Ling Ao shows how it should be done5 August 2002
Recent experience in China has demonstrated how to build nuclear plants on, or even ahead of, schedule and well within budget - while at the same time incorporating design improvements and undertaking a major programme of technology transfer. Bernard Debontride, Ling Ao project manager, Framatome ANP, Paris, France
The Ling Ao nuclear plant is located on the Dapeng peninsula, 45 km east of Shenzhen in Guangdong province. It consists of two 1000 MW pressurised water reactors (PWRs). Unit 1 began commercial operation on 28 May 2002 and was inaugurated on 2 July 2002. Fuel loading at unit 2 was completed on 18 July, with first criticality expected before the end of August and commercial operation slated for the beginning of 2003.
Ling Ao is one of the most ambitious projects carried out in the People's Republic of China in recent years. The work took place between 1996 and 2002 and necessitated very close collaboration between Framatome ANP - a subsidiary of AREVA and Siemens - and Ling Ao Nuclear Power Co Ltd (LANPC), the owner, operator and lead contractor on the plant. LANPC is a wholly-owned subsidiary of China Guangdong Nuclear Power Holding Co Ltd (CGNPC).
In October 1995, LANPC and Framatome ANP signed a contract sealing their close partnership. Framatome ANP's role went beyond that of supplier, being an active partner in the project, with responsibility for supplying two nuclear islands, manufacturing the first fuel loads, carrying out a major knowledge transfer programme and providing technical assistance during construction and startup tests. The units were constructed by Chinese companies, in particular by Company 23, a subsidiary of China Nuclear Engineering Corporation.
The two conventional islands were supplied by Alstom. LANPC acted as the lead contractor for other plant systems and equipment falling under the heading of BOP (balance of plant). LANPC called on the services of local and international companies. Electricité de France (EDF) acted as consultant to the lead contractor, while civil engineering work was carried out by a Chinese company, Hua Xing.
Building on Daya Bay
Ling Ao is the second large nuclear power plant to be built in the region, following the construction of Daya Bay, the reference plant, whose nuclear island was also supplied by Framatome ANP. The Daya Bay site is operated by Guangdong Nuclear Power Joint Venture Co Ltd (GNPJVC).
To help ensure the technical as well as the economic success of the Ling Ao project, a policy was adopted of building on and developing the reference plant (Daya Bay) design. The strategy consisted of drawing heavily on the reference model while incorporating improvements based on operating feedback from more than 90 nuclear plants built throughout the world by Framatome ANP.
These plants have also had the benefit of operating feedback from Electricité de France and the research and development activities of the Commissariat à l'Energie Atomique.
The Ling Ao project thus took advantage of the proven design of these plants and also took on board the most recent developments, including greater systems and equipment reliability and availability, safety improvements, limitation of exposure to radiation, optimisation of the fuel cycle, and shorter construction times.
The main technical characteristics of the Ling Ao plants are as follows:
• Nominal thermal output 2905 MWth
• Gross electrical output 980 MWe
• Containment prestressed concrete with leak tight metal liner
• Number of loops 3
• Primary system pressure 155 bar
• Steam generator steam pressure under nominal conditions 67.1 bar
• Nominal steam flow rate 1600 kg/s
• Steam generator outlet moisture content less than 0.1 per cent
• Number of fuel assemblies 157
Relative to Daya Bay, more than fifty improvement measures have been incorporated into the Ling Ao plant design. The most important modifications included:
• Use of the most recent IT equipment for the computer and data processing system and the safety panel, making operation easier and improving safety with regard to managing alarms and normal and incident operating conditions.
• Use of digital technology for the reactor in-core instrumentation system, greatly improving the man-machine interface and saving time when drawing up core flux maps, thus improving availability.
• Introduction of additional automatic protective measures against the risk of sudden boron dilution in the primary system. These measures are a major advance in the area of safety with regard to the prevention of risks associated with reactivity accidents. By the end of 1998, they had been progressively implemented in all the existing French nuclear plants, in the light of the results of risk assessments carried out in France since 1986.
• Introduction of protective measures against the risk of core exposure during cold shutdown phases when the level of water in the primary system is very low. These measures are also a major advance in the area of safety based on the most recent risk assessments carried out on existing French nuclear plants.
• Implementation of measures to permit primary system venting during the preparation for cold shutdown phases, thus saving time when opening the primary system, and therefore greatly increasing plant availability by reducing the standard outage time for refuelling.
• Introduction of a steam generator feedwater system for use at startup which is independent of the steam generator emergency feedwater system. Thus, recourse to emergency feedwater system equipment on startup, a standard operating procedure, is now avoided. The overall safety level is further improved and operation is made easier.
• Implementation of various operating improvements in the waste processing systems, such as the use of additional decay tanks in the gaseous waste processing system and the liquid waste processing system, as well as the addition of a supercompactor to the solid waste processing system, making it possible to reduce the number of metal drums containing solid waste (which can be further compacted) by a factor of three in comparison to solid waste generated by the reference plant. These modifications amount to major advances in the area of waste management.
In addition to increasing the level of safety, the modifications should make it possible to improve even further on the performance of the Daya Bay plant, whose availability and average load factors for the two units respectively reached 89.5 per cent and 87 per cent in 2001, with an electrical output of 14 364.8 million kWh.
The planned construction schedule for the Ling Ao units envisaged a period of six years between the authorisation to begin work and the commercial operation date for unit 1, with the work schedule for unit 2 eight months behind that for unit 1. In the event, work was completed well ahead of schedule.
From fuel loading for unit 1, work was ahead of schedule, so that 48 days had been saved at the commercial operation date. There were no hitches in startup tests, mainly due to the reliability of the plant design stemming from extensive feedback from a large population of operating plants, as well as flawless project management from LANPC and all the local and international companies involved.
Unit 2 is following in the footsteps of unit 1 and is also well ahead of schedule.
Localisation and technology transfer
Framatome ANP undertook an ambitious localisation programme within the framework of the nuclear island supply contract.
In 1995, Framatome ANP, as well as Alstom and EDF, signed technology transfer agreements with LANPC. Under these agreements, all French nuclear technology, including that used for the N4 model, is made available to the Chinese.
The nuclear island supply contract was extended in September 1997 to:
• construction of the primary system managed by Framatome ANP, including a major self-reliance programme to enable Company 23 to become technically independent;
• technical assistance provided to Company 23 through the technical support of specialists from Framatome ANP and SPIE Enertrans to work within the teams of Company 23 in the following main areas: detailed design carried out on site and document management; planning and technical co-ordination of internal and external interfaces up to the transfer of systems to the customer's startup teams; quality assurance and handling of any non-compliances; training of construction teams; and equipment management.
The aim of these two programmes,focused on the development of self-reliance, was to transfer to Company 23 all Framatome ANP's knowledge and know-how in the area of nuclear island erection for future projects, including primary system construction, so as to facilitate the implementation of China's future nuclear power programme.
Moreover, in 1995, Framatome ANP, with the help of its main subcontractors, launched a campaign to select the best Chinese suppliers to manufacture equipment in compliance with European quality standards and with whom a long-term partnership could be established.
The localisation programme was implemented in various ways through "joint ventures", co-operation agreements, and technical assistance programmes. It focused particularly on the high-tech nuclear equipment to be used mainly for unit 2. This was for the following reasons:
• to give sufficient time to set up technical assistance and training programmes;
• to enable our Chinese partners to draw up the technical documents, and carry out the investments and qualification processes needed; and
• to ensure there was enough time to resolve any problems, without getting behind on the work schedule.
The Chinese companies chosen and the equipment partly or completely manufactured by them were as follows:
• Dong Fang Boiler Works (DEC/DBC), a company located in Sichuan - three steam generators and one pressuriser;
• Shanghai No 1 Machine Tool Works - reactor internals;
• Xian Nuclear Equipment Factory - equipment for the fuel handling system;
• China Nuclear Erzhong - supports for the primary system and some handling equipment;
• Sichuan Chemical Machinery Plant - components for primary system pipes;
• Shanghai Xiang Feng - some of the components for the control rod drive mechanisms;
• University of Shanghai for Science and Technology Factory - steam generator tube support plates;
• "Joint Venture" Company 23 / SPIE - fabrication of stainless steel pipes for both units;
• Changzhou Electric Manufacturing and Repair Factory - fabrication of water/steam system pipes for both units;
• Shanghai Power Equipment Company Ltd - some of the tanks and heat exchangers;
• Shanghai Cable Works - some of the electric cables;
• Zhenjiang Electrical Equipment Factory and NingBo Zhenhua Electrical Equipment Factory - cableways and accessories.
A technology transfer programme was also set up within the framework of the contract for fuel supplies. As of the next cycle for units 1 and 2, fuel reloads will be supplied by the Chinese fuel fabrication plant at Yibin in Sichuan province.
There are various reasons for the success of the localisation programme, including the determination and strong motivation of Framatome ANP, its subcontractors and its Chinese partners, the major investment of financial and human resources, and, last but not least, the tireless assistance provided throughout the construction programme by the customer, LANPC, and the Chinese authorities.
Increasing investor confidence
The Ling Ao project has been a great success so far, not just in technical terms, but also in economic terms, as the initial deadline and overall budget targets set by the customer were met and even improved upon.
These excellent results demonstrate the accuracy of the construction targets set for the units and provide a basis for shortening construction times even further in the future.
This is very important because meeting or even improving on plant construction schedules is essential for achieving a good return on investment. It also increases investor confidence in future plant construction projects.