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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Fusion Science and Technology
Latest News
INL makes a case for eliminating ALARA and setting higher dose limits
A report just released by Idaho National Laboratory reviews decades of radiation protection standards and research on the health effects of low-dose radiation and recommends that the current U.S. annual occupational dose limit of 5,000 mrem be maintained without applying ALARA—the “as low as reasonably achievable” regulatory concept first introduced in 1971—below that threshold.
Noting that epidemiological studies “have consistently failed to demonstrate statistically significant health effects at doses below 10,000 mrem delivered at low dose rates,” the report also recommends “future consideration of increasing this limit to 10,000 mrem/year with appropriate cumulative-dose constraints.”
Paresh Patel, C. B. Sumod, D. P. Thakkar, L. N. Gupta, V. B. Patel, L. K. Bansal, K. Qureshi, V. Vadher, U. K. Baruah, N. P. Singh
Fusion Science and Technology | Volume 64 | Number 1 | July 2013 | Pages 39-44
Technical Paper | doi.org/10.13182/FST13-A17045
Articles are hosted by Taylor and Francis Online.
Regulated high-voltage power supplies (RHVPSs) have been developed at Institute for Plasma Research and utilized for neutral beam and radio-frequency heating applications of the steady-state superconducting tokamak (SST-1) up to 80-kV, 130-A rating. They were developed in-house and are being delivered to different research institutes for various applications.The RHVPS delivers power to various loads at the megawatt level. These loads have very low fault energy tolerance; therefore, fault protection is mandatory. In addition to this, at each stage of the power transformation/conversion, a special diagnosis is necessary to protect the power supply components. Also, the output fault protection has to be done in such a manner that fault energy is not more than 10 J. In fault conditions, the output has to be turned off within 2 s. Having these requirements, an output fault-protection system has been developed with suitable sensors and to manage fast turn off, choosing appropriate components.The multiple-secondary transformers (two of them, each at a 5.6 MVA rating with 40 outputs) are used at the front end of the RHVPS. They may become damaged for overload at any one of their secondaries, while remaining secondaries carry much less current or no current. Such a localized overload is not sufficient for tripping the main circuit breaker, whose tripping level is set to an actual overload of the transformer. A special technique is applied to sense and diagnose this fault in addition to routine overload sensing. Differentiation of such a typical fault from a real overload condition is done by sensing and monitoring the primary current of the transformer with reference to different operating scenarios. Electronic means are used for fast detection and isolation of the RHVPS from the utility supply. The presented system effectively protects the transformer from fault at any one of its 40 secondaries and in an actual overload situation.This paper describes an overall RHVPS power scheme along with output fault protection and an internal fault diagnosis system and test results thereof.
