Milestones reached at Xudabao construction site

China National Nuclear Corporation (CNNC) announced that hot functional tests - which simulate the temperatures and pressures which the reactor systems will be subjected to during normal operation - were completed at Xudabao 3 on 2 June.

Hot functional tests involve increasing the temperature of the reactor coolant system and carrying out comprehensive tests to ensure that coolant circuits and safety systems are operating as they should. Carried out before the loading of nuclear fuel, such testing simulates the thermal working conditions of the power plant and verifies that nuclear island and conventional equipment and systems meet design requirements.

_{(Image: CNNC)}

Cold functional tests - which are carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition - were completed at Xudabao 3 in December. The main purpose of those tests - which marked the first time the reactor systems were operated together with the auxiliary systems - was to verify the leak-tightness of the primary circuit.

CNNC said the completion of the hot tests at Xudabao 3 "lay a solid foundation for subsequent nuclear fuel loading, grid connection, and power generation".

Unit 2 reactor vessel in place

CNNC said the reactor pressure vessel (RPV) of unit 2 was successfully hoisted into place on 28 May, "marking the official start of the peak period for the installation of main equipment for unit 2".

_{(Image: CNNC)}

The high-strength steel RPV - weighing more than 300 tonnes - will house the reactor core and all associated components, including the reactor vessel internals which support and stabilise the core within the reactor vessel, as well as providing the path for coolant flow and guiding movement of the control rods.

Background

The Ministry of Ecology and Environment announced in November 2023 that the National Nuclear Safety Administration had decided to issue a construction licence for Xudabao units 1 and 2, which will both feature 1250 MWe CAP1000 reactors - the Chinese version of the Westinghouse AP1000. A ceremony was held later that month at the Xudabao site near Xingcheng City, Huludao, to mark the start of construction of unit 1.

The Xudabao project (also known as Xudapu) was originally expected to comprise six CAP1000 reactors, with units 1 and 2 in the first phase. Site preparation began in November 2010. The National Development and Reform Commission gave its approval for the project in January 2011. CNNC noted that the total investment in units 1 and 2 exceeds CNY48 billion (USD6.6 billion).

However, with a change in plans, construction of two Russian-supplied VVER-1200 reactors as Xudabao units 3 and 4 began in July 2021 and May 2022, respectively.

_{Xudabao 3 and 4 (Image: CNNC)}

The Xudabao plant is owned by Liaoning Nuclear Power Company Ltd, in which CNNC holds a 70% stake with Datang International Power Generation Company holding 20% and State Development and Investment Corporation owning 10%. The general contractor is China Nuclear Power Engineering Company Ltd, a subsidiary of CNNC.

Two further CAP1000 reactors are proposed for units 5 and 6 at the Xudabao plant.

Upon completion, the six-unit project - with a total installed capacity exceeding 7.6 MWe - will provide nearly 54 billion kilowatt-hours of clean electricity annually, saving 19.2 million tonnes of standard coal and reducing carbon dioxide emissions by 56.7 million tonnes annually, CNNC said.