We will be using the Three Mile Island incident to demonstrate how a Technique for Human Error Rate Prediction (THERP) analysis is done. First, take a look at this Summary Sheet on THERP (PDF) (Links to an external site.) hosted by Alion’s System Reliability Center website.
Next do the following activities. Steps 1-3 of the Summary Sheet on THERP are given below as a guide for your THERP analysis:
Step 1: Define the system or process. This involves describing the system goals and functions and the consequences of not achieving them. It also requires identifying mission, personnel, and hardware/software characteristics.
https://www.youtube.com/watch?v=D8W5hq5dsZ4)in Module 1 gave you an understanding of the situation on that fateful day, Wednesday, March 28, 1979. Review the video if needed (use time segment 3:15 – 4:10 to focus on the key aspects needed for this assignment).
Step 2: Identify and list all the human operations performed and their relationships to the system or process tasks and functions. This requires an analysis of all operator and maintainer tasks.
Take a look at the human operations depicted in the Fault Tree (PDF) of what occurred in segment 3:15 – 4:10 of the video.
Step 3: Predict error rates for each human operation or group of operations. Errors likely to be made in each task or subtask must be identified. Errors that are not significant in terms of system operation are ignored. This step includes estimating the likelihood of each error occurring and the likelihood of an error not being detected.
For this step, use the Event Tree (PDF) provided to fill in the error rates.
Determine the basis human error probability (HEP) based on the event tree provided. You will be using data found in the NRC: Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications (PDF) (Links to an external site.) (NUREG/CR-1278). Go to Chapter 20 to see how to use the THERP tables to locate probability values.
For this case, the data sources in the NUREG/CR-1278 tables are shown for each action in the table below. Given that the operators omitted a procedural step from a long (>10 items) list of procedures, what should the Basic Human Error Probability (HEP) for each action be?
ActionsHEP (error factor)
Data Source in
Operators fail to restore signal power
Operators fail to restore power to controls
Operators fail to close the relief valve
Operators fail to close the drain valve
Upload your event tree with associated Basic HEP for each branch of the tree.
At Myrestlab.com, we always work diligently to provide our customers with high-quality nursing assignment help services. We ensure that all papers by our writers possess 100% originality. We also guarantee all students of 100% privacy and confidentiality when working with us.
At Myrestlab.com, our mission is to provide quality services to all students. We, therefore, guarantee money-backs for the rare occasions of satisfaction. Your satisfaction is our goal.Read more
All our nursing assignment help services are 100% original. Each of our professional writers develops custom papers from scratch to reduce the chances of plagiarism. In addition to this, we always run completed papers through advanced anti-plagiarism checkers for 100% originality.Read more
Our free revision guarantee is a courtesy service by Myrestlab.com to ensure that we achieve 100% customer satisfaction rates. In case you feel unsatisfied with the outcome of your paper, you can always request for free unlimited revisions. We recommend a revision request within 14 days after the delivery date for short papers and 30 for dissertations.Read more
Myrestlab.com also guarantee 100 privacy and confidentiality. We do not share any of our customers’ personal details with third parties. We have also fitted our websites with security features to ensure secure connections. Our security features also prevent damages that might occur through attacks by outsiders.Read more
By ordering a paper through My Rest Lab, you agree to receive nursing assignment help services offered by our nursing assignment writers. Our assignment help experts will always endear to provide quality services as promised. We always expect maximum cooperation from our students to help us achieve our mission and vision.Read more