NUREG-1601 

@@@ Chemical Process Safety 

at Fuel Cycle Facilities bg6 @ 

*ST' 

U.S. Nuclear Regulatory Commission 

Office of Nuclear Material Safety and Safeguards 

D. A. Ayres 

MASTER 
AVAILABILITY NOTICE 

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Most documents cited in NRC publications will be available from one of the following sources: 

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2055!5-0001 

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The National Technical Information Service, Springfield, VA 221 61 -0002 

2. 

3. 

Although i:he listing that follows represents the majority of documents cited in NRC publications, it is not intended to be exhaustive. 

Referenced documents available for inspection and copying for a fee from the NRC Public 

Documenl: Room include NRC correspondence and internal NRC memoranda; NRC bulletins, 

circulars, information notices, inspection and investigation notices; licensee event reports; 

vendor reports and correspondence; Commission papers: and applicant and licensee documents ani3 correspondence. 

The following documents in the NUREG series are available for purchase from the Government 

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1001 8-3308. 
NUREG1601 

Chemical Process Safety 

at Fuel Cycle Facilities 

Manuscript Completed: July 1997 

Date Published: August 1997 

D. A. Ayres 

Division of Fuel Cycle Safety and Safeguards 

Ofllce of Nuclear Material Safety and Safeguards 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 



ABSTRACT 

This NUREG provides broad guidance on chemical safety issues relevant to fuel cycle facilities. 

It describes an approach acceptable to the NRC staff, with examples that are not exhaustive, 

for addressing chemical process safety in the safe storage, handling, and processing of 

licensed nuclear material. It expounds to license holders and applicants a general philosophy 

of the role of chemical process safety with respect to NRC-licensed materials; sets forth the 

basic information needed to properly evaluate chemical process safety; and describes plausible 

methods of identifying and evaluating chemical hazards and assessing the adequacy of the 

chemical safety of the proposed equipment and facilities. Examples of equipment and methods 

commonly used to prevent and/or mitigate the consequences of chemical incidents are 

discussed in this document. 

iii NUREG-I601 

CONTENTS 

Paae 

ABSTRACT ............................................................... iii 

PREFACE ............................................................... vii 

ACKNOWLEDGEMENTS ................................................... ix 

1 . INTRODUCTION ......................................................... i 

2 . DISCUSSION ............................................................ 2 

2.1 

2.2 

2.3 

2.4 

2.5 

2.6 

Chemical Process information .......................................... 3 

2.1 . 1 Process Description ........................................... 3 

2.1.2 Auxiliary Systems ............................................. 4 

2.1.3 Specialty Chemical Data ........................................ 5 

HazardAudit ........................................................ 5 

2.2.1 System Review ............................................... 5 

Identification of the Hazards ............................................ 6 

2.3.1 Potential Accident Scenarios ..................................... 6 

2.3.2 Instruments and Control Functions ................................ 7 

Design Basis ........................................................ 8 

2.4.1 Physical Barriers .............................................. 8 

2.4.2 Mitigative Features ............................................ 9 

Hazard Evaluation ................................................... IO 

2.5.1 Methods ................................................... IO 

2.5.2 Results .................................................... 11 

Continuing Assurance of Chemical Safety ................................ 11 

2.6.1 Management Structure and Concepts ............................. 11 

2.6.2 Procedures ................................................. 11 

2.6.3 Training .................................................... 12 

2.6.4 Maintenance ................................................ 12 

2.6.5 Configuration Management ..................................... 13 

2.6.6 Emergency Planning .......................................... 14 

2.6.7 incident Investigations and Corrective Actions ...................... 14 

2.6.8 Audits and Assessments ....................................... 14 

2.6.9 Quality Assurance ............................................ 14 

2.6.1 0 Human Factors Program ....................................... 15 

3 . REFERENCES .......................................................... 16 

V NUREG-1601 

PREFACE 

NUREG-I601 is being issued to provide broad guidance on chemical safety. It describes an 

approach acceptable to NRC staff, although the examples offered are not exhaustive. 

NUREG-I601 is not a substitute for the regulations, and compliance is not a requirement. This 

guidance document describes a general philosophy of the role of chemical process safety with 

respect to NRC-licensed material. 

vii NUREG-1 601 

ACKNOWLEDGEMENTS 

The author acknowledges and appreciates the contributions to this document from Dr. Lidia 

Roche, Barry Mendelsohn, Robert Pierson, Donald Stout, Leslie Fields, William Troskoski, 

Garrett Smith, Dr. Richard Milstein, Dr. Tin Mol Richard Cassano, Thomas Cox, and Michael 

Weber, all from the Office of Nuclear Material Safety and Safeguards at NRC Headquarters. 

ix NUREG-I601 

1. INTRODUCTION 

The issuance and continuance of specific 

licenses for activities involving source and 

special nuclear materials require that the 

applicant's proposed procedures, 

equipment, and facilities be adequate to 

protect health and minimize danger to life or 

property in accordance with 

10 CFR 40.32(c) and 70.23(a)(3) and (4). 

To protect health and minimize danger, the 

applicant should address all hazards of 

nuclear material, including chemical 

hazards posed by radioactive materials, 

chemicals, and plant conditions which may 

directly or indirectly affect the licensed 

nuclear material in an adverse manner. 

According to the October 21 , 1988, 

Memorandum of Understanding (MOU) 

between NRC and the Occupational Safety 

and Health Administration (OSHA), the 

regulation of these hazards is the 

responsibility of NRC. Also, 10 CFR 76.87 

requires gaseous diffusion enrichment 

plants to establish procedures and/or 

equipment to address chemical safety. 

Performing an adequate analysis of 

chemical safety in processing licensed 

material at fuel cycle facilities decreases the 

potential for radiological and nonradiological 

exposures to workers and the public and 

minimizes releases to the environment. 

This report highlights the importance of 

chemical process safety at facilities where 

licensees handle, process, and store 

nuclear materials. It provides broad 

guidance on chemical process safety 

issues at such facilities and discusses 

methods of preventing or mitigating the 

consequences of chemical incidents. 

1 NUREG-1601 
Most NRC fuel cycle licensees possess 

materials that are chemically hazardous 

and/or pose some sort of nonradiological 

risk. Chemical and radiological risks have 

been known to compound one another, and 

in many cases, radioactive materials are 

also chemically hazardous. A chemical 

explosion in a fuel cycle facility could 

disperse radioactive material, just as the 

radiation environment could make it more 

difficult to respond to a hazardous chemical 

spill. Thus, chemical process safety plays a 

major role in the proper operation of nuclear 

fuel cycle facilities. Virtually all processes 

of source and special nuclear materials use 

chemicals which can be considered 

hazardous or potentially hazardous under 

certain conditions. 

For the purpose of this document, 

hazardous chemicals are substances which 

are toxic, explosive, flammable, corrosive, 

or reactive to the extent that they can cause 

significant damage to property or endanger 

life if not adequately controlled. Some of 

the more common hazardous chemicals 

used in nuclear fuel cycle facilities are 

uranium hexafluoride (UF,), strong acids, 

ammonia, and hydrogen. Additionally, 

systems containing substances which are 

not normally considered hazardous under 

ambient conditions may, under extreme 

conditions or in combination with other 

chemicals, produce hazardous situations. 

These substances include hot water, steam 

and cryogenic or compressed gases such 

as air, nitrogen, and carbon dioxide. 

Many hazardous chemicals are also 

regulated by other agencies, but mainly in 

the prevention of catastrophic events or 

major releases to the environment. This 

regulation of hazardous chemicals is based 

on threshold limits. The NRC's concern is 

not only with the effect of the chemicals on 

public and worker safety, but also with their 

effect on safe operations, regardless of the 

total amount ofihe chemicals onsite. The 

MOU between NRC and OSHA on chemical 

safety issues makes provision for the NRC 

to assume responsibility for the control of 

risks which may affect radioactive materials. 

Paragraph 3 of the MOU states: 

There are four kinds of hazards 

that may be associated with NRClicensed nuclear facilities. 

a. Radiation risk produced by 

radioactive materials; 

b. Chemical risk produced by 

radioactive material; 

C. Plant conditions which affect 

the safety of radioactive 

materials and thus present an 

increased radiation risk to 

workers. For example, these 

might produce a fire or an 

explosion, and thereby cause 

a release of radioactive 

materials or an unsafe reactor 

condition; and 

d. Plant conditions which result 

in an occupational risk, but do 

not affect the safety of 

licensed radioactive materials. 

For example, there might be 

exposure to toxic 

nonradioactive materials and 

other industrial hazards in the 

workplace. 

Generally, NRC deals with the first three 

hazards listed in paragraph 3 (a, b, and c), 

and OSHA deals with the fourth hazard (d). 

The risks covered by NRC include those 

posed directly by radioactive chemicals, 

NUREG-1601 2 
such as with UF,, and any other condition 

which may directly or indirectly affect 

radiation risk to workers or the environment. 

Thus the NRC does not regulate chemicals 

per se; rather, the NRC verifies that the 

interactions of chemicals with NRC-licensed 

nuclear materials and/or with equipment 

which processes, transports, or stores 

these licensed materials have been 

considered in the design of the equipment 

and facilities and in the operating and 

maintenance procedures. Such interactions 

may cause degradation of equipment, loss 

of confinement, and misdirection of licensed 

materials, resulting in potential danger to 

workers, the public, and the environment. 

2.1 Chemical Process Information 

Safety of chemical processing of nuclear 

materials depends largely on the 

information available about the process and 

about the chemicals used in the process 

(including chemical intermediates, process 

parameter limits, etc.). The following 

information should be documented and 

made available to persons responsible for 

verifying and maintaining chemical process 

safety throughout the facility. 

2.1.1 Process Description 

A description of the proposed chemical and 

mechanical process steps for the licensed 

material aids the reviewer in understanding 

the design basis. A complete description of 

the processes should contain the following 

elements. 

2.1 .I .I Purpose 

The process description should state the 

purpose or objective of each process step, 

including the operation@) to be performed, 

the equipment to be used, and destinations 

of outputs and effluents. 

2.1 .I .2 Material Form 

The process description should include the 

chemical and physical form@) of the 

licensed material at each process step. It 

should include inputs, outputs, and any 

intermediary transformations occurring at 

each step. 

2.1 .I .3 Process Chemicals 

The process description should include a 

list of all chemicals input to each process 

step, specifying which ones are to be in 

contact with the licensed materials and 

which chemicals could potentially contact 

licensed materials in case of leaks or 

human error. 

2.1 .I .4 Process Variables 

The process description should include the 

approximate ranges of temperatures, 

pressures, and mass flow rates for each of 

the process chemicals and the licensed 

materials. These ranges should be 

included for inputs, outputs, and materials 

and chemicals in process. 

2.1 .I .5 Process Control 

The process description should generally 

cover the process equipment and 

engineering design features used for 

process control in each process step, 

including setpoint ranges for safety controls. 

Any special administrative or procedural 

controls should also be described. 

2.1 .I .6 Materials of Construction 

The process description should provide a 

list or description of the materials of 

construction used in the processing, 

3 NUREG-I 601 
storage, and in-process transport of 

licensed material when that information is 

necessary for understanding the potential 

degradation, or the effect of radiation on the 

strength and properties, of the construction 

material. 

2.1 .I .7 Safety Features 

The process description should include the 

structures, systems, equipment, 

components, engineered design controls, 

and human actions and administrative 

controls relied on for chemical process 

safety. Such-features may include not only 

the engineered design controls and 

materials of construction mentioned above, 

but also items such as chemical 

confinement, barriers, leak suppression 

equipment, emergency shutdown or 

response procedures, and passive 

engineered controls such as rupture disks. 

Where special nuclear material (SNM) 

might accumulate, as in dikes or bags to 

contain leaks, criticality-safe geometries 

may need to be considered. 

2.1.2 Auxiliary Systems 

The process safety information should 

include a description of other systems 

(including safety features) in the licensedmaterial process areas, transport areas, or 

storage areas, such as plant utilities, bulk 

chemical systems, and ventilation. These 

systems are not necessarily part of the 

licensed-material processing system but, 

under off-normall conditions, could affect 

licensed material processing. 

'Off-normal conditions refers to conditions that are in 

some respect outside of the range for routine operations but 

have not resulted in an accident. 

2.1.2.1 Bulk Chemicals 

Attention should be given to systems which 

contain toxic and hazardous substances 

under NRC jurisdiction as defined by the 

MOU between OSHA and NRC. These 

include hazardous substances identified in 

29 CFR Part 191 0, Subparts H and Z, 

regardless of quantity. 

2.1.2.2 Utilities 

A description of utilities near licensedmaterial processing should be part of or 

referenced by the process safety 

information. Steam, water, vacuum 

systems, compressed gases, and electrical 

power supplies could, if interrupted or 

uncontrolled, cause a hazardous condition 

to develop with the licensed materials. 

2.1.2.3 Ventilation 

The operation of the ventilation system may 

be the single most important protection 

against radiological exposure. Design 

information of the Ventilation system 

ducting, scrubbers, filters, and controls 

should be included or referenced in the 

process safety information. 

2.1.2.4 Chemical Traps and Filters 

These systems may be considered a subset 

of the other process or auxiliary systems, 

but are important enough to be mentioned 

separately. The design of chemical traps 

and filters should be part of the process 

safety information. Trap design, filter media, 

operating temperatures and pressures, 

cleanout or filter change procedures, and 

automated controls should be described. 

NUREG-1601 4 
2.1.2.5 Emergency Systems 

Systems which provide mitigative services 

(e.g., fire suppression equipment) or 

backup for main systems (e.g., emergency 

power supply) should be included or 

referenced in the process safety 

information. Descriptions of their locations, 

operations, and testing methods may be 

important with regard to chemical process 

safety. 

2.1.3 Specialty Chemical Data 

The process safety information should 

provide the general information included on 

the Material Safety Data Sheets2 for any 

specialty chemical used in the 

licensed-material process areas, transport 

areas, or storage areas. 

2.2 Hazard Audit 

In order to minimize the probability of 

accidents3 and their impact on the licensed 

material, potential chemical process safety 

hazards should be identified through a 

hazard audit. 

2.2.1 System Review 

The first step is to thoroughly review the 

facility to identify potential chemical 

hazards4 of radioactive materials and 

radiation hazards caused by chemicals. The 

2Pursuant to 29 CFR 1910.1200g, OSHA requires 

Material Safety Data Sheets to be supplied by US. chemical 

manufacturers and importers. 

3An accident is an unplanned event or sequence of 

events that results in undesirable consequences; or an incident with specific safety consequences or impacts. 

4A hazard is an inherent physical, radiological, or 

chemical characteristic that has the potential for causing 

harm to humans or to the environment. 

system review should include the following 

elements. 

2.2.1 .I ProcessChemistry 

Observe the chemical components added 

to each process step. Identify all chemical 

process hazards where chemical reactions 

could produce hazardous materials which 

were not previously present (e.g., the 

evolution of hydrogen when metals are 

dissolved in acids). 

2.2.1.2 Effects of Variable Chemical 

Additions 

At each process step, analyze the effect 

that adding variable amounts of chemicals 

has on generating hazardous materials and 

on the chemical and physical forms of the 

licensed material. Evaluate the possibility 

and effects of adding the wrong chemicals 

to a process step or adding them in the 

wrong sequence. Also evaluate the 

potentially unwanted dissolution or 

precipitation of the licensed material, 

especially if the licensed material could 

thereby be released into a waste stream. 

2.2.1.3 Energy Sources 

Evaluate the potential energy sources of the 

process components, such as source 

elevated temperatures and pressures, 

electrostatic forces, exothermic reactions, 

erosion caused by abrasive materials, and 

flammable and explosive materials. The 

potential effects of these sources of energy 

on equipment and personnel should be 

considered as part of any hazard audit. 

2.2.1.4 Materials of Construction 

Determine whether the materials of 

construction and the process equipment 

have been chosen in such a manner that a 

catastrophic failure resulting in a release of 

5 NUREG-1601 
hazardous materials is unlikely. A 

catastrophic failure could be caused by 

chemical incompatibility, thermal cycling, or 

excessive heat and pressure. 

2.2.1.5 Process Control and Safety 

Devices 

Determine whether adequate safety devices 

or systems are in place to minimize 

potential hazards from process chemicals 

or chemical reactions; for example whether 

ventilation, pressure relief valves, 

combustible gas detectors, double-walled 

pipe, etc., are available to prevent, mitigate, 

or warn of a hazardous condition. 

Determine whether process controls are 

adequate to prevent avoidable chemical 

hazards (e.g., controls for temperature, 

pressure, level, interface, pH, conductivity). 

2.2.1.6 Other Chemical Systems in the 

Licensed-Material Process Areas 

Chemical systems which are not directly 

involved in the processing of licensed 

materials but are in the same general area 

can interact with the licensed materials 

and/or associated equipment. Therefore, 

review the controls that are in place to 

prevent these systems from leaking into 

and onto equipment containing licensed 

material. A review of whether potential 

releases from other chemical systems 

could affect the access to or operability of 

equipment containing licensed materials 

should also be considered. 

2.2.1.7 Management Controls 

The administrative controls placed on 

chemical systems and the requirements 

placed on workers can have an overriding 

effect on the operation of the facility. The 

management control systems needed to 

maintain chemical process safety (Section 

2.6) should be reviewed during each 

iteration of the hazard audit. 

2.2.1.8 Human Factors 

Potential human errors in the operation and 

maintenance of the process should be 

guarded against. The review of chemical 

systems should consider ergonomics and 

worker fatigue as a potential cause of 

hazards. The design and location of the 

equipment, the layout of the process, and 

the clarity and sequence of instructions in 

procedures should all be reviewed with 

human factors in mind. 

2.3 Identification of the Hazards 

2.3.1 Potential Accident Scenarios 

If the system review reveals, potential 

chemical hazards of radioactive materials 

and radiation hazards caused by chemicals, 

the hazards should be identified, 

documented, and analyzed to determine 

their effects. Whenever possible, a 

licensee's own experience should be used 

to supplement the identification of potential 

chemical hazards. Chemical accidents that 

have occurred in the past show the more 

common hazards, but reliance on past 

experiences alone may cause many 

hazards to be overlooked. The lack of 

chemical accident occurrences in a 

particular area does not mean that chemical 

hazards do not exist there. 

There are many different methods of 

identifying potential chemical hazards. 

Some of the more common methods 

involve developing interaction matrices or 

using specific hazard evaluation techniques. 

However, any method which sufficiently 

identifies potential interactions of the 

process area chemicals with the licensed 

material and its associated confinement, 

process equipment, and workers would be 

NUREG-I 601 6 
acceptable. Regardless of the method 

chosen for identifying hazards, the 

consequences to people and the 

environment must be considered in 

determining which conditions are hazards. 

2.3.1.1 Effects on Public and Workers 

The most commonly faced situation at fuel 

cycle facilities is the exposure of workers to 

chemicals containing the licensed material. 

Such situations could adversely affect the 

health of workers and/or members of the 

general public and should be identified as 

potential chemical hazards. Chemicals 

which do not contain licensed materials 

should also be identified as potential 

chemical hazards because, even in the 

absence of workers, release of such 

chemicals may affect the process by 

releasing the licensed material or may 

affect the confinement of the licensed 

material in a favorable geometry. 

2.3.1.2 Effects on the Environment 

Chemicals which can cause a release of 

licensed material to the environment above 

NRC-prescribed limits should be identified 

as potential chemical hazards. Such 

releases include onsite and offsite 

contamination of air, water, and soil. 

2.3.1.3 Effects on the Facility 

The impact of chemicals on facility systems, 

structures, equipment, and components 

(i.e., process equipment) is an integral part 

of any chemical hazard analysis. Chemical 

effects causing degradation of process 

safety equipment (equipment for 

preventing, mitigating, and annunciating a 

process hazard), process control 

equipment, and confinement vessels and 

structures should be identified as chemical 

hazards if the degradation could affect the 

licensed material and potentially have a 

human or environmental impact. 

2.3.2 Instruments and Control 

Functions 

Instrumentation and control systems, as 

identified by the integrated safety analysis5 

(ISA), should be provided to monitor 

variables and operating systems important 

to safety during normal and off-normal 

operations, accidents, and shutdown 

conditions. In addition, the overall 

confinement system, the confinement 

barriers, and the other systems which affect 

plant safety should be monitored. Controls 

should maintain variables within prescribed 

operating ranges under all normal 

conditions, and control systems should be 

designed to fail to a safe state. Protection 

systems whose primary functions are to 

prevent releases, facilitate process 

shutdowns, or protect worker and public 

health and safety should be designed to: 

a. initiate actions to ensure that design 

limits are not exceeded, 

b. sense potentially hazardous conditions, 

c. have reliability and testability, 

d. maintain function with loss of a single 

active component, 

e. maintain function with removal from 

service of any component6, and 

Integrated safety analysis means an analysis to 

identify hazards and their potential for initiating event 

sequences, the potential event sequences and their 

consequences, and the site, structures, systems, 

equipment, components, and activities of personnel, that are 

relied on for safety as stated in the Draft NUREG-1513. 

e.g. Use of acceptable compensatory measures or 

backup equipment to assure availability and reliability of 

items relied on for safety or remove hazard from system. 

7 NUREG-1601 
f. fail to a safe state in loss of power. 

Thus, the identification of hazards should 

consider accident scenarios where 

instrumentation and control systems can fail 

in the performance of one or more of these 

safety functions. 

2.4 Design Basis 

Assurance of chemical safety within a 

facility begins with a good design basis. 

Adequately designed chemical systems, 

including the controls used to prevent 

accidents, will have few safety problems 

through most of their operating life. Properly 

specified features such as materials of 

construction, equipment sizing, and system 

fabrication techniques will prevent many 

chemical accidents from occurring. The 

system's engineered-design process control 

schemes enhance these features to provide 

an even higher margin for safety. When the 

risk involving the licensed material is high, 

additional measures should be taken to 

ensure the chemical safety of the process. 

2.4.1 Physical Barriers 

The establishment of physical barriers is an 

effective method to prevent releases of 

licensed materials to unwanted locations. 

Physical barriers can be used to prevent 

auxiliary systems which do not contain 

licensed material from interacting with the 

licensed-material systems. Commonly used 

physical barriers are described below. 

2.4.1.1 Double-Walled Piping and Tanks 

These physical barriers capture liquid leaks 

and (when properly installed) alert 

personnel to the occurrence. They should 

normally be used on piping and storage 

vessels containing highly corrosive 

materials (such as hydrogen fluoride) in 

areas where a leak could easily affect the 

licensed material or its confinement. They 

are not normally recommended for SNMbearing solutions unless adequate 

provisions are made in the criticality control 

calculations. 

2.4.1.2 Liquid Confinement Dikes 

These barriers are widely used in bulk 

chemical storage areas for confinement of 

large spills. Dikes should also be used to 

contain smaller amounts of spilled 

corrosives to prevent potential interaction 

with licensed-material process equipment. 

Dikes used to contain SNM-bearing 

solutions should not exceed criticality 

design constraints on volume, 

concentration, and enrichment. 

2.4.1.3 Glove Boxes 

In licensed-material handling areas where 

chemicals are present, glove boxes should 

be used to contain the licensed material and 

protect it from undesired chemical 

interactions. If other barriers are not in 

place, glove boxes should be constructed 

from materials that are resistant to the 

chemicals in the area. 

2.4.1.4 Splash Shields 

Splash shields can be used to direct spills 

of hazardous liquids away from licensed 

material storage and process areas and 

should also be used to protect workers from 

potential spills of solutions containing 

licensed material. Splash shields should be 

transparent when possible so that a 

dripping solution can be identified and 

corrected quickly. 

2.4.1.5 Fire Walls 

Fire walls can be used to protect licensedmaterial storage and process systems from 

potential fires and explosions. They should 

NUREG-I601 8 
be used as a barrier between licensed 

material and large quantities of flammable 

or explosive chemicals which, when ignited, 

could disrupt the integrity of confinement 

systems. Fire walls should also be used as 

a barrier for high-pressure systems located 

near licensed materials. 

2.4.1.6 Protective Cages 

These barriers are used to protect chemical 

and licensed-material systems from impacts 

with moving objects. They are particularly 

useful in protecting polymer or glass 

components of chemical piping systems. 

Protective cages should be utilized where 

such components are exposed to major 

traffic areas. 

2.4.1.7 Backflow Preventers and Siphon 

Breaks 

These devices can be used in piping 

systems to prevent chemicals or licensed 

material solutions from flowing into 

undesirable locations and creating 

hazardous conditions. They should only be 

necessary where the process design 

requires interconnection of two or more 

potentially incompatible systems. Good 

process design practices should be used to 

minimize such connections. 

2.4.1.8 Overflow Vessels 

There should be an overflow strategy for 

each process vessel containing licensed 

materials and/or hazardous chemicals 

associated with it. In most instances, a 

separate vessel can be provided to 

accommodate possible overflow of the 

primary vessel. Such an overflow vessel 

should contain an alarm system so that the 

overflow condition can be recognized. 

Automatic cutoff systems on the process 

vessel feed lines can also be used. Multiple 

process vessels can be piped into the same 

overflow vessel if all of the associated 

solutions are chemically compatible with 

each other and with the overflow vessel 

construction materials. 

2.4.1.9 Chemical Traps and Filters 

These are typically used for collecting 

vapors, aerosols, and particulates from air 

and gas streams. Chemical traps capture 

vapors and aerosols by absorption or 

adsorption onto a collection medium. An 

example is the use of alumina to collect 

small quantities of UF, vapors from an air 

stream. Filters are widely used to remove 

radioactive particulates from air flows, but 

can be used in other situations. 

2.4.2 Mitigative Features 

Mitigative features help reduce the impact 

of chemical accidents. Chemical systems 

which tend to have an associated high risk 

level should include mitigative features in 

the equipment design. Multiple mitigative 

features may need to be combined to truly 

minimize the hazard. Some of the more 

common mitigative features in fuel cycle 

facilities are described below. 

2.4.2.1 Driving Force Controls 

These controls help stop the driving force of 

the hazard. They are typically devices 

which cut power to heating elements or 

other electrically driven equipment. They 

also include cutoffs for air-driven 

equipment, pressure relief devices, and 

emergency cooling systems. These 

controls should be in place on any system 

which contains licensed materials or 

hazardous substances at elevated 

temperatures or pressures. 

9 NUREG-1601 
2.4.2.2 Solenoid and Control 

Valves 

These valves help stop the flow of 

hazardous substances from their 

confinements in cases of pipe breakage or 

downstream equipment failure. To be 

effective, they should be used in 

conjunction with inline pressure- or 

flow-monitoring equipment. They should be 

used on any system containing highly 

hazardous chemicals or explosive gases 

which does not have a secondary 

confinement system (e.g., double-walled 

piping). For fuel cycle facilities, highly 

hazardous chemicals7 would typically 

include ammonia and ammonia solutions 

(=.44wt%), fluorine, hydrogen chloride and 

concentrated hydrochloric acid, hydrogen 

fluoride and concentrated hydrofluoric acid, 

hydrogen peroxide (>52wt%), concentrated 

nitric acid (>94.5wt%), and uranium 

hexafluoride. 

2.4.2.3 Spray Systems 

Spray systems can be used to lessen the 

effects of a chemical accident by scrubbing 

chemicals from the air, diluting chemicals 

on the ground, or providing a quick cooling 

mechanism. The most common spray 

medium is water, but spray media can 

include dilute solutions which react with the 

hazardous chemical and render it 

nonhazardous. Carbon dioxide is a typical 

cooling medium. Equipment containing 

licensed material should use spray systems 

only after thorough consideration of their 

effect on criticality control. 

2.4.2.4 Auxiliary Ventilation 

Auxiliary ventilation systems can be located 

in high-risk areas to reduce the effects of a 

7Highly hazardous chemicals as listed in 29 CFR 

1910.119, Appendix A. 

chemical release. These systems can be 

run continuously or on demand when a 

release occurs. Since these systems 

typically have a limited capacity, they 

should be used in conjunction with other 

mitigative features. They are particularly 

useful in areas where spray systems are 

not feasible. 

2.4.2.5 Alarm systems 

Alarm systems can be used as a mitigative 

feature by alerting workers to the situation 

and enabling them to act quickly to reduce 

the effects of a chemical release. These 

actions could include measures to stop the 

release and/or evacuate the area. Alarm 

systems should be used in all high-risk 

chemical process areas. 

2.5 Hazard Evaluation 

The potential chemical hazards, once 

identified, should be evaluated for their 

impact on humans and the environment. 

The evaluation of chemical hazards should 

be performed as part of an integrated effort, 

along with other safety and safeguards 

measures, including fire protection, 

radiation safety, criticality safety, and 

physical security measures. Electrical and 

industrial safety concerns may also be part 

of the integrated safety analysis if their 

effects on workers can have a subsequent 

effect on the confinement of the licensed 

material. 

2.5.1 Methods 

The methods used for performing the 

hazard evaluation can vary from a simple 

qualitative checklist to a complex 

quantitative risk assessment. The 

Integrated Safety Analysis Guidance 

Document (Draft NUREG-1513) and other 

documents referenced therein describes 

most of the techniques used by the 

NUREG-1601 10 
chemical industry for hazards evaluation. 

The method chosen should be consistent 

with the apparent risk associated with the 

facility, the level of detail desired from the 

results, the amount of process safety 

information available, and the current stage 

of the process life cycle. 

2.5.2 Results 

The results of the hazard evaluation should 

undergo internal peer review for 

reasonableness by personnel not involved 

in the original evaluation. The peer review 

team must be knowledgeable of the 

process facility operations. Management 

should then scrutinize the results and 

decide how to address each potential 

chemical hazard. It is important to update 

and revalidate the evaluation periodically 

and when a significant change to the 

process is made. Radiological and 

chemical accidents which already have 

adequate preventive and mitigative controls 

and those involving very low risks (low 

probability and low consequence) may not 

require any further action. Other chemical 

hazards may need to be addressed by 

establishing additional engineered-design 

controls; by installing protective barriers; 

and by implementing administrative controls 

(e.g., revised procedures, a preventive 

maintenance schedule, or an inspectionand/or test-based predictive maintenance 

system). A risk matrix can be used to 

provide guidelines for accepting or not 

accepting the analyzed frequency and 

consequence of the potential chemical 

hazard. 

2.6 Continuing Assurance of 

Chemical Safety 

Effective implementation of chemical safety 

demands management involvement and 

control. The inherent uncertainties 

associated with the input parameters for the 

hazard analysis can affect the accuracy of 

the results. Therefore, the elements 

discussed below may affect chemical 

processes at the facility and should be 

considered in the analysis. These elements 

should be reviewed iteratively with 

subsequent hazards analyses as new 

knowledge is gained. This periodic review 

should reduce the uncertainties and provide 

assurance of chemical safety at the facility. 

2.6.1 Management Structure and 

Concepts 

The management structure at a fuel cycle 

facility can vary widely according to the 

licensee’s mission and capabilities. The 

important aspects of management structure 

and functions have been assembled in 

NUREG/CR-6287, “Management Concepts 

and Safety Applications for Nuclear Fuel 

Facilities.” It is recommended that each 

licensee and license applicant designate 

one person to have overall responsibility 

and authority for chemical process safety in 

each facility, as is done for other disciplines 

such as criticality and radiological safety. 

2.6.2 Procedures 

Clear and comprehensive procedures are 

necessary to assure the safe operation of a 

fuel cycle facility. Without such procedures, 

measures taken to assure chemical safety 

would quickly lose their usefulness. 

Chemical safety issues identified by the 

hazard evaluation as having potentially 

significant impacts’ on people or the 

environment should be addressed within the 

licensee’s procedures. Procedures for fuel 

cycle facilities are generally of two types, 

Impacts are considered significant if they could involve 

violations of Federal statutes. 

11 NUREG-1601 
operating procedures and management 

control procedures. 

2.6.2.1 Operating Procedures 

Operating procedures directly control 

process operations and should include 

instructions on handling chemical safety 

concerns during normal and off-normal 

conditions. These procedures should 

provide specific direction regarding 

administrative controls to ensure process 

chemical safety. Procedures for process 

operations which can affect chemical safety 

should include process operating limits and 

controls and the required actions for normal 

and off-normal conditions of operation. 

Off-normal conditions are conditions 

created by human failure or failure of any 

system, structure, or component. 

2.6.2.2 Management Control Procedures 

Management control procedures should be 

used to manage activities such as 

configuration management, maintenance, 

piant-wide safe work practices, training, 

audits, and incident investigations. There 

should be an overall chemical safety 

element describing the methods, activities, 

and implementation of the overall safety 

program. 

2.6.3 Training 

Effective chemical safety training helps 

employees understand the nature and 

causes of problems that could arise from 

process operations and increases 

awareness of the particular hazards of a 

process. The training programs described 

in a licensee's safety program description 

should include provisions for chemical 

safety training of all personnel who routinely 

access licensed-material areas, including 

contractor personnel, and visitors who are 

allowed unescorted access to those areas. 

More intensive chemical safety training 

should be provided to qualify personnel as 

chemical process operators. 

2.6.4 Maintenance 

Effective maintenance and surveillance of 

facility equipment ensure that equipment 

used to process, store, or handle hazardous 

materials is constructed, installed, and 

maintained to minimize the risk of 

accidental releases because of equipment 

failure. The mechanical integrity of all 

structures, systems, components, and 

detection and monitoring equipment 

important for ensuring chemical safety 

should be included in the maintenance 

activities. These activities should include 

corrective maintenance, scheduled 

preventive maintenance, instrumentation 

calibration and testing, and scheduled 

surveillance and inspections for verifying 

the'integrity of the chemical safety of the 

facility. Maintenance and surveillance 

activities on chemical safety systems should 

include: 

a. pre-maintenance reviews of the work to 

be performed; 

b. confirmed notification to pertinent 

operators and supervisors of the 

maintenance to be performed and its 

potential effects of maintenance on 

ongoing operations, and notification of 

the completion of the planned 

maintenance and the restoration of the 

affected equipment; 

c. comprehensive procedures which 

address qualification of personnel 

authorized to perform the maintenance 

or surveillance, controls on and 

specification of any replacement 

components or materials to be used, 

post-maintenance testing to verify 

operability of the equipment, and 

NUREG-I601 12 
documentation of the results of the 

maintenance or surveillance activity. 

2.6.5 Configuration Management 

Configuration management (CM) ensures 

oversight and control of all design bases 

and modifications (both temporary and 

permanent) to equipment, procedures, and 

processing conditions important to chemical 

safety. Configuration management is one 

of the measures that should be integrated 

into a single safety program that 

incorporates chemical safety systems. A 

Configuration Management system should 

include the following elements. 

2.6.5.1 Implementation Plan 

The implementation of a CM system should 

determine the scope of the safety elements 

to be considered, a description of each CM 

activity and its objectives, and prescribe the 

functional interfaces with quality assurance, 

maintenance, and training. All chemical 

safety hazards identified as significant 

should be considered. The CM system 

should also have formalized configuration 

management procedures and provide a 

method for initiating immediate corrective 

actions to problems found with the CM 

system. 

2.6.5.2 Design Requirements 

Design requirements and associated design 

bases should be established and 

maintained by an appropriate organizational 

unit. These design requirements should be 

kept current and suitable hazard analysis 

methods should be used to evaluate 

chemical safety aspects of proposed 

changes to the process. The design basis 

should be a set of facts about the chemical 

safety elements covered by the CM system 

and should be reviewed and approved by 

an appropriate authority within the 

organization. A specific group should be 

assigned the responsibility for maintaining 

the design and licensing bases and the 

design requirements. 

2.6.5.3 Document Control 

The control of documents w3thin the CM 

system should be established to include 

cataloging the document data base and 

maintaining and distributing the documents. 

Such documents should include items from 

the process safety information (design 

requirements, chemical hazards analysis, 

as-built drawings, specifications, operating 

and non-operating procedures pertinent to 

chemical safety, etc.), emergency response 

plans, system modification documents, 

assessment reports, and any other 

documents deemed necessary. Original or 

master copies of documents should be 

stored under quality assurance (QA) 

requirements. 

2.6.5.4 Change Control 

The CM system should maintain strict 

consistency among the design 

requirements, the physical configuration, 

and the facility documentation. Methods 

should be developed for identifying changes 

in the configurations relied on for chemical 

safety, ensuring technical and managerial 

review of proposed changes, and tracking 

and implementing those changes by placing 

documentation in a document control center 

and disseminating information to the 

training, engineering, operations, 

maintenance, and QA functions. 

2.6.5.5 Assessments 

Assessments of the CM system should be 

conducted to determine its effectiveness 

and to correct deficiencies. Periodic 

physical assessments (walkdowns) of the 

chemical safety systems should be 

13 NUREG-I601 
performed to confirm the program's 

accuracy and adequacy. 

2.6.6 Emergency Planning 

The emergency plan, prescribes a 

comprehensive response to chemicalrelated accidents and plant emergencies to 

protect the public, the workers, and the 

environment. The portion of the emergency 

plan relating to chemical process safety 

concerns should describe the significant 

chemical hazards identified in the hazard 

evaluation process and methods to be used 

to detect and mitigate the corresponding 

chemical accidents. 

2.6.7 Incident Investigations and 

Corrective Actions 

Incident investigation activities identify the 

root causes of and responses to chemical 

safety incidents that affect the licensed 

material and that have or could have 

significant health and safety implications. 

Such investigations should identify 

corrective actions to be taken to minimize 

the incident or prevent it from recurring. A 

system should be developed with an 

organizational structure and procedures for 

establishing investigation teams, 

determining root causes, tracking and 

completing corrective actions, and 

documenting and applying the "lessons 

learned" to other operations. 

2.6.8 Safety Program Audits 

Audits and assessments provide assurance 

that the safety program is functioning as 

intended and should be used to determine 

the effectiveness of chemical process 

safety controls. Audits and assessments 

should be conducted according to written 

procedures and checklists that ensure the 

documentation of findings, the distribution 

of reports, and the assignment of follow up 

responsibilities. The audits and 

assessments should be conducted by 

qualified personnel who are not responsible 

for chemical safety controls, and the results 

should be reviewed and acted upon by the 

licensee's management. 

2.6.9 Quality Assurance 

Quality assurance (QA) provides confidence 

that the structures, systems, equipment, 

components, and human actions relied on 

for chemical safety are of acceptable 

quality. Items relied on for chemical safety 

should be subject to the quality assurance 

criteria described below. 

2.6.9.1 Design Control 

Systems, structures, and components relied 

upon for chemical safety should be 

designed with well-defined objectives and 

functions. The design should be controlled 

to adhere to its defined function and should 

be verified by knowledgeable personnel not 

directly involved in the original design. 

2.6.9.2 Procurement Document Control 

Applicable design bases and other 

requirements necessary to ensure 

adequate quality should be included or 

referenced in documents for procurement of 

items or services related to chemical safety. 

If possible, suppliers should have a QA 

program consistent with the quality level of 

the item to be procured. 

2.6.9.3 Control of Purchased Material, 

Equipment, and Services 

Purchased material, equipment, and 

services should be controlled to ensure 

conformance with specified requirements. 

Materials should be inspected upon receipt 

for accuracy and quality, and critical 

measurements should be verified. 

NUREG-1601 14 
Equipment should be tested for operational 

acceptance before being relied upon for 

chemical safety. Purchased services which 

are relied upon for chemical safety should 

be monitored frequently for assurance of 

adequacy and completeness. 

2.6.9.4 Identification and Control of 

Unacceptable Materials, Parts, 

and Components 

Provisions should be made to identify and 

control those items which were to have 

been relied on for chemical safety and are 

discovered to have incorrect or defective 

materials, parts, and components. 

Unacceptable items should be physically 

segregated from acceptable or untested 

items when possible, and clearly marked or 

tagged as unacceptable so that they cannot 

be mistaken for acceptable items. 

2.6.9.5 Measurement and Test Controls 

Provisions should be made to ensure that 

tools, gauges, instruments, and other 

measuring and testing devices used on 

items relied upon for chemical safety are 

properly identified, controlled, calibrated, 

and adjusted at specified intervals. Testing 

requirements for chemical safety systems 

should be specified in written procedures. 

2.6.9.6 Corrective Actions, 

Record keeping, and Audits 

Provisions should be made to ensure that 

conditions adverse to the quality of 

chemical safety systems are promptly 

identified and corrected and measures 

taken to preclude repetition. Provisions 

should also be made for the identification, 

retention, retrieval, and maintenance of 

records that furnish evidence of the control 

of quality for activities important to chemical 

safety. Audits should be performed to verify 

compliance with all aspects of the QA 

program and to determine its effectiveness. 

2.6.1 0 Human Factors 

Human factors are a potential cause of 

accidents involving hazardous chemicals 

and should be evaluated when humans 

interface with structures, systems, 

components, or functions that are 

considered important to chemical safety. 

Such human actions should be supported 

by information such as data, alarms, 

directions or management policies, training 

programs, and control displays so that they 

can be performed properly. A human 

factors program should contribute to 

reducing the probability of significant 

chemical-safety-related human errors, 

provide for the detection and correction of 

the human errors that do occur, and 

integrate with other programs to provide 

reasonable assurance that system 

performance will degrade in a safe manner, 

despite failures to prevent, detect, or correct 

human errors. 

15 NUREG-1601 
3 REFERENCES 

American Institute of Chemical Engineers, Center for Chemical Process Safety,. Guidelines for 

Hazard Evaluation Procedures, (2d edition with worked examples), New York, 1992. 

American Society of Mechanical Engineers, "ASME Code for Chemical Plant and Petroleum 

Refinery Piping," ASME B31.3, New York, 1993. 

U.S. Code of Federal Regulations, "Domestic Licensing of Source Material," 10 CFR Part 40. 

U. S. Code of Federal Regulations, "Domestic Licensing of Special Nuclear Material," 

10 CFR Part 70. 

U.S. Code of Federal Regulations, "Occupational Safety and Health Standards," 

29 CFR Part 191 0, Subpart H, "Hazardous Materials." 

U.S. Code of Federal Regulations, "Occupational Safety and Health Standards," 

29 CFR Part 191 0, Subpart Z, "Toxic and Hazardous Substances." 

U.S. Nuclear Regulatory Commission, "Guidance on Management Controls/Quality Assurance, 

Requirements For Operation, Chemical Safety, and Fire Protection for Fuel Cycle Facilities," 

Federal Register, Vol. 54, No. 53, March 21, 1989, pp. 11590-1 1598. 

U.S. Nuclear Regulatory Commission, "Integrated Safety Analysis Guidance Document," (Draft 

Report for Comment) NUREG-I 51 3, February 1995. 

U.S. Nuclear Regulatory Commission, "Management Concepts and Safety Applications for 

Nuclear Fuel Facilities," NUREG/CR-6287, May 1995. 

NU REG-I 60 1 16 
JRCFORM 336 US NUCLEAR REGULATORY COMMISSION 

;2 BIBLIOGRAPHIC DATA SHEET 1102, 

(seeinsbuctions cn thsrsvase) 

NUREG1601 1. TITLE AND SUBTITLE 

1. REPORT NUMBER 

(Mgmd by WRC. Md VoL. Supp, Rw.. 

8nd Addmdum Numkn. Ifany.) 

Chemical Process Safety at Fuel Cycle Facilities 

h4oNnl YEAR 

i. AUTHOR(S) 

I Technical 

August 1997 

4. FIN OR GRANT NUMBER 

6. TYPE OF REPORT 

D. A Ayres 

7.PERIOOCOMRED @xkmhmh&u) 

j. PERFORMINQ ORQANWTION * NPME AND ADDRESS (rrNRC, pia Divkh, ffi ~rwicn. U.S. Nud.u R-UkLry CUI)- Md e if--, 

pm/ldb MIM Md lt'ld/\W ddnu) 

Division of Fuel Cycle Safety and Safeguards 

Office of Nuclear Material Safety and Safeguards 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

Md Idling addnw.) 

Same as 8., above. 

).SPONSORlNQORQANlZATKUJ-NAMEANDADDRESSpNRC, lypeSr~~.bov~~if~hda~~pwidsNRCDivision. ffi~wb, U.S. Nua*rR.g~WryIOIS~PLEMENTARY NOTES 

11. ABSTRACT (200 wad8 akrs) 

This NUREG provides broad guidance on chemical safety issues relevant to fuel cycle facilities. It describes an approach 

acceptable to the NRC staff, with examples that are not exhaustive, for addressing chemical process safety in the safe storage, 

handling, and processing of licensed nuclear material. It expounds to license holders and applicants a general philosophy of the 

role of chemical process safety with respect to NRClicensed maten'als; sets forth the basic information needed to properly evaluate 

chemical process safety; and describes plausible methods of identifying and evaluating chemical hazards and assessing the 

adequacy of the chemical safety of the proposed equipment and facilities. Examples of equipment and methods commonly used 

to prevent andlor mitigate the consequences of chemical incidents are discussed in this document. 

2. K€Y WORDSDESCRIPTORS (us1 wads wphnsss fbel wi/lavisfratsazhaa in bdng therapat) 

Chemical Process Safety, Chemical Hazards, Chemical Safety, Fuel Cycle Facilities, Nuclear Material 

Hazards, Chemical Risks, Fuel Cycle Safety, Hazard Evaluation, Process Hazards, Integrated Safety 

Analysis 

13. AVNLABILTY STATEMENT 

unlimited 

14. SECURIR MsslFlcATloN 

fik) 

unclassified 

(Thisunclassified 

15. NUMBER OF PAGES 

16. PRICE 
on recycled 

Federal Recycling Program