Many new nuclear safety program debut in Beijing

After the Fukushima accident, the international community paid more attention to the safety of nuclear power. On October 23, a two-day international symposium on "Requirements for Higher Safety Standards and Solutions for Nuclear Power Plants" was held in Beijing. Senior experts in nuclear power industry both at home and abroad, such as China Nuclear Power, China Guangdong Nuclear Power, National Nuclear Power, Huaneng Power and China Power Investment, Enterprises and relevant research institutes conducted a heated discussion on the latest international research on serious accident research, the requirements for the improvement of nuclear power plant safety in our country, the technical improvements of the containment of nuclear power plants and their related systems (components).

China's nuclear power plant safety requirements for improvement

After the Fukushima accident, the IAEA and various countries conducted a great deal of research and exploration in raising nuclear safety standards and regulatory requirements.

The EU stepped up its nuclear safety legislation by requiring member states to design new nuclear power plants to ensure that the power plant's exterior will not be affected even if the reactor core is damaged. The resolution by the European Parliament's Energy Commission to upgrade the safety of European nuclear power plants is expected to cost € 25 billion for the upgrade.

In our country, the National Nuclear Safety Administration and relevant departments conducted a comprehensive safety inspection on civil nuclear facilities and formulated the "General Technical Requirements for Improvement Operations of Nuclear Power Plants after the Fukushima Nuclear Accident." In flood control, emergency replenishment and related equipment, mobile power and Set up, spent fuel pool monitoring, hydrogen monitoring and control systems and other aspects of the specific improvement requirements.

As for the safety requirements of new nuclear power plants in the future, the "Twelfth Five-Year Plan for Nuclear Safety and Radioactive Pollution Prevention and Control and the Vision for 2020" gives the overall objective: for nuclear power plants under construction during the "12th Five-Year Plan" period, The melting frequency is below 10-5 per heap, and the large-scale radioactive release is below 10-6 per heap. The nuclear power plant started construction during the "13th Five-Year Plan" will strive to eliminate practically the possibility of release of large quantities of radioactive material.

At the meeting, Tang Bo, deputy director of the nuclear power safety supervision department of the Ministry of Environmental Protection, revealed that at present the National Nuclear Security Administration is organizing efforts to compile the safety review principles for new nuclear power plants during the "12th Five-Year Plan" period. The review principles included improvements identified in the integrated safety inspection while being considered for enhancement in site safety evaluation and external event evaluation, environmental impact assessment, enhancement of earthquake resistance, measures to deal with SBOs and reinforcement of core safety Margin and so on.

"The scope of the safety margin remains controversial. At present, the National Nuclear Security Administration has organized relevant studies to formulate a specific explanation and operational standard for" striving to realize the possibility of practically eliminating the release of significant quantities of radioactive material from design. " "Tom said.

New technologies, new ideas shine venue

At the meeting, experts and enterprises from France, Germany, South Korea, the United States and other countries introduced their new technological solutions and design products. Among them, the United States IEEE member Jim - Gleason (Jim.Gleason) introduced a new product called GLS fast moving gas sensor ceramic hydrogen sensors, aroused the widespread attention.

Similar to the gas, the hydrogen content in the air exceeds 4% and explodes. In the Fukushima accident, the hydrogen gas leaked due to a problem with the containment seal, so that a hydrogen burst occurred. In view of the danger of hydrogen explosion, our country has added a safety monitor hydrogen concentration monitoring instrument to the improvement requirements of nuclear power plants. Reporter learned from China Guangdong Nuclear Power, China Guangdong Nuclear Power Project has been installed in the hydrogen monitoring device.

The distinctive feature of the GLS fast gas sensor is its ability to detect not only the hydrogen concentration in time, but also the location of hydrogen accumulation. And inside and outside the containment can be installed.

For this new product, the presence of many industry expressed strong interest. However, it is understood that at present the product has not been introduced into China.

In addition to this hydrogen detector, the design of the triple containment structure under the serious accident caused by the national design master Xia Zu of the China National Nuclear Engineering Research and Design Institute became another focal point of the audience.

Currently the world nuclear Denko process, used are single or double containment design. Xiazu satir said in his speech that the Fukushima nuclear accident showed that the integrity of the containment structure of the nuclear power plant was too weak in the face of a serious accident. The new nuclear power plant to face a serious accidental melt-out of the core requires the design of a new and more robust containment to block the release of large quantities of radioactivity to the environment under severe accidents.

"In terms of measures to deal with serious accidents, all of the other next-generation units except the AP1000 and EPR units are in between, and all the measures so far have only been mitigated by serious accidents in the process. Can be said that there are still many deficiencies. "Xiazu satirical said that more importantly, all units are not considered after the collapse of the core eventually collapse in the containment will be delayed overpressure may be as high as the original traditional design pressure 2 To 3 times; and under the effect of delaying overpressure, the containment can only utilize the designed margin of the structural strength itself, but its structural integrity capability is obviously insufficient and the leakage greatly increases, which means the containment can not be blocked Discontinue radioactive release to the outside world.

ASME's BPV Specification 2009 Reference Guide, Vol. 3, Vol. 1, for the first time proposed the concept of a "triple containment structure" for the aftermath of the melt-out of the core. Shanghai Nuclear Engineering Research and Design Institute made further improvements on the basis of this scheme: the prestressed main containment structure has a wall thickness of 2.4m, which is enough to block the malicious impact of any large aircraft and to improve some design configurations of the containment , Determined the overall arrangement of the steel strands and also improved the core melt chamber configuration.

According to the scheme of the hospital, the waste heat in the main containment vessel is controlled by a set of pneumatic pressure release valves on the top to discharge the radioactive pressure steam to the middle steel containment vessel. The containment vessel can contain both radioactive and containment heat Transmitted to the surface of the shell, sprayed through the outer shield shell and air-cooled heat can not pass into the atmosphere.

For the actual effect and feasibility of this program, many industry insiders expressed their own views and questions, and the program designers conducted a lively discussion.

"In fact, this solution adds only a little more costly construction materials costs than traditional designs, but it can eliminate some of the expensive processing facilities that only deal with serious accident design. It can be regarded as a safe solution for the current serious accident design, and it It can be applied to any nuclear power unit and achieve the same effect, and people are freed from the fear of nuclear power plants at the lowest economic cost for the benefit of the community. "

Spandex Warping Machine

Spandex Warping Machine

Spandex warping machine also called spandex yarn warping machine; elastic yarn warping machine.

A-ZEN spandex warping machine AZE318 with vertical creel is driven by 5 sets high performance servo motors and adopted with advanced precisive laser to measure distance so that spandex warping is more stable, well equipped with and easier to operate. It is suitable for warping all kinds of spandex, especially for requirement of knitting high quality elastic textiles.

Technical Data:

Warp Line Speed: 100-600m/min;

Beam Size: Φ21"*21";

Warping ends: According to customers` demand;

Pre-drafting: 0-200%; Final Draft: 15-100%;

Brake time less than 0.6 s, the deviation of stop synchronization is less than 3%;

Creel Capacity: 616, 700, 728, 784, 792, 896, etc.

Servo Motor Power: Warper head power 13.2KW, Warper Head Tension Roller 2.9KW, Draft Roller 4.6KW, Creel: 2*6.9KW;

Main Motor: 10KW AC frequency conversion control;

Control Mode: Computerized real-time control, and user-friendly operation interface.

Spandex Warping Machine,Elastic,Beam Warping Machine, Yarn, Computerized Split Yarn Warping Machine

CHANGZHOU A-ZEN TEXTILE TECHNOLOGY CO.,LTD , https://www.barmachinery.com