Introduction:
Elements of Safety Culture
Last minute changes are a human error trap!" Ask yourself the questions ‘if’ before any action and decision. Negative thinking is conclusively painful. It involves finding and exposing your inadequacies, which can be irresistible. And not every problem discovered can be solved. You live in a state of lasting dissatisfaction.” Learn from the mistakes of others. You can’t live long enough to make them all to yourself. A popular saying is that “You can’t manage what you can’t measure.” "Not everything that can be counted counts and not everything that counts can be counted." I think it's from Einstein.
The elements of safety cultures are: (1) Vision, (2) Leadership, (3) Focus, (4) Defined and Consistent Practice, (5) Transparency, (6) Maintaining a "no frills" philosophy, (7) Data driven decisions, (8) People driven practices, (9) Establishing rules that work for the particular situation, and (9) Cutting to the chase. All of these can be translated to other kinds of organizations, personally don't think that it would be a good nuclear safety culture leader (because the last element, that isn't outline above, is relevant experience in the field), but these principles can definitely be applied in a nuclear safety organization.
Safety Culture is Management Performance
Personally, safety culture is all about management. How are the plants being managed Are we developing employees to meet site and industry expectations and are we really managing their performance Those are the questions. Worker engagement, critical decision making, Work Management, Human engineering are all issues with management responsibility for both implementation and maintenance. We have managers and management teams that cannot recognize their organizations are in trouble (from a safety perspective, etc) until a team from the regulators Korea Institute of Nuclear Safety (KINS) comes in to evaluate.
That is not a culture issue, it is people, and it is a management issue. Safety culture is an excellent impact of how the organization is managed, positive or negative. I think KINS would be better served by developing models of management for employee development and performance management with certain levels of skill application. Organizations should have management team members on nearly teaching and developing of employees by management, those are the real precursors for safety issues and much easier to measure and understand.
Boiling Water Reactors (BWRs)
The Fukushima accident was a Boiling Water Reactor (BWRs). Better understanding of a generic BWR behavior is a must during a station blackout. Due to the absence of steam generators, BWRs use reduced volume pressure suppression containment, which consist of a drywell and a wetwell. In the Mark I containment design used in Fukushima units 1, 2, and 3, the drywell consist of an inverted lamp shaped steel vessel that houses the reactor vessel. The lower wetwell is a steel torus half filled with water. The drywell and wetwell are connected by pipes partly submerged in the wetwell water. Both chambers are inerted to avoid burning or explosion of hydrogen formed during a loss of coolant accident.
Monitoring Critical Variables
A BWR reactor is designed so that its core is surrounded by shroud. The cooling waters enter into the “jacket-like” space between the shroud and the wall of the reactor. The water travels down the outside of the core and then rises up inside it. As it rises, the fuel rods heat it and it starts to boil. As steam bubbles form, the steam-to-water ration rises and the water “swells”. The goal of the level control system is to keep the fuel rods always covered to protect them against overheating and melting. But in many BWRs, the water level and the steam to water ratios are not measured inside the core but instead, they are measured “ex-core” between the shroud and the reactor wall. During emergency condition, this measurement no longer reflects the water level inside the core, thus , ex-core level measurement can be useless during Loss Of Coolant Accident (LOCA) emergencies.
Not Dependable Measurement
In the reactor, water levels were not reliably measured, but were only assumed to be correct by the operators. Operators must know if the fuel rods are covered with water or not, and safe plant operation requires automatic response if this level drops too low. False readings suggested that water levels were several meters above the actual and in the primary containment vessels they were not even measured. As lesson learned from Fukushima accident, “an alternative automated plant design is envisioned in which detectors monitoring critical variables would be reliable and accurate, and would be triple-redundant, configured in a voting arrangement, in order that if one sensor disagrees with the majority, its reading is immediately disregarded and its recalibration is requested automatically.
South Korea’s NPP
South Korea has 21 operating and 7 under construction Nuclear Power Plants (NPPs). The 4 CANDU operating reactors and 17 Pressurized Water Reactors (PWRs) with a combined output of 18.7 GW that provide 30% of Korea’s generated electricity.
After the Fukushima accident on March 11, 2011, the South Korean government implemented the Comprehensive Special Safety Inspections (SSI) on all NPPs in Korea.
The following recommendations are the results of SSI on all NPP in South Korea:
- Automatic Seismic Trip System-activated above 0.18g will be installed at all Korean Nuclear Power Plant by 2012
- Strengthening the bridge at the Wolsong site and raising the height of a seawall at the Kori NPP site
- Safety Shutdown System at all existing and new NPP units will be upgraded to withstand a design earthquake level of 0.3g and the potential for earthquakes at each NPP site will be reassessed.
- Waterproofing electrical components such as pumps and high and medium voltage switchgears
- Installing additional emergency generators as a back-up contingency for spent fuel pool cooling
- Simplifying fire protection site plans by strengthening cooperation from internal and external fire stations.
- Introduction of a performance based fire protection system design
- Alternative water sources to be secured for firefighting purposes in case of tsunami, supplied by minimum number of emergency workers retained at each Nuclear Power Plant site to be able to operate fire trucks
- Revision of Severe Accident Management Guidelines (SAMGs) for low-power shutdown situations, as well as increasing the duration of operator simulator training for severe accidents to ten hours per year.
- Installation of passive hydrogen removal equipment in Nuclear Power Plants (NPP) plants where it is not available
- Filtered vents to prevent containment overpressure as well as new points for injecting emergency cooling water that will be carried out in the medium term.
- Improved emergency response that call for additional radiation protection equipment such as gas masks, potassium iodide tablets to secure the population within 16 km of each NPP
- Improved emergency plans to include simultaneous unannounced emergency exercises at multiple NPP units
- Alternative automated plant design for the detectors monitoring critical variables to be reliable and accurate, such as triple-redundant sensor, in order that if one sensor disagrees with the majority, its reading is immediately disregarded and its recalibration is requested automatically.
Ensuring Asset Wide Contingency Planning
The South Korean government to ensure asset wide contingency planning implemented that all new NPP at the final stage of Operating Licensing must apply the Fukushima Lesson Learned that has been affected particularly for the new NPP such as Shin Kori 2 and Shin Wolsong 1 (OPR-1000 reactors) that are due to commercial operation by late 2012. The following contingency planning are recommended:
- Installation of a cooling water flow path to spent fuel pool
- Preparation of a portable diesel generator so supply power to essential equipment with the installation of a full capacity generator by 2014
- Installation of primary and secondary injection paths for emergency cooling water supply
- Installation of Hydrogen removal system
- Reinforcement of operator simulator training for Severe Accident Management Guidelines
- Amendment of emergency plans to include multi-unit emergency applications
Uniform Safety Culture Extension throughout the KEPCO-E&C NPP Network
Uniform Safety Culture throughout the KEPCO-E&C NPP Network is coordinated through Self Assessment Program to various department activities of the Quality Assurance Department, Safety Department, and the Plant Review Board. Implementation of this program contributes to the prevention of problems by monitoring and evaluating plant performance, providing assessment and findings, and following up on corrective action recommendations. Self Assessment Program also performs independent technical evaluation of plant activities including maintenance, modifications, operational problems, and operational analysis.
South Korean NPP Uniform Safety Culture Objectives are:
The following recommendations related to Safety Culture Objectives are made:
- Develops and presents recommendations to the management to improve plant safety and reliability and reduce human error.
- Identification of potentially significant problem areas to plant management
- In-depth technical evaluations of selected plant activities in progress, including operations, maintenance, and modifications, to access if they are performed correctly. Although the emphasis is on the technical perspective, programmatic issues are documented when found and forwarded to the responsible organization for action.
- Evaluation of selected significant Operating Experience Review Program for the completeness and effectiveness of corrective action implementation.
- Performance of selected special investigations on technically complex issues at the request of plant management
- Documentation of recommendations related to procedures, equipment, or other means to improve plant safety.
- Assures tracking of responses, verification of effective implementation of corrective actions, and escalation of untimely or unsatisfactory responses to higher levels of management.
- Performance regarding the adequacy of self assessment program evaluations is measured by the results of Korea Institute of Nuclear Safety (KINS) evaluations.
- KINS Systematic Assessment of Licensee Performance ratings and other self assessment program effectiveness review.
Management Support
Self Assessment Program is responsible for the performance of independent self-assessment evaluations from a technical perspective. Areas for evaluation include maintenance, modification, operations, operational problems, and operation analysis. Such evaluations are done in progress and are limited in scope. Responsibilities also include the review of Licensee Event Reports (LER’s), enforcement history, inspection reports, management meeting reports, performance indicators, Self-assessment Licensee Program and Institute of Nuclear Power Operations (INPO) reports and industry Operating Experience (OE) information that may indicate areas for improving plant safety.
Interfacing
The following are recommendations for effective interfacing:
1. Communication focal point from department managers who review the findings identified by the self assessment program.
2. Plant Management interface as required to address NPP safety concerns.
3. Monthly summary report on self assessment program activities is provided to the executive management
4. Developed strict detail procedure for the distribution and dealing of non-conformance reports, to ensure timely initiation of corrective action.
5. Operation and Maintenance training should include general information about the special requirements to be met in the modification of a nuclear power and industrial plant as well as guidance on practices for ensuring nuclear safety. Training should also be provided for the personnel of manufacturers that fabricate equipment specifically designed for the NPP
6. Comments made during audits and inspections should be analyzed systematically in order to identify recurring observations. Particular attention should be paid to observations concerning deficiencies and problems in the performance of the maintenance subcontractors' organizations.
7. Assess together with design group why most of the non-conformances recorded in Nuclear Regulatory audits have not been noted in own
The self assessment program independently observes and evaluates selected plant activities in order to provide pant management with additional insight as to where improvements can and should be made to procedures, equipment, and training to improve plant safety and reliability.
In order to maintain an accurate understanding of how activities are being performed, a priority is given to reviewing activities in progress and the day-to-day physical condition of plant equipment.
The effectiveness of planning, preparations, documentation, and problem solving can only be accessed through a combination of documentation review and direct activity evaluations. Self assessment program tasks are scheduled such that at least one fourth of the available technical staff’s work time involves evaluating activities in progress in the direct preparation for follow-up of these activities. Problems identified at an early stage occur at lower levels and are less costly to handle. Problems that need to be solved at higher levels exist because they have grown complicated and are more costly to fix.
Pre-job briefing should be organized for all groups of persons involved. Examples of issues to be covered include the significance of the job to safety, the responsibilities and authorities of different subcontractors, the schedule, work stages and critical points, overall coordination of work and actions to be taken in potential problem situations. In this context, the potential problems foreseen by the persons implementing the work should be discussed. Pre-job briefing is particularly important for work implemented jointly by several organizations.
Conclusion
The effectiveness of self assessment program and the Fukushima Lesson Learned application depends on communication throughout the organization and in identifying performance issues vs. compliance issues, as well as the ability of the self assessment program engineers to communicate and present solutions to problems. The identification and correction of specific performance problems helps prevent the repetition of similar failures. Approved NPP plant safety and availability leads to the goals of electricity generation in a safe manner.
