SPIC Boosts Pakistan's Stable, Safe Nuclear Power Supply

The No.4 unit of the Chashma Nuclear Power Plant in Pakistan had continuously and safely operated for more than 265 days in its second fuel cycle by March 20, breaking the record set in its first cycle.

The plant features four units with a total installed capacity of 1.3 million kW. Its annual power output accounts for six percent of the electricity used in Pakistan.

All the plant's four units were developed and designed by Shanghai Nuclear Engineering Research and Design Institute Co., Ltd. (SNERDI), a subsidiary of State Power Investment Corporation (SPIC), and have provided stable power during the COVID-19 epidemic outbreak.

A model of South-South cooperation, the plant started construction of its No.1 unit on Aug 1, 1993, and in June 2000 the unit went into operation. Later in September 2017, the No.4 unit, the last at the plant, went online.

Cooperation between the SNERDI and the Chashma Nuclear Power Plant can be traced back to the 1980s.

As early as 1988, members at the Pakistan Atomic Energy Commission (PAEC) visited the SNERDI and were given a progress report of the Qinshan Nuclear Power Station which was still in construction at that time.

The next year, 38 Pakistani technicians attended a three-month technical training program at the institute.

In the meantime, Chinese technicians also visited Pakistan to confirm the site of the units of the Chashma plant and carried out preparation work including geological surveys and transport plans for large-scale equipment.

The 300,000 kW nuclear power plant contract was finally signed on Dec 31, 1991, the first time China had exported its self-developed nuclear power generation unit overseas.

Located at the border of the inland desert area, the China-built units of the plant were to be constructed on sandy sedimentary soil as thick as 190 meters. Building a 20-ton workshop on such soft soil inevitably meant some sedimentation. The key was how to avoid an inclination during the subsidence.

To guarantee that, the power plant would be earthquake-proof with seismic equipment.

Technicians also designed the nuclear island into an 85 meters × 87 meters rough cube and set the reactor base at the center on a baseboard much thicker than normal.

The No.1 unit of the plant sank 51 millimeters during the construction period between 1993 and 1998, with a differential settlement of only three millimeters.

In addition to the unit construction, the SNERDI transferred a large amount of technology and initiated a lot of training to help improve Pakistan's nuclear power technical capacity.

It provided 206 design materials as well as design approaches and testing materials to Pakistan, including standard design regulations on a nuclear steam supply system, radiation analysis design and containment criteria as well as requirements for transient design, control and protection functions.

Software for neutron spectrum computing and the Monte Carlo program which simulates slowing down and scattering of energetic ions in amorphous targets was also transferred to the Pakistan side.

Almost 400 technicians at the PAEC were sent about every month to the SNERDI to participate in design of engineering components electrification, nuclear equipment and the conventional island. At the same time, 1,265 Pakistani technicians were trained at the SNERDI.

From designs to materials, and from computer programs to talent cultivation, the Chinese side helped the Pakistani side gain technical skills and nuclear power talents to improve its nuclear power industry system.

The cooperation and exchanges also promoted relations between technicians in the two countries.

On May 4, 2004, four years after the No.1 unit went into operation, China and Pakistan signed another contract on design and construction of the No.2 unit at the Chashma plant.

Advanced management tools like PSA were adopted in the unit which improved prevention of serious accidents and practice procedures should they occur.

Soon after the operation of the No.2 unit in March 2011, the No.3 and 4 units started construction successively in the same year and went into service respectively in October 2016 and July 2017.

Upon completion of the four units, the SNERDI kept offering technical supports to all the plant's units, from the very original one to the four recently completed. The institute now receives more than a hundred expert consultation orders every year and dispatches technicians to give on-site solutions.

Operation assessment, refueling schemes and outline of equipment maintenance as well as emergency technical suggestions are also given to the Pakistan side.

In the past decades, the SNERDI has helped the Pakistan side complete several technical works including hot workshop renovation, simulator improvement, accumulator changing, irradiation monitoring of tube neutron fluence and factor calculation, facility and pipeline vibration measurement, neutron flux measurement and neutron fitting program computing and security risk assessment. It even suggested improvements after the Fukushima nuclear power event in Japan.

The four China-built units are now operating stably and the SNERDI will continue to support clean, highly-efficient and safe power supply in Pakistan.

(Executive editor: Wang Ruoting)