would result in large doses of radiation to the employees, radioactive contamination of the other storage pool in the building as well as the brook flowing into the Litsa Fjord. The ineffectiveness of the action taken by the experts from Minatom resulted in the Northern Fleet assuming responsibility for stopping the leak and averting a larger catastrophe in the local area. Considerable resources were directed to the effort, and a decision was made to place a lid of iron, lead and concrete over the pool to shield against gamma radiation.

On October 5, 1982, Admiral A. Mikhaylovsky, Commander of the Northern Fleet, approved a plan for managing the accident and further cleanup in which the following measures were also taken:

• Completion of the work to cover the site of the leak in the concrete;
• Putting in a purifying plant to reduce radioactivity in both pools;
• Preparing the nuclear fuel in pool no. 2 for removal;
• Building a pipeline to add water to the pools which could also be used to empty them;
• Intensifying the work to complete concrete tank 3A in order to be able to receive spent fuel from Building 5;
• Decontamination of the area around Building 5.

A new project staff was appointed to achieve these points, headed by A. Petrovsky, technical director of the Navy. It was he who had suggested using concrete tanks 3A, 2A, and 2B to store spent nuclear fuel assemblies.

While work was underway to cover the first pool, in November 1982 it was discovered that the water level in the second storage pool was also sinking. In the course of one week, water was leaking out of the pool at an average rate of 10 tonnes a day. The activity of the water was 11 MBq/l (3 x 10^-4 Ci/l). By December 1982, the lid over the first pool had been completed, and the rate of the leak had been reduced so that the level of water could be maintained at about three metres. The activity of the water in this first pool was 1,9 MBq/l (5 x 10^-5 Ci/l). The second pool was leaking at a rate of about three tonnes a day, and here the activity was still 11 MBq/l (3 x 10^-4 Ci/l). Since fresh supplies of water were continually pumped in, the water level stayed at about four metres.

On February 14, 1983, a special commission form the Ministry of Defence visited Andreeva Bay. The commission approved both the measures that had been taken to stop the leak and the modification plans to turn the three concrete containers into storage tanks for spent nuclear fuel. Simultaneously it was decided that Building 5 would no longer be used to store spent nuclear fuel assemblies. In June 1983, work was started to remove the containers holding fuel assemblies from the second storage pool. At this time, the activity was highest in this storage pool. Most of the containers were transferred to concrete tank 3A, while a few more were transported to Mayak. By January 1984, all 1,000 containers had been removed. A complicating factor was that a considerable number of the fuel assemblies had fallen out of their containers and had to be raised from the bottom of the pool. About 70 containers could not be raised in the normal way; subsequently special cranes were constructed for them. A decision was made to wait two years to allow the levels of radiation to drop before removing the containers from the first storage pool.

Once the first storage pool had been covered with a lid and the second pool had been emptied, the employees who had carried out the work were rewarded with an additional vacation period and engraved watches. The project leader received a bonus of 240 roubles, equivalent to one half of his monthly salary.

In 1989, work was started to remove the fuel elements from the first storage pool and the remaining containers that had been left in the second pool. Both pools were emptied, and a total of 1,400 containers of fuel assemblies were taken out. A special group of experts was formed to remove the fuel assemblies that had fallen to the bottom of the pool. These specialists were drawn from a number of institutions that reported directly to Minatom, including NITI (Sosnovy Bor), VNIPIET (St Petersburg), FEI (Obninsk) and individuals from the Navy’s training centre in Sosnovy Bor. The group of 12 to 14 people was led by V. Bulygin in the task of raising approximately 120 damaged fuel assemblies from the bottom of the pool and transporting them away. The most dangerous part of the work lay in placing the damaged fuel assemblies into new containers, and it has been reported that seven or eight members of the group received radiation doses of 90 to 100 mSv (9 to 10 rem). The highest permissible annual dose is 50 mSv (5 rem).

The containers were raised and taken to another storage area, most probably the storage facility for solid radioactive waste at Andreeva Bay. Upon the completion of the work, the members of the team were recognised and various honours of the Soviet Union were bestowed upon them. Some were even granted the privilege of a car. The leader of the group, V. Bulygin, was awarded the medal “Hero of the Soviet Union”. The total cost of the work to empty Building 5 was about 5 million roubles (1989 figures).

It has been estimated that a total of about 3,000 m³ of water with an activity of 110 TBq (3,000 Ci) leaked from the storage pools. Measurements made in 1995 showed that the brook running from Building 5 was contaminated, A total area of 1,300 m^² is radioactive contaminated. In the Sea outside the Andreeva Bay there have also been measured contamination. It seems likely that much of the radioactive water from the leakage was absorbed into the ground outside the building. No samples have been taken from this area.

As of today, Building 5 is not in use, and it is in very poor condition. Nothing has been done to deactivate the building, and a great deal of equipment remains there. Levels of gamma radiation as high as 400 mGy/h (40 R/h) have been detected in certain areas at the bottom of the storage pools, probably due to spills of irradiated uranium from the fallen fuel assemblies. One suggestion is to cover the bottom of the pool with concrete, but this has not been done.

Parts of the actual construction of the storage pools as well as some of the equipment inside the building are considered to be high and medium level waste. There have been other proposals to use Building 5 as a storage area for other kinds of solid radioactive waste since the existing storage facility at Andreeva Bay is filled beyond capacity; however, because the building is in such poor condition, this has not been done either.