The China Advanced Passive pressurized water reactor 1400MWe (CAP1400) is one of the serial research and development of PWRs adopting passive engineered safety features initiated by Shanghai Nuclear Engineering Research & Design Institute (SNERDI), which consists of CAP50, CAP150, CAP200, CAP1000, CAP1400 and CAP1700. The design of CAP1400 is based on the experience of the PWR technology R & D for more than 40 years, construction and safe operation for more than 20 years in China. It absorbs the accumulated experience and achievements of the world's first batch of AP1000 units. Furthermore, it adopts safety enhancement measures based on lessons from Japanese Fukushima nuclear accident.
Conforming to the safety and availability goals of design, CAP1400 takes simplicity, where possible, to enhance safety, constructability, operability and maintainability, on the other side, simplicity reduces the initial capital investment. It utilizes proven technology and absorbs a number of advanced design features to achieve the economic goals and to guarantee the safety requirements are satisfied. Extra margins have been incorporated in the design of CAP1400 to enhance availability and investment protection.
By simplifying system design, the CAP1400 improves operability of system, reduces the amount of components and has less requirements of relevant maintenance. Especially, the CAP1400 reduces the surveillance requirement of safety system because of its simplified technical specification. In the layout of the CAP1400, the feasibility of inspection and maintenance has been considered, including space, equipment accessibility and radiation protection. The CAP1400 design obeys the principle of “as low as reasonable achievable” (ALARA), the specified measures include: reducing the radiation time for plant personnel, adopting shielding material and reducing the source intensity.
IAEA Submitted Final Report on CAP1400 GRSR
The modularization design is also adopted to reduce the workload and shorten the construction duration. It adopts proven components to achieve high-level credibility under the precondition of low maintenance requirement. The standardized design of component will reduce the amount of spare parts, simplify the relevant maintenances and required trainings and shorten the maintenance period.
CAP1400 has systematic severe accident prevention and mitigation strategy, including passive containment cooling system, hydrogen control system, and especially, the in-vessel retention of molten core debris (IVR) which is the key mitigation strategy. IVR is used to ensure the reactor vessel remains intact and eliminate the consequent threats to containment integrity by the external reactor vessel cooling (ERVC). It can avoid the more severe and complex ex-vessel phenomena of melt.
Moreover, due to the Fukushima nuclear accident happened in Mar 11 2011, the standardized design has been reevaluated based on the lessons learned. Specific design improvements have been taken to enhance the plant’s capability to resist flooding and seismic and to supply cooling water and electrical power after 72hrs of postulated accident initiation. The basic design of CAP1400 started in July 2010 and completed in Dec 2011.
At the beginning of 2014, the basic design has been approved by National Energy Administrator (NEA). A series of experiments have been carried out to validate advanced design features (especially, for passive safety systems) which build a solid confidence in safety and main components. The safety analysis by deterministic approach and probabilistic risk approach has been completed and documented in preliminary safety analysis report (PSAR). All the licensing application documents have been submitted to the regulator -National Nuclear Safety Administrator (NNSA) in China and the approval of the licensability for CAP1400 was announced in Feb, 2016.
Starting from August, 2015, the International Atomic Energy Agency (IAEA) conducted a review on the CAP1400 Preliminary Safety Analysis Report (PSAR) regarding the completeness and comprehensiveness of the safety documentation based on the latest IAEA Design Safety and Safety Assessment requirements,which incorporate the feedback from Fukushima Daiichi Accident. In April, 2016, according to the report finalized by IAEA experts, the CAP1400 PSAR submitted by SNERDI meets the latest IAEA safety requirements.
The first CAP1400 unit is going to be constructed in Shidao Bay,Rongcheng Shandong provincein China. The construction duration for the first unit is expected to be no more than 56 months from the start of structural concrete placement to grid connection. As scheduled, 18 months later, the FCD for second unit will be initiated with construction duration being decreased to be 50 months.