They produce both less heat (reducing the need for cooling systems) and less radioactivity.

它们所产生的热量(减少冷却系统的需要)和放射性也更小。

youdao

The result shows that if the cooling system of the spent fuel storage pool can be retrieved in 19 hours, the natural circulation cooling ability is sufficient to prevent radioactivity release.

计算结果表明。恰希玛核电厂乏燃料池冷却系统失效后， 只要在19 个小时内修复冷却系统， 不会出现大量放射性物质外泄。

youdao

The six-reactor Fukushima Daiichi nuclear plant was badly damaged after the 11 March 2011 earthquake and tsunami knocked out cooling systems to reactors, leading to meltdowns and the release of radioactivity.

BBC: Japan panel: Fukushima nuclear disaster 'man-made'