21st Annual Report, Volume I, Section 4.4, Human Performance: Human Errors and Improving Safety and Efficiency of Plant Performance

4.4.1 Overview and Previous Activities

Human Performance is usually used to refer to “human error” and the term is used herein in that manner. The issues around plant safety and plant efficiency having to do with human error reduction are also included in this section.

The goal of the human performance program is to reduce the number of human errors to improve plant safety and plant efficiency by improving human performance.

During the previous period (2009–2010) the DCISC reviewed the following human performance-related item:

The DCISC concluded that at the plant level DCPP Human Performance (HP) has been steady at a good level within its goal. The goal has a built-in continuous improvement factor, which is positive. There has been effective HP performance during recent outages, resulting in no HP events significant enough to cause a clock reset (a resetting to zero of a clock measuring the elapsed time without significant HP events). There are challenges in Maintenance work control quality and rework, which the DCISC should follow.

4.4.2 Current Period Activities

During the current period (2010-2011) the DCISC reviewed the following human performance-related item:

DCPP Human Performance (Volume II, Exhibit D.7, Section 3.5)

The DCISC Fact-finding Team met with the Supervisor of Human Performance (HP) and Industrial Safety, who reports directly to the DCPP Station Director, a high reporting level, which indicates the importance DCPP places on both HP and industrial safety.

DCPP’s Human Performance Program (HPP) is controlled by Procedure OM15.ID1, “Human Performance Program.” The stated purpose of the program is to “ … improve performance by reducing the frequency and severity of events … ” using “ … error prevention techniques as appropriate for the task.” The procedure outlines program definitions; management and personnel responsibilities; and processes and criteria for identifying and processing Department-Level Event-free Days events and Site Event-free events and the associated clock resets. In general, all individuals performing work at DCPP are responsible for:

  • Performing activities within established procedures, standards, and guidelines
  • Demonstrating and promoting the use of error prevention tools
  • Identifying via the Corrective Action Program (CAP) conditions, which may contribute or cause HP errors.

Error prevention tools (e.g., three-way communication, independent verification, phonetic alphabet, etc.) are taught in various “just-in-time” training tool kits, emphasized by management, and displayed prominently throughout the plant and on reminder cards required to be carried by all. The Fact-finding Team reviewed the Three-Way Communication Training Tool Kit and found it to be well designed. It included a student workbook, Maintenance Site-Level Event Awareness Bulletin, two-minute rule activity, student feedback form, and outline of an in-class activity of determining a battery voltage using three-way communication.

The error rate (numbers of Department Error events per 10,000 work-hours) increased slightly from August to October 2010; however, the overall trend is downward (good) and the current rate (0.192) is below the plant goal of 0.22. It is interesting and challenging that the plant goal is revised downward at a rate of 10% of the 12-month average rate. Overall plant performance is good based on no HP clock resets in 529 days. DCPP has a running “clock” which measures how long the plant has operated without a serious human error event. A “clock reset” is the result of a significant human error which causes a plant “clock” to stop and begin again at zero.

Department-Level Event Comparison 1R16 vs 2R15

The primary reasons for higher error rates during the outage were reported to be time pressure, more people working, and less frequent (i.e., less familiar) activities being performed. DCPP began to look more closely at the severity level of HP events in Outage 1R16. This will mean revising event trends and processes, which the department PICOs (Performance Improvement Coordinators) are developing. The DCISC should review these new severity-based trends near the middle of 2011.

DCPP is planning to augment its pre-outage personnel safety and human performance training for both plant personnel and supplemental personnel. There will be “new to nuclear,” “experienced worker,” and “supervisor” modules. The DCISC has attended DCPP pre-outage training and found it well done. The DCISC will consider attending the new training in March or April.

4.4.3 Conclusions and Recommendations

DCPP human performance (HP) is good and improving overall with plant-wide performance better than a progressively tightening goal and over 529 days without a clock reset, which is an indicator of outstanding performance. Most departments are within their goals with one, Operations, slightly better than their goals.

For more information contact:

Diablo Canyon Independent Safety Committee
Office of the Legal Counsel
857 Cass Street, Suite D, Monterey, California 93940
Telephone: in California call 800-439-4688; outside of California call 831-647-1044
Send E-mail to: dcsafety@dcisc.org.