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Quality Assurance - Question Bank

Quality Assurance - Question Bank with answers

( Answers shall be taken only as guide. They may not be full-fledged answers)

A QA concepts

Knowledge based uestions

!. "hat is uality# "hy is it different for different persons#

Quality is

- Conformance to requirement

- Fitness for service

- Zero defect

- Providing the required service

- Customer satisfaction

- Degree of excellence

Quality is different for different person because of the different requirements.

For example eavy !ater that is having "#$ %P is quality heavy !ater for

P& but not for 'oderator.

$. "hy uality is important in %& "hy safety is linked with uality in

%&

Quality is important in (PP because in a (PP quality means safety. %f an

unsafe condition occurs) it may lead to release of radioactivity. &he effect of

the same may be irrecoverable even by future generations. For the same

reason Quality and safety are lin*ed in (PP.

'. efine and differentiate between Q and Q*.


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Q+%t is the inspection of the end product for conformance to requirement.

&his may involve visual and dimensional chec*. &he concept !as developed

and !idely used !hen manufacturing !as for small utility items.

+scertains only end productconformanceto stipulated requirements or

specifications through dimension measurement) (D& methods) testing) or

chemical analysis etc.

Q*+&his concept !as evolved !hen a third party ,an individual or a concern

but not the supplier or manufacturer is carrying out the inspection of an item.

For example) (PC% Q/ offices situated in various locations throughout the

country inspects the items for various stations of (PC%.

&he activities of inspection may be same) but by !hom and for !hom is

different.

Q/ may be done by a supplier on a sub-contractor on sample basis.

Counter chec*ing) rechec*ing or selective inspection on sample basis using

the above quality inspection and quality control techniques by o!ner or his

representative.

0x1 + big company sub contract a part to another company. &he sub

contracted company has its o!n inspection group and method. 2ut the big

company ) on sample basis may get a component and do the inspection

activity for conformance.

,. efine and differentiate between Q and QA

Q3 &his concept evolved !hen manufacturing matured to produce pressure

vessels and reactors !here the consequences of accident are devastating

and destructive. ence various (D& techniques are evolved to detect error

during manufacture and during in service in the operation.


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QC tries to control) not only end product but production process itself.

&his is done through qualification of (D& procedures) (D& personnel )

!elders) !elding procedures) heat treatment procedures) inspectors etc

QA+ &his concept evolved in the age of space and nuclear industry !here you

cannot ma*e error and learn. &he very first mista*e may prove itself the end

of the industry. ence an all encompassing umbrella program is made !hich

not only covers QC aspects but also management aspects and in each and

every stage of product ) namely design) procurement) construction)

commissioning) operation and de-commissioning.

%n short) Q+ is a comprehensive quality program aimed at controlling

everything !hich can affect end product4s quality.

%+0+ code defines Q+. as 5planned and systematic actions necessary to

provide adequate confidence that an item or facility !ill perform satisfactorily

in service.4

. "hat does *hri &hilip rosby tell about uality#

e tal*s about four absolutes of quality.

6ne3 &he definition of quality is conformance to requirement.

&!o3 &he system of quality is prevention) not cure.

&hree3 &he target of quality is 7ero defect.

Four3 &he measurement of quality is the price of non conformance.

/. "hat is the * 0,1$ definition of Quality and Quality Assurance#

Quality+&he totality of features and characteristics of a product or service

that bear on its ability to satisfy a stated and implied requirement.


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Quality Assurance++ll the planned and systematic activities implemented

!ithin the quality system and demonstrated as needed) to provide adequate

confidence that an entity !ill fulfill requirements for quality.

2. efine the QA &3453A667 for a %&&.

Quality in (PP means safe 8 economic generation of electricity


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0. "hat are the 8iews of r. 9eignbaum and r. eming on uality#

7:plain with an e:ample based on our plant.

Dr. Feignbaum emphasi7ed that quality can be controlled by

- setting quality standards

- +pprising conformance to these standards

- +cting !hen standards are not met

- Planning for improvements in standards

&his principle is !idely used in (PC%. For example) 'an-rem budgeting one

such thing .

Dr Deming Focused on the problems of variability in quality in production.

Coolant channel life enhancement is a classical example of this. 9ariability in

the fracture toughness !as improved by controlling the amount of impurities

present in the coolant tube material.

Parameter

%nitial

specification

%mproved

specificatio

n

0ffect on coolant tube

ydrogen:;# ppm : #ppm 'inimi7e hydrogen

embitterment

Chlorine --- : < ppm

%ron ---- : ?#< ppm 'inimi7e hydrogen pic* up

'eltingprocess

--------- Quadruplemelting

process

quadruple melting to minimisehydrogen) chloride) phosphor 8

carbon

;. raw the QA loop< mark the elements and e:plain each element.


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5ood planning- Preparing plans 8 procedures for all performance activities important to

safety 8 plant performance.

5ood e:ecution- Performing as per the above procedures and plans and *eeping proper

records as ob@ective evidence for the same.

5ood feedback- Performance revie!) root cause analysis) revie! of the above

records leading to corrective actions.

!1. "hat is uality audit#

+ systematic and independent examination to determine !hether quality

activities and related results comply !ith planned arrangements and !hether

these arrangements are implemented effectively and are suitable to achieve

ob@ectives.

!!. "hat are the different audits conducted in KA&*# "hy they are so#

&he different audits conducted in A+P/ are

> %ntegrated management internal audit B compliance to %/6 "


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; %ntegrated management external audit B /urveillance audit for

compliance to the above standards by the certifying agency.

E Corporate Q+ audit B Q) (PC% audit for the compliance of Q+

programme.

%/% audit B +udit by Q+ dir) Q) (PC% for compliance of the %/%

programme.

# /afety audit B +udit by Q) (PC% for the compliance to the %ndustrial

safety programme

? +udits conducted in +dministration) accounts and C''

&here are so many audits because the purpose for each is different.

!$. =ow A73B regulatory inspection is different from other audits#

+02 regulatory inspection has the authority to stop the operation of the

(PP if !e are not complying !ith them) !hereas other audits are not having

that po!er

!'. escribe the audit methodology in simple terms. "hat are the steps

in8ol8ed#

+udit is a documented activity carried out by qualified auditors against a

particular standard. &he various steps involved automatically explains the

audit process.

> Preparing an audit schedule

; %dentifying the audit team

E Carrying out the audit

/ubmission of audit report G non- conformance


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# esponse by the auditee for the audit report G non - conformance

? 9erification of the response G compliance to the non B conformance

!,. "hat is Quality system# "hat is its ad8antage#

&he organi7ational structure) responsibilities) procedures) processes and

resources for implementing quality management is called quality system.

&he advantage of having a quality system is it helps us in achieving

quality irrespective of the man involved in carrying out the activity.

!. 6atch the following ( *olution not gi8en)

/ln

o+ 2

Quality inspection /afety and economy


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!or*er comes to you and complains that a !or* is being carried out

!ithout proper permit. Hhat is your action as an auditorI

E. 6ne particular equipment is having high brea*do!n rate. +s a Q+ person

approach the problem.

. +n operator operated a !rong valve during a routine test. +pproach this

problem as a Q+ person. /uggest solutions.

#. + tan* level !as found abnormal. 6n further chec*ing it !as found that the

level transmitter is !or*ing properly. 2ut the po!er supply to that is having

problem. Hhere the problem may be lyingI

B %on- estructi8e Testing

Knowledge based uestions

!. "hat is %T# =ow many techniues are there< in general#

(D& means (6( B D0/&JC&%90 &0/&%(K. &he part that is being

sub@ected to testing is available for use. %t does not get damaged due

to the process of testing.

&he various techniques are

> 9isual examination ,by na*ed eye or CC&9 system or ens or

dimensional chec*

; iquid penetrant examination

E 'agnetic particle examination

adiographic examination

# 0ddy current examination

? Jltrasonic examination

= ea* detection) Pneumatic testing) ydro testing

%nfrared thermography


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" +coustic examination

>< (eutron radiography

$. "hat are the ad8antages of %T#

&he main advantages of (D& are

> &esting is possible !ithout affecting the functional capability of a

product.

; &he item is available even after testing !ithout any change in property.

E %n-process inspection possible.

igh speed testing is possible

# &he material property changes in various stages right from

manufacturing up to scrap can be trended.

? &ests are made directly on the ob@ects

= >


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? /*illed @udgment and experience are required to interpret

the indications

,. efine indication< flaw and defect.

%ndication3 +ny signal in the instrument.

Discontinuity3 +ny local variation in material continuity such as change

in geometry) structure) composition) or properties or presence of

cavities) holes or crac*s..

Fla!3 +ny indication that represents a discontinuity.

Defect3 +ny fla! that is more than the acceptance criteria.

. "hy defects occur in materials#

(o material is ideal. +ll materials are having discontinuity. 2ut our

requirement ,the degree of discontinuity decided !hether a material is

suitable for a particular application or not. &he defects in the materials

occur because of various metallurgical and or machining process to

!hich materials are sub@ected to.

/. "hat are the metallurgical process defects in the material#

Casting defects B inclusions) blo! holes) porosity) shrin*age fla!s)

cold shut) crac*

olling defects B lamination

Forging defects B burst) lap

=. "hat are the possible welding defects#

Helding defects B Kas inclusion) Porosity) /lag) ac* of fusion) ac*

of penetration) crac*s) under cut.

0. %ame a few the causes material failure during ser8ice.

> /tatic load

; Dynamic load


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E /ervice at high temperature

/tress above elastic limit

# Corrosive environment

? 9ibration

= +buses

;. "hat should one know before carrying out inspection in a system

> euipment > material#

> Ano!ledge of material properties.

; Ano!ledge of the processes the material has undergone.

E &he service condition.

&he various types and nature of defects that can occur due

to the above.

# &he acceptance criteria.

? +ccessibility of the component to perform (D&.

= &ype of equipment available.

&ime available.

" Cost involved.

!1. =ow the 8arious %T testing techniues can be classified#

/urface tests

Dye Penetrant &est ,DP&

'agnetic Particle &est ,'P&

9olumetric tests

adiographic &est ,&

Jltrasonic &est ,J&

0ddy Current &esting ,0C&


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!!. "hat is the principle of ?&T# "hy is it not applicable to porous

materials#

C+P%+L +C&%6(. Penetrant inspection mainly depends on the

ability of the liquid to !et the surface of a solid !or* piece or specimen

and flo! over that surface to form a continuous and reasonably

uniform coating) thus penetrating into the cavities that are open to the

surface. Capillary action is the phenomenon of rise or depression of

liquid in narro! cavities) !ithout need G application of any external

force. +s porous materials have many cavities that are open to surface

P& is not possible.

!$. "hat are the ad8antages and disad8antages of ?&T# %ame two

euipments > process where ?&T is carried out in our plant.

+D9+(&+K0/3 9ery simple) fast and easy to practice) can be used

as a preliminary test.

D%/+D9+(&+K0/3 Cannot be applied to porous materials1 (eeds

qualified personnel to do the @ob1 only discontinuities open to the

surface can be detected.

+pplication at A+P/ - &urbine blades) Held @oints

!'. "hat is 6&T# "hat are the ad8antages and limitations#

Hor*s on lea*age flux principle. Hherever there is an abrupt change

in the permeability of the materials) the magnetic flux lines see* the

high permeability path. &his property is utili7ed in the 'P&

+DD9+(&+K0/3 6n any ferromagnetic materials) Detects /urface as

!ell as sub-surface defects1 Quic* and relatively easy to apply.


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!2. "hy 3T should be a8oided in general# %ame one process >

euipment where 3T is done in KA&*.

'ainly because of the radiation ha7ard involved & shall be carried

out only !herever necessary.

& is done in A+P/ for all the !eld @oints of safety systems.

!0. "hat is @T# "hat are the ad8antages and limitations#

%n Jltrasonic testing high frequency sound !aves are used. &hey get

reflected !hen there is an acoustic impedance change in their path.

&his reflected ray is sensed by the sensor and interpreted for defects.

Change in acoustic impedance occurs in materials !hen there is a

discontinuity.

+dvantages3 /peed of inspection1 ease of automation1 good depth of

penetration1 single side accessibility of the ob@ect is enough1

immediate results1 relatively cheaper1 under !ater inspection is

possible.

imitations3 Complicated technology1 interpretation requires s*ill1

highly operator dependent1 in coarse grained materials) inspection

capability is very much reduced.

>". ifferentiate between @T and 3T.

/lno Parameter & J&

+ccessibility 2oth sides are reqd. 6ne side is enough


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$1. "hy in cast iron and stainless steel @T is not ad8isable#

Cast iron and stainless steel are of relatively coarse grains. ence the

acoustic !aves get easily scattered. ence the depth of penetration

!ill be less as !ell as more difficulty !ill be there in the interpretation

of the results.

$!. "hat is 7T# "hat are the ad8antages and limitations# %ame

two euipments where 7T is carried out in KA&*.

0C& is based on the principle of electro magnetic induction. Hhen

there is a discontinuity in materials) there !ill a change in electrical

impedance. &his change in impedance is detected as change in eddy

current and interpreted for defects.

+dvantages3 elatively speedy1 ease of automation1 simultaneous

multi-frequency testing is possible1 permanent record is available1 /ub-

surface fla!s can also be detected1

imitations3 Complicated1 interpretation requires s*ill1 only conducting

materials can be tested1 the depth of penetration is limited even in

conducting materials1 equipment are costlier.

/team generator tubes and heavy !ater heat exchangers tubes are

tested by J& in A+P/.

$$. "hy steam generator tube inspection is carried out by 7T#

/team generator tubes are sub@ected to various defects in their service

life. Failure of even one tube means mixing of heavy !ater !ith light

!ater and hence release of tritium into the atmosphere.

0C& is the only method !here many of its defects can be detected at

relatively less time. ence steam generator tubes are inspected by

0C&.

$'. "hat is leak testing# "hy =elium is used for the same#


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ea* testing is employed to detect lea*s and determine the rate at

!hich a liquid or gas !ill penetrate from inside a MtightM component or

assembly to the outside or vice versa as a result of the pressure

differential bet!een the t!o regions or of permeation of some!hat

extended barrier.

elium is used in lea* testing because of the follo!ing properties

> %t is light. hence can easily lea* through small openings

; %t is inert. ence it !ill not react !ith any other material.

E %ts availability in air is only # ppm. ence bac* ground

signal problems are less.

$,. ifferentiate &neumatic testing< =ydro testing

Pneumatic testing means testing any system G component !ith air ,or

any other gas such as nitrogen pressuri7ation and is done to chec*

gross lea*s existing in system G component. Hhereas ydro testing

means testing any system G component !ith !ater ,or any other fluid

such as D;6) oil pressuri7ation and is done to chec* integrity of

system G component.

Kenerally) Pneumatic testing is done prior to hydro testing *eeping in

mind the ris* involved in the later.

$. "hat is nfrared thermograph# "here is it used in KA&*#

+ll ob@ects around us emit radiations. +t ambient temperatures and

above these are primarily infra red radiations. &hough invisible to the

na*ed human eye )this 9ariation in the temperature of the surface of

the ob@ect can be visualuised fro m the thermal image of an ob@ect by

using suitable detector. &he image thus formed is called infra red

thermograph.


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%n A+P/) electrical equipment and installations are chec*ed for

abnormality by this method.

$/. "hat is neutron radiography# =ow is it different from or

gamma ray radiography#

(eutron radiography is one of the gro!ing (D& field. %n principle) it is

li*e conventional radiography. 2ut it has one difference. %n the

conventional radiography) relatively denser materials are detected in a

lighter material envelope. %n neutron radiography lighter materials

enveloped in denser materials can be detected.

$2. "hat is acoustic emission testing# "hat are the ad8antages and

limitations of the same#

+coustic emission technique is emerging as a po!erful tool for (D0 of

plant components such as pressure vessels) pipes) !elds) etc.

+coustic 0mission ,+0 is defined as the class of phenomenon

!hereby transient elastic !aves are generated by the rapid release of

energy from locali7ed sources li*e places of transient relaxation of

stress and strain field. Fracture) plastic deformation) crac* initiation

and gro!th are a fe! examples of the phenomenon resulting in +0.

+dvantages3 9ery small crac*s can be detected1 it is very sensitive to

locate discontinuity !hile they are gro!ing1 can detect signals in

electrically noisy area.

Disadvantages3 &he evaluation is complicated1 s*illed operator is

required.

$0. 6atch the following (*olution not gi8en)

/lno + 2

0ddy current inspection %ntegrated lea* chec*


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%n a (PP components are sub@ected to various extreme environments

li*e ioni7ing radiation) pressure) temperature. Failure of a component

may also lead to release of ioni7ing radiation and radioactive materials

to the public.

ence in vie! of the nature of the ha7ards involved it becomes

mandatory to *no! the condition of the component !hen in service. %t

can be replaced) in case the deterioration exceeds the limit before any

brea*age occurs.

,. "hat are the three criteria for including an item in *#

> 0nergy release ratio

; /tress intensity factor

E Fatigue usage factor

. "hat are the systems that are subCected to *#

> /ystems 8 systems connected thereto) containing the fluid that)

under normal conditions) directly transport heat from nuclear fuel)

!hose failure may result in release of radioactive substances ,e.g.

P&)'6D0+&6) 0CC/ 0&C

; /ystems essential for the safe shutdo!n of the reactor and G or

safe cooling of the nuclear fuel ,e.g. P//)///)+P+/ 0&C

E /ystems) !hose failureGdislodgement could @eopardi7e the integrity

of systems in item ,a or ,b or both. ,e.g. PCP fly !heel) Karter

spring etc

/. =ow different categories are decided in * programme# =ow the

programme is different for different categories#

2ased on fatigue usage factor 8 stress intensity) inspection

requirements are categori7ed as follo!s...

>. Category O+- >


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;. Category O2- EE$ quantity inspection in each %/% interval

E. Category OC>- (o periodic inspection required) unless

other!ise specified

. Category OC;- (o periodic inspection required

2. "hy coolant channel inspection is important for &="3#

Coolant channel is a component in a (PP !hich is sub@ect to the !orst

environment. %t !or*s under extreme temperature) radiation and

pressure. 'oreover !e do not have the prior *no!ledge of the

behaviour of Zircaloy under this environment. ence it is mandatory to

*no! the integrity of the coolant tubes !hen in service.

%n addition) our safety concept on coolant channel guarantees that M

coolant channel !ill lea* before brea*M. ence the reactor can be

brought to safe shut do!n before brea*age. &o ensure that this safety

concept is guaranteed coolant channel inspection is mandatory.

0. 4n what basis coolant channel to be inspected is decided#

&he basis on !hich the coolant tube to be inspected is decided are

> Creep contact time ; Fuel failure history

E %nitial hydrogen (earness to ad@usters

# Creep abnormalities ? /tation specific problems

= Flux level

;. "hat are the parameters that are inspected# "hat are the

inspection techniues used#

/lno Parameter ,P&- Pressure tube1 C&-

calandria tube

%nspection technique

P& !all thic*ness J&


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24/26

; Change of coolant tube material from Zircaloy B ; to Zr B ;.#$

(b.

E +nnulus gas monitoring system ,Closed annulus

Quadruple melting process in the coolant tune manufacturing.

# 0nhanced inspection methods to eliminate defects.

? %mproved specifications ,Pl. /ee Q no3 in Q+ concepts.

!'. "hat is 763# "hy is it reuired# "hy KA&* -$ may not ha8e

763#

0'CC stands for 0n-mass coolant channel replacement. &he life of

the coolant tube ,P& is expected to be >> 0FPLs. +fter that !e cannot

guarantee for Mea* before brea* M safety concept. &his is the situation

for the reactors built up to A+P/ >. ence all the coolant channels

have to be replaced !ith ne! ones.

2ut for the reactors from A+P/ ; on!ards because of the

improvements carried out in manufacturing) inspection 8 in site the life

is expected to be E< 0FPLs. &he sole decisive limiting factor for the

life of the coolant tube is no! Mydrogen concentrationM in that.

!,. "hy of late secondary cycle thickness gauging become

important#

&his is because of a phenomenon called Flo! +ssisted Corrosion

,F+C. Hhere there is high flo!) the erosion of the material is more.

/ome of the conditions necessary to cause erosionGcorrosion damage

include a susceptible pipe material ,carbon steel ) piping layout that

results in high local turbulence levels ,such as near valves or no77les)

do!nstream of orifices) etc. ) variables such as !ater chemistry , p

and oxygen content) t!o phase flo! conditions) fluid velocityGlocal


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velocity) system temperature) operating condition etc.

0rosionGcorrosion damage due to these conditions has occurred in

single-phase !ater and t!o-phase ,!ater and steam systems.

!. "hat are the * acti8ities carried out on &=T feeders#

> Feeder thic*ness measurement B elbo!) pipe ,near graylo*)

header) header stub

; Fla! detection B !eld @oints of pipe and elbo! ,near graylo*

E Fla! detection - Dissimilar !eld @oint ,%nconel orifice

!/. "hat is creep# "hat is irradiation growth# "hat is radiation

enhanced creep#

Plastic deformation of material under stress and temperature is called

creep. %rradiation of material enhances the creep rate. &his enhanced

creep is called radiation enhanced creep.

!2. %ame the * carried out in *team generators# %ame the cause

for the failure of *5 tubes in KA&*.

/K tubes B 0ddy current testing

/K manhole fasteners B DP&G 'P&

/K shell !eld - 'P& 8 J& fla! detection

/K secondary side B 9isual inspection through hand hole.

&he main cause for failure of /K tubes in A+P/ is the presence of

foreign material. &here !as no generic degradation of tubes.

!0. 7:plain in short the relationship between plant chemistry control

and the plant *.

Plant chemistry control plays an important role in the aging of plant

components) equipments and systems. %/% is carried out on the plant

components) equipments and systems to asses the remaining life.


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ence plant chemistry control in a !ay decides ho!) !here and !hen

%/% is to be done.

For example) due to some reason if the C6;in the annulus gas is

containing more air) it !ill result in more pic* up of hydrogen in P&.

&his !ill result in more inspections on P& and more no of P&

inspections.

He *no! that the p and dissolved oxygen content affects the F+C.

hence they) in turn) decides the quantum of %/% to be done.

&he Cu B (i condenser tubes deposits Cu in the secondary side of /K

tubes. &his poses a problem in the %/% of /K tubes as false failure

indication. &his is another example of the relationship bet!een plant

chemistry control and %/%.

19. 6atch the following (*olution not gi8en)

/ln

o+ 2

0ddy current inspection Coolant channel

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