Safety Directives of USA’s Nuclear Regulatory Commission

Nuclear (Information) Power, UCS,  , DIRECTOR, NUCLEAR SAFETY PROJECT | OCTOBER 18, 2016 DISASTER BY DESIGN/SAFETY BY INTENT #54

Safety by Intent

Robin Morgan wrote that “Knowledge is power. Information is power.”

Among many lessons learned from the March 1979 core meltdown at Three Mile Island was the need to collect, assess, and disseminate relevant operating experience in a timely manner. In other words, nuclear information has the power to promote nuclear safety, but only when that information is shared so as to replicate good practices and eradicate bad ones. Both the Nuclear Regulatory Commission (NRC) and the nuclear industry undertook parallel efforts after Three Mile Island to improve operating experience efforts.

NRC’s Information Sharing

The centerpiece of the NRC’s operating experience efforts is its generic communications program. The NRC instituted this program before the Three Mile Island accident, but took steps following the accident to expand the program and to shorten the time between events and advisories. The NRC also lowered the threshold used to screen the information to share more operating experience with plant owners.

The NRC has issued thousands of generic communications since the Three Mile Island accident.Bulletins and Generic Letters typically alert owners to a potential problem and require them to either confirm their facilities are not vulnerable or implement measures to reduce vulnerabilities.Regulatory Issue Summaries and Information Notices typically apprise owners about operating experience but do not require that the owners take specific actions in response.

Examples illustrating these various generic communications are:

    • Bulletin 2003-01, “Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized Water Reactors,” warned owners that a rupture inside containment of a pipe filled with steam or water could generate large amounts of debris as the high pressure fluid jetting from the broken pipe ends scoured coatings off equipment, insulation off piping, and even paint off walls…….
    • Generic Letter 2007-01, “Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients,” warned owners about a rash of unexpected failures of electrical cables. Many of the electrical cables had been qualified for 40 years of service, but failed before the end of their qualified lifetimes due to submergence in water. Several of the failed cables had been routed through underground metal conduits and buried concrete trenches. Groundwater or rainwater leaked into the conduits and trenches, subjecting the cable insulation to more rapid deterioration than anticipated………
    • Information Notice 2011-13, “Control Rod Blade Cracking Resulting in Reduced Design Lifetime,” warned owners of boiling water reactors about experience at a foreign nuclear plant. Workers discovered severe degradation of the control rods caused by irradiation-assisted stress-corrosion cracking. …….
    • Regulatory Issue Summary 2015-11, “Protective Action Recommendations for Members of the Public on Bodies of Water,” reminded owners of their obligations under Appendix E, “Emergency Planning and Preparedness for Production and Utilization Facilities,” to 10 CFR Part 50. Specifically, the regulatory issue summary reinforced the NRC’s expectation that owners’ emergency plan measures account for all affected members of the public whether on land or on water.
    • Regulatory Issue Summary 2014-12, “Decommissioning Fund Status Report Calculations—Update to Low-Level Waste Burial Charge Information,” informed owners that they could use data in Revision15 of NUREG-1307, “Report on Waste Burial Charges: Changes in Decommissioning Waste Disposal Costs at Low-Level Waste Burial Facilities,” in preparing periodic funding status reports required by 10 CFR 50.75(f). Owners are required to estimate the cost of decommissioning their facilities based on (1) labor rates, (2) energy costs, and (3) low-level waste disposal costs. The U.S. Department of Labor periodically publishes data on labor and energy costs that owners can use. The regulatory information summary identified a source of low-level waste disposal cost data acceptable to the NRC.

Nuclear Industry’s Information Sharing

The nuclear industry formed the Institute for Nuclear Power Operations (INPO) in December 1979 as part of its responses to the Three Mile Island accident. Information sharing is one of several functions performed by INPO to support the nuclear industry……..

UCS’s Disaster by Design/ Safety by Intent series of blog posts is intended to help readers understand how a seemingly unrelated assortment of minor problems can coalesce to cause disaster and how effective defense-in-depth can lessen both the number of pre-existing problems and the chances they team up.

http://allthingsnuclear.org/dlochbaum/nuclear-information-power

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