The Report covers the following topics:
A relatively high percentage of all operating LWRs in the world have implemented or are considering some kind of increase of the power (power uprate). This Report provides a worldwide review of power uprates. Water chemistry and radiology experiences of power uprates are presented separated on BWRs and PWRs. Key issues are identified and discussed and available options to assure maintained or improved conditions at power uprates are presented.
(LCC11 AR)
Operational issues with their link to other aspects are of large interest for Utilities as well as Regulators, Designers, Manufacturers and Laboratories. This LCC11 Report is covering two technical aspects dealing with: 1) Recycling of waste in primary coolant and, 2) Secondary water chemistry options and Hide out return of impurities from Steam Generators (SG).
Recycling of primary water wastes, is becoming more important to minimize both chemical and radiochemical releases into the environment. A specific focus is given to Tritium impact since this element is not eliminated by purification systems and thus recycled together with concentrates and distillates.
The secondary side chemistry is one of the key factors that are influencing safety, reliability and particularly availability of PWR and VVER Nuclear Power Plants. This Report gives: 1) all the relevant information to select the best chemistry options with the type and concentration of reagents that are used – with their advantages and disadvantages and, 2) the relation between the chemistry specification at SG blowdown and the various options of secondary treatment and purification systems.
The Hide out process and influencing parameters for different types of chemical elements and Hide Out Return of species from the Steam generators is also covered in this Report.
(LCC11 STR)
All materials used in nuclear power plants, as bare material (steels and alloys), are not stable in the reactor water and dissolve by corrosion. They are protected by passive oxide layers formed by the corrosion attack of the water to the metal surface under operating conditions. However, to some small extent these oxide layers dissolve in the reactor coolant and are transported as corrosion products (called also CRUD) to the reactor core. There they deposit on the fuel assemblies and are activated. The deposition of the crud on fuel assemblies and their release to the coolant highly influences the core and plant performance with respect to fuel cladding integrity and radiation fields.
The purpose of the Volume II of this Report, in LCC11, is to describe the tools and their application to adequately control the coolant crud in order to improve the fuel and out-core radiation performance. This information can support the plant chemists to establish strategies of applying the mitigating tools for crud control to achieve their plant specific goals. The information given in this Report is also valuable for fuel vendors and plant fuel engineers to evaluate the possible ways of improving the fuel performance. In a similar way, this information helps the Regulators at properly examining the relative importance of various CRUD Control Mitigating Tools to ensuring an improved fuel performance for safe operation. The associated Volume I containing: Mechanism of Sources, Transportation in Coolant, Fuel Deposition and Radiation Build-up, was published within the LCC10 Programme.
(LCC10 AR)
Key Emerging Issues and Recent Progress Related to Plant Chemistry/Corrosion in PWR/VVER/CANDU Reactors (LCC10 AR)
The objective of this Report is to provide a good understanding of the special problems and appropriate good practices during shutdown as well as during startup of LWRs. The Report provides a worldwide review of Startup and Shutdown Procedures both in the Primary and in the Secondary Circuit of PWRs, CANDUs and VVERs, and in the reactor coolant and main steam containing systems of BWRs.
Operational Issues, Practices and Remedies are important issues for plant personnel and designers. This report combines the following subjects of limited extent but potentially important consequences:
Crud in PWR/VVER Coolant. Volume I – Sources, Transportation in Coolant, Fuel Deposition and Radiation Build-up (LCC10 STR) The topic is covered in two separate volumes. Volume I which is provided within the LCC10 Programme, and Volume II which will be provided in the LCC11 Programme. This document, Volume I covers the following topics:
(LCC8)
The report covers the impact of manufacturing on microstructure and in-reactor performance of Zr-Nb alloys. The report was co-authored by Russian scientists involved in the development of the Russian Alloys E110, E635 and E125.
