R2.01/06 PART A Development of modernisation measures of primary and secondary water chemistry monitoring systemsfor unit 1 and 2 of Kalinin NPP

Appropriate water chemistry of both primary (nuclear) and secondary (non-nuclear) cooling circuits of a nuclear power plant is necessary to maintain safe, reliable and economical operation of the plant. Among others, it helps to

• Minimize radioactive deposits on internal surfaces of primary circuit components decreasing the collective dose rate of the plant personnel;
• Minimize deposit creation on the heat-exchanging surfaces optimizing the heat transfer;
• Minimize corrosive damage of primary and secondary circuit components;
• Maintain integrity of the fuel cladding.

In order to keep the water chemistry appropriate, the related chemical parameters (pH, conductivity, impurity concentration) at specific points have to be carefully monitored.

In the past, water chemistry at Russian NPPs had been monitored mostly “manually”, i.e. by laboratory analysis of manually taken samples. The available on-line water chemistry monitoring equipment had been obsolete and not compliant with up-to-date technology. Being aware of the persisting gaps in the NPP water chemistry control against the best international practice, the Concern Rosenergoatom asked the European Commission for support in this area. To provide the assistance, the EC established the R2.01/06 TACIS project.

The project was implemented within two separate contracts: (1) this fee-based contract 132487 concluded with an EU-based consultant, Chemcomex Prague, and (2) another, global price contract 172020 concluded with a Russia-based Director of Experiments (DoE) EREC Institute in Elektrogorsk, as described in a separate summary. The overall project management was the responsibility of the consultant, Chemcomex, a.s.

The general objective of the R2.01/06 project had been to support the Concern Rosenergoatom in monitoring the water chemistry at VVER-1000 power plants and to modernize it by taking into account the international experience and best practice.
The specific objectives of the 132487 contract had been to:

• Deliver to the beneficiary a design of up-to-date on-line/automated monitoring systems for the VVER-1000 primary and secondary circuit including
  • water chemistry monitoring methodology
  • hardware specifications of online sampling and monitoring equipment
  • water chemistry parameter database
  • water chemistry monitoring and data processing software;
• Experimentally verify the proposed design (for secondary circuit only) to be implemented at pilot nuclear power plant;
• Improve the general the water chemistry management and associated knowledge at the pilot power plant.

As the pilot plant, the Kalinin NPP (4xVVER1000/320) was selected.

The EU based consultant implemented the contract in several technical tasks, where it was supposed to (1) review the water chemistry monitoring practices existing both at the Kalinin NPP and western NPPs, (2) prepare technical requirements for a water chemistry concept and chemistry monitoring systems for primary and secondary circuits at Unit 1 and 2 of the Kalinin NPP, (3) propose a design of the water chemistry instrumentation & control equipment for the primary and secondary circuit including a software application for automated processing of data obtained from both on-line and laboratory sampling, and (4) train the Kalinin NPP personnel in the proposed solutions. Within a separate task, the proposed secondary circuit chemistry monitoring system design was supposed to be experimentally verified by DoE (EREC) at its V-3 experimental facility at Elektrogorsk, Russia.
Within the first technical task (task 2 as per the Contract Terms of Reference), the consultant reviewed the water chemistry monitoring systems used at Kalinin NPP and compared them to those used at Temelin NPP (VVER-1000/320 reactor) and Biblis B NPP (standard western PWR). Based on the comparison, basic water chemistry monitoring principles, reflecting mostly the Temelin NPP experience and practices, were recommended to the Kalinin NPP units.

Within the second technical task (task 3), the consultant developed a comprehensive concept of the water chemistry monitoring system consisting of:

• Field equipment for sample conditioning and on-line monitoring of chemical parameters (pH, conductivity, concentration of specific chemicals and impurities in the primary and secondary circuit water);
• Data concentrator, collecting data from individual on-line monitors and transferring them to the data processing system;
• Data processing system, consisting of a database server, application software and users workstations integrating outputs of continuous on-line measurements, individual off-line laboratory analyses as well as basic information on NPP unit operation into a single system.

Based on current Russian requirements for the water chemistry monitoring systems, the consultant provided general recommendations and technical specification of the sample conditioning and on-line water chemistry monitoring equipment for Kalinin 1 and 2. The recommendations had focused mainly in on-line monitoring of specific points and sub-systems of the primary circuit, secondary circuit and tertiary cooling water, but have included also off-line sampling and laboratory analyses of chemical parameters. Moreover, the consultant suggested potential changes of water chemistry parameters to be monitored and controlled. Last but not least, the consultant presented sampling conditioning and on-line chemistry monitoring equipment available on European market and recommended those eligible for use at Kalinin 1 and 2.

Within the third technical task (task 4), the consultant elaborated specific design features of the water chemistry monitoring system for both primary and secondary circuit as proposed within the previous task. The design has included piping and instrumentation diagrams (P&ID) of the sampling and on-line monitoring equipment as well as electrical wiring diagrams. Specific sampling points at primary and secondary circuit were identified, and location, measured value, measuring range, accuracy, type of measuring equipment, as well as references to master P&ID were specified for each of them. Basic information was also provided to the beneficiary on possible design of data concentrators and the system computer network.

The consultant handed over to the beneficiary a Russian version of the data processing system software called CHEMIS and installed its demo version at Kalinin NPP. A full version of the CHEMIS software was installed also at DoE in EREC Elektrogorsk for performance of the verification experiments. After the installation, user’s manuals in Russian were handed over to the beneficiary and DoE and their relevant personnel were trained in the system operation.

As a part of the personnel training, the consultant also organized study tours to the Temelín NPP, Czech Republic and Biblis NPP, Germany to familiarize Rosenergoatom, Kalinin NPP and DoE experts with the international practice in on-line monitoring of water chemistry.

Within the “experimental” task, the consultant assisted DoE in preparation of the test procedures to verify the proposed design of secondary circuit water chemistry monitoring system. Because of technical problems with the V-3 experimental facility due to its previous long-term shutdown, the test had to be postponed and project implementation period was extended by 6 months. The DoE finally carried out the tests under the consultant’s supervision in December 2011 and January 2012.

Conclusions

All activities required by the Contract Terms of References were successfully implemented and all objectives were achieved. The verification experiments were successfully performed and confirmed eligibility of the proposed design of the water chemistry monitoring system.