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Conference Spotlight
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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What’s the most difficult question you’ve been asked as a maintenance instructor?
Blye Widmar
"Where are the prints?!"
This was the final question in an onslaught of verbal feedback, comments, and critiques I received from my students back in 2019. I had two years of instructor experience and was teaching a class that had been meticulously rehearsed in preparation for an accreditation visit. I knew the training material well and transferred that knowledge effectively enough for all the students to pass the class. As we wrapped up, I asked the students how they felt about my first big system-level class, and they did not hold back.
“Why was the exam from memory when we don’t work from memory in the plant?” “Why didn’t we refer to the vendor documents?” “Why didn’t we practice more on the mock-up?” And so on.
A. Bousbia Salah, J. Vlassenbroeck, H. Austregesilo
Nuclear Technology | Volume 192 | Number 1 | October 2015 | Pages 1-10
Technical Paper | Fission Reactors | doi.org/10.13182/NT14-51
Articles are hosted by Taylor and Francis Online.
Following an accidental event in a nuclear pressurized water reactor, involving the loss of primary-side forced coolant flow, the core decay heat is generally removed through a natural circulation convection process. The cooldown of the reactor coolant system is carried out through the secondary-side heat sink following prescribed guidelines. However, under asymmetric primary-side cooling conditions, natural circulation interruption (NCI) in the loops with an inactive steam generator may take place. Under such conditions, the cooldown of the primary side may be hindered and the transient may evolve toward a degraded state. The NCI issue was recently addressed within the thermal-hydraulic experimental projects ROSA-2 and PKL-2 of the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development. The objective was to identify the conditions that may lead to the occurrence of NCI, to develop cooldown procedures that prevent the occurrence of NCI, and to assess the thermal-hydraulic code capabilities in predicting this phenomenon. In the current study, NCI experimental tests carried out in the LSTF (Large Scale Test Facility) and PKL (Primaer-KreisLauf) facilities are assessed using the best-estimate thermal-hydraulic system codes CATHARE and ATHLET. The simulation results are presented and conclusions are derived accordingly.
