...how many people involved with "something going wrong" at a nuclear plant have died as a result in the last 70 years of commercial nuclear power?
Anything like the roughly 19,000 people who will die today, died yesterday, died every day last year, and will die every day this year and next year from fossil fuel plants operating normally, dumping fossil fuel waste, aka "air pollution" into the planetary atmosphere?
Global burden of 87 risk factors in 204 countries and territories, 19902019: a systematic analysis for the Global Burden of Disease Study 2019 (Lancet
The top five risks for attributable deaths for females were high SBP (5·25 million [95% UI 4·496·00] deaths, or 20·3% [17·522·9] of all female deaths in 2019), dietary risks (3·48 million [2·784·37] deaths, or 13·5% [10·816·7] of all female deaths in 2019), high FPG (3·09 million [2·403·98] deaths, or 11·9% [9·415·3] of all female deaths in 2019), air pollution (2·92 million [2·533·33] deaths or 11·3% [10·012·6] of all female deaths in 2019), and high BMI (2·54 million [1·683·56] deaths or 9·8% [6·513·7] of all female deaths in 2019). For males, the top five risks differed slightly. In 2019, the leading Level 2 risk factor for attributable deaths globally in males was tobacco (smoked, second-hand, and chewing), which accounted for 6·56 million (95% UI 6·027·10) deaths (21·4% [20·522·3] of all male deaths in 2019), followed by high SBP, which accounted for 5·60 million (4·906·29) deaths (18·2% [16·220·1] of all male deaths in 2019). The third largest Level 2 risk factor for attributable deaths among males in 2019 was dietary risks (4·47 million [3·655·45] deaths, or 14·6% [12·017·6] of all male deaths in 2019) followed by air pollution (ambient particulate matter and ambient ozone pollution, accounting for 3·75 million [3·314·24] deaths (12·2% [11·013·4] of all male deaths in 2019), and then high FPG (3·14 million [2·704·34] deaths, or 11·1% [8·914·1] of all male deaths in 2019).
Note that these deaths do not include deaths from extreme weather resulting from extreme global heating.