Cold test is not the first pass of "physical examination" for "cold" nuclear power plant

Recently, the cold state function test of the fuqing no. 5 unit of "hualong no. 1", the world's first reactor demonstration project, was successfully carried out.As China's third-generation nuclear power plant with completely independent intellectual property rights, hualong 1 withstood the "high voltage" and passed a "big test" to test the unit's performance.This marked that the unit broke the first heap must drag "magic spell", early into the commissioning phase of the first step to win.

What is a cold test?Why is hualong one cold tested?Reporter of science and technology daily interviewed relevant personage about this.

Withstand "high pressure", reactor performance to withstand "big test"

If you compare a power station to a giant charging station, then hualong I is a huge nuclear fuel charging station -- nuclear power station.

One of the most important indicators for a nuclear power plant is safety.

Cold test, is short for cold function test, is a large comprehensive special plant commissioning test, the main purpose is to verify the circuit system and equipment and its various properties of auxiliary pipeline under high pressure, and pressure in each platform into the line of the primary system and auxiliary system related test, is the first time on the properties of the whole reactor comprehensive "examination".

It is also regarded as the first step to test the "nuclear power treasure", which can verify the integrity of each system, verify whether the normal pressure can be maintained in the state of exceeding the design benchmark, and test its performance and pressure resistance in excess of the design benchmark.

Whether the first reactor can advance as scheduled, the "physical examination" report is very critical.

Pressure is one of the first indicators to be evaluated in a cold test.The atmospheric pressure we are in daily contact with is 0.1 mpa, while the working pressure of the primary circuit of the nuclear power plant is 15.5 mpa.According to the design scheme, the design pressure of the primary circuit is about 17 mpa.But the cold test peaked at 22.3 megapascals, an area the size of the palm of a hand that would carry the weight of 10 fully loaded sedans.

People involved in China national nuclear corporation fuqing nuclear power co., LTD. (referred to as fuqing nuclear power co., LTD.) explained that the so-called peak pressure can be understood as the value of 200 kilometers per hour displayed on the dashboard of some cars, taking the cars we drive as an example.Design pressure is like the car we usually drive, the maximum speed can be up to 160 kilometers per hour, the work pressure of the primary road is 15.5 mpa, like the usual driving speed, such as 120 kilometers per hour.

It is worth mentioning that the pressure in cold test did not rise to 22.3 mpa in one step.After 16 hours of stepped-up pressure from 10 a.m. to 2 a.m. in the second sun ling, the main system pressure of the "hualong no. 1" fuqing no. 5 unit reached 22.3 mpa and stabilized for 10 minutes before passing the test.

The cold test will be followed by a long hot test

Literally, some people think cold trials are cold.In fact, the temperature of a cold test circuit is 35-70 degrees Celsius.

How is water heated without nuclear fuel?Relevant personage introduces, through blade agitate, advocate pump rotates in airtight space, kinetic energy converts heat energy, drive primary circuit to heat up.

The construction of a nuclear power plant has to go through several stages: preliminary preparation, civil construction, equipment installation and commissioning.After the cold test, the "hualong no.1" will be followed by hot test, critical test, platform test and performance test.

The so-called cold test is relative to the hot state performance test (referred to as hot test), it is also considered as the hot body of the hot test.After the cold test, the nuclear power plant is about to conduct a hot test.

Compared with the cold test temperature of 35-70 c, the hot test temperature is up to 300 c.

Different from the cold test, during the hot test, the staff will try their best to simulate the actual operating conditions of the nuclear power plant to verify whether the performance of the system is consistent with the design requirements and further verify the reliability of the nuclear power plant, including ensuring that the equipment cannot leak at room temperature and even cannot leak at high temperature.In addition, it is necessary to verify the reliability of the instrument and equipment under high temperature, check whether the temperature, pressure, flow, vibration, clearance and other measurement parameters meet the design value requirements.

In short, anything that may be affected by temperature must be checked, both at room temperature and at high temperature.In addition, many functions and safety of nuclear power plants need to be verified, including the natural circulation capacity of the passive core cooling system and the heat transfer capacity of the passive preheat and discharge heat exchangers

For this reason, compared with the cold test, the subsequent hot test will be a relatively long process, which is not a single test, but the sum of a series of tests.

It is understood that, according to the different units, the heat test less than a few days, more than a few months.During the thermal test, the operating procedures of the nuclear power station will be fully verified, the functions of the nuclear power plant will be fully inspected, and the team of operators in the nuclear power plant will be trained.

After the hot test, the material will be loaded. According to the plan, the first batch of "hualong no.1" fuqing nuclear power plant, the world's first reactor, will be loaded for the first time by the end of this year.If the 62-month construction period is followed, unit 5 is scheduled to be officially connected to the grid in July next year.

Big data and sand table deduction realize risk control in advance

Since May 7, 2015, when the world's third generation nuclear power units under construction got stuck in the "quagmire", the world's first reactor demonstration project hualong I has been progressing smoothly, and construction according to the planned schedule has become an important label.

"Hualong I is a complex systems engineering, an innovation process from scratch."Xing ji, chief designer of the "hualong no.1" project of China national nuclear corporation, especially introduced that one of the key problems of the demonstration project is to complete the construction drawing design of the first reactor on schedule.

Through the continuous promotion of "Internet +", CNNC combines the design of nuclear power, application software integration with the Internet and other technologies to establish a long-distance integrated collaborative design platform. Through network connection and various terminal devices, multiple design units nationwide carry out long-distance collaborative design on the same platform.The number of collaborative design platform terminals reaches 500 and can be expanded as required.

On this platform, nearly 1,000 "hualong no. 1" site engineers and designers realize timely communication and sharing of information, speed up the transmission of design data, reduce the repetition of design exchange process, and effectively improve the design efficiency.

While carrying out the design work, CNNC made full use of the efficiency and convenience of the design information platform to timely summarize the technical problems encountered in the construction of the demonstration project into the big data in the design field, which was not only fed back to the equipment manufacturer and the project builder, but also passed on to the subsequent nuclear power projects.

"This has laid the technical foundation for the standardized design and mass construction of hualong no. 1 nuclear power project, and improved the economy of construction and operation."The xing said.

Starting from 300,000 kw, hualong I is a new product introduced, absorbed and created by China's nuclear power research and development.The hualong 1 has a design life of 60 years, with 177 reactor cores and 18 months of refueling.Among them, the independent intellectual property rights cover the design, fuel, equipment, construction, operation, maintenance and other fields, and has independently developed special software for nuclear power, forming a complete intellectual property system, is the only three generation model that can be independently exported in China.As the world's first demonstration reactor project, the localization rate of construction equipment for unit 5 of fuqing nuclear power plant is no less than 85%, and more than 100 sets of "three new" equipment have been purchased and installed.

Chen guocai, general manager of fuqing nuclear power plant, told reporters that the constantly optimized project management mode and innovative project management mode have ensured the steady progress of demonstration project construction and provided valuable practical experience and reference basis for the subsequent batch construction of "hualong no.1".

In the first reactor construction, the construction team used sand table for simulation and deduction for the first time in China.For example, in the design field, six typical design organization and management tasks, such as DCS capital raising planning for power plant, are selected for sand table deduction.

According to Chen guocai, by summarizing the basic facts, testing the management team's management knowledge, experience and problem solving ability, and analyzing and predicting the development trend of the project stage, the goal of advance management and risk control can be achieved.