Last month, US nuclear developer NuScale Power announced it was cancelling its first-of-a-kind small modular reactor (SMR) project in Idaho, in what is widely being seen as a blow to the nascent technology. SMRs have been hailed as one of the best hopes for achieving net zero, and while the concept is great on paper – after all small reactors have been powering nuclear submarines and ships for decades – there are real questions over its deliverability in practice.