History of Risk Assessment – Part III

History of Risk Assessment – Part III

By Marvin Rausand & Stein Haugen

Preliminary hazard analysis was introduced in 1966 as a tool to fulfill the US Department of Defense’s requirement for safety studies in all stages of system development. Perhaps the most important achievements in the 1970s was the “Reactor Safety Study” (NUREG-75/014 1975). A wide range of new methods and new approaches were developed, either as part of, or inspired by this study. Important methods include the “kinetic tree theory” (KITT) by William Vesely and models for treatment of common-cause failures (Fleming 1975). The Reactor Safety Study was heavily criticized, but this criticism does not diminish its importance. The risk of nuclear energy was discussed in most Western countries and new education programs in risk and reliability emerged in several countries. The US Nuclear Regulatory Commission (NRC) has played a very important role in the development of risk assessment. Two major landmarks are the publication of the “Fault Tree Handbook” (NUREG-0492) in 1981 and the “PRA Procedures Guide: A Guide to the Performance of Probabilistic Risk Assessment for Nuclear Power Plants” (NUREG/CR-2300). Another US report that led to a lot of risk assessments in many countries was “Critical Foundations: Protecting America’s Infrastructures” that was published by the President’s Commission of Critical Infrastructure Protection in 1997. The infrastructures are exposed to natural hazards, technical failures, as well as deliberate hostile actions. The concepts vulnerability, hazard and threat, and security suddenly became common ingredients in most discussions among risk analysts. In many countries, it became mandatory for all municipalities to carry out “risk and vulnerability analyses” of infrastructure and services. Many of the developments of risk assessment have been made as a response to major accidents (see Section 1.3). In Europe, two major accidents occurred close to the publishing of the Reactor Safety Study. The first of these, the Flixborough accident occurred in 1974 in North Lincolnshire, UK. It killed 28 people and seriously injured 36 out of a total of 72 people on-site at the time. The casualty figures could have been much higher if the explosion had occurred on a weekday, when the main office area would have been occupied. The other important accident occurred in 1976 in Seveso approximately 20 km north of Milan in Italy, where an explosion led to the release of a significant amount of cancer-causing dioxin. Together with the Flixborough accident, the Seveso accident triggered the development of the new EU directive on “the major-accident hazards of certain activities,” which is known as the Seveso directive and was approved in 1982. In the 1970s and 1980s, a range of laws and regulations on safety and risk emerged in many countries. Two well-known laws are the US Consumer Product Safety Act from 1972 and the UK Health and Safety at Work act from 1974. Many new organizations were established to prevent accidents. The United Kingdom Atomic Energy Authority (UKAEA) was formed already in 1954. In 1971, UKAEA formed its Safety and Reliability Directorate (SRD). The UKAEA SRD was an active organization and published a range of high-quality reports. One of the central persons in SRD was Frank Reginald Farmer who became famous for the Farmer curve (FN-curve) that was used to illustrate the acceptability of risk. Farmer was also the first editor of the international journal Reliability Engineering, the forerunner of the journal Reliability Engineering and System Safety (RESS). Another early organization was the IEEE Reliability Society that was established already in 1951. This society is responsible for the journal IEEE Transactions on Reliability. A forerunner to this journal appeared in 1952 under a different name. It changed name three times and finally got its current name from 1962. The first scientific society that was dedicated to risk analysis, the Society of Risk Analysis (SRA) was established in 1980 and its associated journal, Risk Analysis: An International Journal, appeared in 1981.

Source :

Risk assessment : theory, methods, and applications 2nd edition

Marvin Rausand, Stein Haugen

Wiley 2020