ML19308C364

Communications Needs of Nuclear Power Plant Operator, Presented at IEEE Power Engineering Soc Summer Meeting on 780716-24

ML19308C364
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Site:	Crane
Issue date:	02/02/1978
From:	Pack R, Seminara J ELECTRIC POWER RESEARCH INSTITUTE, LOCKHEED MISSILES & SPACE CO., INC.
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?J. L.,Seminara.

R. W. Pack 1Lockheed Missiles and Space Corp.-

Electric Power Research Institute -

-L 4 Sunnyvale, CA '

Palo Alto, CA:

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~iBSTRACT:

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MaclearLpower plant' operators.and: trainers were -

Jcommunication system?". The responses to this question

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l' ninterviewed 'to examine human factors considerations -

' reveal the need'for major improvements in the design of associated with control ' room operation. 40ne part of-communication systems. Eighty-one percent of those n

1nterviewed pointed to inadequacies-in their ability to -

xthis review dealt with'cocraunications. J 0ver eighty

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percent cf the interview sample reported' problems and.

corriunicate with plant personnel.outside the control frustrations with existing comunication systems. The-s room. -These problems stem mainly from the inability of y nature of the problems uncovered and > future research -

ipaging systems to overcome the extremely high ant)fent 1

gneeds are the subjects of. this paper.

1 noise levels within'many sections of the plant.'

INTRODUCTION' EFFECTIVENESS OF COMMlalCATION SYSTEMS IIn nid-1975 the Electric Power Research Institute '

The five power plants varied in the nature, number,

" awarded Lockheed an 18 renth contract entitled: " Human -

and configuration of communications devices and chan-Factors Review of Nuclear Power Plant Control Room nels available to the control room operators and the m

Design", described in (1,2). The human factors aspects.

auxiliary operators in the plant._ The situations un-of five representative nuclear power plants were eval- ' covered at the five plants is described below.

'uated using such methods as a checklist guided obser-cvation system. structured interviews with forty oper-;

plant A 3 aters 'ar.d : thirteen trainers, 260 hours0.00301 days <br />0.0722 hours <br />4.298942e-4 weeks <br />9.893e-5 months <br /> of direct ob '

The control room operator has telephones and access fservatices of operator behavior in control rooms and to a public address paging system. The paging system sirulators, task analyses,-procedure evaluations, and is neither reliable nor always audible in high noise

-. historical error analyses, environments. The person the operator is trying to

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- reach may be weadng ear mums & dse Wectkn.

The study explored man-machine interfaces in the Moreover, the operator cannot override other messages

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cortrol room including the ' layout of control rooms, the on the paging system and his messages, when superim-Ldesign cf control boards, anthropometric factors, posed on others, will be garbled. ' The telephone is not

'cocing practices.' and the potential for accidental effective as.a-backup system since the men in the field C ' activation of controls. Onffacet of this work, which move about and the operator does not always know the

'this ;acer will restrict.itself to, was an examination specific phone location at which they can be reached.

- of comungcation. systems.

Furthermore, the operators claim that with the loss of power they lose public address communications.

Ihe control room is.the hub of communications

'activitynin the plant.

C. J. Hodges Jr.- (3) of the The reverse problem, that of incoming connunications -

- Te essee Valley Authority sumarized the situation as deficiencies, is also reported. One operator states:

ces.

"When we sound the EVACUATE CONTAINMENT ALARM there is The control room operator is the key comunica-no feedback that~ the page or the audible' alarm has been

- ti*ns > tai en the unit. No raintenance, tests ' or op-heard by the men in that area. We can expose people -

- eratiens'should be perforried until he is informed. He to radiation because there* is no way for the operator sie the cisseminator of. inforration from the shift

' to know that the people in the contair. ment can hear the

. su;er.isor to operators under his direction. The1 alarm."

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ccT:nications required are both written and verbal,

'ard itds vital that he keep a coralete and accurate The operators at this plant see the need for.

" tweeters " devices that sound in the protective ear Ele;.' 1 Ar operator who is ' unwilling or unable to com-.

muffs,'and'" beepers," radio page devices worn by men r;eicate-is,an accident looking for a place-to happen."

in the field. They also feel that a. redundant power

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Titi these'words in mind, one of the questions put supply for the public address page system is needed.

' L to cperators and trainers as part of the structured J intervie.< reads as follows:."The operator has need to Plant B

, ccTmicate effectively with others in the plant.. What The operators in the Plant B control room have four pircreverents,'if. any, are required with regard to your primary means for reaching outside operators: a page

. phone, ordinary telephone lines, portable two-way ra-1 dios, and bell signals coupled with red lights in high P.ticce 1 rbtM $2.50' Nonnesben $3.00 noise areas, referred to as the Auto Call system for

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AC Mceib:s $2,00 ;

. key people.

4 The operators at this plant also found the phone page

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'A paper reur-mded and aportwed byL.

system unreliable for reaching people in.hich noise 4

the

?cuer Generatim Ca=ittee of the M Pcuer -

areas. They feel that an increased distribution of

~".E..;inee:hg Society for presentatim at the M PES i

? speakers is needed..There were a h o complaints that (S=rm: 'inetingples Angeles, CAi hly 16-21, 1978.

portable radio systems were too bulky and were inef-Wra: script sub=itted February 2,~ 1978; made avail-fective. 0thers feel tha*. the number of phones in the (cble fer printing' April.-2E,11978.

plant is insufficient. The Auto Call system is also

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MMpa upreli:bli for; reaching outside pers:nnel4 Some/ c

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afithe Vcoemunicatirns problems-cr frustraticas,that the opera-t 18k.

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& [ %joperators, recosmonded that pocketipage systems,beaddedJ ' torLis;likely5 o encounter 1n the operatio 7

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to the;present; list. of communications: devices. - ;

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• k-TABSI2 $ FREQUENCY OF-COPMJNICATIONS PROBLEMS i 9

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- tREPORTED BY OPERATOR $1

%g3MThis:controliroom; included a. phone page: system.;they< CATEGORY OF: PROBLEM -

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. ' J, tusualstelephone6and aWhends-off"Jtelephone-speaker J

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%g g$ arrangement.VThese: operators:alsol remarked that the -Di "A Inabilit/to connunicat[withl 28.

y 34 page system was-unreliable in:high noise:areasn Some

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• complained that~ they got; cross-talk:and low-volume. _ i; personnel located in high noise-r

' Em iproblemsLcr phone lines. pThe operator. had to yell:toi, amasy :

%C Fbeinderstood on the " hands off"fphone system. &This ;

j B, Requirement for a'dditional'-

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i % plant had the largest' number. of auxiliary operatorsd Qforms of.conpunication devicesi 4

V[{1p ytherefore,wthe communication needs were greater than 4

% y g under:the control, room. operator?s supervision and.m,- y Q ff M N c M k 32 J15'L Scoverage 'with existing'conmunications; A:- ;at other plants. LNormally.there were.two operators--

d@ Jin the' control room even though-~only..one operator-is:

> system

- M _ 3 required by= tech' specs t When two men are in the con -

D DM Unreli able J or; faul ty. 'connuni-

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%G trol room one goes outxinto:the plant when communi-s Ycations equipment F

( g [ cations withloutsi.de personnel: break ~down.x Howeverp Ei [ Arrangement IfIconnunications 3i 4-

_ q ;w en on y one man. s. n t e con rol room.mthis option l 4 equipment in, the control room h

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, y V41s'pollonger'available and the lone operator feelsj

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s F. ; Communications system control.

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Wy@NyiThe' operators suggested a1better distribution of '

as f fespecially. vulnerable t '

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1 1problemsJ a

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W J[*~ Miscellaneous 6

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% phocesi.in the plant. (More11sportant Jthey felt the-a

' UdM need for a combined audio-visual system with.which by; Total-82-1001=

y + 7 dialing a special-code on 'an emergency call basisR L

_ 6 Q ' dbothia visual' alert and a coded horn message would be:

Ni t category of complaints. 34%, had to do 7,j T; transmitted;throughythe plant s high; noise areas. ac

' with the problem of reaching people or connunicating 2.A'

+r with them in the high noise areas of the plant, e.g.'

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."In the reactor building.11t:is impossible to hear the P

gM D gWe - 70peratorslat.this plant have a; paging system, tele-f paging system'" <The necessity for. protective ear muffs 7 > ' 1phoce, walkie-talkies and an Auto-Call-signal bell'

' in such areas compounded the problem.

T ' Msystem that:is available by dialing the phone. There e

I; i Mare also visual $ signals in high noise areas. - Despite The second category of comments, 275,'~ hadito doj.

! J3thessfultiple channels for reaching auxiliary opere with a perceived necessity for. additional ~ or alternate.

e datersdall of the operators land trainersiinterviewed '

. forms of comunication or attention getting devices

? agreed that the communciation'lystem.is inadequate for ; allowing the operator? to reach and converse with plant.

ly, t higUnoise areas. -

personnel in high noise areas. This category of com-l

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..ments is not entirely independent of-the complaints a

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. J Spedfically/the complaints were as fol. lows:

~ reported in the first category since they are a ~deriva-Ein cplant ;;ersonnel. sway from their stations do not hear tive of the high'anbient noise level environment..The.

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, the' phene; ring; the PA system is frequently garbled _

. major recomendations rade by operators 'for alleviating -

!~"W idue:to; echoes and can't be heard inlhigh; noise areas; these problems'were*

O S he Auto Callibells can't be' heard; and the visual-t

" $sig*als ire so placed that-they. 90 unnoticedi

- Tweeters incorporated.into protective ear. muffs-

- Pocket page systems or pocket beepers m.

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My one auxiliary operato'rfis assigned per gen;

< - Readily observable visualjsignals to supplement N

erasiri auditory cues kg~ ' iget;nid; Onit~ and as one ~ operator said,:"If you can't.

- Walkie-talkies tol respond, sometimes;you just stand and watch Ja e slant go down.""Another says plaintively,' Ne have The' third category of, problems reported ' 15%, were

~th p*cMed renching people in 'hich noise areas. It's a:

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e ? ad: feeling when yo_u can't reach your mang-a lonely

- concerned with inadecaute communications coverage...

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throughout the plant, i.e., these coments recomended a f,g g n 4e /,^.

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. beefing 'up the existing system rather'.then calling (

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for new' channels of comunications. ' Among the bene :

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k...1 ficial steps pointed to'were:

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Je ihe !cperators at1this plant'had-the fewest comi

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plaintsiregarding their connunications system 4 -'They L 'More phone stations ifndicated the availability of page phones'and five/

e More page: speakers;-'e.g., "in' the lun'chroom where -

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Steleph ne lines. 4The ' operators stated,that the auxiliary operations tend to congregate" s

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M corrunicationesystem was. recently adjusted. 7 Spe'akers :

l'- Additional: phone lines.

$" J ' dthat had been disabled or turned.down.during construc '

- Direct phone lines without dialing-9e

_ Stieneres7 turned up;realiloud."1 Since these improve-E-- Paging phones in areas not presently. covered, =

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' % ;;irents were made', the operators 1 generally! felt.there" Je.g. Radiation Monitoring panel and Service ?

. ywere;ngproblems in;' reaching; auxiliary operators. ~

< Water. panel; 3

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N[E 2.gDEfkTIVh FREQUENCUI)F COMNICATIONS hROBLEMS

' JFaulty:or unreliable'comunication channels -

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. ' accounted;for IIT of the. complaints. -Included in thisj H

j?T fn - E ~iln all,'L82-specific complaints were! reported by thef icategory were;

.d' hi'3The'prependerance:of?these conplaints= were made by.the :,

V% -interviess&mple in'the : categories showniin Table I. e :n l. f ~_

S o Loss ~ of PA comunications with the loss of primary

' N N d, for*,yncperators ?interviewedpas opposed to the. thirteen.

ipowerf...

Mhstrainer$@ Apparentlyi present control room' simulators ~

o-Radio systemsuthat were unreliable or. "had trouble -

S M dc cot; provide realistic.sinulation.of the types:of M ' figetting around concrete"f

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o Cross talk'and low volume in phone circuits o Excessive echo in the PA system

' The remaining low frequency categories of com-

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plaints dealt with the arrangement of comunications nith D!!

goar in the control room, the desire for improved con-1D:U:D::.:n-ID:D:D:D 't trol options and such miscellaneous concerns as the 1 :

extra burden placed on the comunications system when I!'DWIDI!' J I'

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!D D cc. tractors swarmed the plant during the construction '

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[G CG@ @EGECy p of an additional generating unit. These categories of L.k u J,,

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.cencern are addressed separately below.

d Ig h.r-WaNGEt'ENT OF COMMUNICATIONS EQUIPMENT IN THE

S tr; CONTROL ROOM

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A representative arrangement of comunicatiens f i goar :n the operator's desk is shown in Fig.1. Because the cperator spends a considerable portion of his time 2

comunicating with others, the manner in which his com-

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r:unications equipment is integrated into the control

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roon has an important impact on his effectiveness.

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This is readily observable in Fig. 2.

In this control rocm, the phones and the page systems are arranged at tbo cperator's desk so that the operator sits with hir be'ck to the control boards most of the time. This Fig. 2.

Poerly placed comunications system on the crran;erent is extremely undesirable from the human operator's desk requires him to sit with his facters standpoint. Fortunately this problem was back to the control boards when he comun-found at only one of the plants visited.

icates with others.

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g room be equipped with all incoming phone lines.

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- 4, During a plant trip, or whenever the plant is ex-Mi W

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periencing trouble, the number of phone calls to the control room increases considerably. This adds a comunication burden to an operator who feels his pri-mary task should be to attend to the emergency at hand rather than explaining the situation to others. In

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cases where the control room houses multiple-unit con-N trol boards, the operator controlling the quiescent unit pitches in with the comunications task, thereby relieving the operator who is coping with the emer-gency (see Fig. 5). Often, it is the center desk operator in a multi-unit control room (see Fig. 6) who Tig.

• Fa;resentative arrar.ger.ent :f comunications assumes prirrary responsibility for corrunications epi;nect on the ::strol re 7 eperator's desk.

during emergencies and with the outside during back shifts. Coping with ortside calls when the center desk operator is relieving one of the unit operators or when a test or evolution is in progress is a nuisance and distraction for the center desk operator. Perhaps l

a sw.itchboard operator is regt.1 red to handle incoming

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calls around the clock.

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t.other problem is that the operator must have MISCELLANEOUS COMMUNICATIONS PROBLEMS a: cess tc the control boards while corriunicating with l

ctrars, e.g. during maintenance activities (see Figs, A few operators stated quite openly that a problem l

32-d2).

ehe distribution of phone and the length of sometimes encountered in reaching auxiliary operators

t: e cords proved a problem in sore plants. For ex-was due to a refusal to answer the control room oper-ar:.e. at ene plant an operator pointed out the lack ator's page, perhaps as the close of shift neared. The

.cf a raging phone on the radiation monitoring panel auxiliary operator presumably did not want to become are t*e service water panel. Both of these panels are involved in an activity that might cause him to delay

.ae re cved from the primary control board area and his leaving the plant on tine. It was, of course, not

. ; e c:erator s desk phones.

possible to verify the accuracy of this complaint. In any case, this was not a widespread concern. -However,

'- c-e multi-unit control room, the ope' ators if it is an accurate observation, remedial action is c---$ned + hat incoming phone lines were divided among required because operators have reported instances This required the operator where the plant has gone down for lack of timely sup-E*=~e["eratingstations.

EIc e from his station from time to time to comun-port from an auxiliary operator. Delays are also re-

• b5$e at another post within the control room. They ported in locating or reaching a shift supervisor who S

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rea.ded that each separate tation in the control is away from the control room.

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In multi-unit control rc:tss the operators 8i,,,

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comunicatio::s chores becone a burden during

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The Center Lesk Operater provides backup 55 55 55 55 55 for unit operat0rs i" sone mvlti-unit control F/1 g

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~he distribution of ;n:nes and cerds al:ng the With the overwhelming majority of the interview

trol beards is a pr:ble. at sone plants.

sample reporting comunications problems, it is evident that further attention should be directed at both re-medying existing prcblems and in designing rore ef-fective systems for new plants. If the high noise environments in the plant present insuperable problems, 3 reications is hich radiaticn areas of the then it is clear that the design of control rooms needs

-la-- -f'er special problems 'cr raintenance personnel, to reflect a greater degree of central control rather YreN is a concern for licitir,c -he spread of contamin-than remote control of events through the intervention att0n f*:. gicved hands to t e' exposed face. The com-of hard-to-reach auxiliary operators. The operators cn te'e:n re which brines hand and face in proxicity relate that, in times of emergency, there is no rore centaninate facial areas. An alternative to frustrating experience than to be unable to reach their k

k n:s "t heid telephone see s ir.dicated.

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manpower resources in the field. The consequences of e nar b

inadequate c:iirnunications can obviously ha.e s:rious in-Tcst methods f r evaluating sp;ech intilligibility

' plications. F4110 wing an incident that resulted in a associated with military voice connunication equipment plant outage, one operator observed: " Power supplies should be considered for evaluating nuclear power plant were out that could have been put into service in ten comunications. Standard tests exist with phonetically minutes with connunications." Considering that the loss balanced w rd lists and special sentence lists as de-of ore day's power generation can cost $250,000 and up-scribed in (4 and 5). These tests allow a determination, 1

wards, we need not belabor the point.

respectively,of " percent word intelligibility" and "per-i cent sentence intelligibility." Speech intelligibility

. The results of this study serve only as a starting of each test list of words er sentences is computed by point. While it is evident that communications problems dividing the nurber of correctly interpreted words or exist, we cannot rely solely on operator recomendations sentences by the total number of test items presented.

for solutions. For example, some operators recommend A speech intelligibility score of ninety percent is con-the addition of additional communication channels that sidered adequate for most communication systems. A have apparently not solved similar problems in other higher standard may be required for nuclear power plant plants where such devices exist. Many of the problems operations, and proposed solutions are, no doubt, plant-specific and each plant needs to be reviewed on a case-by-case It may also be necessary to review hearing standards

. basis for remedial actions. Also, at least one plant applied in selecting and requalifying operators and seemed relatively free of communications problems. It maintenance personnel. One specific case impels us to would be useful to study such plants in greater depth

. maxe this recor:rendation. In discussing the nurber and to determine how ccmmunications difficulties have been types of different auditory warnings presented in the avoided. For example, some plants utilize sound iso-control room, one operator observed that one particular lation devices as shown in Fig. 7, while others do not warning cue seened to elude him. It was pitched at a employ such techniques.

frequency that he could not readily hear. He knew of its existance only when it perservered for about one-half hour and he ". tarted to develop a headache. This fT -- E,f" 1 dl

'I !"LE R ] fj p' case, we are happy to report, was unique.

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REFERENCES.

1 i

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J.L. Seminara, W.R. Gonzaleg, and S.0. Parsons, f

di

" Human Factors Review of Nuclear Power Plant Control Room Design," Electric power Research Institute, EPRI 4

NP-309, Noverber 1976.

(2)

J.L. Seminara, R.W: Pack W.R. Gonzalez, and Sl0.

l' f

I Parsons, " Human Factors in the Nuclear Control Room,"

4 g7 pp. 774-790.

Nuclear Safety, vol.18-5, Noverber-December,1977, yjg (3)

R.W. Pack, Ed., " Power Plant Operator Selection l

4A Methoos," Electric power Pesearch Institute Conference

' M' 4 Proceedings, EPRI SR 28, Speical Report, January 1976, pp. 5-11.

g t' m;. ;

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(4)

T.B. Malone and S.W. Shenk. "uman Facetrs Test and

/

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Evaluation Manual," Volumes I. II and III pacific 4

' J Missile Test Center, TP-76-11 A,B, & C, 30 September gg 1977 Vol. II pp. 101-102, Vol. III, pp. 59 87.

(5)

H.P. Van Cott and R.G. Kinkade Eds., Human Fir. 7.

_o=3 isolatien bcoth used to fa:111 tate Engineering Guide.c ipment Desien Washington, D.C.

cc unications in noisey plant areas.

U.S. Government Print-r Of fice, T972, pp.161-226.

5