$3.$ A maintenance technician, Alex, is called in for an urgent repair on a critical cooling system in a nuclear power plant. It's late in the evening, and the plant is operating at near$-$full capacity. A minor coolant leak was detected, and although contained, it demands immediate attention to prevent any escalation. Alex has extensive experience in routine maintenance, but this particular task is both complex and rarely performed, involving multiple steps that require precise calibration. As he prepares for the task, the pressure is palpable. The plant supervisor emphasizes the importance of a quick turnaround, as even a slight delay could impact cooling efficiency and safety margins. The control room is bustling with activity, and Alex can feel the weight of the situation. He reviews the procedure twice, double$-$checking each step. Yet, time pressure looms, and with every passing minute, he feels the urge to work faster. Adding to the challenge, the procedure requires a unique tool he has not used in months, and the steps are intricate, involving a sequence of precise actions to safely restore the coolant line without triggering an alarm. Under these high$-$stress conditions, Alex knows that even a small oversight could lead to a costly delay or worse. a$.$ Conduct human error probability $($HEP$)$ for the above scenario. $[15$ marks$]$ b$.$ Discuss the implications of HEP in part a$,$ and the importance of reducing Error Producing Condition $($EPCs$)$ in high$-$stakes environments by giving appropriate examples and relevant calculation. $[15$ marks$]$