​What is the SPAR-H Method?

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The U.S. Nuclear Regulatory Commission (NRC), together with the Idaho National Laboratory (INL), developed the Accident Facility Analysis Risk Model (ASP/SPAR) in 1994. It is the human reliability analysis (HRA) method used in the development of nuclear power plant (NGS) models. Based on experience gained in field tests, this method was updated in 1999.

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Renamed SPAR-H for Standard Facility Analysis Risk-Human Reliability Analysis method. Since then, NRC staff analysts have used this method to develop an integrated operator performance measure based on risk information.

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​How is the SPAR-H Method applied?

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Except for the SPAR-H method, most of the methods are presented as quantitative approaches to estimating HEP, i.e., Human Error Probability. The SPAR-H method estimates HEP both qualitatively and quantitatively.

The SPAR-H approach decomposes probability into contributions from diagnostic failures and action failures, accounts for the context associated with human error events using performance shaping factors (PSFs), and uses dependency assignment to set a baseline Human Error Probability (HEP). The method uses eight PSFs that affect human performance. PSF are environmental, personal or operational factors that have the potential to affect performance positively or negatively.

Major Accident Scenario Document Communiqué According to the Regulation on Preventing Major Industrial Accidents and Reducing Their Effects
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Obligations:

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The operator of a lower or higher level organization prepares or has a major accident scenario document prepared by complying with the specified format and general rules and fulfilling the minimum requirements. The major accident scenario document is not sent to the Ministry of Family, Labor and Social Services, but is kept in the organization.

 

Annex-1 FORMAT AND GENERAL RULES OF MAJOR ACCIDENT SCENARIO DOCUMENT
8.3 Operator errors
The probability of the operator making a mistake is analyzed in calculating the frequency of occurrence of major accident scenarios in which the operator is the root cause or operator intervention is involved.
Possibility of operator error within the scope of 8.3 in this section;
a) At least “0.01” in calculations where the operator is the root cause,
b) At least “0.1” in calculations involving operator intervention,
is evaluated. Data with probability lower than this cannot be taken into account in the calculations.

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Major Accident Scenario Document Communiqué According to the Regulation on Preventing Major Industrial Accidents and Reducing Their Effects
​
Obligations:

​

The operator of a lower or higher level organization prepares or has a major accident scenario document prepared by complying with the specified format and general rules and fulfilling the minimum requirements. The major accident scenario document is not sent to the Ministry of Family, Labor and Social Services, but is kept in the organization.

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NOTIFICATION OF MAJOR ACCIDENT SCENARIO DOCUMENT TO BE PREPARED REGARDING MAJOR INDUSTRIAL ACCIDENTS

Annex-1 FORMAT AND GENERAL RULES OF MAJOR ACCIDENT SCENARIO DOCUMENT

8.4. Principle of independence and effectiveness
In calculating the frequency of occurrence of scenarios, the principle of independence, the effect of common cause errors and the principle of effectiveness are also taken into account.

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MINIMUM REQUIREMENTS FOR MAJOR ACCIDENT SCENARIO DOCUMENT:

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• Major accident scenario document team: A team should be formed to prepare the scenario document.

• Steps for preparing scenarios: Steps such as identification and classification of hazardous substances, identification of hazardous equipment, identification of internal hazards, identification of external hazards, creation, analysis and evaluation of major accident scenarios are followed.

• Identification and classification of hazardous substances: Hazardous substances are identified and classified. The SEA Regulation is taken as basis.

• Identification of hazardous equipment: Hazardous equipment is identified and listed.

• Identification of internal hazards: Internal hazards related to hazardous equipment are identified.

• Identification of external hazards: External hazards in the organization's environment are identified.

• Creation, analysis and evaluation of major accident scenarios: Scenarios are created, frequencies are calculated, compared with limit values and necessary measures are decided.

• Other issues: Other important issues such as critical equipment, frequency calculation methods, operator errors, independence and efficiency principles are stated.

 

The steps to be followed to prepare the major accident scenario document are explained in detail below:

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Step 1: Identification and Classification of Hazardous Substances

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Step 2: Identifying Hazardous Equipment

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Step 3: Identifying Internal Hazards

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Step 4: Identifying External Hazards

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Step 5: Creation, Analysis and Evaluation of Major Accident Scenarios

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This document specifies how the major accident scenario document should be prepared in accordance with the requirements of the "Regulation on the Prevention of Major Industrial Accidents and Reducing Their Effects" and the limit value of the major industrial accident frequency.

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Limit Value of Major Industrial Accident Frequency:

 

For hazardous equipment that may cause major accidents, the operator reduces the frequency of occurrence of each major industrial accident scenario to 1x10-4/year or less.

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This document explains how an enterprise should prepare its major accident scenario document in accordance with these regulations and what kind of values are targeted in order to prevent major industrial accidents and reduce their effects.

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To get a detailed idea about Quantitative Risk Assessment and GMS, please review the Article and Blog section.