United States Nuclear Regulatory Commission - Protecting People and the Environment

TH26  Conservatism in Decision-Making (Recent Operating Experience)

In the second half of 2011, the NRC Operating Experience (OpE) Branch reviewed reactive inspection reports and other relevant data from the Reactor Oversight Process to determine whether recent significant events involving a lack of conservatism in decision making and operator errors were merely an anomaly or part of an overall increasing trend. NRC's analysis showed evidence of leading indicators from the Reactor Oversight Process prior to the recent spike in significant events. Our analysis compliments the insights shared by The Institute of Nuclear Power Operations (INPO) in SOER 10-2, "Engaged, Thinking Organizations," and IER L1 11-3, "Weaknesses in Operator Fundamentals." In addition, NRC staff discovered evidence of further issues related to conservatism in decision making by licensee staff during technical specification (TS) interpretations and operability evaluations. The purpose of this session is to present the staff's findings to the audience, discuss several of the events that led to NRC reactive inspections, and discuss whether the reactor oversight process, licensee internal processes, and activities related to INPO recommendations are adequate to address these trends. Panel members will include NRC Headquarters and Regional staff, along with representatives from INPO, Duke Energy, and Dominion Generation.

Learning Objectives:

  • Inform the audience of recent trends related to conservatism in decision making, and discuss the staff’s findings including how ROP cross-cutting aspects and TS evaluations also contribute to the issue
  • Update the status of INPO’s activities related to SOER 10-2 and IER 11-3.
  • Discuss current and proposed actions that NRC is taking/will take to address the issues (OpE Smart Sample, possible Info Notice)
  • Discuss how industry is addressing the issue following events that occurred in 2011


John Thorp, Branch Chief, Division of Engineering, NRC/NRR



Eric Thomas, Sr. Reactor Systems Engineer, Division of Inspection and Regional Support, NRC/NRR, tel: 301-415-6772, e-mail: Eric.Thomas@nrc.gov

Page Last Reviewed/Updated Wednesday, August 08, 2012