Hazop

The HAZOP team consisted of a HAZOP leader, scribe, process engineer, senior operator, and a safety engineer. Previously, the HAZOP leader collected information on the process design (e.g., P& IDs, operating procedures, emergency procedures and incident reports) for distribution to each team member. The leader sectioned the process and identified process deviations prior to the HAZOP. The actual HAZOP required a 1-week meeting and a 3-day meeting. During the first meeting, the team HAZOPed...

Critique of the Reactor Safety Study RSS

WASH-1400 (FINAL), Appendix XI presents comments and responses on the draft report. Some of these resulted in changes that were incorporated in the final report. Only a few critiques of the final report have been published. Two of these are NUREG CR-0400 (Lewis Report) and Kendall, 1977. Of these, the Lewis Report's comments are the most objective (Leverenz and Erdmann, 1979, provide a review of the Lewis review). Some comments are summarized 1. Despite its shortcomings, WASH-1400 provides at...

Qra

The QRA was conducted by risk analysts and design personnel to determine the probability of explosive releases of the chemical. Fault tree Ca,a sl analysis identified several combinations of equipment failures and operator errors that could cause the top event (reactor explosion). Failure data were obtained from plant experience and industry databases to quantify the fault trees to estimate the frequency of reactor explosions. The fault trees suggested several safety improv 11.4-3 Proposed New...

7123Twenty Eight Die at Flixborough6

On June 1, 1974, a vapor cloud explosion destroyed __Bellows the 70,000 tons per year, Flixborough Nyprocyclohexane oxidation plant killing 28 people. Other plants on the site were seriously damaged or destroyed and the site was destroyed. The plant was a stage in the production of nylon. It manufactured a mixture of cyclohexanone and cyclohexanol Fig' z (known as KA, for the ketone alcohol mixture) by oxidizing cyclohexane, a hydrocarbon similar to gasoline, in a series of reactors. When...

D

Prioritization of test, maintenance and inspection activities may be prioritized according to their order in a cutset listing. A cutset listing also indicates systems that may be taken out for repair when the system is operating. For example, G may be taken out as long as H is functioning, but if L is taken out, the failure of M, N or O will fail the system, thus giving L a higher importance than G. This ordering by singles, doubles and triples takes added meaning when the failure...

Fmea

Identification of hazards for improving safety Qualitative also used for accident investigation Qualitative used to synthesize fault trees complexity increases rapidly Model and evaluation of components or Quantitative assumes constant failure and repair rntes 1. A library of generic fault logic for common system configurations and components. These MFT logic models are those needed by the analyst for constructing system models. 2. Standardized procedures to aid and guide the analyst in...

71216 Four Die at New Jersey Chemical Plant Explosion

A slow response to a smoldering mix of chemicals at the Napp Technologies plant in Lodi. NJ is blamed for an April 21,1995 explosion and fire that killed four workers and injured dozens of others. The blast destroyed more than 70 of the plant, which made pharmaceutical and cosmetic intermediate products, and employed 110 workers. The explosion wrecked several stores housed in the Napp building, damaged nearby buildings, and forced evacuation of 400 residents for about 13 hours. Chemicals leaked...

Info

Report includes a brief system description, a list of drawings or equipment analyzed, the design intents, the HAZOP study tables, and a list of actions items. Staff requirements for a HAZOP depend on the size and complexity of the process being analyzed. Time and cost are proportional to the size of the process and the experience of the study leader and team members. Table 3.3.4-5 presents estimates of the time needed to perform a PrHA using the HAZOP study method (CCPS, 1992). Study sessions...

4

I hemic.il and Nuclear Accident Analysis Methods procedures, and operations. The What-If part of the analysis uses the team's creativity and experience to brainstorm potential accident scenarios. Because the What-If analysis is usually not as detailed, systematic, or thorough as some more formal methods, e.g., HAZOP or FMEA. the Checklist fills in gaps in the thought process. The number of individuals needed depends upon the complexity of the process and, to some extent, the stage at which the...

R

Dicular distance from a nuclear power plant control room air intake on which 10 trucks day pass carrying 10 tons of chlorine each. Assume the probability of truck accident is constant at 1.0E-8 mi, but if an accident occurs, the full cargo is released and the chlorine flashes to a gas. Assume that the winds are isotropically distributed with mean values of 5 mph and Pasquill F stability class. What is the probability of exceeding Regulatory Guide 1.78 criteria for chlorine of 45 mg m3 (15 ppm)....

Xoq

Two of the previously mentioned accidents Salti and the Oklahoma City bombing showed the explosive potential of nitrogen fertilizer so this is a good place to start. Fertilizers represent one of the largest markets for chemicals. Elements needed for agriculture are nitrogen, phosphorus, and potassium calcium, magnesium, and sulfur are secondary nutrients copper, zinc or molybdenum are needed in trace quantities. Nitrogen makes up 78 of the atmosphere, hence, it is readily available. Ammonia is...

144 References by Author and Date

AAR, 1973, Summary of Ruptured Tank Cars Involved in Past Accidents, Association of American Railroads, AAR Report 130. AAR, 1972, Analysis of Tank Car Tub Rocketing in Accidents, Association of American Railroads, AAR Report 146. Abbitt, J. F., 1969 A Quantitative Approach to the Evaluation of the Safety Function of Operators in Nuclear Reactors, Atomic Health and Safety Board, UK. AHSB(s) R 160. Abramowitz, M, and I. A. Stegun, 1970 Handbook of Mathematical Functions, U.S. Dept. of Commerce...

Psa

Interfacing system LOCA (demineralized water) The PSA began with ATR familiarization as it was in May 1989. This included plant design, operating practices and procedures, test and maintenance procedures and training programs. Initiating event identification and quantification was an extensive process because of the unique nature of the plant. Both comprehensive engineering evaluation and a master logic diagram were used to identify 152 initiating events which were grouped into 22 initiating...

61 Nuclear Power Reactors

When a neutron enters the nucleus of a fissionable atom (U-235 when the reactor core is new, but Pu-239 after operation) several neutrons come out of the atomic debris. These neutrons also can produce fission and more neutrons. Given a suitable geometry, a chain reaction may be sustained. The effectiveness of neutrons in causing fission is greatly enhanced by slowing them down (moderating) in a low atomic mass material such as water which also may be the coolant. Nuclear fission results in the...

10223Data Adequacy

The nuclear equipment failure rate database has not changed markedly since the RSS and chemical process data contains information for non-chemical process equipment in a more benign environment. Uncertainty in the database results from the statistical sample, heterogeneity, incompleteness, and unrepresentative environment, operation, and maintenance. Some PSAs use extensive studies of plant-specific data to augment the generic database by Bayesian methods and others do not. No standard guidance...

112 industrial Revolution

The other effects on safety brought by industrialization resulted from new and more powerf ul energy sources. Although water and wind power was used in the Middle Ages, these forces were natural and believed to be understood. However, the steam engine was something new. The original condensation engine was sub-atmospheric, but with Watt's invention and Carnot's theory, the quest for higher steam pressure and temperature began. The original steam generators were simple pressure vessels that were...

7125 Twenty Five Hundred Die at Bhopal lndiad The Accident

December 3, 1984, the accident occurred that took 2,500 lives at the Union Carbide (India) Ltd. (UCIL) operated pesticide plant. The first indication of process upset was when the control-room operator (CRO) noted that the temperature in a supposedly refrigerated tank storing methyl isocyanate gas (MIC), had risen to 77 F. The pressure, normally 2 to 25 psi was rJ Adapted from Shrivastava (1987) and Crowl (1990). While running to the storage tank area, the CRO heard a loud...

9218FEM3C Dispersion

FEM3C is a three-dimensional finite element model for simulation of atmospheric dispersion of denser-than-air vapor and liquid releases. It is useful for modeling vapor dispersion in the presence of complex terrain and obstacles to flow from releases of instantaneous or constant-rate vapors or vapor liquid mixtures. The algorithm solves the 3-dimensional, time-dependent conservation equations of mass, momentum, energy, and chemical species. Two-dimensional calculations may be performed, where...

833 Radiation Shielding and Dose 8331 Geometric Attenuation of Radiation

If an accident occurs, people are protected from radiation by materials, distance, and limited exposure times. Dose is related to the amount of radiation energy absorbed by people or equipment. If the radiation comes from a small volume compared with the exposure distance, it is idealized as a point source (Figure 8.3-4). Radiation source, 5, emits particles at a constant rate equally in all directions (isotropic). The number of particles that impact the area is S*t*Trg where Trg is a geometric...

Nsss

The RCS illustrated in Figure 6.1-3 has two cold legs and one hot-leg for each of the two loops. Two canned-motor pumps are welded to the bottom of steam generator. A l arge pressurizer is attached to one of the hot legs. The low-power-density, low enrichment reactor core uses soluble boron and burnable poisons for shutdown and fuel burnup reactivity control. Low worth grey rods provide load following. A heavy uranium flywheel extends the pump coastdown to allow for emergency action during...

75 Summary

Chemical accidents were identified to consist of initiation, propagation, and termination. Eliminating the initiation of an accident is the most effective step. In spite of the best efforts, some accidents will be initiated then their propagation must be suppressed. If that cannot be done, the accident must be terminated in as benign manner as possible. To appreciate the magnitude of chemical safety, statistics from the hydrocarbon-chemical industry placing the losses at about 2 billion year....

832 Health Effects

Once the radionuclide concentration in the air, and the ground deposition at a certain location have been computed, the next step is to consider how the radiation reaches the people at that location. The four major pathways are Immersion (external exposure to air), Inhalation (internal lung exposure from breathing), Ingestion (eating and drinking), and Radiation from the ground (external). The relative importance of these pathways varies with the distance from the accident, weather conditions,...

Rwst Tk

For example, a distinction is made between LOCAs if they require a different complement of systems for RCS inventory control. 2. Interactions between Initiating Events and Systems. Some initiating events affect either the function or the availability of mitigating systems. Therefore, the set of systems available for mitigating events will be reduced from the full complement because of interactions. An obvious example is the situation which can occur such that a...

357 Example of the Beta Factor Method Emergency Electric Power

Consider a plant having two power trains A and B with diesel generators DA connected to train A and DB to train B and DS. a swing diesel that can connect to train A or B as fault tree diagramed in Figure 3.5.7-1. Experience shows that the failure rate of one of these diesels is Aj 8.7E-5 hr, and they are tested every 30 days (720 hours). A study of related plant data shows that common mode contributes 10 hence 0 0.1, and (1+P) 9.6E-5 hr. The failure rate of one doubly redundant system QAB * QAC...

71213 Six Die in Benzoic Acid Explosion in Rotterdam1

December 13, 1991, a benzoic acid tank exploded causing six deaths and three injuries at the Dutch chemical firm DSM's chemical complex in Rotterdam Harbor. Shipping traffic was halted for an hour in the world's busiest port while the fire was controlled. A platform was being constructed from one storage tank to another, without the workers knowing that mixture of benzoic acid and air in the open storage tank could explode. DSM is the largest European producer of benzoic acid which is used in a...

42 Incident Reports

Nuclear Power Licensee Event Reports According to 10 CFR 50.73, the holder of an operating license for a nuclear power plant (the licensee) must submit an LER for a reportable event, within 30 days after discovery. An event is reportable regardless of the plant mode, power level, structure, system, or component that initiated the event. In addition the licensee must report the completion of any nuclear plant shutdown required by the plant's Technical Specifications or any operation or condition...

454 Example of Human Error Analysis

Automatic 4 failure vj Problem-Solving Time (NUREG CR-2815 based on NUREG CR-3010) Automatic 4 failure vj Problem-Solving Time (NUREG CR-2815 based on NUREG CR-3010) Fig. 4.5-4 HRA Event Tree. Here A, B, and C are the first, Fig. 4.5-4 HRA Event Tree. Here A, B, and C are the first, In some BWR transient scenarios, the high pressure injection systems are postulated to fail. To make use of the low pressure injection system, it is necessary to depressurize the reactor coolant system, a function...

Appendix Software on the Distribution Disk

The distribution disk located at the Butterworth-Heinemann website http www.bh.com contains the following software for use on an IBM or IBM-clone personal computer operating in DOS, Windows 3.1 or Windows 95. The programs are small, operate in the DOS mode with minimal system requirements. It is recommended that a directory (folder) be constructed on your hard drive and copy them to this directory. No guarantees are made use them if you find them useful. They are 1. ANSPIPE Calculates pipe...

71213 Six Die in Charleston Explosion

An explosion and fire at an Albright & Wilson Americas phosphorus chemicals plant in Charleston, SC (June 17, 1991) killed six and injured 33. The damaged unit lost part of its walls and roof. Eight other units on the 200 employee site, sustained minor or no damage, but were shutdown for a few days. At the time of the accident, plant workers were mixing chemicals in the No. 2 reactor in the special products unit when an explosion and fire occurred. Five of the people killed were contract...

515 Fragility Curves

The fragility is the failure probability of a component conditioned on parameters, such as stress, moment, or spectral acceleration. A fragility curve for a component is calculated by knowing the conditions that will fail it. These conditions are calculated, deter-ministically by a structure analyst. The PSA specialist determines the variability of the conditions which together gives the probability of failure vs acceleration forces for given operating conditions. A separate fragility curve is...

London 1 Coastal Oil Whahv6s

II.' - Map of the Convey Island Thurmck Area Mobil Oil Company Limited, Coryton occupies three adjoining sites on the mainland of Thurrock bordering the Thames and Holehaven Creek the oil refinery, a bulk distribution depot associated with the refinery, and a large research and technical services laboratory. About 800 people are employed. Crude oil is imported by sea, stored in tanks for distillation into components which are either transferred directly to storage tanks, or chemically reacted...

9222 Gasflow

GASFLOW models in-facility transport and vapor space combustion by solving the 3-D compressible Navier Stokes equations and the transport equations for internal energy and chemical species. The geometry is made discrete by a mesh in Cartesian or cylindrical geometry. The primary hydrodynamic variables in the final analysis are the cell-face-centered nominal velocity and cell-volume-centered density, internal energy, and pressure. Three different turbulence models are available for modeling...

126 Unitscnv

To run UNITSCNV go to the directory containing the distribution files and type uniiscnv. A banner announces the program. The next screen explains the program. This is followed by the main menu (Figure 12.6-1). Units are grouped by type. For example, to change from one kind of pressure units to another, select 9. Another screen comes up to identify the units you are in. It then asks the quantity. When this is provided, it presents another screen displaying the quantity of the units provided and...

355 Geometric Mean

WASH-1400 introduced this method for unknown common mode effects. The procedure was not presented in the best light and was severely criticized by the Lewis Committee for lack of a physical basis, although the approach is not unreasonable. Basically, the procedure considered the failure rate of a system, with a common mode, to be between two bounds. The lower bound is the one with no common mode between subsystems, hence, all prob- cm indeP* dei) (3.5.5-1) abilities are treated as independent....

Ieee 500

IEEE Std 500-1984 (IEEE, 1984) contains failure rate and out of service, repair and restoration times for electrical electronic, and sensing component, and mechanical equipment. It is a considerable improvement over IEEE STD 500-1977. The reported values are the consensus of over 200 experts. Each expert submitted a low, recommended, and a high value for the failure rate under normal conditions and a maximum value that would be applicable under all conditions (including abnormal ones). The...

47e3

If the explosion occurs in an unconfined vapor cloud, the energy in the blast wave is only a small fraction of the energy calculated as the product of the cloud mass and the heat of combustion of the cloud material. On this basis, explosion efficiencies are typically in the range of 1-10 . In some cases, however, only the part of the cloud which is within the flammable range is considered to burn. This may be a factor of 10 less than the total cloud. For further discussion of explosion...

Atws

-Revise training on bound control rods (b) -Install automatic ADS inhibit (b) -Install alternate boron injection system (b) -Capability to remove power to bus on enp breaker failure (p) -Install Wcstinghouse ATWS mitigation (p) -Evaluate or replace RCP seal material (b.p) -Independent seal injection or charging pump for station blackout (p) -Operator training on tripping pumps on lo> s of cooling (p) -Revise procedure for higher inventory of water in the BWST or refill BWST -Procedures and...

92 Chemical Accident Consequence Codes

The chemical and physical phenomena involved in chemical process accidents is very complex. The preceding provides the elements of some of the simpler analytic methods, but a PSA analyst should only have to know general principles and use the work of experts contained in computer codes. There are four types of phenomenology of concern 1) release of dispersible toxic material, 2) dispersion of the material, 3) fires, and 4) explosions. A general reference to such codes is not in the open...

Build

Column the right column uses three selections from FTAPLUS. Although the suite of programs can be run from the floppy disk, for reasons of speed and problem size, running from a hard disk is recommended. To do this, in DOS, type MD directory name, enter, and cd directory name, enter. Type copy a *.* and the disk will be copied to that directory.11 Type FTAPSUIT and the screen shown in Figure 6.4-3 is presented. First, system information must be input. From FTAPSUIT, type 1 and enter. This...

916 Vessel Rupture Physical Explosion6

If a vessel containing a pressurized gas or vapor ruptures, the release of the stored energy of compression produces a shock wave and flying vessel fragments (CCSP, 1989). Previously we modeled explosive reaction of the gas with air if such energy also is involved, the effects will be more severe. Such vessel ruptures may occur from 1) over-pressurization of the vessel which involves failure of the pressure regulators, relief valves and operator error, and 2) weakness of the pressure vessel...

921 Source Term and Dispersion Codes

Some codes just calculate source terms (release quantities) and others just calculate the dispersion after release, and some codes do both. Each heading in the following identifies the codc's 9.2.1.1 Adam 2.1 (Release and Dispersion) The Air Force Dispersion Assessment Model (ADAM -1980s) calculates the source term and dispersion of accidental releases of eight specific chemicals chlorine, fluorine, nitrogen tetroxide, hydrogen sulfide, hydrogen fluoride, sulfur dioxide, phosgene, and ammonia....

143 Electric Power Research Institute Reports Identified by NP Number

A., et al., Tornado Missile Analysis, 1978. 2170-3 Hannaman, G. W. et al., Human Cognitative Reliability (HCR) Model for PRA Analysis, 1984. 2301 McClymont, A. S. and B. W. Poehlman, Loss of On-Site Power at Nuclear Power Plants Data and Analysis, SAIC, March 1982. 2433 McClymont, A. S. and G. McLogan, Diesel Generator Reliability at Nuclear Power Plants Data and Preliminary Analysis, SAIC. 2682 Von Hermann, J. L. and P. J. Wood, The Practical Application of Probabilistic Risk...

Degatec

DEGATEC is a user-friendly program that calculates the hazard zone surrounding releases of heavier than-air flammable and toxic gases. It incorporates the FORTRAN program DEGADIS 2.1, (Havens, 1985). Its Windows implementation inputs and outputs easier than the original DEGADIS2.1. DEGATEC was developed for the Gas Research Institute (GRI) by Tecsa Ricerca and Jnnovazione, s.r.l. (TRI) and Risk and Industrial Safety Consultants, Inc. (RISC). Custodian and Developer Tecsa, Via Oratorio, 7, 20016...

3461 Modular Fault Trees MFT

The use of component logic models to build system fault logic has been discussed by several authors for chemical and electrical systems (Powers and Thompkins, 1974 Fussell, 1975 and Powers and Lapp, 1976). In addition, generic sabotage fault trees have been used for some time in the analysis of security concerns for nuclear power plants (NUREG CR-0809, NUREG CR-3121, NUREG CR-3098, and NUREG CR-2635). MFT draws on this experience for logical modeling of process plants. An early version of MFT...

Preface

This book aims at a unified presentation of probabilistic safety assessment as it is applied to the chemical processing and nuclear electrical generation industries. As John Garrick points out in the foreword, probabilistic safety assessment has developed over the latter part of this century to assess and thereby enhance safety in industries that have a remote possibility of affecting many people. PSA's genesis was in the space industry to achieve better equipment reliability. Its application...

71212 One Dies in Union Carbide Ethylene Oxide Plant Explosion

An explosion and fire (March 13, 1991) occurred at an ethylene oxide unit at Union Carbide Chemicals & Plastics Co.'s Seadrift plant in Port Lavaca, TX, 125 miles southwest of Houston. The blast killed one, injured 19, and idled the facility, that also produces ethylene, ethylene glycol, glycol ether ethanolamines, and polyethylene. Twenty-five residents were evacuated for several hours as a safety precaution. The plant lost all electrical power, for a few days, because its cogeneration unit...

Hbhhdi

Fig. 3.6-1 The Saphire Main Menu and the Fault Tree Editor Menu. Symbols are selected and pasted into the working space Choose this to build and edit-event trees. The Event Tree List dialog appears listing all event trees and subtrees in the current family. A pop-up menu provides the following options Edit Graphics - constructs and edits event trees using the graphical Event Tree Editor. Edit Rules - defines and edits event tree linkage rules using the Linkage Rules Editor. A linkage rule is a...

Iv

Does not cause injury, property damage, but may result in unscheduled maintenance or repair. Functional system or process descriptions describe system, process and or component behavior for each operational mode. They describe operational profiles of the components, the functions and input and outputs of each. Block diagrams assist by illustrating operations, inter relationships, and interdependencies of functional components. Interfaces should be indicated in these block diagrams. The FMEA is...

9214 Calpuff Dispersion

CALPUFF is a multilayer, multispecies non-steady-state puff dispersion model that simulates the effects of time- and space-varying meteorological conditions on chemical transport, transformation, and removal. It uses 3-dimensional meteorological fields computed by the CALMET preprocessor or simple, single-station winds in a format consistent with the meteorological files used to drive the ISC3 or AUSPLUME steady-state Gaussian models. CALPUFF contains algorithms for near-source effects such as...

1e5

Fig. 8.3-2 Vertical diffusion parameter vs distance from the source. This does not consider meander and building effects Radioactivity decays exponentially according to the half-life and time. All effluents can undergo dry deposition by sorption onto the ground surface. However, the dry deposition rate for noble gases, tritium, carbon-14, and nonelemental radioiodine is so slow that this depletion mechanism is negligible within 50 miles of the release point. Elemental o radioiodine and other...

642Overview of Ftapsuit

The suite consists of the following FORTRAN programs 1. FTAP - Give it a fault tree or equivalent as linked Boolean equations, and it will find the cutsets Section 2.2 , but it does not numerically evaluate the probabilities. 2. PREPROCESSOR - Modifies the FTAP punch file output for common cause and dependent analyses conditional probabilities , removes complemented events, and corrects for mutually exclusive events. 3. BUILD - Accepts a file from FTAP or PREPROCESSOR to calculate the...

9219FiRAC Release

FIR AC is a computer code designed to estimate radioactive and chemical source-terms associated with a fire and predict fire-induced flows and thermal and material transport within facilities, especially transport through a ventilation system. It includes a fire compartment module based on the FIR1N computer code, which calculates fuel mass loss rates and energy generation rates within the fire compartment. A second fire module, FIRAC2, based on the CFAST computer code, is in the code to model...

11431 HAZOP of an HF Alkylation Unit

A large oil refinery had a failure in their alkylation unit resulting in a significant release of hydrofluoric acid HF . This incident and others in refineries during recent years prompted members of the hydrocarbon processors to turn to HAZOP to better understand their risks. Figure 11.4-2 shows process flows for an HF alkylation unit. The three sections are 1 reaction, 2 settling and 3 fractionation. In the reaction section isobutane feed is mixed with the olefin feed usually propylene and...

144 Public Perception of Risk

The preceding section shows the rather abstract, mathematical methods used to present the results of PSA. While the public is a very diverse group, the majority do not receive information in this fashion but receive it through the news media. It is not the nature of news to attempt a balanced presentation but to emphasize the unusual. To illustrate, the fact that 50,000 people die each year in traffic accidents, involving a few deaths at a time, is not newsworthy. Furthermore the latency of a...