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Hungarian Atomic Energy Authority

Guideline 4.13

Environmental qualification and

maintenance of the qualified state of

equipment in operating nuclear power

plant

Version number:

2.

2007 March

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Issued by: Jzsef Rnaky PhD, director-generalBudapest, 2007 March

The publication can be purchased from:Hungarian Atomic Energy Authority

Nuclear Safety Directorate

Budapest

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PREAMBLE

The legal hierarchy of nuclear safety regulations in Hungary is as follows:

1. The uppermost level is represented by the Act CXVI of 1996 onAtomic Energy (Atomic Act).

2. The next level basically consists of two government decrees issued asexecutive orders of the Atomic Act. The 114/2003. (VII.29.) Korm.

government decree defines the legal status of the Hungarian Atomic EnergyAuthority (HAEA), while the 89/2005. (V.5.) Korm. government decree

specifies the HAEAs generic procedural rules in nuclear safety regulatory

matters. The nuclear safety code consists of seven volumes, which are

issued as the annexes of this latter decree. The first four volumes address the

NPP, the fifth one the research and training reactors, whilst the sixth volume

addresses the spent fuel interim storage facility. These six volumesdetermine the specific nuclear safety requirements, whilst the seventh

volume contains the definitions applied in the code. The regulations are

mandatory; failing to meet any of them is possible only in those specific

cases that are identified by the decree.

3. The regulatory guidelines constituting the next level of the regulatory

system are connected to one of the volumes of the code. The guidelines

describe the method recommended by the proceeding authority for meeting

the requirements of the nuclear safety code. The guidelines are issued by the

director general of the HAEA, and they are regularly reviewed and reissued

based on accumulated experience. So as to proceed smoothly and duly theauthority encourages the licensees to take into account the recommendations

of the guidelines to the extent possible.

4. In addition to the described regulations of general type, individual

regulatory prescriptions and resolutions may also address specific

components, activities and procedures.

5. The listed regulations are obviously supplemented by the regulating

documents of other organizations participating in the use of nuclear energy

(designers, manufacturers, etc.). Such documents are prepared andmaintained in accordance with the internal quality assurance system of the

user.

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Before applying a given guideline, always make sure whether the newest,

effective version is considered. The effective guidelines can be downloaded

from the HAEA's website: http://www.haea.gov.hu.

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Guideline 4.13 4/57 Version: 2

Environmental qualification and maintenance of the qualified state of equipment in

operating nuclear power plant

TABLE OF CONTENTS

1. INTRODUCTION 6

1.1. Subject and objective of the guideline 6

1.2. Corresponding laws and prescriptions 7

2. DEFINITIONS 8

2.1. Abbreviations 13

3. RELATION OF ENVIRONMENTAL QUALIFICATION WITH

OTHER PROGRAMMES 14

4. QUALIFICATION OF OPERATING EQUIPMENT 17

4.1. Organizational conditions for realization of qualification

programme 17

4.1.1. Organization responsible for establishment of qualificationrequirements 17

4.1.2. Organization responsible for meeting the qualificationrequirements 19

4.1.3. Organization responsible for verification of meeting thequalification requirements 19

4.2. Initial conditions of development of the environmental qualification

programme 19

4.2.1. Assessment of environmental circumstances 19

4.2.2. Service conditions 22

4.2.3. Scope of equipment to be qualified 23

4.2.4. Identification of the existing qualification documentation 254.3. Requirements and methods of modern environmental qualification 25

4.3.1. Qualification by testing 26

4.3.2. Qualification by testing material tests 27

4.3.3. Qualification by analysis 29

4.3.4. Consideration of operational experience 30

4.3.5. Selection of the qualification method 31

4.3.6. Application of the Space method 32

4.4. Execution of environmental qualification programme 33

4.4.1. Elaboration of the environmental qualification programme 34

4.4.2. Assessment of the actual status of qualification 36

4.4.3. Documentation of qualification 37

4.4.4. Evaluation of the actual status of qualification 40

4.4.5. Supplement of missing qualification 41

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4.4.6. Measures in case of losing qualification 43

5. MAINTENANCE OF THE QUALIFIED STATE 43

5.1. Functional tests 46

5.2. Monitoring 475.3. Diagnostics 49

5.4. Reliability of data of diagnostics and monitoring systems 49

5.5. Maintenance 49

5.5.1. Harmonization of maintenance and results of environmentalqualification 50

5.5.2. Maintenance of active components 51

5.5.3. Measures to be taken if insufficient maintenance 51

5.6. Condition monitoring 52

5.7. Trend analysis of failures 52

5.8. Equipment modifications and design modifications 53

5.9. Feedback of operational experience 53

5.10. Repair and replacement 54

5.11. Extension of the qualified lifetime 55

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1. INTRODUCTION

1.1. Subject and objective of the guideline

The activity aiming at maintaining the qualified state postulates the

existence of the required initial qualification of equipment. The initialqualification is discussed in Guideline 3.15.

The subject of this guideline is the environmental qualification of electric,

instrumentation and control and certain active engineering components and

of certain structures. Their qualification is not a single action, but it lasts

during the whole lifetime of equipment through the maintenance of the

qualified state.

The design requirements of nuclear power plants built in accordance with

former standards do not include the requirements for initial qualification ofsafety equipment; therefore the activities connecting to the demonstration ofenvironmental qualification and the correction of revealed deficiencies

should be performed simultaneously with the activities connecting to themaintenance of the qualified state, and if the replacement of equipment and

instruments become necessary then with the environmental qualification

tasks of the new components.

This guideline describes how the above mentioned complex activities

should be executed.

The objective of the guideline is to describe recommendations, which

facilitate to execute those activities that support:

the making up for the missing qualification of installed equipment,

subsequently, the maintenance of the qualified state and the validity

of existing qualifications, or

if those above cannot be fulfilled, then the implementation of the

necessary measures.

This guideline describes a possible method for being in compliance with the

regulations of Volume 4 of Nuclear Safety Code.

The licensee may fulfill the referred regulations in a way other than

described in this guideline. However, it should be justified in this case that

the chosen approach ensures solutions equivalent to this guideline.

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1.2. Corresponding laws and regulations

Pursuant to the paragraph 7.003 of Chapter 7 of Volume 4 of Nuclear Safety

Code (NSC) issued based on the authorization of section 4. (1) of the Gov.

decree 89/2005. (V.5.) Korm on the generic rules of procedures of the

Hungarian Atomic Energy Authority in nuclear safety regulatory matters,

the specified operating limits and conditions are required for maintaining

the qualified state of equipment having environmental qualification.

The compliance with limits and conditions is a necessary, but not sufficient

condition of that the components complete their qualified or service lifetime

in the facility.

The Chapter 8 of the Code discusses the detection of deviations, monitoringof their variations in time and the requirements for documented

maintenance. The Chapter 18 prescribes the feedback of operational

experience in order to evaluate the design and expected residual lifetime ofthe components.

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2. DEFINITIONS

Active components:

Components fulfilling their safety function with moving parts or bychanging their shape or properties.

Design lifetime of a nuclear power plant unit:

Lifetime that is taken into account during the design of the nuclear power

plant unit, for which the safe operability is justified by the facility safetyreport.

Identical part, structural element, component:

The part, structural element or component is identical, if all of its properties

(material, geometry, mode of operation, environmental resistance,

reliability, mode of fabrication, type, etc.) are the same as those of theoriginal one.

Equipment qualification:

The demonstration of that the safety classified equipment of the nuclear

power plant can fulfill their design safety function during their whole

lifetime. Various qualifications are exist: environmental qualification,

seismic qualification, fire resistance qualification, electromagnetic

compatibility qualification, etc.

The maintenance of performance parameters necessary for ensuring the

functionality and for achieving the safety function should be justified both

under normal conditions (including: designed special service states), and

under conditions taken place in the case of deign basis events.

The equipment qualification should take into consideration of the ageing

effect of environmental and operational circumstances occurring during thelifetime of the equipment. The process of equipment qualification includes

the measures connecting to both achievement and maintenance of thequalified state.

Safety analysis:

Examinations and tests to be performed in order to evaluate whether the

safety of systems, structures and components of a nuclear power plantcomply with the requirements.

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Lifetime:

Lifetime specified during design; besides the design lifetime, the service

lifetime, which means the period between installation and disassembly, can

also characterize certain equipment.

Earthquake:

OBE, SL-1 - Design earthquake

During and after the design earthquake the plant operates undisturbed or

shuts down, but it can be restarted after (or even without) the

accomplishment of certain tests. This American definition is identical with

the SL-1 earthquake as defined by the IAEA.

SSE, SL-2 - Maximum design earthquake

The largest earthquake in the case of which the plant can be safely shut

down, and maintained in shut down state without release of any radioactivematerial. This American definition is identical with the SL-2 earthquake as

defined by the IAEA.

Similarpart, structural element or component:

A part, structural element or component is similar, if the safety analysis

approved by the authority has justified that it is equivalent to the originalone.

Authentic data:

Information compiled and documented in an understandable and followable

manner, which provides the opportunity for independent reviewing thedeductions made and conclusions drawn.

Such data are the manufacturers technical descriptions, testing records and

analyses, etc.

Maintenance:

Activities performed on nuclear power plant systems, structures and

components that aim at guaranteeing that they can reliably and economically

fulfill their function as designed within the design lifetime of the unit. Two

types of maintenance activities are distinguished as follows:

- preventive maintenance,- corrective maintenance, i.e. repair.

The preventive maintenance consists of cyclic maintenance (independently

of the actual condition; its scope, method and frequency is specified on the

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basis of experience and prescriptions) and condition dependent maintenance

(its scope, method and duration is determined based on changing of

measured or observed parameters).

The corrective maintenance is to be accomplished because of the occurrenceof a failure. The scope, method and time point of the repair is dependent on

the extent and nature of the failure.

Maintenance programme:

Long term plan of maintenance activities to be performed on certainsystems, structures and components, which plan is developed for

maintaining the design function of systems, structures and components, andfor preventing and avoiding the safety consequences of failures.

Initiating event:

Such event resulting in deviation from the designed service states, which

occurs due to technical reasons inside the facility, the intervention ofpersonnel, or due to artificial or natural effect originating from the outside

environment, and which may lead to anticipated operational occurrences,

design basis accidents or severe accidents.

Environments:

The following environmental conditions are reasonable to be distinguished

in a nuclear power plant:

- Mild: environmental conditions appearing during normal operation of

the nuclear power plant that do not alter significantly if an accident

(including abnormal operating states) occurs.- Harsh: environmental conditions appearing during a design basis event

(DBE) of the nuclear power plant that alter significantly in comparison

with those appearing under normal service /such events are LOCA,HELB, MSLB/.

- Degraded: service conditions that altered in comparison with the initial

environmental conditions or with those that were considered during the

initial qualification (higher temperature, humidity, radiation, fungus,

etc.).

Environmental resistance qualification or environmental qualification:

Determination of resistance to environmental and service conditions ensuing

during the lifetime of the equipment. This is the environmental part of the

equipment qualification. The validity period of equipment qualification is

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specified during the qualification by the simulation of the service

environment.

Qualification:

Evaluation of the applicability of organizations, persons and/or tools forperforming activities relating to the safety of the nuclear facility, and for

fulfilling functions in order to support the decision to be made on their

approval.

Maintenance of the qualified state:

In the case of certain types of equipment and instruments, the process of

environmental qualification is followed by the accomplishment of a

programme, which ensures the long-term maintenance of operational

environmental parameters, environmental effect parameters and other

conditions that were taken into account during the qualification. The control

of monitoring the environmental parameters that are necessary fordemonstration of the maintenance of the qualified state of equipment is

performed during the process of Monitoring of Maintenance Effectiveness.

Qualified lifetime:

That lifetime of components during which the component, based on the pre-installation qualification procedure is (certified) able to fulfill its design

function during the necessary time-period even under such physicalcircumstances, which do or might appear in the environment of the

component during fulfillment of the safety function.

Qualification margin:

Difference between the actual service parameters and those parameters

belonging to conditions (that are more rigorous than the actual service

conditions) postulated during equipment qualification.

Normal service:

Such operation of the nuclear facilities during which the operational limits

and conditions approved by the authority are complied with; including load

changes, shut-down, start-up, refueling, maintenance, test, etc.

Ageing:

Effect of operational, environmental and technological conditions onequipment that result in occurrence and further development of degradation

mechanisms during a certain period of time, which conditions are within the

design basis accidents (but do not include them).

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Ageing management:

Series of those analysis, operation, maintenance, in-service inspection and

testing, monitoring, repair and reconstruction activities related to

degradation processes caused by ageing identified on designatedcomponents of the nuclear facility, which activities ensure that the

component remains able to fulfill its function with the maintenance of theminimum necessary safety margin.

Passive component:

Those components, which perform their design safety function without

moving parts and changing their shape or properties. (General examples ofpassive safety functions are included in the Annex of Guideline 4.14.)

System:

Entirety of components serving for fulfillment of a given function.

Component:

A unit performing individual sub-function of a given function (e.g.

equipment, instrument, piping, building structure).

Significant ageing process:

Damage caused by such a degradation process, as a consequence of which

the equipment, under normal and abnormal service conditions, become

responsive in a more and more serious and observable manner with regard

to its function to be performed during a design basis event.

Seismic classification:Categorization of systems, structures and components of nuclear facilities in

relation to their role in prevention of the safety of the facility during an

earthquake.

Design basis:

Those attributes of a nuclear facility, the existence of which is required for

the controlled management of anticipated operating events and postulated

accidents by complying with the specified radiation protection requirements.

The design basis includes the anticipated service states and the accidentconditions generated by postulated initiating events, the significant

assumptions and in certain cases the specific analysis methods as well.Those anticipated operating events belong to the design basis, which can be

derived from the postulation of the lack of a safety actuation.

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2.1. Abbreviations

PSRR Periodic Safety Review Report

NSC Nuclear Safety CodeSSC System, structure and component

FSAR Final Safety Analysis Report

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3. RELATION OF ENVIRONMENTAL QUALIFICATION

WITH OTHER PROGRAMMES

The nuclear power plants are designed for meeting the prescribed nuclearsafety, radiation protection and technical safety objectives during their

operation. Those safety functions are specified, the performance of whichensures the meeting of these objectives. The safety functions are performed

by systems, and their components. These systems, structures andcomponents (SSCs) perform their safety function through their availability

and through their operation according to a given performance parameter.

During the operation of the nuclear power plant the licensee should

continuously demonstrate the ability to perform the required safety

functions (including the performance capability according to required

performance parameters) in the following scope:

SSCs performing safety function(s) (SC 1-3),

SSCs not performing safety function, but their failures risk the safety

function.

This demonstration can be made through safety analyses, environmental(environmental resistance) qualification, implementation of ageing

management programmes, monitoring of the maintenance effectiveness, and

through their joint and harmonized realization (see Figure 1).

The licensee should decide on the method to be applied, with the limitation

that

environmental resistance qualification should be performed for

electric, instrumentation and control components operating in harsh

environment,

ageing management should be realized pursuant to Guideline 4.12for equipment listed, ageing locations and degradation processes

identified in the Annex of Guideline 1.26.

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Figure 1 Demonstration of the ability to fulfill safety functions and to comply with the requiredperformance parameters (SC 1-3 +)

Safety analyses:

the safety analyses should justify that

Ageing management

- Preventive programmes

- Mitigating programmes

- Condition monitoring

Maintenance

effectiveness

monitoring

(MEM)

MAINTENANCE

ISI,

TRP,

MAINTENANCEIndividual ageing management programmes

TLSAs

EQ

ACTIVE

ACTIVE and PASSIVE

SAFETY ANALYSES

Objective:

To demonstrate equipment functionality through

- harmonized realization of existing

programmes (material testing, TRPs,

maintenances),

- development and implementation of necessary

individual programmes

ACTIVE and PASSIVE

Objective:

To justify by analysis that

-

the given piece of equipment (material,construction)

- under the given circumstances

(environmental parameters, loads)

- during the specified period

is able to fulfill the required function

Objective:

To justify that the SSC, by effective

maintenance, is able to fulfill the required

function and to operate according to

specified parameters

DESIGN BASIS

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the given piece of equipment (material, construction, etc.),

under the given circumstances (environmental parameters. loads,

etc.),

during the specified period

is able to fulfill the required function.

The time limited safety analyses are able to justify this for a period of time

limited by taking account of ageing processes of components, altering loads

expected during operation or of parameters occurring during an design basis

accident that the component will be able to perform its safety function.

Environmental analysis qualification:

The limits of resistance ability against environmental, operational and

accident circumstances occurring during the lifetime of equipment are

specified during the environmental or (with other words) environmentalresistance qualification. The validity period of environmental qualification

is calculated by the simulation of the operating and accident environment.

The qualification is valid, if the long term preservation of operating andaccident environmental parameters and other conditions considered during

the qualification, thus the maintenance of the qualified state is continuouslyjustified and ensured.

Besides this guideline, the Guideline 1.27 and Guideline 3.15 include

recommendations with respect to environmental resistance qualification.

If the safety analysis or the environmental qualification is valid for limited

period of t ime, then the suitability of a component is justified for a limitedtime period. In such cases the further suitability of a given component

should be qualified prior to the end of the limited period or it should be

replaced by an element having qualification.

Ageing management:

The design aims at preventing the appearance of ageing processes, however

several such effects occur on the SSCs, which may adversely affect the

performance of their function. The objective of the ageing management

programme is to identify all ageing processes postulated to occur on the

given component, and to minimize their negative effects. In certain cases the

monitoring of the condition and condition changing of the given componentcould be sufficient.

The recommendations regarding ageing management are included inGuideline 1.26, Guideline 3.13 and Guideline 4.12.

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Monitoring of maintenance effectiveness:

The monitoring of maintenance effectiveness means the monitoring of all

the results of such activities, which play role in the preservation of the

required level of functionality of components. The general objective ofmonitoring of maintenance effectiveness is to justify that the executed

maintenance activities can ensure the compliance with the maintenanceobjectives defined for systems and components subject to maintenance or

the implementation of the necessary corrective measures.

Beyond the identification and correction of actual and possible failures, the

maintenance includes such support activities like the in-service inspections,

tests and exercises, the evaluation of maintenance results and monitoring of

the compliance with maintenance criteria.

The recommendations with respect to the monitoring of maintenance

effectiveness are included in Guideline 1.19 and Guideline 4.5.

If the licensee intends to demonstrate the suitability of the SSC through

environmental resistance analysis, then recommendations are given in thisguideline. Further recommendations regarding environmental resistance

qualification can be found in Guideline 1.27 and Guideline 3.15.

4. QUALIFICATION OF OPERATING EQUIPMENT

4.1. Organizational conditions for realization of qualification

programme

4.1.1. Organization responsible for establishment of qualification requirements

The environmental qualification requirements should be basically

determined by the designer; it should have been elaborated during the

design phase of the nuclear power plant. During the development of the

original design the comprehensive environmental qualification

documentation was not elaborated for formerly built nuclear power plants.

An additional specialty is that due to development of design and operationalexperience and to other reasons the plant implements a significant (relating

to its safety significant part) safety improvement modification programme.

The tasks resulting in the provision of design input data for environmentalqualification can be grouped as follows:

organization of equipment to technological and safety systems,

establishment of the technological, protection, control, etc. links,

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categorization of equipment to safety classes,

evaluation of safety analyses in order to specify the environmental

conditions and required performance parameters occurring duringnormal service, abnormal operation and accident states,

more accurate specification of design input data based on operationalexperience.

The above listed tasks may be executed by the operating organization with

external designer(s), however the verification and approval of the designinput data is the absolute responsibility of the licensee.

The determination of environmental qualification requirements does not

require, however does not exclude either the establishment and operation of

an independent organizational unit (persons) entrusted with this task. The

task should be reasonably managed within the organization coordinating the

design and planning with the involvement of engineers responsible formaintenance.

The following requirements should be met by the organization responsible

for determining the requirements:

It should be aware of the documents specifying the input data of

environmental qualification; it should have possibility to comparethem, to analyze the differing or contradictory data, to determine the

authoritative input data.

It should elaborate and maintain the environmental qualification

specification regarding the entire plant. It should be informed about the scientific-technical development and

the environmental qualification related operational (service andmaintenance) experience accumulated at the plant (including the

analysis of operational experience of other plants).

It should have available resources for executing analyses,

experiment and measurements necessary for more accurate

specification of environmental qualification requirements.

It should be informed about modifications that are planned at theplant; it should have capabilities to enforce the environmental

qualification aspects in the course of the connecting purchase,installation, commissioning and operation activities.

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4.1.2. Organization responsible for meeting the qualification requirements

The maintenance of adequate qualified state of equipment requires such

design, analysis, fabrication, purchase, assembly, operation, maintenance,

in-service inspection, etc part activities, which are achieved by the executorsof the given activities during their normal work.

In such sense an independent organization responsible for meeting the

qualification requirements should not be necessary. The meeting of the

environmental qualification requirements should be ensured in the relating

work instructions.

4.1.3. Organization responsible for verification of meeting the qualification

requirements

The grounding of qualification and the maintenance of the qualified state

(altogether, with other words: equipment qualification) is such a process,

which lasts from the design to the removal of equipment.

Accordingly, it is justified to assign such organizational unit or person(s),

whose duty is the verification of the meeting of environmental qualificationrequirements during the whole lifetime of the equipment.

4.2. Initial conditions of development of the environmental

qualification programme

The results of activities conducted by designers and manufacturers of

equipment and the equipment safety classification serve as input data for

that process during operation, which monitors the environmentalqualification conditions of the equipment, by taking account of alterations

resulted by implemented modifications, operational and maintenance

experience, condition monitoring, failure analyses, in-service tests and other

activities.

The monitoring of alterations should be conducted parallel to thesupplement of the required information or if it is missing to guaranteeing the

operational safety.

The activities relating to the compilation of initial conditions are as follows:

4.2.1. Assessment of environmental circumstancesDuring the design of the nuclear power plant the equipment and systems are

sized for tolerating various, postulated events.

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Due to design basis accidents, the environmental circumstances of certain

equipment of the nuclear power plant significantly alter, whilst no or not

significant change occurs on other equipment.

Those regions/rooms should be pointed in the nuclear power plant, wherethe accident conditions result in significant change of environmental loads.

Those equipment, which are installed in these regions and the operability of

which during accident is required by the safety analyses should be

considered as equipment to be qualified for operation under harsh

conditions.

The other safety equipment should be qualified for mild environment.

The environmental conditions of certain equipment should not be

characterized by the step function between the two extremums (mild and

harsh).

Consequently, the detailed analysis of environmental conditions is thesource of all concrete information making the qualification conditions more

precise. The events having role in generation of environmental conditions

should be assessed at least in the extent of initiating events analyzed in the

Final Safety Analysis Report (FSAR).

The environmental conditions of rooms falling under the effect of DBE

events and of those not falling under such effect.

Beyond the initiating events identified in the FSAR, the effect of other

environmental conditions (see examples below) affecting the equipment

operability should be analyzed by taking account of the single failure

criterion:

fungus generation,

internal flooding,

electromagnetic effects.

The possibility of damages caused by rodents in outside regions of thefacilities should be taken into consideration.

Determination of performance parameters in the case of failure of various

equipment and loss or output reduction of support systems (e.g. with the

failure of venting and air conditioning systems), and the effect of deviationregarding failure, output or efficiency of certain components (sealing, heat

insulation) affecting environmental parameters.

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The duration of harsh conditions and the operating time required under

given circumstances should be carefully analyzed for equipment to be

qualified for harsh environment.

The deviation of environmental parameters may be smaller (e.g. in the caseof an interface LOCA than of main circulating pipeline break), however the

duration of events, and consequently the required time of functionality ofcertain safety equipment may be much longer. It is similar to the mitigation

of beyond design basis accidents, and to the determination of qualificationconditions of equipment serving for condition monitoring.

The postulation of mild environmental parameters should mean the

analysis of a possible alteration ra ng e of parameters, in which the

conduction of a formal environmental qualification procedure does not

result in significant contribution to increasing the anticipated operability of

equipment. The maintenance of the reliability of equipment operating under

such circumstances may be sufficiently ensured by:

conservative design practice,

demonstration of mild nature of DBA conditions,

assurance of adequate quality of fabrication, assembly, operational

and maintenance processes,

investigation and analyses of failures.

This approach simultaneously brings with itself that the in-service failures

of equipment are resulted generally by individual, human, process and

material failures, which cannot be revealed by equipment qualificationmethods.

In the range of harsh environmental conditions, the previously mentioned

measures are necessary, but they are not able to guarantee the reliable

operation of equipment under DBA conditions.

Certain accident conditions cannot be simulated during tests prior to

operation (commissioning) and during in-service tests. At the same time theharsh environment causes such change of external parameters, which

leads to change of properties of materials used in equipment (e.g. withincreasing temperature the mechanical and electrical properties of certain

materials are changing; moreover if the parameters changes occursimultaneously, then new failure mode may appear).

The environmental qualification aims at preventing such possible failures.

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A specific area of qualification is the seismic qualification, the specialty of

which is that the resulted harsh environmental conditions affect all

equipment of the nuclear power plant. The seismic qualification is a part of

the general process of qualification, its separate management is not

adequate. The standardized practice follows the sequence of ageing earthquake harsh environment, where the ageing is the simulation of

ageing affects of service environment. The seismic qualification should be

only performed on aged equipment.

Adequate qualification margins prescribed in standards should be required

during environmental qualification. The qualification margin means the

difference between environmental parameters applied or postulated during

initial environmental qualification and those actually expected at the

installation location of equipment.

The design conservatisms and the applied safety factor may also result in

margins.

The application of statistical approach is not recommended, since it should

be postulated that the unqualified equipment do not live through the harsh

conditions, even with statistical probability.

The harsh environment should be simulated. In the case of non-harsh

environments, if significant ageing factor exists, then the environment

should be simulated according to the validity period of qualification.

Nevertheless, the realistic evaluation of results requires considering that

only a few specimens are really tested during the initial environmental

qualification, since the quantitative testing of statistically sufficient numberof specimens make the qualification process unreasonably expensive.

4.2.2. Service conditions

The service conditions are determined by operational and environmental

conditions together. These conditions due to various reasons may alter

between certain extremums. The knowledge of service conditions is

required both for specification of mild environmental parameter range to

be considered during equipment qualification and for identification of

ageing induced degradation processes of equipment.

The specification of anticipated service conditions is possible only with

limited accuracy during the design because of:

equipment failures,

condition degradation,

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modifications.

The most reliable method for considering these possible effects is: the real

verification of parameters important to environmental qualification during

operation, in different service modes and under various environmental (e.g.

weather) conditions.

The instrumentation and control equipment should be distinguished during

the implementation of environmental qualification and ageing management

programmes in relation with environmental conditions under which and the

room in which they operate. The consideration of categorized environmental

conditions may provide significant advantages during the initial

qualification (or if it misses, then during its supplementation) of equipment

and instruments operating in various premises. The greatest attention should

be paid to components operating in harsh environment.

The environmental qualification related management of the table of

operational parameters (the entire list of parameters to be monitored, and the

method for processing, etc.) should be practically conducted by the

organization or person(s) responsible for specification of qualification

requirements.

4.2.3. Scope of equipment to be qualified

In accordance with up-to-date requirements, such environmental

qualification specification should be compiled during the design of thenuclear power plant, which at least identifies:

the scope of equipment to be qualified, the service and accident conditions to be considered in relation with

qualification,

the qualification methods to be applied, and

the criteria of environmental qualification.

Such requirements did not exist for formerly designed nuclear power plants;

therefore equipment qualification list was not compiled.

During the identification of equipment to be qualified, those should be

selected, the operation of which is required during a design basis accident,

and which, based on their location, are under harsh environmentalconditions during the given period due to the accident situation to be

mitigated.

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The selection of components falling under to scope of environmental

qualification are discussed in Guideline 3.15 and in Chapter 3 of this

guideline (SC 1-3+).

Special attention should be paid to those functions, the loss of which affectsthe environmental conditions of the operation of that given piece of

equipment or others.

Care should be taken for the maintenance of the qualified state of structures

being boundary of harsh conditions, if their failures under such conditions

can hinder the fulfillment of the safety function necessary for event

management.

The environmental qualification should be achieved on system level on

equipment basis; accordingly the applied equipment are qualified and then it

is postulated that qualification of the systems consisting them is also

demonstrated. The adequacy of this assumption always should be carefully

assessed.

The identification of the boundary of a system and its components isimportant in order to understand the role of sub-units, which can be

individually assembled in the traditional sense, but are connected to eachother from electrical and functional viewpoints of operation. The breaking

electric component, so the breaker or the fuse is the component boundary

for motor operated components (valves, pumps). The high current cables

may belong to a component if they supply only that one, or may be handled

individually if they supply more components. The transformers connecting

different voltage levels should be considered as system boundary, as a part

of the system.

A certain assembly unit should mean the boundary; and if such identifiersystem exists for registering components that includes the assembly units,

then it should be followed during the identification of boundaries.

The equipment used for different function having different identifiers, but

operating in similar environment and having similar construction should

require totally uniform qualification activity. This fact should be taken into

account during the recording of the environmental qualification and

organization of the relating databases.

Those equipment should be taken into a common qualification package ofthe environmental qualification programme, for which the uniform type and

identical normal service and accident environmental conditions could be

justified.

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Sometimes, by taking account of the establishment (including the design)

circumstances of formerly built nuclear power plants, the precise

specification of the normal service environmental parameters are not

sufficiently documented; therefore this deficiency should be considered

during the identification of the scope of the environmental qualificationprogramme.

4.2.4. Identification of the existing qualification documentation

Specific environmental qualification documentation was not prepared forformerly built nuclear power plants. However, general and equipment

specific prescriptions including certain requirements were effective, and themanufacturer documents of certain equipment are also available, in which

environmental qualification information can be found.

The equipment specific analysis of the differences between the information

of former documents and the requirements of the modern regulations shouldbe achieved for the specification of actions necessary for reaching the

environmental qualification level pursuant to modern requirements.

4.3. Requirements and methods of modern environmental

qualification

The assurance of the quality of installed equipment of nuclear power plant

in service can be divided into two phases: establishment of qualification

requirements, assurance of quality.

The establishment of qualification requirements demands those available

qualification systems for equipment having different functions and installedin different environment, the adequate implementation and positive results

of which provide the qualification of a given equipment(type) to certainaccident environmental conditions.

It should be verified during the plant specific analysis that the accident

environmental parameters expected to occur in a given installation location

do not exceed the limits of toleration of the given equipment as justified by

the appropriate methods.

If the qualification reveals a degradation process progressing in time and

existing under given environmental conditions and parameters, then the

equipment have a limited lifetime that can be characterized by the number

of operating cycles or a period of time.

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The possible tools of qualifications are: testing, analysis, operational

experience, and their combinations, and processing of information collected

during maintenance. Nevertheless, the different qualification methods can

be applied to different cases; each method has its advantages, disadvantages

and application limits.

4.3.1. Qualification by testing

The qualification by testing aims at demonstrating the performance

characteristics of an equipment group. The selected specimen of theequipment should be tested in the appropriate sequence of environmental

conditions, during which its operability and performance indicators shouldbe demonstrated.

The testing is the most reliable method from environmental qualification

point of view. Any operating condition may be modeled during testing

(including ageing as well), and also the accident conditions with therequired margins. Not only the performance indicators of the equipment can

be demonstrated during testing, but the environmental conditions to beprovided by the support equipment and systems.

Nevertheless, the testing results do not justify the appropriate operation of

the given type of equipment (due to the non-statistical sampling), but the

deterministic failure of the given type of equipment should not be assumed.

The tests should be accomplished in line with written testing document,

their results should be recorded in test reports, which are applicable for

detailed description of the test configuration, the applied parameters, the

validity range of test and the arisen issues.

Occasionally tests could be only accomplished for certain part areas or part

units, or for justifying the toleration of certain selected loads. Thesemethods often should be combined with analysis methods regarding

toleration of other occurring loads.

The partial tests very often are accomplished by the manufacturers of the

equipment or by laboratories entitled by them, but without taking account of

the application in the nuclear industry. The utilization of these tests in the

nuclear industry is possible, if the authentication, accuracy and

representativity of the provided data is justified in accordance with the

circumstances of the nuclear industrial application. An example for partialtesting is the demonstration of radiation resistance of certain materials by

testing (by taking account of the former proves of other required propertiesof the material).

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If the equipment does not fall under the scope of environmental

qualification, and significant ageing factor cannot be identified, the

simulation of accelerated ageing can be rejected. However other tests could

be necessary pursuant to other aspects of qualification, thus the connecting

tests should also be accomplished.

4.3.2. Qualification by testing material tests

The classical method for identification of effects caused by temperature and

irradiation, and for quantifying ageing is the examination of the specimensof cables, measuring instruments and other components. It is fortunate, if

the specimens are from the real service environment.

Mechanical, electrical and chemical tests and simulations should be

performed on cables.

The classical method for evaluation of the consequences of environmental

effects (temperature, radiation, humidity, chemicals, etc.), for evaluation ofthe ageing condition of cables and other components, and for determination

of residual lifetime is the testing of specimens from the service

environment. The tests can be accomplished by non-destructive and

destructive methods.

4.3.2.1. Non-destructive analyses

The non-destructive test methods could be primarily applied for equipment

in service. These tests can be made by electrical, mechanical and chemicalmethods.

The most frequently used electrical method is the measurement of insulationresistance, and of direct and alternate current voltage resistance. The

measurement of the elasticity of cable insulation (sheath) and the

examination of color changes of sheath that indicate the start of ageing

(appearance of rupture, break, crack) of insulation material are among the

mechanical tests. A chemical method is the laboratory analysis (infrared

spectrophotometric analysis, density measurements, plasticity measurement,

etc.) of the micro size material samples from the insulation and the cable

sheath.

The organized storage and periodic inspection (visual inspection,

measurement of changing of insulation resistance, examination of insulationof cables being in wet and humid environment) of representative cable

samples under conditions worse than the service environment, and their

accident testing belong to the non-destructive testing. The data obtained in

this way should be used for estimation of expected lifetime.

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Other methods used in the international practice for non-destructive analysis

of cables are:

Insulation examination by measurement of penetration modulus

(INDENTER monitor).

Examination of cable insulation by return voltage method.

Measurement of loss factor.

During the realization of lifetime extension the non-destructive methods

should be used for monitoring degradation processes during the extended

lifetime.

4.3.2.2. Destructive analyses

The analysis methods entailing the destruction of the material serve forassessment of the ageing condition of insulation materials (primarily cable

insulations). The samples necessary for analyses should be prepared formthe insulation material of equipment (cables) that are out of service.

The insulation material of cables becomes brittle and tough due to the

ageing effects of service environment. In general this alteration is well

followed by the elongation at break of the material; therefore the break

analyses of samples of cable insulation material provides valuable

information on the ageing process. During the analysis the elongation of

break of the sample is measured in comparison with the initial state of the

sample. The evaluation of the analysis results requires the knowledge of theinitial elongation at break values of the insulation materials. IN the

international practice the condition of insulation material is adequate if itselongation at break value is not lower than 50% of the initial value.

Otherwise, it is postulated that the cable insulation is not able to fulfill itsrequired function in the case of a possible accident state.

Other methods used in the international practice for destructive analysis of

ageing of cables are:

Flexibility and tensile strength examinations of the insulation and

sheath materials.

Density analysis of insulation materials.

Thermoanalyitical analyses with differential scanning calorimeter(DSC).

High voltage insulation analyses.

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During the realization of the lifetime extension, the destructive examination

methods should be applied in order to monitor the degradation of cable

samples ageing in the actual service environment.

4.3.3. Qualification by analysisThe qualification by analysis is successful, if the analysis model can

correspond to the element to be qualified. All relevant properties (shape,material properties, etc.) of the model should correspond to the element to

be qualified, whilst the postulated loads should correspond to the anticipatedservice loads and other effects.

The qualification by analysis requires logical evaluation and application of a

validated mathematical model. The analysis should include natural laws,

testing and examination data, operational experience and condition

indicators.

The adequacy of the model is the critical point of the applicability of thisqualification system. The sufficient similarity between the model and the

product should be justified on the basis of natural laws, analysis results,

operational experience, or other verifiable database.

The qualified state can be demonstrated by evaluation of tests and data fromthe viewpoint of material properties, the resistance to environmental

circumstances and by failure statistics. Nevertheless, the analysis cannotdemonstrate the qualified state individually.

In general, the qualification by analysis can be used for demonstration of

toleration of individually affecting loads (e.g. earthquake, temperature

effects).

The qualification by analysis cannot be used as lonely method for

instrumentation and control, and control equipment.

Usually, the analysis methods can be well applied to extension of existing

test results by extrapolation. The extension of the use of detailed test resultsby analysis is very often performed.

The effects of applied simplifications and unavoidable uncertainties should

be taken into consideration during analyses by application of appropriate

margins, safety coefficients and of simplification methods that are justified

as conservative.

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4.3.4. Consideration of operational experience

The operational experience can provide applicable input data only to the

qualification of mild environmental conditions. Its applicability to

qualification for harsh environmental conditions is very limited.

During qualification for mild environmental conditions both the tests results

of the equipment of the given unit prior to installation and during

commissioning, and the operational experience of similar equipment

installed in units in operation provide relevant input data for equipment

qualification in the power plant under construction.

In particular, the results of in-service tests and overload tests are worthmentioning within the operational experience.

In general the overload tests (pneumatic and hydraulic pressure tests, load

tests, etc.) are performed pursuant to industrial standards with a load

exceeding the normal service load, and it is postulated that if the componenttolerates the overload at a given moment, then it will be able to tolerate the

normal service load for a given period of time.

The circumstances of in-service tests are highly dependent on the designer

foresight (design for testability) and the installation conditions of the

equipment.

At a major part of equipment, especially of safety equipment, only partialtesting conditions are arranged (see e.g. ECCS pumps), and the

instrumentation controlling the normal service conditions are not always

applicable for recording the test parameters with sufficient accuracy.

In other cases (e.g. hermetic zone) the actual physical testing of qualified

state is avoided in order to prevent ageing or degradation due to the high

values of test parameters.

Consequently, the representation of accomplished tests from environmental

qualification aspects should be individually assessed.

The statistical processing of operational experience can be well used for

qualification of mass products. However it has two conditions: on the onehand reliable event (failure) recording system should be used for sufficiently

long period (because the lack of event recording may cause false judgment

on applicability), on the other hand the monitoring of the load value is

required.

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The total utilization of operational experience is dependent on the

monitoring of loads, since the experience gained at locations with higher

loads can provide prospective information for locations with lower loads.

4.3.5. Selection of the qualification methodThe below limitations should be taken into consideration during the

selection of the method for environmental qualification:

Qualification by analysis is only possible if the component has initial

qualification and it is intended to be operated under environmental

circumstances differing from the initial state.

Qualification by analysis can be used for justification of toleration of

independently affecting loads (e.g. earthquake, temperature effects).

The operational experience provides input data to qualification for

mild environmental conditions only.

The appropriate selection of the methods to be applied aims at

demonstrating that the ageing degradation of equipment in a service period

does not result in common cause environment induced failure either during

normal service of the unit, or if the equipment will be under harsh

environmental conditions that are considered in a design event at the very

end of its qualified lifetime.

The mild or harsh nature of the environment should be taken into accountduring the selection of the method; inspection and testing should get

priority.

One of the most effective methods from environmental qualification

viewpoint is the type testing of equipment to be installed. Accordingly, the

resistance of the given equipment type to ageing, environmental and seismic

effects could be demonstrated in the adequate sequence under both normalservice and accident conditions.

The analysis method is less applicable; its conclusions are highly dependent

on the suitability of the applied model, the scope, and on how rigorous and

accurate the analysis is. Nevertheless, the testing method rarely applicable

individually for already installed equipment without certain supplementary

analyses. A typical example of application is the seismic qualification by

analysis.

The qualification by analysis cannot be applied to seismic qualification of

complex instrumentation and control, or electronic equipment. Exemption isonly possible on the basis of the size or mass of equipment. Such equipment

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are e.g. the Diesel generators. The analysis provides the vibration spectrum

of the input signal calculated for the location of small equipment, but it is

not applicable for the entire qualification.

In general, a limitation of operational experience as an equipmentqualification method is the adequately documented operational information.

The applicability for qualification for worst case should be assessed

during the selection of the qualification method. The qualification list

should be merged for those equipment (and groups) which can be qualified

for the worst possible environmental conditions in the plant. However care

should be taken that the parameters of the worst case should cover the

parameters of all individual harsh environmental conditions.

The selection of the qualification method to be applied is dependent on the

function to be fulfilled by the equipment and on the phase of the accident in

which it should be fulfilled. If e.g. the active functions of equipment are

performed before the occurrence of the accident conditions, then their

related elements should not be qualified for toleration of the given accident

conditions.

4.3.6. Application of the Space method

The subject method is one of those formalized procedures, by which the

scope of components requiring ageing management can be identified. It canbe primarily applied for qualification and ageing management of cables,

connectors and extensions.

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Figure 2

4.4. Execution of environmental qualification programme

The environmental qualification programme aims at examination of

equipment that are sensitive to harsh environmental conditions, or the

collective appearance of ageing and harsh environmental conditions. The

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environmental qualification programme should take into account that the

seismic effects also load the equipment operating in mild environment.

The execution of the environmental qualification programme consists of

three major phases, as follows:

elaboration of the programme,

execution of the programme,

maintenance of the qualified state.

The status of qualification of nuclear power plant equipment should bereviewed during the elaboration of the programme. If the qualification is

missing, then the concrete action necessary for achieving the qualified stateof equipment should be identified, the preliminary schedule of these actions

should be elaborated.

The priorities of actions should be specified during the realization by takingaccount of the correction of problems requiring immediate measure that

occur during the specification of qualification requirements. The

environmental qualification programme should be executed parallel to theoperation of the nuclear power plant; therefore certain measures necessary

for continuous maintenance of safety may require immediate measures.

The maintenance of the qualified state should include the appropriate

documentation of the process, and if necessary the modifications of the

operation, maintenance and testing methods.

4.4.1. Elaboration of the environmental qualification programme

The knowledge about environmental conditions of equipment and their

required operation during accident situations has become much more

accurate since the commissioning of formerly built nuclear power plants.

The parameters occurring during various initiating events became more

accurate, and the list of initiating events was extended as well.

Such significant modifications could be implemented, which modifies theoperational and environmental resistance properties of equipment such a

way that they are getting closer to requirements prescribed in modernstandards and regulations.

During the modifications the authority requires purchasing and installingsuch new equipment, which are in compliance with environmental

qualification requirements that seem to be necessary on the basis of the

latest knowledge.

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Accordingly, the elaboration phase of environmental qualification is not a

single action to be executed and finished, but a process that should be

continuously performed parallel to the operation of the plant, extension of

the engineering knowledge and development of more rigorous regulatory

requirements.

Figure 3

Role of qualification as a function of environmental conditions

The environmental qualification aims at assuring that the equipment of thenuclear power plant will fulfill their required functions during the whole

lifetime of the plant.

Safety result

Without EQ

By taking account of EQ

Controlled

conditions

Normalservice

conditions

Abnormalservice

conditions

Limited harshconditions (e.g.

only radiation)

DBA(e.g..

LOCA)

Severeaccident

(BDBA)

Mild environment Harsh environment

Worsening of environmental conditions

Probability of failure that is independent of the environment

Probabilityoffailure

orinoperability

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The safety functions fall under the scope of regulatory supervision, whilst

the performance of other functions is governed by production interests.

Therefore, the economical aspects should also be taken into account.

The development of the environmental qualification programme shouldinclude the review of the qualified state of equipment and the enhancement

of their qualification level.

The economical aspects cover the followings:

maintenance of the qualified state is in close relation to the further

operability of the plant,

cost of maintenance of the qualified state of an existing equipment

versus the cost of reconstruction,

requalification of an existing equipment versus cost of replacement,

specification of date and schedule of requalification or replacement,

value and distribution in time of the needed human resources.

The decision made on the basis of economical considerations should belong

to the competence of the operator.

The elaboration of the environmental qualification programme is basically

dependent on those regulatory requirements, which in various forms are theconditions of granting or extending the operating license.

The regulatory requirements should in any case include the list of initiating

events to be considered as the basis of environmental qualification,

practically together with the associated environmental parameters. If theenvironmental qualification programme is developed in an operating nuclear

power plant, other important aspects are: the approval of the list of systemsand equipment to be qualified, the regulatory statement on the sequence and

deadlines of correction of environmental qualification deficiencies.

4.4.2. Assessment of the actual status of qualification

The most important part of the development phase of the whole

environmental qualification programme is the assessment of the actual state

of equipment qualification.

The scope of equipment and instruments to be qualified should be identifiedon the basis of initiating events belonging to the design basis, and of other

events requiring measures. The SC1-3+ safety classification provides

support to the evaluation of the functional criteria. The equipment and

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instruments required in case of fire, anticipated transients without scram

(ATWS), temperature and pressure shock of equipment belonging to the

primary system boundary, and of total loss of power should also be taken

into account.

Those components should also be qualified, the failure of which may hinder

the fulfillment of a basic safety function or a safety function (seedefinitions).

The environmental parameters occurring during normal service of the unit

and accident occurrences should be identified for each room.

The document templates serving for documentation of qualification andtheir rules of filling in should be developed. Those principles and methods

should be clarified, which should be applied during the qualification.

4.4.3. Documentation of qualification

The documentation of qualification should be made in a unified, clearly

organized form. The documentation should contain the input data of

equipment qualification, the description of reference basis and thequalification results. The documentation should determine:

the achieved qualification level and the conclusion that can be drawn

accordingly,

the installation requirements,

those operational limits, within which the qualification conclusions

remain valid,

those maintenance, in-service testing and replacement requirements,which are necessary for the maintenance of the qualified state,

the qualified lifetime of equipment, and

the documents grounding the evaluation of environmental qualification,

and their conclusions.

The documentation should be organized for equipment groups; the

determinant conditions should be highlighted: the extreme environmental

parameters and the equipment lifetime.

The recording of qualification in a database is an important aspect ofadministration and data management.

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It is advantageous from practical and administration points of view, if the

recording of components falling under the scope of equipment qualification

is consistent with the already existing registry of components.

The basic safety system functions should be assessed to the boundarysurfaces. Beyond the boundary surface the function performed by another

system should be assessed: whether it serves for the fulfillment of basicsafety functions, or may hinder it by their failure or false operation.

The database should include the environmental parameters occurring during

normal service and accident occurrences, the criteria for fulfillment of the

required functions, and the associated parameters values in the various

rooms of the facility.

The number of databases should be minimized; links should be developed

between them.

The various databases may be linked via components, product groups,components groups that are qualified in the same way, participation in the

required function, rooms, etc.

The validity period of environmental qualification should be specified by

the simulation of the service environmental during qualification.

The documentation of equipment should be stored until the end of their

qualified and service lifetime.

Pursuant to the relating standards the documentation of environmental

qualification should consists of the following chapters.

4.4.3.1. Documentation for mild environment

The following documents should demonstrate the qualified state of

equipment operating in mild environment and fulfilling safety functions:

Designer or purchase specification, which includes the description of

function requirements to be fulfilled under specific environmental

conditions appearing in case of operational occurrences.

Reports (records) of seismic tests, evaluation and certification ofcompliance.

4.4.3.2. Documentation for harsh environment

The documentation of equipment operating in harsh environment and

performing safety function should demonstrate that the equipment are

qualified for the conditions of their service and their qualified lifetime, and

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the rules of their in-service testing, maintenance and condition monitoring

are specified.

The considered data should be specific to the application of the equipment.

The data should be available in easily understandable and up-to-datemanner; they should facilitate the verification and independent audit of the

drawn conclusions.

The documentation of equipment operating in harsh environment and

performing safety function should include the following compulsory items.

Certain items may be not relevant.

a) Identifier data required for identification of qualified equipment,including data for identification of the manufacturer, type family and

type.

b) Description of the safety function, data applicable for its

identification: denomination, symbol, sign.c) Description of the qualification method, data applicable for its

identification.

d) Data, signs serving for identification of tested specimens.

e) Description of normal environmental conditions and denominations

applicable for their identification, including the description of

environmental conditions appearing during normal occurrences and

denominations applicable for their identification. Such like

temperature, pressure, irradiation, relative humidity, characteristics

of electromagnetic an radiofrequency interference, attributes of

occurring overvoltage, number and attributes of service load cycles,

and those design basis events, the toleration of which the equipment

should be qualified for.

f) Description of acceptance criteria and values of performance

parameters necessary for fulfillment of the function, and of the

values produced by the equipment during testing.

g) Description of the sequence of inspections and testing.

h) Description of designer considerations relating to the installation

location: assembly, characterizing geometrical directions, connecting

surfaces, insulation tubes, sealing and other protections.

i) Description of configuration used during testing in order to

demonstrate whether the connections of equipment in the testing

room (chamber) were affected by the simulated accident events.

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j) Demonstration of that the examined and tested specimens can

adequately represent the equipment to be qualified or the equipment

group created by type categorization of loads.

k) Description of the revealed ageing mechanisms, and of how they areconsidered during qualification tests.

l) Declaration of the qualified lifetime, justification of the given value.

m) Results of tests determining the lifetime simulated by artificial

ageing.

n) Description of the simulation of design basis events, including

temperature-time and pressure-time functions, humidity, mechanical

load, electrical load, applied voltages, frequencies, chemical effects

water spraying or flooding.

o) Description of irradiation tests, including type of radiation, dose

intensity and value of total dose

p) Description of results of seismic tests

q) Evaluation of margins against extreme parameters with respect to

temperature, pressure, irradiation, voltage of electric supply, service

time and earthquake.

r) Description of surveillance, in-service inspection and testing,

maintenance and part replacement required for maintaining thequalified state.

s) Description of deviations occurred during testing belonging to initial

qualification, and of their effects on qualification.

t) Summary of qualification results, discussion by description of the

limitations of qualifications, the related warnings, the value of

qualified lifetime, the time interval of in-service tests and inspection

activities necessary for maintenance of the qualified state.

4.4.4. Evaluation of the actual status of qualification

The evaluation of the status of environmental qualification should include

the following aspects:

It is demonstrated that a part of equipment is in full compliance with therequirements of the defined environmental qualification.

It is demonstrated that another group of equipment is resistant to certainenvironmental loads.

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The resistance of other equipment is not demonstrated, or obviouslymissing.

It is obvious that certain equipment will become disfunctional underthose accident conditions, for which the functionality is postulated in the

safety analyses.

The unit should continuously operate in a safe state, consequently if such a

significant safety deficiency is detected that was not revealed during

equipment qualification, then immediate corrective actions should be a

condition for further operation.

The correction of deficiencies or uncertainties should be scheduled on the

basis of the priority of the safety function. Other aspects may be relevant

during compilation of the corrective programme for a plant having moreunits, e.g. age of units, schedule of main overhauls and other safety

improvement measures.The probabilistic based risk assessment (PRA) may facilitate the

prioritization of measures provided its conditions are at present.

4.4.5. Supplement of missing qualification

The qualified state of equipment should be demonstrated by testing,

analysis, based on operational experience, or the combinations of the three

methods. The limitations discussed in paragraph 3.3.5 should be taken into

consideration!

If the equipment may be tested, then the following should be considered:

The operational and maintenance history of equipment should be

reconstructed, in order to provide authentic supplement of the

accelerated ageing effects necessary for achieving the state

simulating the end of the lifetime. If alternatives exist in theselection of the specimen, then the specimen providing the most

representative information should be selected.

Operational limits due to the removal of equipment.

Identification of the root cause of failures occurring during

equipment testing. (The failure may be an unknown event

occurred during the lifetime of equipment or damage appeared dueto disassembly or transport!)

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If the testing device is transported from the store, then the storagehistory (with special respect to the environmental parameters)

should be reconstructed.

During qualification by testing, attention should be paid to the

analysis of whether sufficient similarity exists between the testedequipment and those being in service.

As far as possible the supplementary qualification in operating plants should

be performed on equipment disassembled from service. The precise

knowledge of operational history of samples is significant.

If the supplier of the equipment is reachable, then similar equipment should

be purchased.

The qualification tests of equipment performing basic safety function or

safety function should be anyway accomplished by taking account of the

service environmental circumstances.

The operational experience could be applied to environmental qualification

in a correct manner, if it can be justified that the service loads are at leastsuch rigorous for the equipment as those occurring during environmental

qualification; therefore the application of the method is rather limited.

Testing can be combined by analysis. It can be used for e.g. calculation of

qualified lifetime by mathematical models of thermal ageing effects (themost often applied model is the Arrhenius-equation).

A special utilization of operational experience for cables is the destructive

test after a certain service period. The test results provide good picture of the

state of cables operating under similar circumstances. The greatest safety

benefit of such qualification is obtained from the analysis of specimens

collected either from the first unit of multi-unit power plant or from the

oldest one among units with similar construction.

The residual lifetime of components not qualified pursuant to the former

regulation should be demonstrated by testing and analyses!

Other possible method for management of missing qualifications is the

movement of equipment to such a region or room, where the environmental

parameters occurring during accidents are milder than in the original

installation location thereof.Qualification for flooding is needed, if it may occur in the installation

location of equipment and the meeting of single failure criterion requires it.

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4.4.6. Measures in case of losing qualification

The violation of the environmental and other effect parameters considered

during qualification may lead to degradation not considered during

qualification or assumed to be slow then but being faster under the newcircumstances; therefore the qualification loses its validity.

If the qualification cannot be obtained for an electrical, and instrumentation

and control component that is technically and reasonably replaceable, and

the qualification loses its validity or reaches the end of its qualified state

specified during qualification, then it should be replaced by

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