1, AP1000 and EPR safety system adopts two completely different design concepts
AP1000 safety system adopts the "non-energetic" design concept, to better achieve the "simplified" design policy. The safety system utilizes the natural properties of matter: gravity, natural circulation, the energy of compressed gases, and other simple physical principles, without the need for pumps, AC power, Class 1E emergency diesel engines, and the corresponding ventilation, cooling water and other support systems, greatly simplifying the safety system (they only act in the event of an accident), greatly reducing human error. The design concept of "non-energetic" safety systems is a major innovation in pressurized water reactor nuclear power technology.
The EPR safety system is based on traditional second-generation pressurized water reactor (PWR) technology, and utilizes a "plus" design concept, which means that safety is improved by increasing redundancy. All safety systems have been increased from two to four series, and EPR has increased the complexity of the safety system while increasing the level of safety. The design of safety systems in nuclear power plants basically belongs to the second generation of pressurized water reactor (PWR) nuclear power technology, which is an improved change.
2. Comparison of the safety of AP1000 and EPR
Since the safety systems of AP1000 and EPR use two completely different design concepts the safety of AP1000 and EPR are quite different.
The core damage frequency of AP1000 after an accident is 5.0894×10-7/year, which is 2.3 times smaller than that of EPR (1.18×10-6/year), and the probability of large amount of radioactivity release is 5.94×10-8/year, which is 1.6 times smaller than that of EPR (and the reliability data of the equipment used in AP1000 are more conservative).
After a nuclear power plant accident, an AP1000 operator may not intervene for up to 72 hours, compared to half an hour for the EPR;
The AP1000 can effectively prevent the reactor pressure vessel (the second barrier) from melting through in the event of a core meltdown, and keep the core radioactive melt inside the reactor pressure vessel, minimizing the probability of radioactive release to the environment; whereas the EPR has the lowest probability of release to the environment; and the EPR has the lowest probability of release to the environment; and the EPR has the lowest probability of release to the environment. The EPR does not prevent the reactor pressure vessel from melting through, the core radioactive melt is temporarily retained in the reactor cavity, and then measures are taken to delay the interaction between the melt and the concrete of the containment (third barrier) floor to prevent the containment floor from melting through.
AP1000 human error accounted for 7.74% of the meltdown frequency of the pile, *** due to failure accounted for 57% of the meltdown frequency of the pile, while the EPR were 29% and 94%, the AP1000 is significantly better than the EPR.
3, maturity
The most important feature of the AP1000 is that the safety system adopts a non-energetic technology, Westinghouse has done a lot of tests, calculations and verification work. Westinghouse has done a lot of tests, calculations and verification work, the results of these tests have all been accepted by the U.S. Nuclear Regulatory Commission, the non-energetic safety system has reached the maturity requirements. Reactor and reactor coolant system design and the second generation of nuclear power plants similar to the mature technology. AP1000 coolant shielded motor pump power than the past shielded motor pump products are larger, belonging to the first time the design of large pumps, but their power has been quite close. EMD shielded motor pump manufacturer EMD company has a wealth of manufacturing experience, the production of a large number (about 1,500 units) of different power, different sizes of shielded pumps for the military, the early nuclear power plants and other industrial sectors, and achieved a good track record of use, the design and manufacture of technology is mature, credible. It can be said that the AP1000 shielded motor pump main problem is to speed up the first pump manufacturing progress and engineering verification.
EPR is characterized by increasing the thermal power of the reactor and increasing the redundancy and diversity of safety systems. The design concept is mature; the EPR increases the thermal power and size of the reactor, and the major equipment (reactor pressure vessel, in-reactor components, steam generators, and main coolant pumps, etc.) is increased in capacity and size. However, the testing of some of the major nuclear equipment (reactor pressure vessel and in-reactor components, steam generators, main coolant pumps, etc.) has not yet been completed, and they have yet to be engineered and verified on the test rig and in the field.
The maturity comparison between the two is comparable.
4, economy
AP1000 safety system adopts the concept of non-energetic, safety system configuration is simplified, safety support system is reduced, the safety level equipment and seismic plant is reduced, IE level emergency diesel engine system and a lot of dynamic equipment is canceled, as well as a significant reduction in the demand for bulk materials. AP1000 safety system and its equipment has been a large number of reductions in the number of such as The number of safety grade pumps and valves for the AP1000 is 6 (including 4 main pumps) and 599 respectively, compared to 88 and 7000 for the EPR. Coupled with the modular design and construction of new technologies, which derives a series of effects such as simplified design, simplified system setup, simplified process layout, reduced construction volume, shortened construction period, as well as easy to operate and simple maintenance. From a long-term point of view, AP1000 not only improves safety performance significantly, but also significantly reduces the cost and long-term operating costs, and is also economically competitive. This advantage will become more and more obvious after a number of AP1000 nuclear power units are built in batches (say 8 to 10 units).
EPR improves safety by increasing the redundancy and configuration of safety systems; however, it is more economical due to the large capacity of a single unit and the high utilization of the site.
5, safety review
AP1000 safety review: Westinghouse submitted to the U.S. Nuclear Regulatory Commission (NRC) on March 28, 2002, the AP1000 standard design of the "standard design certificate" application, which includes the AP1000 design control documents, PSA reports. The application was accepted by the USNRC on July 25, 2002, and was reviewed in accordance with 10 CFR Part 52 and related regulations, the Serious Accident Policy, etc., and the Final Safety Evaluation Report (FSER) was officially issued in September 2004. On September 23, Westinghouse received the NRC's Final Design Approval (FDA) for the AP1000. On December 30, 2005, the NRC issued Westinghouse a Standard Design Certificate for the AP-1000 standard design, following hearings held in accordance with U.S. law.
Safety review of the EPR: Finland has introduced the EPR from France to build the OL3 nuclear power plant in Finland. The Finnish Nuclear Safety Authority (FNSA) has completed the review of the EPR Preliminary Safety Analysis Report (PSAR) and on February 17, 2005, issued the "License to Construct OL3 Nuclear Power Plant". The Finnish Nuclear Safety Authority is said to have included in the construction license conditions those issues that were not closed during the review.
Based on the information available, combined with preliminary engineering judgment, AP1000 or EPR in the nuclear safety license application and review, there will be no major problems.