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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Empowering the next generation: ANS’s newest book focuses on careers in nuclear energy
A new career guide for the nuclear energy industry is now available: The Nuclear Empowered Workforce by Earnestine Johnson. Drawing on more than 30 years of experience across 16 nuclear facilities, Johnson offers a practical, insightful look into some of the many career paths available in commercial nuclear power. To mark the release, Johnson sat down with Nuclear News for a wide-ranging conversation about her career, her motivation for writing the book, and her advice for the next generation of nuclear professionals.
When Johnson began her career at engineering services company Stone & Webster, she entered a field still reeling from the effects of the Three Mile Island incident in 1979, nearly 15 years earlier. Her hiring cohort was the first group of new engineering graduates the company had brought on since TMI, a reflection of the industry-wide pause in nuclear construction. Her first long-term assignment—at the Millstone site in Waterford, Conn., helping resolve design issues stemming from TMI—marked the beginning of a long and varied career that spanned positions across the country.
Wolfgang Kröger, Johannes P. Wolters
Nuclear Technology | Volume 74 | Number 1 | July 1986 | Pages 53-64
Technical Paper | Neuclear Safety | doi.org/10.13182/NT86-A33818
Articles are hosted by Taylor and Francis Online.
Advanced nuclear reactors in the Federal Republic of Germany (FRG) must analogously fulfill the deterministic safety criteria developed for the light water reactor (LWR). In earlier high-temperature reactor (HTR) concepts, the interpretation of this requirement led to exaggerated safety precautions. Efforts are being made in recent HTR concepts to develop a more specific safety concept making use of probabilistic risk assessment and probabilistic safety analysis. The basis for development and evaluation is formed by a requirement concept of frequencyoriented limits. Design-relevant accidents are divided into three categories and the appertaining maximum permissible doses are allocated based on the FRG Radiation Protection Ordinance. For even more infrequent events it must be demonstrated that the collective damage and risks remain clearly below those of a comparably large LWR. This probabilistic requirement concept has been applied to two HTR concepts under development and the result has been judged positively by a group of experts established by the Federal Ministry of the Interior. The most extensive experience for HTR-500 is discussed in detail. At the planning stage, the accident spectrum was studied and results were compared with predefined limit values. If necessary, design modifications were undertaken by the manufacturer. The safety concept thus developed is essentially different from that of other reactor facilities. Accidents initiated by the failure of active core cooling result in a slow rise in core temperatures; a period of ≈5 h remains for repair and for operator actions. Core heatup alone does not lead to unacceptable doses. It could therefore be accepted as an accident relevant for design. The envisaged two-train design of the afterheat removal system and the comparatively low degree of automation of the reactor protection system have proved to be sufficient. Core heatup accidents associated with failure of the liner cooling lead to the highest consequences and dominate risk. A simple modification—provision of an emergency feed for the liner cooling system — turned out to be necessary for risk reduction. The analyses were further used to replace the usual gastight containment by a more economical vented confinement with filtered release in case of small helium leaks. All together the safety concept of the HTR-500 ensures that accidents (>10≈5/yr) remain below the frequency-related dose limits and that the risk is extraordinarily slight. In no case does the necessity of evacuation and rapid resettlement arise.
