Status of the astrid gas power conversion system option

International audienceWithin the framework of the French 600 MWe Advanced Sodium Technological Reactor for Industrial Demonstration project, two options of Power Conversion System (PCS) were studied during the conceptual design phase (2010-2015)- the use of a classical Rankine water-steam cycle, similar to the solution implemented in France in Phenix and Superphenix , but with the goal of greatly reducing the probability of occurrence and limiting the potential consequences of a sodium-water reaction; chosen as the reference for the ASTRID Plant Model during the conceptual design phase due its high level of maturity,- the use of a Brayton gas cycle which has never been implemented in a Sodium Fast Reactor. Its application is mainly justified by safety and public acceptance considerations in inherently eliminating the sodium-water and sodium-water-air reaction risk existing with a Rankine cycle.The ASTRID conceptual design phase period allowed to greatly increase the maturity level of a standalone Gas Power Conversion System option. It has been thus decided to lay during the 2016-2017 phase the ASTRID Gas PCS integration studies at the same level as that achieved by ASTRID Water based PCS at the end of 2015. The 2016-2017 period, in which the Gas PCS has been integrated in the overall layout of the reactor, has allowed to better specify the technical and economic implications of the selection of gas PCS taking into account all the aspects of the integration of such an option. A well-documented comparison between the two systems is therefore facilitated.This paper resumes progress in the integration of the Gas Power Conversion System in the ASTRID Reactor Plant Model. It describes the main characteristics defined particularly on the Balance of Plant (BOP), the turbomachinery, the Sodium Gas Heat Exchangers (SGHE) as well as expected performances, operability and safety analysis

Main operation procedures for ASTRID gas power conversion system

International audienceUntil the end of the first part of the basic design phase (2017), the ASTRID project has made the choice of studying a power conversion system (PCS) based on a Brayton cycle with nitrogen as coolant. The justification is related to a safety and public acceptance considerations in order to inherently eliminate the sodium-water and sodium-water-air reactions risks. The objective of the studies engaged is to enhance the level of maturity of the gas PCS. The choice of two PCS of 300 MWe each has been made in order to limit the gas inventory, the size and length of gas pipes as well as maintaining a high level of availability. This paper presents specific operating procedures as start-up and normal shutdown of the plant, scram, rapid shutdowns, gas inventory control system, house load and grid frequency control. The current procedures of the plant and the expected regulation are presented. A focus will be made on the nitrogen inventory control which takes part of the electric power regulation provided to the grid. Finally some perspectives of remaining operation studies to be performed until the end of 2017 will be presented. Indeed the level of maturity of the gas PCS must be at a similar level than the classic water-steam Rankine cycle in order to make the best choice for the future of the sodium fast reactors in terms of better cost-effectiveness and reliability through optimization of the Brayton cycle technology and operations