ML19325F092
| ML19325F092 | |
| Person / Time | |
|---|---|
| Issue date: | 08/28/1989 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| References | |
| TASK-PINC, TASK-SE SECY-89-266, NUDOCS 8911140070 | |
| Download: ML19325F092 (21) | |
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August 28, 1989 SECY-89-266' For:
The Com b NnErs From:
Jr.nes M. Taylor Acting Executive Director for Operations
Subject:
EVENT SEVERITY SCALES FOR COMMERCIAL POWER REACTOR FACILITIES o
A
Purpose:
To inform the Commission of a proposed NRC position
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regarding international development of an event severity scale for commercial power reactor facilities.
Backaround:
An increased interest in the development of event severity scales for commercial power reactor facilities has been recently expressed by various national and international organizations.
Committees have been formed by the International Atomic Energy Agency (IAEA) and the Organization for Economic Cooperation and Development (0 ECD)
Nuclear Energy Agency (NEA) to investigate the possible needs and uses of severity scales.
Several meetings have m
been held :.nd several more are planned for the near future.
Individual member countries of these organizations have also studied the potential development of severity scales and France and Japan have implemented severity scale systems on a trial basis.
NRC personnel have attended these international mactings, and have evaluated the potential benefits and impacts associated with implementation of an intere tional severity scale.
A severity scale for events at commercial power reactor facilities is intended to categorize events ranging from routine occurrences to severe accidents.
To date, the primary purpose for developing severity scales has been to facilitate communication to the media and improve public m-understanding of the significance of event 3 at commercial i
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power reactor' facilities.
Severity scales offer a proposed solution for countries wanting or r.eeding to improve communications with the media and the public regarding operational events.
In this regard, however, it is important to point out that the U.S. has benefitted from a long-term policy of extensive and open communications to the media and public on all operational events at U.S. nuclear power plants.
The characteristics of an international scale and the classification criteria are currently under review by a joint IAEA/NEA committee.
For example, experience to date with the scales developed in France and Japan and the U.S.
system are part of the review by the IAEA/NEA committee.
The French severity scale system was developed to clarify the significance of nuclear reactor incidents and accidents to the media and general public.
The scale is graduated from 1 to 6 in ascending order of severity.
A more detailed description of the French scale and eports regarding the trial period are provided as Enclosure 1.
The structure of the Japanese severity scale is similar to the scale developed in France.
The Japanese scale consists of nine levels.
A more detailed description of the Japanese scale is provided as Enclosure 2.
The U.S. system of reporting and classifying events at nuclear facilities is comprised of reporting regulations, four emergency response categories, and the subsequent evaluation of events by the NRC and nuclear industry.
The U.S. system identifies a significance or safety perspective with consideration given to the release of radioactive material, personnel exposure, degradation in facility safety systems, and ot.ier criteria.
A major advantage of the U.S.
approach is that the same reporting system and emergency classes are used for incident response action and for public information purposes.
A more detailed description of the U.S. system is provided as Enclosure 3.
Discussion:
Since most countries have well established systems for event rep ' ting to and event evaluation by the regulating a,encies, the severity scale systems (including France and Japan) are being developed solely to serve public information goals.
The intent is for the public to become familiar with the scale, much lite the familiarity with the Richter scele for earthquakes, and thereby have a better understanding of the significance of events reported by the media or described in pub 1h.l> available information.
The existirg technical and regd 3ry functions, including emergency response, are cons rared to be separate functions from implementation of severity scaies.
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t The principal U.S. connent provided at the meetings held to 7
date has been that any severity scale system developed for public information purposes should be as consistent as l
possible with the emergency response classifications.
Having two separate event classification systems, one for emergency respcnse by technical authorities and the other for public informatien, could cause confucion, and, in fact, could cause the opposite effect than is intentied. Another coment expressed by the U.S. participants has been that implementation of a severity scale concept ray be useful and appropriate for those countries where there are public concerns regarding the extent of communication about operating events, and as a result, new initiatives are desired to improve public comunication. However, for those countries which have well established public notification systems and open access to information regarding nuclear facility events, the cost and effort to implement a new severity scale, particularly one that does not correspond to established emergency classifications, is not considered justified and may, in fact, have an adverse 'apact.
1 For example, the existing U.S. system of reporting anc responcing to emergencies has been evolving for nearly a decade via the rulemaking process, actual use in response to events, and the many exercises conducted and planned. The system is well entrenched in the training and procedures usec by licensees, state / local governments, anc other federtl Lyncies.
Replacement of the existing emergency
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response system is thus not considered by the staff as practichl or appropriate.
Therefore, the primary question regarding implementation of such a scale in the U.S. revolves sround the need or advan-tages for a parallel ano separate scale for public infor-mation purposes.
Introduction of a numerical severity scale for public notifications, independent from emergency response classificaticns, introduces various problems and opportuni-ties for confusion.
The first problem to resolve would be which party in the process should assign the severity rating to events. Licensee classification would be the most i
timely, but for other reasons is probably not practical.
These reasons include a potential perception of conflict of interest, inherent inconsistencies due to differing judg-ments, and the need for rulemaking if licensee classification was to be mandatory.
Representatives of the Nuclear Utility Management and Resources Comittee noted that an industry task force reviewing emergency action levels has concluded that implementation of accident severity sct.les in the U.S.
does nut appter to offer any advantbges over the existing system and is not supported.
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'The Commi sioners '
f The NRC classification of events for such a numerical severity scale would likely involve a-delay of several days.
Consequently, in order to promptly inform the public of significant events, it would be necessary to maintain the current sys',em of licensee and/or NRC press releases and press briefings for events involving noteworthy safety significance or public interest.
Further, implementation of a severity scale would overlay the current event classifi-cations suun as Significant Event classifications reported in the Performance Indicator program and Abnormal Occurrence classifications reported quarterlyfto Congress.
These types of evaluations and classifications are available to the public via reports and the Public Document Room, but are not routinely the subject of individual press releases.
'b Additionally, it was noted that should ar international scale be developed for use in international communications, it would be possible to provide a pre-established conversion relationship between the existing U.S. event classification and the proposed international scale.
Summary:
The evaluation of the possible use of severity scales in the U.S. concluded that the benefit would be negligible and there is a potential for confusion and adverse impacts on existing emergency response repot ting and response systems.
Thus, the cost and effort of implementatira of a replacement or parallel scale is not considered justified.
As a result, the proposed U.S. position to be expressed at future IAEA/NEA meetings is as follows:
1.
The U.S. supports the implementation of such systems for countries without established public notification systems.
2.
Severity scales should be the same or at least consistent with emergency response classifications to reduce the likelihood of confusion in a true emergency.
3.
The U.S. wishes to be involved in the discussions of severity scales, but is unlikely to adopt such a system for routine use.
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The Commissioners.
Recommendation:
That the Commission note that the staff intends to develop prtientations and express the above positions in upcoming IAEA/NEA meetings and other forums discussing numerical severity scales unless otherwise instructed by the Commission.
The first of these meetings is IAEA Reactor Safety meeting the week of September 25, 1989.
i J n.e M. Taylor A
ng Executive Director for Operations
Enclosures:
1.
Description of French Severity Scale 2.
Description of Japanese Severity Scale 3.
Description of U.S. Reporting and Emergency Response Systems l
SECY NOTE:
In the absence of instructions to the contrary, SECY will notify the staff on Wednesday, September 13, 1989, that the Commission, by negative consent, assents to the action proposed in this paper.
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DESCRIPTION Of THE SCALE
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This scale is designad to bring found particularly in the field of fied at the top end of the scale (le-about greater mutual understanding nuclear safety regulation, vel 6), the least severe incidents being and harmony between speciahsts o.
Its main purpost is to avoid misun, situated at 15e bottom (level 1),
the nutiear industry and pubhc opi-derstandings and to clanfy the pee.
The accident levels are differentia-nion. To do so, it uses a simple and sentation of nuclear incidents and ted according to the degree of risk of comprehensible classification of the accidents in the eyes of all. Events radioactive release outside the instal.
Seventy of nuclear incidents and acci-which are not associated with the laten where the accident has occured, dents.
nuclear o ration of the installations it is not intended to be either defi-wi.ll there e be classified as 'off sca.
The term incidents apphes to those eve:.ts in which the level of radioac-nitive or restnctsve. It will first of all tive release is less than the authorized be apphed on a inal basis, it can then On 20th April 1988, the minister in annual limit. It also covers operational be modified in accordance with the charge of industry announced the problems which, although not invol-reactions of the two parties concer. implementation of this scale for inct-ving direct radcactive nsk, may indi-ients and accidents occunng in cate weaknesses in the installation ned : nuclear speciahsts and pubht
- opinion, iuckar pown plants. H can be refn. which should be remedied, red to by the pubhc.
_This scale Mee nc t renlue tht Chi.,
lacidents telated to nuclear opera-l tena already m force for the definition Reading the scale tion the seventy of which is less than i ano tecnnical gnalyusTo( rEclear inci-The scale is graduated from 1 to 6.
level 1 may also be announced but cents and acudents, and which are The most severe accidents are classi-will be classified as *below scale *,
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i HOW TO USE THE SCALE i
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i Generai ruies it is not always possible to give a -Level 5 covers accidents which This scale does not replace tne cei.
<ery precise definition cf the hmits of effectrvely lead to considerable ra-teria adopted for the definition of each category in such a general classi-dioactive releases into the environ.
events relating to the safety of nucle,tr fication of complex technical events, ment (Windwale) and a;so those in !
power plants which must be declared ludgement plays a certain part in the w+iich the releases remain at the I
by the operators (ref. SIN /1732 82 u exing of levels. Where necessary, a ' threat
- stage but which are however s
l 7th Apnl 1982). These declaratios., tustmcation of the class;fication can considered sufficiently senous for remains an integral pr.rt of the proce. usefully be added to the descnpton protectrve measures outside the site dures to which the operators are sub-of facts and consequences, to be taken (Three Mile island).
jected by the safety authorities, the An event which possesses characte-pnmary purpose of which is the detal ristics common to several level! is -Level 4 comprises three categories i
led technecal analysis of operatonal classified in the most severe level, of acodents, the effects of which experience as a whole,.nd the resd-remain limited to the installation itself ting lessoas to be drawn for safety.
Comments on the levels and to its per,onnel :
The scale defines and classifies,la The table compnses colum ded *cnteria and *exarnples,ns hea.
accidents resulting in significant but decreasing order of seventy, those spece-limited radioactive releases which do events relating to nuclear safety which are systematically and rapidly fying the definiton of the levels.
not require measures for the protec-brought to tne attentMn of the gene.
tion of the public and the environ.
ment. The reference values taken, in ral publec by the operators and the The three " accident
- levels (6,5,4)
I authorities.
are defined by reference to their terms of order cf magnitude, are the authorized annual release rates, el l
radiological consequences accordiri to extenal r&ase cntena.
- acodent* - :<?ig partial damage to l l ClassiGcation directives and com-the core of the installaton, which is menM
" ' 5 #'Ci"IY 5 " ' 'O " P5 "
- l l General
-Level 6 refers to an ' equivalence
- se sous threat to the exterior but of fission products released in terms w ch necessitate difficult repairs.,
I Certam events which will naturally of radiological nouousness in relation with radiological protection pro-i be published do not come into any of to iodine 131 which is the most signifi-5' the scale s categones (eg, deaths, pet. cant radonuchde for short term sons injured or damage to propeny consequences. This presentation is a - accidents resulting in the exposure L in a non nuclear part of the mstalla-simphtied one. In reakty, it will be of plant personnel to ionizmg radia-1;cns of the site). This information necessary to take into account all the tion at doses which require the need should figure exphcity in tha corres-radioactive products rel.used and for speciahted medical treatment to pondmg publicatons : non nuclear evaiuate their noxiousness m terms be considered, i.e. exposure above a event, off sca8< t.n the seve tv scale, of attack routes and time.
threshold cf 100 rem (1 Svt
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i he these *' incident" levels 0,2,1)
. common mode failures in systems. abnormal dew 6opment of an auto-
> refer to the *delence m ciepth' ' important to safety, matic shutdown sequence, em mstalle I for the preventen of
- idents and which, althous:h main.. independent ms haple failures of sys-
- tripping of the fire protection m the.
tems important to safety durmg one nuclear island.
' ing its overall efficacy, is more or single sequence.
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l 8"cusly damaged.
. human errors in cases where they The events occunng dunng the ;
l avel 3 c;mprises 4 categones of revcal deficiencies in
- safety culture-penod between fuel loadmg and dents :
liable to have consequences, power merease (before the formation
. fires in she nuclear island involving of signWeant quanmes oMisson pro.
cidems iving nse to low lesels of relatively si nitscant enmal resaur-ducts) will, deptadmg on each indivi.
trnal re ase, i.e., several tenths ces(interna emergencyplan leveill, a 5 a v i
o the - authorized annual release. incidents affecting equipment 2 (serious incident affectmg an
- s. These r; leases are not signife important to safety and resultmg in t in terms ti danger to health, but an unavailability of more than 1 equipment). Ewnts endangenng the e teve,al a defect m the state of the month, cc.ntrol of radeactivity must t,e sub-
)ec1ed to special examinaton in order ochucts the nv ronr
- incidents of a nuclear nature which to evaluate the potential nsk involved.
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orollary. releases of less than one have significant consequences for the h of the annual limits do rot m mstaHaten tprolonged shutdowns, -Selow scale : a certain number of nselves c:nstitute a classification long and difficult repairs, etc.). The events declared to the safety authorp
'ren ; the underlying event must soosum leak detected in 1967 in the ties do not appear on the scale as et nah' sed' fuel storage drum o, Ln p Malville is can be considered that they are part a typical example, of the normal operation of a large
>< dents leadmg to the presence et industnalinstallaron and are covered znificant quantity of radioactivity. Level I concerns functional or ope. by the usual procedures. This is the Te installatons m areas whete it ratonal anomalies which do not case, for example, of spurious opera-Jid not be found - (*mternal involve any nsk but which are signifi-tion of the safety systems, followmg ;
, s'); Quantitatively, teierence is cant in terms of the lessons which which the installation is started :p '
- e to an unprogrammed passage, can be drawn from them i deviaten again according to normal procedu-i ng a period of more than 24 from authorized fur.ctbnal domains res. The followeg hst summanaes a
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- green
- aones to
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- defmed by the technical specifica-certain number ofexemples :
- 15. Such meidents will require tions for operation, justified actuation. random single failure in a redundant venton in an environment which of safety systems. '.': events which s aiang13 a certain degree, have caused a ra&cactive release.. *ystem *,
single human isilure of no conse.
idents which result in the expo-even at a very low.evel, into the quence',
roundwater table vai 6 e classified at feast at level 1. These cc me automatk
- unavailability or anomaly, outwith of plant personnel Io ionirmg
, tion at levels greater than the fixed f:r 1 year for workers,5 callv into the category of deviations common mode, discovered during i G0 m5v),
from the authonzert dos.iain. Depen-periodic inspectens or tests *,
ding on the quantiv cf radioactivity. automatic shutdown sequence pro-
- dents which involve a significant and t%e rew!ts of the nicasurements ceedm8 normally, etion in safety, without eirternal carned out, they may
,r classified by.wchnical sWicaten limbs rea.
6 Ses, intirnal leaks or irradiatien the SCPRI (central se.iie for protec. ched and normal passage to fallback 2rsonnel: barners or saf?
- sys-tion aJamst ioniary ra.liations) at a state, affected. The importade to higher level. Level
".ill include in
- spurious operiten of the protects e
. y of the faults and failures ooser-particu:ar ;
system, and normal return '.o opera-must be appreciated by evalua-the risks faced by the installation. anomalies important to safety disco- ' * " '
vered tortuitously and not observed.incidem [mWinng an item of e de iund, graded situation in which it dunng '.he normal periodic inspec. equipment smiertant to safety, taking into account the tons and tests,
+ a nors.significant degradaten of the
- ion of the f ailures and the opera-
- onditions cf the installaton.
- deviations from the %$nical specifi. barriers (leak rate less than specifica-catons without paytap to falltack I*"'I' el 2 comprises 2 categones of state and non obser ae:e of the tech-. working accident in a nuclear envi-ents :
nical specifications without justifica-ronment not involving an installation
- tion, fault.
'ous technical incidents or ano-. justified actuation of the safety sys.
s which, although not direct'y tems, such as the safety injection, umg safety, are liable to lead to contamment spraymg, startmg the
~ quent reevaluation of the safety diesel generator sers m the event of,,
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SEVERITY SCALE FOR RATING NUCLEAR POWER PLANT INCIDENTS AND ACCIDENTS 5
' LEVEL DEFINITION CRlTE RI A EXAMPLES I
6 Major accidents External release of a significant fraction of the Chernobyl,1986 core inventory in the form of fission products (equivalence in terms of iodine 131 : several hundred thousand to several million curies).
r 5
Accidents giving rise to Accidents necessitating off site protective mea-Wir dscale,1957 off wite risks sures in the event of releases or the threat of Three Mile island,1979 releates (equivalence in terms of iodine 131 :
several thousand to several ten thoJsand curies),
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Accidentsin the Accident giving rise to external releases of the Saint.Laurent A2,1980 t'
installation same order of magnitude as the authorized an.
(c/ t'#lletin SN No 74) nuallimits, involving no significant health risks for the public and/or partialcore damage and/or irradiation or rariioactive contamina-tion of workers, at a, level requiring specialized medical care.
3 incidents affecting incidents giving rise to releases greater than or 8 m 5.1984 safety equa' to one tenth of the authorized annual (c. 6c'letinsSNNo40 limits dit) and / or significant internal radioactive leaks L
and/or ciegradation of the safety barriers or I
systems
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and / or irradiation or radioactive contamination
'l of workers to a level greater than the authori.
zed annual dose.
i 2
incidents liable to give incidents with potentiel cunsequences for sa-Fuelsicqe drum of l
rise to subsequent fety Creys.Malville,1987
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developments and/or necessitating prolonged repairs or (c/. bulletins SNNoS6,60 works.
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Operationalanomalies Deviation from the domain authorized by the Tricastin.1987 l
technical specifications (cf. bulletin SN No SS) and / or justified use of safety systems.
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NUCLEAR REGULATORY COMMISSION L
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MEMORANDUM FOR:' Chairman Carr Comissioner Roberts Comissioner Rogers Connissioner Curtiss FROM:
ames R. Shea, Director, GPA/IP
SUBJECT:
JAPAN'S USE OF AN " EVENT EVALUATION SCALE" On July 10, the Japan Ministry of' International Trade and Industry (MITI), responsible for the licensing and safe operation of nuclear power reactors in Japan, began a one-year trial use of an event p
evaluation scale. The primary purpose for the scale is to inform the-Japanese public of unusual events at nuclear power reactors and not as an emergency response tool.
The evaluation scale, not referred to as a-severity se:1e, uses nir.e levels and three criteria. This would categorize TM1 at Level 5 and Chernobyl at Level 8.
I Attached is the MITI June.26 Press Release on the use of the scale and a copy of the evaluation scale.
The response from the media to the evaluation scale has been neutral.
Attachments:-
i As stated cc:
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b3valdtion Sealhfor Incidesta an! Failures in. Ruelear Power raanse June St.1949 f
1.Parpose (1) Najor. lacidente and failures in aselear uMmte plante la Japan haa been released - positively to the public ine.,uding alaos ossa. Bewever.
7 there miskt have 'heen some occasion in which proper understanding by.
public on. the antend of effecte to the safety of everall nuclear power plaats have met been obtained because the inforestion released contained technical and speciallised explanation which caused difficulties for public to understand Assediately la eene instanees.
(2) la the ateasophare in which poh31e laterest 9a the suelear power seaeration is growias e, ARRfAt171 intspduces the ladicator. ( h incident Evalaation i
Scale) which explain alatly sad clearly the pealtiesing of eac and failure in the safety of auelear power planta in order to preeste L
fartha idde eAd Sroper,anderstanding by pahlic of jacidente sad failuren.
This
- Ernisation Saale" differ free the criterie in the safetP regnieties si anclear power plaats la its purpose and centests.
- 2. Process of Establia' ment Threvsk six tiaes of meettag ( *Committe on 'the ' Evaluation scale ;
1acidente e.ad fallaces on Nacasar Power Plants * ( Chairmaa : Profesoit Esadt-r? 7ekyo Calversity ) which assaisted of technical specialists 'of i
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the related Field.. and has been enrablished in the RUFEC ) ainue Deceeber of 1989, the " Severity Scale"(draft )has besa established.
J 1a the course of the work the results of disessalsa havs been l
explained to the Nuclear Safety Casassaien. Baclear Poner coaaration Tocha1*al Advisory Costaittee and se on, and their recopendations were l
reflect ed.
AEREpJT!
has received the pecposal of
- severity Scale *(draft) free the oosaittee, and instituted them.
' 3.Evalsstian Scale Detail of " Evaluation Scale" instituted la described ta the attachment.
la the process of classification of events each event, are eva3aated through the three categories of critera
( the criterion No.l. the criterion No.2 and the criterios lio.3 ) la the Evaluation Scale". and.
the legal flaally esigned is. giver. by the t.ighest level reached by one of" the criteria.
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(Esample )
The level 2 is flaauy assisaed for the following evaluation results :
level 0 :for the criterion No.l.1 etel 0 for the criterson gio.l. level 3 fet the criterlea lle.3.
- 4. Applicetes Preedesare (1) ha the case ed the applicaties of this Ivainatten Scale". the facidents and failures are evaluated free the specialised and technical g
.i standpoint in the mostralised organisation at the appropeists time after the erett. and after that. ANRE.ttITI taleases the Saal evaluation results based en that veport.
AllREIN 7! will' trF to release the tentative evaluaties results within auewed range..even at the time of event eeentence.
(1) Even after the starting of applicatica of the *8vslanton scale'.
this flamework wul be reevaluated based et the consenta en them. _(l ywM 6
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Ivaistien Scale it>r freide,ts and Failures of' Nuclear PW Plamt Scale criterion - 1 Criterien - t criterisa - 4
~~
!afisence of Radioactive Caplanned ?.aposure of status of Reacter i
Natorials to the outside Workers estaued in Faellity of Reacter Facility
. Radiation re;,eted Works i
case of no elsalticant Unplanned sapestre dose Event which does aet release of radioacters of werkere essaged la related to the safety i
saaerials due to the radiatica related works of teattor ' facility i
Level e, sat to the eusside (heree,fter salled as o-of reactor facility
'uaplanned supesare")
_-j it less than astv Case of release of
" Unplanned espesure" is Event which does met radleactive esteriale more than satt and less tafluence en the due to the event to the than tente Level outside of reaeter safety of reseter-I feeility and predicted facility but may resate to it rediaties espeente done et the surreatdiar l
- aesitering area boundary le less thaa 0.01m6v Predicted radiation "Unplc.aaed amposure" is Evsat which does not Level esposure dose at the more that leasy and less influer.ee es the 3
as rous. dias sealtering than Sease safety of reester area benadary hereafter called as 'pr,e(dicted facility but relates to it i
sapoctre') le meee than Oleta6v and less than
- 0.0Salv Level
'Fredicted amposure' is "Daplanned exposure" is Event which laflusaces,
4 i
3 more than 0.05mSv ated more than 50stv and less on,the safety of less than 0.lutv than 0.18v reacter facility Level
- Predicted exposure" is
'Unplaahed espesure ie Event which exceede-t 4
.more than 0.1asv and more than 0.15v and less time event of level-3 less than anst than 0.tltv Level
" Predicted azoosure" le "Unplansed espesure" is 5
more than 2nst and less more thea 0.288v than 8 ate Level
" Predicted exposare is 6
acre than SmSe and less than 30n85 Level "FredJeted espeesre' le 7
as e than 20mse and less thea 0.1sv Level
'Predleted espesure" la 4
acre than 0.34v
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ENCLOSURE 3-U.S. EVENT REPORTING AND EMERGENCY CLASSIFICATION SYSTEM The United States (U.S.) system of reporting, classifying and responding to
' events at nuclear power plants and other f acilities has evolved to serve both the thort-term and long-term activities for minimizing risks to public health and safety.
The short-term activities deal with ensuring that adequate responses are take to inform and protect the public from possible radioactive releases which have occurred or are likely to occur as a result of an ongoing event.
The long-term Lctivities involve the review and analysis of events ta identify generic concera, trends, and otherwise minimize the probability and/o-consequences of ' A.te events.
An important aspect of the U.S. system, i
indeed a basic premise,.. openness to the public.
The reporting requirements, immediate incident response, longer term analysis and evaluation, and a summary of public information are discussed belcw.
Reporting Requirements The immediate_ actions taken by the licensee and government agencies (federal, state, and local) in response to an event are determined based upon the assessed risk to the public.
To facilitate determination of the appropriate response, the licensees are required to evaluate any unplanned event and classify the event into one of the following categories:
1.
Not Reportable / Inconsequential 2.
Reportable (Non-Emergency) 3.
Emergency Class a.
Notification of Unusual Event b
Alert c.
Site Area Emergency d.
General Emergency The 10 CFR 50.72 requires reporting to NRC whanever an event is classified into one of the emergency categories based on criteria provided in NUREG-0654 and certain other events within either one or four tours of the occurrence.
NRC personnel review the event and determine if any immediate response by government agencies is warranted.
Those events which are required to be reported to the NRC, but do not war 9nt inclusion in the emergency classes are primarily described in 10 CFR 50.72, 10 CFR 50.73, ar.d 10 CFR 20.403.
The 10 CFR 50.72 reports and the written reparts required by 10 CFR 50.73 are used to trigger followup actions, evaluate plant-specific performance and determine generic concerns or trends.
A matrix constructed from the reporting requirements and criteria is provided in Table 1.
Events which arc not required te be reported to the NRC generally involve items such as the randem failure of single components, problems with balance of plant equipment, or other occurrences which pose no significant threat to the general public.
Although not reported directly to the NRC, such events may be important in licensee and/or nuclear industry tracking of items related to plant reliability and efficiency.
Plant specific component failure data
c s;
a
-2 maintained by industry on a reactor unit basis in the Nuclear Plant Reliability Data System are directly accessible to the NRC staff undsa a memorandum of understanding and a contrect with the Institute of N; clear Power Operations, t
Incident Response l
Upon the decision by the licensee that an event should oe classified within an emergency class, notifications are made to state / local recponse agencies as well as to the NRC.
The level of response of the agencies will be based upon the classification by the licensee 6nd independent assessments, as appropriate, by the various agencies.
Exanples of the type of events which result in an emergency classification are described in NUREG-0654.
Actual classifications will be based upon specific plant conditions or events detailed in plant-specific emergency response plans.
The four levels of emerger.cy classifications are discussed below.
Notifications of Unusual Events are events which are indicative of a potential degradation of the level of safety of the plant.
No release of radioactive material requiring offsite response is expected.
The purpose of the notifications is to heighten the awareness of offsite personnel.
The licensee may augment on-shift resources but staffing of offsite response facilities is not necessary.
Communication with the public regarding a specific event classified as a Notification of Unusual Event is usJally not required, but the licensee and/or the NRC m3y issue press releases if the event or other circumstances involving the plant might generate public interest.
Alerts are events which involve an actual or potential degradation of the level of safety of the plant that is deemed to be substantial but radiation releases, if any, re expected to remain well below safety guidelines.
The purpose of the notifications is to ensure that emergency response personnel are readily available to respond if the situation becomes more seriour and to provide offsite authorities periodic plant status information.
Tne licensee might augment onsite operational support and place the offsite operations facility in a standby status.
State and local response agencies are notified and may place primary response centers on a standby status.
The NRC is also notified and may escalate to a standby status and arrange for continuous communication with the licensee.
Communica+ ion with the public regarding a spceific event classified as an Alert will usually consist of press releases issued by the licensee and/or NRC.
Site Area Emet gencies are events which involve actual or likely major failures of plant functions needed for protection of the public.
Although in plant radiation releases are likely, radiation releases are not expected to result in offsite exposures exceeding guidelines.
The purpose of the not'fications are to ensure response centers are staffed, monitoring teams are dispatched, and involved organizations are prepared to take appropriate actions.
The licensee will staff onsite and offsite operational cupport and response facilities and provide continuous plant data and dose assessment data to other response organizations.
State and local resp >nse facilities will become staffed and will provide prompt notification to the public near the plant via emergency notification networks (sirens, radio stations, etc.).
The NRC will staff the
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.g Headquarters and regional response centers and dispatch personnel to the affected site.
Other federal agencies.uch as FEMA, DOE, HHS, USDA, FDA, etc., may become involved with the response at the Site Area Emergency classification.
Periodic press releases will be made and press briefings will be held.
Procedures have been establisned to coordinate information released by the licensee and other response organizations in order to minimize the potential for conflicting statements which. night confuse the public.
The responses to General Emergencies are basically the same as those described for Site Area Emergencies, but ofnite radiation releases that may exceed protectivt action guidelines are moce likely.
Licensee and government response centers will be staffed and the public near the plant will be rotified via emergency notification systems.
The general public outside the emergency planning zone will be kept informed via periodic news releases and press briefings.
Information released will be coordinated between toe licensee and other response organizations to minimize the potential for cor.flicting information.
The classification system described above has been incorporated into the procedures and t"aining of licensoes, state / local agencies, and the federal response agencies.
The years of experience associated with the day-to-day use of the system have revealed relatively few significant problems.
A summary of the number of events within the various classifications occurring over the last several years is provided in Table 2.
In addition to the routine use of the U.S. system, hundreds of exercises have been conducted to t-sure that the various aspects of the incident esponse plants are effective.
Lessons learned from the exercises and routine use of the system are incorporated h ocessary to ensure the plans provide an effective response capability.
A NUMARC working group has examined recent experience with emergency action levels and is developing guidance to further improve consistency of classification of emer-gencies.
The staff has discussed the proposed guidance and suggested promulga-tion as an industry standard or topical report.
Analysis and Evaluation Notifications of events made to the NRC are evaluated and used to identify potential safety concerns and trends for the industry and specific licensees.
The evaluations result in feedback to the licensees which recommend or require inspections and possible actions, reports to Congress, and input to the assessments of licensees' performance.
For example, in 1988 approximately 2,500 Licensee Event Reports (LERs) were provided to the NRC and over 3,000 events were reported to the NRC Operations Conter.
These reports are available to the public and occasionally used by the media.
The analysis of a specific event or group of similar events can result in the NRC issuing an information notice. bulletin, or generic letter.
Information notices are used to info m licensees of potential problems which might impact plant safety.
No specific actions or responses by the licensees are required.
Bulletins and generic letters are issued to identify significant safety concerns, request lic.ensees to take specific a:tions and ebtain information
t f
o.
needed by the NRC regarding findings and potential problems.
Although specifically directed at licensees, notices, bulletins and generic letters are available to the peblic.
In many cases, press releases are issued highlighting
'the' actions being taken.
Analysis of a specific event, routine inspections, special inspections, summaries of operating histories, identification of generic concerns or trends, or other evaluations are routinely published as detailed reports and are dvailable to the public.
Such reports may address problems with specific components or systems, operating procedures, and/or trends in plant or system performance.
Quarterly, the NRC prepares a report to Congress which describes those events which are considered to involve major degradations in the protection to the public and health.
These events are called Abnormal Occurrences.
The report also serve. to inform licensees, other government cgencies and the general public of the events considered to be the most significant.
The criteria used in classifying events as Abnormal Occurrences include exposure to or release of radioactive materials in excess of regulatory limits, degradation of safety-related equipment, and deficiencies in design, construction, or operation of a facility.
Abnormal Occurrances at. nuclear power reactor facilities have declined in number over the past several years from seven to ten a year to abo"t three a year currently.
Events reported to the NRC by licensees are evaluated to identify and assess
- potential accident precursor events.
Precursor events are identified by consideration of cri?.eria related to failure of plant safety systems, degraded redundancy for safety functions, or occurrence of potential initiating events such as high energy line breaks, loss of offsite power, or other plant transients which proceeded in a manner other than expected.
The precursor data are used to better quantv the risk of reactor core damage and equipment end/or. design problems whicn centribute to that risk.
Reports of these ai.slyses are published annually and are publicly available.
Data from events reported to the NRC are also used to assess the performance of licensees in key areas.
The data used as performance indicators include reactor trips, safety system actuations, safety system failures, olant and equipment outages, collective radiation exposures, significant events, and event causes.
Significant events are determined by comparison to criteria associated with degradation of safety equipment, plant response to transients, design deficiencies, or degradation of fission product barriers.
Approximately M0 events per year are classified as significant events.
The performance indicators are used as an objective view of operational performance and facilitate recognition of poor and/or declining safety performance.
Performance indicator reports are issued quarterly and are public'y available.
j The above analyses und evaluations of information derived from event reports
-comprise the long-term activities to minimize the probability and/or consequence of future events.
The NRC reports iegarding the evaluations are available to the public.
The result of this openness is that the public has access to facility information including summaries of daily and monthly operation, individual event dcscriptions, summaries of significant events and
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Abnormal Occurrences, and engineering evaluations of possible technical issues.
t With the obvious exceptions of security and safeguards and proprietary information, nearly all information regarding the operation of U.S. nuclear power plants is available to the public.
e Summary The U.S. event report 6g and evaluation systeu involves a systematic and structured approach to meet a nutuber of specific objectives.
The threshold for reporting is relatively low, and as a result, about 10 events are reported to the NRC each day.
Each of these prompt reports is carefully reviewed to determine whether an immediate response is needed and whether follow-up action is warranted.
Subsequently, the more detailed written event report is reviewed and classified as to its significance, and whether it meets the criteria for reporting to Congress as an Abnurmal Occurrence.
A basic premise of this sy: tem is openness and availability of all reports and evaluations to the public.
The NRC routinely makes available its technical judgment' regarding the significance and implications of operating events, both in terms of immediate press releases and longer term evaluations and studies.
Thus, the public has available evaluated and classified events in addition to the basic input.
As a resuli., a reasonably high con'idence has been developed that the public, local and State, and federal authoricies will be kept informed of significant safety concerns, issues and events as well as emergency conditions that may involve the need for protective action.
In summary, the U.S. program embodies the following steps and principles:
1.
Safety significant events and eme*gencies are required to be reported to the NRC.
2.
NRC aggressively reviews licensee adherence to requirements.
3.
Emergency conditions are required to be reported directly to state and local authorities.
4.
Utilities and NRC have credibility with media near plants from exercises and real events.
5.
National media has general understanding of emergency classification f rom exercises, NRC seminars, iiidustry information ano r eal events.
l d.
All event-related information is available in public document rooins j
for media and special interest groups.
Thus, in the U.S. the public is generelly well informed concerr, ng nuclear L
plant operations and, as a result, a relatively high degree ot' confidence has I
developed that they will continue to be kept informed.
l b
s r TABE 1 MAIRIX OF EVENT CRTIERIA US CRTITRIA REPOIUDG AND RADICACTIVE FISSION PHODUCT PERSOi9fEL DBGRADrGION OF SVEIY SYSIDE DERCDICY RE ASE BARRIER EXICSURC CLASSES
= _ _ _
GDIERAL 1 REM NHDIE BODY AT EXID05D IDSS OF F0WER IEADING 10 CIRE DhMAGE ENERGENCY SITE BOUNDARY CORE MELT SEQUDKE N/A IDCA WITH FAIIURE OF EOCS i
(>PM OFFSTIE)
IDSS OF HEAT SINK IEADING 'IO (IRE DAMAGE STIE 500 MREM W'UE DODY RCS IEAK > MAFTP IDSS OF AIL AC CR DC POWER FGt > 15 MDETIES ARFA AT STIE BOUNDARY CAPACITY N/A A' INS EMERGENCY
(< PAG OFFSITE)
DEI;RADED CORE IDSS OF FUNCITOi neu ICR IUP SIRTID0 lei MAJOR IOSS OF AND PUNT 'IRANSIENT RCS IEAK >50 GEM MAJOR IDSS OF INDICATION /AIAIM FUNCTI0tG 10 TIMES TEDI SPEC 1.0% FUEL CIAD FAIIe 1 DSS OF FIMCTION RDQUIRED FGt GXD SHUID0tti ALERT
(<PM AT STIE DEGRADATION IN BOUtRRRY)
L OF N/A RADIOACITVE MA*ITRIAL fRAD INDICATIONS INCREASE X1000 W/I Ut0SUAL RCS IEAK > TECH SPEC 'IRANSPORT OF A BOCS ACIUATICN EVDir TP3ISPEC LIMIT DJDIOACTIVELY LOSS OF OFFSTIE PCMER 0.1% FUEG CIAD 00 nam'ITD PERSON PIANT SIUID0hti REQUIRED BY TECH SPEC FAIIURES
'ID OFTSITE MEDICAL l
FACILITY 50.72 (1 OR ANY AIRBORNE OR LI D
IE;RADATICE IN SAFETY 4 HOUR REEASE WHIGI EX DISCDVERY OF IISIGN, ANALYSIS CR Pf0CEINJRAL REIORT) 2 X PART 20 N/A N/A INADEQUACIES CONCENIRATION AVERAGED i
OVER 1 HOUR J
20.403 50.72 MORE RESIRICTIVE
- IMIEDIATE N/A
- 25 REM NHOE BODY N/A
- 24 IKXJR
- 5 REM MHOE BODY ura u r 1
. - ~
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TABLE 2
. US EVENT CLASSIFICATION
SUMMARY
(1)
?
i EVENT r
CLASSIFICATION YEAR 1983 1984 1985 1986 1987 1988 t
30 DAY WRITTEN 2462 3034 2889 2908 2424 REPORTS (50.73) b UNUSUAL EVENT 205 224 312 209 231 212 ALERT 7
8 11 9
9 6
i SITE AREA EMERGENCY 0
0 0
0 0
0 GENERAL EMERGENCY 0
0 0
0 0
0
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[facerg#.#o,.i UNITED STATES
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. NUCLEAR REGULA1ORY COMMISSION l
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W ASHINGTON, D.C. 20666 l
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. November 17,'1989 s:
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' CFFICE OF THE SECRETARY r
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MEMORANDUM FOR:
Teresa Neville, Acting Chief PtOlic Document Room j
THRU:
Sandy Showman, Chief
~';
Correspondence and Records Branch
'FROM:
h'.
Bates, Chief v Operations Branch t.
SUBJECT:
RELEASE OF DOCUMENT TO PDR Attached for placement in the PDR is a copy of:
i.
l
-SECY-89-266 - Event Severity Scales for Commercial Power Reactor Facilities l
This' document is being placed in the PDR at the EDO's request 1
with concurrence by Commissioners' offices.
Attachment:
As stated
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