POWER PLANT COOLING | UPRATING BLACKOUT RELIABILITY
Focus on reliability for coolant pumps
Recent improvements in reactor core isolation cooling (RCIC) emergency cooling pump technology are designed to ensure that nuclear power stations can continue operating safely during extreme events caused by our changing climate
By Pascal Montel, Celeros Flow Technology
THERE IS BROAD AGREEMENT THAT nuclear power is an important part of the transition to clean energy. Indeed, it is widely believed that swiftly scaling up nuclear power capacity could address not only the challenges of climate change but could also tackle energy poverty and promote economic development. However, public confidence in the safety of nuclear power plants is less certain. There have been only two major reactor accidents in the history of civil nuclear power – Chornobyl and Fukushima Daiichi – during 18,500 cumulative reactor-years of commercial nuclear power operation in 36 countries but these events remain in the public consciousness. While the former accident was traceable to flawed design and inadequate training, the sequence of events that led to the failure of the reactor cooling systems and the subsequent explosion at Fukushima were more complex and triggered by natural phenomena, specifically an earthquake and tsunami. As extreme natural events are likely to become more frequent and more severe due to climate change, it is imperative that safety-critical systems in nuclear power plants are capable of functioning under abnormal circumstances.
The sequence of events at Fukushima have been
examined in detail by nuclear regulatory bodies and the scientific community so that lessons can be learned to improve legislation and safety processes. Investigating the performance of the physical equipment and the role that engineering can play in improving safe operation, in particular the role of pumping equipment in the reactor core isolation cooling (RCIC) system led to an improved pump design.
Cause and effect The catastrophic failure at Fukushima began with a severe seismic event that occurred on 11 March 2011 at 14.46 (local time) off the Japanese coast near Honshu Island, approximately 250 miles north of Tokyo. With a magnitude of M9.0, the Tohoku-Chihou-Taiheiyo-Oki earthquake was the largest ever observed in Japan and the fourth largest recorded earthquake in the world. The Great East Japan Earthquake, as it came to be known, also triggered a tsunami that flooded more than 200 square miles of coastal land. The earthquake and tsunami initiated a severe nuclear accident at the Fukushima Daiichi Nuclear Power Station, operated by the Tokyo Electric Power Company (TEPCO).
Above: The failures at Fukushima Daiichi prompted a global reappraisal of the reliability of cooling pump technology in light of natural disaster
32 | May 2024 |
www.neimagazine.com
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