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NUREG 0933
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This task, outlined in Chapter 1 of NUREG-1251, [1] called for the staff to review the administrative controls over plant operations in the U.S. to determine if adequate controls are in place to maintain plant conditions within the safe operating …
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The Chernobyl Unit 4 accident was a prompt critical reactivity excursion that occurred when the operators reduced power to well below the permissible safe operating level and, at the same time, neglected to follow low power operating procedures. Unit 4 …
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The Chernobyl accident, with its absence of effective containment, has focused attention on the strengths and performance limits of the substantial containments for U.S. LWRs. It has led to added recognition of the significance of ongoing work on the …
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A number of facts about the Chernobyl accident have some bearing on emergency planning and preparedness around U.S. commercial nuclear power plants. This task, outlined in Chapter 4 of NUREG-1251, [1] called for the staff to examine the implications of …
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The highly energetic reactivity excursion accident at Chernobyl mechanically disrupted the core, rapidly vaporized the water coolant with which the fragmented fuel came into contact, and generated combustible hydrogen by chemical reaction of core …
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The Fort St. Vrain HTGR and DOE's N-reactor at the Hanford Reservation in Washington State are the only graphite-moderated power reactors operating in the U.S. This task, outlined in Chapter 6 of NUREG-1251, [1] called for the staff to assess the HTGR …
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DESCRIPTION During the administration of the third of a three-fraction vaginal treatment of a patient on January 9, 1996, the treatment console of a Nucletron high-dose-rate (HDR) remote afterloader unit locked up, and the console alarm sounded when the …
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DESCRIPTION This issue was identified [1] by NMSS after several cases were reported where licensees found residual contamination remaining in some components of Krypton-85 handling systems after the standard decommissioning process. The staff's concern …
1
DESCRIPTION This issue was identified [1] by NMSS with the discovery of intergranular corrosion in one manufacturer's 316L stainless steel source used in Category IV irradiator pools. Analysis of data and reports provided by the manufacturer revealed that …
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DESCRIPTION This issue was identified [1] by NMSS after Cobalt-60 radiography sources were stolen from a bankrupt licensee (Larpen of Texas) and sold to a scrap yard where one source fell out of its housing and exposed several individuals. The Bureau of …
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DESCRIPTION This issue was identified [1] by NMSS when Victoreen, Inc., notified the NRC that some of its Model 530 and 530SI Electrometer/Dosimeter instruments were susceptible to developing cracks in their internal resistor networks. These cracked …
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DESCRIPTION This issue was identified [1] by NMSS and addresses the potential for special nuclear material containing unusual moderators to re-concentrate and form a critical mass in low-level waste disposal systems. The results of studies of two …
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DESCRIPTION The importance of computer software (methods and data) in establishing the criticality safety of systems with fissile material is increasing as licensees work to optimize facilities and storage/transport packages at the same time that access …
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DESCRIPTION The Year 2000 computer problem had the potential to pose a threat to public health, site safety and safeguards, and worker safety. Many computer systems could have potentially failed to recognize the change to a new century. The staff believed …
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DESCRIPTION This issue was identified [1] by NMSS after three reports of radiography source disconnects involving drive cable breaks in Amersham equipment were reported. IN 97-91 [2] was issued to alert all industrial radiography licensees to potential …
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DESCRIPTION This issue was identified [1] by NMSS after it was reported in June 1997 that the source from a Troxler moisture density gauge broke off the source rod and was left at a temporary job site. Prior to this event, there had been 6 known …
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DESCRIPTION In early 1997, the NRC became aware that, on four separate occasions, utilities using the ventilated storage cask (VSC)-24 spent fuel dry cask storage system had experienced cracking while making the cask closure welds. In May 1997, the NRC …
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DESCRIPTION This issue was identified when two holders of Certificates of Compliance for shipping packages performed puncture tests using a bar that was not properly mounted, as specified in 10 CFR 71.73(c)(3). As a result, NRC Bulletin 97-02 [1] was …
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DESCRIPTION This issue was identified [1] by NMSS to allow licensees to establish ALIs and DACs for use at their facilities based on new models to show compliance. NMSS believed that 10 CFR 20 needed to be revised so that Appendix B and all references to …
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DESCRIPTION This issue was identified [1] by NMSS to pursue research to provide a methodology to calculate surety for groundwater restoration activities at in situ leach uranium extraction facilities and a post-restoration groundwater quality stability …
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DESCRIPTION As of July 1998, SNM-bearing low-level waste was being disposed of at the following three facilities: (1) Envirocare in Clive, Utah; (2) U.S. Ecology in Hanford, Washington; and (3) Chem-Nuclear in Barnwell, South Carolina. Until 1997, the …
1
DESCRIPTION Exposure to the "unimportant quantities" of source material, defined in 10 CFR 40.13(a) as less than 0.05 wt% uranium or thorium, could result in annual doses to the public of hundreds of millirem exceeding NRC's public dose limit of 100 …
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DESCRIPTION Radioactive products to be distributed under a general license are required to be inherently safe so that they can be used by untrained people. However, licensed devices containing radioactive materials have not always been disposed of, nor …
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DESCRIPTION Two misadministrations resulted when a licensee manually edited treatment data for the Nucletron HDR unit. While attempting to manually edit one parameter, unintended and unnoticed changes to the source step size occurred that caused the …
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DESCRIPTION Several control unit failures in Nucletron Classic Model HDR units occurred over the span of three years: two were reported in 1997; four in 1998; and three in 1999. These nine control unit failures indicated an ongoing problem with …
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Page Last Reviewed/Updated 3/1/2026
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