Like many of you, I watched Chernobyl and admired the simplicity with which Valery Legasov (Jared Harris) explained how the activity of a RBMK reactor goes up and down according to the conditions and controls.
He had to explain a relatively complex strategy to a less-informed, legal audience to support the prosecution of station management. Nowadays we'd be bombarded (pun intended) with PowerPoint slides to convey the message, yet with a few plastic tiles he summarised the delicate balance that needs to be performed either automatically or manually.
If there is a local or corporate (central) perception that everything is under control, then perspective and respect can degrade to the point where literally there is "an accident waiting to happen". We endeavour to avoid this by evaluating hazards, assessing risks and implementing controls, however...
If you don't have design data - how do you know what it's capable of?
If you don't have up-to-date ('As-Is' not 'As-Built') drawings - how do you know what's actually installed?
If you don't have appropriate ('Fit-for-Purpose') procedures - how do you know how to operate, maintain & test it?
If you don't know the operating limits - how do you determine when 'enough is enough'?
If you don't respond to alarms - what advance warnings of distress or damage are you ignoring?
If you override your controls - what protection are you sacrificing (even for a short period)?
If you don't follow up recommendations or actions - you haven't made it any safer!
If you don't assess the impact of those actions (and any other technical or organisational changes) - how do you know your 'remedy' hasn't created a new hazard, exacerbated existing hazards or defeated or degraded existing controls?
If you don't maintain your equipment (including timely testing and refurbishment/replacement) - how can you be confident that controls will operate & perform as expected when required?
If you don't perform tests as thoroughly as necessary - how has that exposed the latent failures that you want to find before the process demands it?
If you don't rehearse your emergency response (when nobody is expecting it) - how can you be sure that onsite/offsite parties can do the right thing in the right time?
If you don't have proficient people evaluating, analysing & implementing - how can you demonstrate that you have a competent culture?
If you don't audit or survey the controls (organisational & technical) - how can you direct your limited resources to potential problems before they occur?
If you don't learn and act upon incidents (from wherever) - how can you avoid the same event or similar events elsewhere?
But we're going to be OK because if all else fails, we've got the AZ-5 button to drop the control rods - I'll not spoil it for you, but that didn't work out as expected.
The messages and language in the programme should resonate with everyone within the Process/Safety community and is peppered with quotes that you'll recognise and no doubt remember including:
"The science is strong, but a test is only as good as the men carrying it out"
So why should we worry ?
"Oh, that’s perfect. They should put that on our money."