70 Development of Nuclear Boiler and Pressure Vessels in Taiwan

Chapter 70, co-authored by Y. B. Chen, S. Chang, and T. Chow, provides an overview of the nuclear energy application and development in Taiwan, which includes historical background of the development, role of the regulatory authority and current status of nuclear facilities. This chapter also addresses important issues such as seismic design features of the nuclear power plants (NPPs), PWR/BWR pressure boundary integrity, power uprate and license renewal, and radioactive waste management of NPPs in Taiwan.

Taiwan is located at a complex juncture between the Eurasian plate and Philippine Sea plate, where earthquakes occur frequently. Hence, seismic design/qualification of structures, systems and components (SSC) of NPPs in Taiwan is an important issue. Although Taiwan is prone to earthquake strikes, up to now Taiwan's NPPs have never experienced any earthquakes that challenged the seismic design of the plants. However, the disastrous Chi-Chi earthquake prompted Taiwan's nuclear regulatory authority Atomic Energy Council (AEC) to request the largest and only nuclear utility, Taiwan Power Company (TPC), to install the Automatic Seismic Trip System in all six operating nuclear units to further enhance the plant safety.

N-service inspections (ISI) followed the ASME Section XI for the operating units are conducted during each scheduled outage to ensure the integrity of the SSCs. Recently, more attention has been focused on the inter-granular stress corrosion cracking (IGSCC) in BWRs and primary water stress corrosion cracking (PWSCC) in PWRs especially at the dissimilar metal (DM) welds connecting vessel nozzle to austenitic stainless steel piping according to both foreign or domestic operating experiences. More details of the inspection results are discussed in this Chapter.

To improve the performance of the NPPs, a power uprate project has been launched for the NPPs in operation. The power uprate considered is the Measurement Uncertainty Recapture (MUR) type and up to 1.7% rated thermal power increase for license application. Submission of operating license renewal applications for all the operating units is under planning and preparation. Preliminary feasibility study of stretch power uprate (∼5%) is also ongoing. Besides the aforementioned activities, radioactive waste management is also an issue receiving more attention. Right now, the application submitted by TPC for construction permit of independent spent fuel storage installations (ISFSI) at Chinshan site is still under review. Before any ISFSI is allowed to be constructed, the on-site spent fuel storage pools are the only available facilities for the spent fuel management of the nuclear power plants.