The Shandong Shidaowan Nuclear Power Project undertaken by China State Construction Electric Power Co., Ltd. started full construction on July 28. It is the first "Hualong One" dual-nuclear island project in northern China and a major construction project in Shandong Province. Once completed and put into operation, it will effectively alleviate Shandong's energy supply and demand. It is of great significance to promote the diversification of Shandong's energy supply structure and ensure energy security, economic security, and ecological security.

Optimize construction logic and manage "construction period accounts" well

The No. 1 nuclear island reactor building of the project has a cylindrical appearance, with a raft foundation radius of 27 meters and a raft foundation thickness of 3.7 meters. The steel mesh and pipe network are densely covered, and the engineering volume is huge. If we want to complete the first tank of concrete pouring for the raft foundation on schedule and with high quality, starting with technological innovation is the biggest breakthrough.

The project actively changes the "inertial thinking" of construction and constantly seeks innovation and change. The traditional construction method of RPE embedded pipelines in nuclear islands is to assemble and weld on-site. However, in order to ensure the quality of welding, civil construction operations have basically stalled. In order to shorten the construction period, the project team introduced the technical concept of "prefabricated assembly" and adjusted the construction sequence so that all welding work was completed before being put into place. At the same time, 60 10-meter short pipes were prefabricated and spliced into 28 long pipes, which only needed to be hoisted on site. , civil construction can also be carried out simultaneously, successfully reducing the construction period by half.

In order to speed up the construction progress and ensure that there is no "empty window period" during the construction process, the project team conducted careful logical design, reasonably planned the location of the raft foundation construction joints, promoted the simultaneous construction of the nuclear island powerhouse and the surrounding powerhouse raft foundations, and proposed domestic The first-of-its-kind FCD+2.5 completes the construction period target of the raft foundation and is expected to save three and a half months compared to the traditional construction period FCD+6.

Overcome geological problems and overcome "roadblocks"

The project site is located in a large area of slip zone and strong weathering zone, which will pose great challenges to foundation pit construction. Faced with unfavorable geological conditions, the project team brainstormed and implemented local strategies to pave the way for construction.

The rock hardness of the slip zone where the project is located is 40-50 MPa, which is only one-third of the construction standard range. Improper handling may lead to large-scale landslides. In order to ensure construction safety, the project team used GPS precise positioning, CAD three-dimensional lofting and other technologies to determine the contour line, design corresponding drilling spacing, and accurately excavate and backfill the slip zone to ensure efficient on-site contract fulfillment.

At the same time, strong wind belts with insufficient bearing capacity are distributed throughout the nuclear island factory area, which is very likely to affect the nuclear island cushion and is not conducive to foundation stability. To this end, the project organized a technical team to analyze data, customize plans, set construction joints according to the distribution areas of strong weathering zones, and prioritize the construction of strong weathering zone areas. After laying the foundation, the nuclear island plant cushion construction will be carried out simultaneously to make the "base" of the nuclear island It can truly "establish a firm foothold" and at the same time shorten the construction period of the nuclear island plant foundation pit by about a week.

Grasping the safety line of defense and protecting "nuclear safety"

During the progress of the project, the project has always adhered to the nuclear safety cultural concept of "safety first, quality first", firmly implemented two "zero tolerances", and innovatively adopted technologies such as visual monitoring systems and RFID intelligent positioning and performance systems. Real-time monitoring of on-site construction practices and management behaviors, and empowering project backend management with high-tech means.

The project teamed up with Huaneng Shidaowan Nuclear Power Development Co., Ltd., CNNC Engineering Consulting Co., Ltd. and other units to form an expert team to conduct 5 rounds of pre-node "physical examinations", conduct detailed inspections of the entire construction process plan, and orderly complete technical briefings and concrete supply chain Guarantee, experience feedback and other preliminary preparations.

The amount of concrete used to solidify the "base" of the nuclear island alone reached 8,883 cubic meters, enough to fill four international standard swimming pools. With such a large amount of concrete, ensuring the quality of concrete has become a key link. The project comprehensively considers various factors and improves quality control throughout the entire chain and from multiple angles. In the preparation of the special construction plan, the thickness of the layers is optimized. Personnel are designated to carry out special control of difficult parts of on-site pouring, and a special "thermometer" is used to detect the "temperature" of the concrete. Body temperature", and timely grasp the quality of the mold. In the later maintenance process, an electronic automatic temperature control system is used, and a maintenance shed is set up to dynamically adjust and control the temperature difference between the inside and outside of the concrete to ensure that the temperature control meets the specifications and design requirements. Multiple measures are taken simultaneously to strictly control the inspection quality and safety.

The nine-story platform starts from tired soil. The project has sounded the clarion call for "charge". After the completion of two 1,200-megawatt nuclear power units, the annual power generation will reach 17.6 billion kilowatt hours, which can reduce the consumption of standard coal by about 5 million tons and reduce carbon dioxide emissions by about 15 million tons, which is equivalent to About 40,000 hectares of forest have been planted. China Construction Second Engineering Group Co., Ltd. will continue to sprint towards the low-carbon track, build more high-quality clean energy projects, and add green momentum to the upgrading of the country’s energy consumption structure.Editor/Jiang Mingyue