If Nimrod [safety risk] is ALARP why is it (largely) grounded?
I understood that the ALARP consideration gave the nimrod fleet until date X to rectifiy the seals. It looks like a decision was taken not to take the operational impact of doing all the seals by this date (i.e. you'd have to tie up so many airframes in depth / out of the flypro that it would impact ops). This was probably on the basis it still gave time to get a mitigating op capability in place. Once this was decided, it was clear that once the date was reached the ac that hadn't had the work done would be grounded until they were fixed.
In any other circumstances an extension to the timeframe may have been considered/granted on the basis of risk, but I suspect this was not sought on the basis of political grounds (i.e. whilst potentially OK from an engineering risk perspective, it might look "bad" from a presentational perspective to be extending the deadline - given the fact that there is still media confusion over ALARP anyway, I think its true that there would have been an media uproar if they had tried to do that).
I understand it has so far cost 30 million to rectify the scp and fuel pipes/seals.
Not sure what your point is - either the cost is so high a judgement could have been made to say it was ALARP anyway without doing the seals? Per ac it seems to me a lower ££ than the cost of losing a crew, even though it seems the contribution of the seal issue to such a event seems very very low (given any ac design must cope with fuel leaks in any case). Is your cost correct just for seals, or mixed up with routine servicing?
Or is the seal issue much more of an issue that I'm led to believe above?