R1.01/04 A5 - Liquid radioactive waste treatment system (LRWTS) for Kola NPP - Lot 5/2 - Oxidation and Filtration Equipment

Kola NPP consists of four VVER-440 power units and comprises two special buildings where liquid radioactive waste (LRW) storage vessels are located. These two special buildings were constructed during the 1st construction stage (Units 1 and 2) and 2nd construction stage (Units 3 and 4) respectively. Accumulated LRW is temporarily stored in stainless steel tanks. It has to be processed in such a way as to allow for safe long-term storage, transportation and final disposal of such waste.

It has been decided to renovate the Liquid Radioactive Waste Treatment Unit (LRWTU) at Kola NPP in order to create a complex of process systems, installations and equipment for handling and treatment of waste which has been accumulated up to the present time and in future. This will be done by means of solidification to reduce the initial amount of waste and conditioning for controlled safe storage and further final disposal.

The complete LRWTU includes the following sub-systems, units and equipment (see the block diagram of the complete LRWTU in the attached diagram):

• А1 – dissolution and extraction of salts (R1.01/94G);
• А2 – concentrating (R1.01/96C);
• А3 – cementation of waste ion-exchange resins and sludge (R1.01/04A Lot 3);
• А4 – extraction of liquid radioactive waste from storage tanks (R1.01/94G);
• А5 – removal of radionuclides from evaporator concentrate solutions (R1.01/04A Lot 5/1 and R1.01/04A Lot 5/2);
• Transport/process equipment for handling the solidified waste (R1.01/04A Lot 1);
• Radiation control (monitoring) equipment (R1.01/04A Lot 2);
• Auxiliary systems and units;
• Solidified waste storage facility.

Several of the above systems and components of the LRWTU have been provided through the TACIS programme, as indicated in the above list (see projects R1.01/94G, R1.01/96C, R1.01/04A Lots1-5). Project R1.01/04A Lot 4 comprised the supply of valves for installation at the connections between the different process systems. A feasibility study was also performed in the framework of project R1.6/91.

Project R1.01/04A, programmed in the TACIS Annual Action Programme of 2004, was the so-called 'large-scale' equipment supply project for Kola NPP. It was divided into several lots in order to purchase the remaining equipment needed for the construction of the LRWTU.

The present contract was for Lot 5, sub-lot 2. Under this contract Oxidation and Filtration Equipment was delivered as part of the radionuclide removal system.

The radionuclide removal system, being a part of the LRW treatment unit, is designed to purify the salt radioactive solutions stored in the LRW storage tanks of Kola NPP 1st and 2nd stages of radionuclides Co, Mn, Cs and corrosion products.

The radionuclide content of the salt solution residue resulting from the removal shall be such that the salt cake fusion end products obtained during further treatment at concentration plant A2 shall be classified as non-radioactive solid waste.

The radionuclides extracted from the salt solutions during the removal process are concentrated in the filtration sludge (Co, Mn, corrosion products and partially Cs) and on the ion-selective sorbent in the filter-containers (Cs radionuclides).

The filtration concentrate is supplied to Cementation unit A3 for solidification.

After preparation (flushing, drying and sealing) the spent filter-containers are supplied to the controlled LRWTU storage facility and subsequently may be transported for storage at the regional radioactive waste final repository.

The process of the salt solution radionuclide removal system makes use of the following techniques:

• Ozone preparation for oxidation of initial solution;
• Initial solution oxidation with the purpose of turning the Co and Mn radionuclides into a sludge component;
• Oxidised solution filtration in order to separate the sludge component from the co-precipitated radionuclides Co, Mn (partially Cs);
• Filtration through the ion-selective non-organic sorbent in order to remove the Cs radionuclides.

The oxidation technique used is that of salt solution ozone oxidation, the one allowing for achieving the system target indices at the minimum chemical reagent consumption, so that the volume of LRW handled is not increased.

The supply of the radionuclide removal system was divided into two sub-lots:

• Sub-lot 1: Ozone preparation system
• Sub-lot 2: Oxidation and Filtration Equipment

Scope of supply

The present contract covers the supply of separate components of Lot 5, sub-lot 2 (Oxidation and Filtration Equipment) of the radionuclide removal system, including equipment, pipeline valves, I & C facilities and electric equipment, as well as associated services as set out hereunder:

Equipment

• Oxidation group;
• Filtration group;
• Pipeline valves;
• Electrical and I & C equipment
• Sampling devices
• Spare parts for the above

Services

• Provision of Documentation
• Acceptance Tests of Equipment
• Certification of Equipment
• Supervision of installation and commissioning
• Personnel Training
• Support to Licensing

The specified equipment was delivered, installed and commissioned and all services, including training of End User personnel, were satisfactorily performed. The Provisional Acceptance Certificate (PAC) was signed in July 2010. The warranty period was completed in accordance with the contract and the Final Acceptance Certificate (FAC) was signed in May 2012;