ML20009H092
| ML20009H092 | |
| Person / Time | |
|---|---|
| Site: | Phipps Bend  |
| Issue date: | 07/28/1981 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8108060002 | |
| Download: ML20009H092 (6) | |
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Mr.11. G. Parris Y
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Manager of Power 2
Tennessee Valley Authority j
500A Chestnut Street Tower II JUL 2 9 Ugo T3 9,,, g, [
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Chattanooga, Tennessee 37401
Dear !1r. Parris:
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Subject:
Class 9 Accident Analyses in the Phipps Bend 1 & 2 Environmen m
Report The Comission's Statenent of Interin Policy dated June 13,1980, (45 FR 40101),
states that, " Environmental Reports submittea by applicants for construction permits and operating licenses on or af ter July 1,1981, should include a discussion of. the environaental risks associated with accidents that 'ollow the guidance herein." Therefore, in accoraance with this policy statement, we request that you consider the more severe kinds of very low probability accidents tnat are physically possible in environnental impact assessments required by the flational Environmental Policy Act. Such accidents are commonly referred to as Class 9 accidents. A copy of this statement is enclosed.
Your analyses of these accidents should be presented in the Environmental Report regarding Phipps Dend 1 & 2 at the time you tender your application for an operating license.
Sincerely, i:Mtul sinal by M a t L Te h Robert L. Tedesco, Assistant Director for Licensing Division of Licensing
Enclosure:
Statement of Interim Policy (45 FR 40101) cc w/ enc 1:
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I' Mr. e. G. Farris Manager of Po.ter l
Tennt:ste '.'Olley Auth0;ity 50:iA : aestnut.itreet, Tower II
'Chattancoga, Tennessee 37401 cc:
Pir. Jerry E. Wills Tenr.essee Valley Authority 303 F ower Building Chattanocga, Tennessee 37401
- .r. Heroer: S. Sanger, Jr.
A-torney for Applicant Division of Law Tennessee Valley Authority EllB33 C-K 400 Coi.nerce Avenue Knoxv.ille, Tennessee 37902 Mr. J. F. Cox Tennessee Valley Authority W10C131C 400 Commerce Avenue Knoxville, Tennessee 37902 Mr. H. N. Culver Tennessee Valley Authority 249-A Hamilton Bank Building Knoxville, Tennessee ' 37902 l
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lead to releases of red ation and/or radioactive matenais. Includine sequences that can result m inadequate cooling of reactor fuel and to melting of the reactor core. In this reFard, attention shall be given both to the probability of 9
occurrence of such releases and to the environmentalconsequences of such releases. This statement of interim policy is taken in coordination with other ongoing safety-related activities that are directly related to accident consideraticns in the areas of plant design. operational safety. siting policy, and emergency p:anning The Commission intends to contmue the rulemaking on this matter when new sitmE reovirements and other safety related requirements incorporating accident considerations are in place.
DATES:This statement of interim policy is effective June i3.1980 Comment period expires September it.1980.
.o CFR Parts 50 and 51 Aconsssts:The Camrnission intends the interim policy gudance contained Nuclear Power Plant Accident herein to be immediately effective.
Considerations Under the National However, allinterested persons who Environmental Po! icy Act of 1969 desire to submit written comments or U.S Nucl[ar Regulatory suggestions for consideration in ActNcy:
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connection with this statement should Commission send them to the Secretary of the ACTION: Statement of Interim Policy.
Commission. U.S. Nuclear Regulatory suum any:The Ni. clear Regulat' v Commission. Washington. D.C. 20555.
Commissicn (NRC)is revising i:. policy Attention: Docketmg and Service for considering the more severe kinds of Branch.
very low probability accidents that are rom runTNtn iNFoPs4ATioN CONTACT:
physically possiblein environmental R. Wavne Houston. Chief. Accident impact assessmen;s required by the Evalua' tion Branch Office of Nuclear National Environmental Policy Act.
Reactor Regulation. U.S. Nuclear (NEPA). Such accidents are commonly Regulatory Cor..inission. Washington.
',' ','#'d o a 's D C. 0555. Telephone: (301) 492-7323.
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,n a nt c a ion scheme proposed by the Atomic Energy suPPLEMENTAny INFonM ATIOK
(;ommission (predecessor to NRC) in Accident Considerations in Past NEPA 1971 for purposes of implementing g, y;,,,
NEPA.'The March 28.1979 accident at i
T Unit : of the Three Mile Island nuclear The proposed Annex to Appendix D plant has emphasized the need for of 10 CFR Part 50 (hereafter the changes in NRC policies regarding the
" Annex") was published for comment considerations to be given to serious on December 1.1971 by the (former) accidents from*an environmental as well Atomic Energy Commission. It proposed as a safety point of view.
to specify a set of standardized accident
- ass mptions to be used in This stetement ofinterim plicy artronmental Reports submitted by announces the withdrawal of the proposed Annex to Appendix D of to appreants for construction permits or CFR Part 50 and the suspension of the operatig lit:enses for nuclear power rulemaking proceeding th.: began with
' reactors. It Jso included a system for the publication of that proposed Annex classifying ac'en:ents according to a on December 1.1971. It is the graded scale of severity and probability i
Commission's position that its of occurrence. Nine classes of accidents' i
EnvironmentalImpact Statenients shall were defined. ranging from trivial to include considerations of the site-very senous. It directed that "for each specific environmental impacts class. except classes 1 and 9. the attributable to accident sequences that environmental conr rquences shall be evaluated as indicated." Class 1 events
- Proposed as an Annes 1010 CDI Port sGL were not to be considered because of Appendia D. 36 At ::sst.The Commission s NEPA.
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g imp;ementmg resalahone were subsequently tjuly 1s.1974) revised and recesi as 50 CTR Part si but at regard to Class 9 events, the Annex that time the Comm ss.on noted that "The Proposed stated as foIIows:
Annen is shl! under consideration * * ** 39 FR 2679
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withm a 50-mile radius of the pIant. and body on which the plant floats. Here the staff emphasized its focus on risk to the The occurrences in Cass 9 involve sequences of postu;sted successive failures some d:fferences between boihng water environment but did not.fmd that the more sesere than these peculaicd for the reactors (BWR) and pressurized water design basis for protective systems and reactors (PWR). Beyond these few probabihty of a core melt event occumng in the first place was enginecied safety features. Their specif cs. the discussions have essentially any different than for land-consequences could I,e severe. However. the reiterated the guidance of the Annex based plant. In its Memorandum and probabihty of their occurrence is so small and have relied uPon the Annex's Order in the Matter of Offshore Power tant their environmental nsk is emiremely conclusion that the probability of Systems.* the Commission concurred in low. Defense in depth imultiple physical occurrence of a Class 9 event is tooJow th'e staff's judgment.Thus, the Reactor bamers). quehty assurance for design, manufacture, and operation. continued to warrant consideration. a conclust SafeiYStudY and NRC experience with surseillance and testieg and conservative based upon generally stated safety these cases has served to refocus,
design are all appl.ed to proude and considerations.
attention on the need to reemphasize maintain the required high degree of With the publication of the Reactor that ermronmental ritk entails both assurance that potential accidents m this Safety Study (W ASH-1400). i.1 draft probabilit:es and censequences. a point class are. and will remam, sufficiently remote form in Atipust 1974 and final form in that was made in the publication of the in probabihty that the environmental nsk is October 1975. the accident discussions Annex but was not given adequate entremely low.For these reasons it is not m Ernironmental Impact Statements necessary to discuss such events in bepn to refer to this first detailed study 97 the NRC commissioned a e
a s appbcants' Environmental Reports.
Risk Assessment Review Group "to A footnote to the Annen stated:
[r cuia ly clanfy the achievements and limitations nt Although this ant:en refers to apphcant's events which can lead to the melting of d the bactor Safety Study., One of the Envuonmental Reports. the current the fuelinside a reactor.8 The references conclusions of this study, published m_
assumptions and other prousions thereof are h
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September 1978, as NURFC/CR.0400.
appiscable.encept as the content may fp g
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" Risk Assessment Review Croup Feport otherwise require. to AEC draft and final relevant information. but it is obvious to the U.S. Nuclear Regulatory Detailed seasements.
that WASH-1400 did not form the basis Commission," w:s that "The Review Dunng the public comment penod that for the conclusion expressed in the Group was unable to determine whether followed publication of the Annex e Arnex in 1971 that the probability of number of criticisms of the Annex were occu.mee of Class 9 eventa was too
- h received. Pnncipal among these were low to warrant their (site. specific)
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the following:
consideration under NET w n those estimates are in general.
l (1)The philosophy of presenbing Tne Com nission's stiff has however.
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assumptions does not lead to oojective identified in certa. in case e uni ue findings of the Review Group have also 9
analysis c umstanen wnich it felt warranted subsequently been referred to in 12ilt failed to treat the probabilities of Enhn, ental Wact 9aurnents. pg
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accidents in any but the most general c[nsid rai n of la s 9 vents. One of with a reference to the Commission s these was the proposed Clinch River.d plicy statement on the Reactor Safety way (N No supporting analysis war given eeder Reactor Rant $RBR4 a hqui Study in hght of the Risk Assessment to show that Class 9 accidents are metal e led fast breeder reactor very Review Croup Report. published on sufficiently low in probability that their different from the more conventional January 18.1979. The Commission's consequences in terms of environmental Hg I water reactw plants f r which the statement accepted the findings of the risks need not be discussed.
safety expenence base is much broader.
Review Croup. both as to the Reactor (4) No guidance was given as to how In the Final Enuronmental Statement Safety Study's achievements and as to accident and norma! releases of f r the CRBRP 8 the staff meluded a its limitations.
radioactive effluents during plant discuss.on of the consideration it had A few Draft Environmental l
operation should be factored into the given t Class 9 nets.
Statements have been published cost. benefit analysis.
in the early site review for the subsequent to the Three Mile Island l
(5)The acciderit assumptions are not Perryman site, the staff performed an accident. These were for conventional Fenerally appbcable to gas cooled or iM rmal assessment of the relative land. based light water reactor plants hquid metal cooled reactors.
differences m Class 9 accident and contmued to reflect the past l
le) Safety and environmental risks are consequences among the alternative practice with. spect to accidents at I
not essentially different considerations.
sit es. (SECY-78'-137) such plants, but noted that the Neither the Atomic Energy In the case of the application by experience gained from the Three Mile Commission nor the NRC took any Offshore Power Sy,tems to manufacture Island accident was not factored into further action on this rulemaking except 0 ating nuclear power piants. the staff the discussion.
in 1974 when 10 CFR Part 51 was judged that the environmer.tal nsks of Our expenence with past NEPA promulgated. Over the intervening years some Class 9 events warranted special reviews of accidents and the TMI the accident considerations discussed in consideration.The special accident clearly leads us to believe that Environments: Impact Statements for circumstares were the potentially a change is needed.
proposed nuclear power plants reflected senous consequences assoctated with
/.ccordingly. the proposed Annex to I
the ruidance of the Annex with it:w water (liquid) pathways leao,mg to Appendix D of to CFR Part 50. published a
i exceptions. Typically. the discussions of radiological exposures if a molten on Dei. ember 1.1971, is hereby accident consequences through Class 8 reactor core were to fall into the water withdrawn and shall not hereafter be 1
(design ' oasis accidents) for==ch case used by applicants nor by the staff. The l
have reflected spec:fic site 9 is of snierest ih.t ihe Re.cior Safeiv StudF reasons for the.vithdrawal are as charactenstid associated with am, refer io nor we. ihe, w..... e.ccident.
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meteorology (the dispersion of releases
.iaoosh ih,. ierm. co....i, wed.. io,iy of radior:tive matenalinto.he ewaient io. core ment.ccident
- Lodemo. sTN w. september ia. ism muarc-mss rebn..ry ts-7.
atmosphere). the actual population e
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u The environmental consequences of issued Staiements.nor, absent a
- i. 'he Annes proscribes consideration of the kmds of accidents releases whose probability of occurence showing of similar special has been estimated shall also be circumstances. as a basis for opening.
[ Class 9) that, according to the Reactor discussed in probabilistic terms. Such reopening, or expandmg any preuous or Safety Study dominee the acc3 dent consequences shall be characterized in ongoing proceeding.*
nsk.
- 2. The definition of Class 9 accidents terms of potentialradiological However. it is also the intent of the in the Annes is not sufficiently precise exposures to individuals, to population Commission that the staff ta.e steps to to marrant its further use in Commission groups, and. where applicable. to biota.
identify additional cases t!.at might policy. rules and regulations, nor as a Health and safety risks that may 'oe warrant early consideraSon of either i
decision critenon in agency practice.
associated with exposures to people additional featuren or other actions 1 The Annex's presenption of shall be discussed in a manner that which would prevent or mitigate the assumptions to be used in the analysis fairly reflects the current siete of consewences cf serious a:ctdents.
of the environmental consequences of knowledge regarding such risks.
Cases for such consideration are those scendents does not contnbute to Socioecono nic impacts that might be for which a Final Environmental objective consideration.
associated with emergency measures Statement has ah eady been isse:ed at
- 4. The Annex does not give adequate during or following an accident should the Construction Permit stage but for consideration to the detailed treatment also be discussed. The envi onmental which the Operating License review of measures taken to prevent and to risk of acci6ents should also be stage has not yet been reached. In mitigate the consequences of accidents compared to and contrasted with carrymg cut this directive. the staff in the safety review of each apphcation.
radiological risks associated with should consider relesant site features.
i The classification of accidents no; mal and anticipated operational including population density, associated with accident risk m comparison to such proposed in that Annen shall no longer releases.
be used. In its place the following In promulgating this intenm guidance.
features at presently operating plants.
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intenm guidance is given for the the Commission is aware that there are Staff should also consider the likelihood trtatment of accident risk and willlikelv remain for some time to that substantive changes in plant design 4
considerations in NEPA reviews.
come many u'ncertainties in the features which may compensate further application of risk assessment methods.
for adverse site features may be more Amident Considerations in Future and it expects that its Environmental easily incorporated in plants when l
NEPA Reviews Impact Statements willidentify major construction has not yet progressed very i
it is the position of the Commission uncertainties in its probabilistic far.
that its EnvironmentalImpact estirnates. On the other hand the Environmental Reports submitted by
' [I Statements. pursuant o Section 102[c!(i)
Commission believes that the state of applicants for ccnstnsction pcrmits and 1
of the National Environmental Policy the art is sufficiently adsanced that a for operating licenses on or after July 1.
<; f-Act of 1969. shall include a reasoned begmning should now be made in the 1980 should include a discuss.on of the
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consideration of the environmental nsks use of there methodologies in the environmental risks associated with (impacts) attributable to accidents at the regulatory process, and that such use accidents that follows the guidance particular facility or facilities within the scope of each such statement. In the
, ill represent a contructive and rational given herein.
w rward tep in the discharge of its Related Policy Matters Under l
analysis and discussion of such nsks.
repons ities.
Consideration epproximately equal attention shall be it is the intent of the Cornmission in 8
gnen to the probabihw of occurrence of issuing this Statement of Intenm Pohcy In addition to its responsibilities releases and to the pro'bability of
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I occurrence of the environmen'tal that the staff willinitiate treatment:,of under NE PA. the NRC also bears accident considerations. in accoroance responsibility under tht Atomic Energy conwouences of those releases.
I 9eleas'es refer to rac iatior and/or with the foregoing guidance. in its Act for the protection of the public radioactive matenals entenng ongomg NEPA reviews. i.e., for any health and safety from the hazards i
environmental exposure pathways, proceedmg at a licensing stage where a associated with the use of nuclear Final EnvironmentalImpact Statement energy. Pur: uant to this responsibility J
includme air, water, and ground water.
Events or accident sequences that has not yet been issued. These new the Commission notes that there are lead su.eleases shallinclude but not be treatments, which will take into account currently a number of ongoing activities limited to those that can reasonably be srgnificant site-and plant specific beir g considered by the Commission features will result.in more detailed and its staff which intimately relate to expected to occur. In. plant accident i
sequences that can lead to a spectrum of discussions of accident risks than in the *C! ass 9 accident" question and releases shall be discussed and shall previous environmental siatements, which are either the subject of current include sequences that can result in particularly for those related to rulemaking or are candidate subjects for inadequate cooling of resctor fuel and to conventionallight water plante at !and.
rulemaking.
melting of the reactor core. The extent to based sites. It is expected that these On December 19.1979 the l
which events arising from causes revised treatments willlead to Commission issued for public comment
- external to the plant which are conclusions regarding the environmental a proposed rule which would considered possible contnbutors to the nsks of accidents similar to those that significantly revise its requirements in nsk associated with the particular plant would de reached by a continuation of to CFR Part 50 for ee.ergency planning shall also be discussed. Detai ed current practices. particularly for cases for nuclear power plants.One of the quantitative considerations ihat form involvmg special circumstances where considerations in this rulemaking was y
the basis of probabilistic estimates of Class 9 risks have been considered by releases need not be incorporated in the the staff, as described above. Thus. this
- comm...%m cmniky end ar.dtord d.usree EnvironmentalImpact Statem<.nts but change in policy is not to be construed
=ih the incl =*a of the precedes i-o *eaiences.
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shall be referenced therein. Such as any lack of confidence in conclusions references shall melude, as applicable.
regarding the environrnental nsas of
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,,,g, reports on safety evaluations.
accidents expressed in any previously
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ths potential consequences of Class 9 cecilents in 4 generic sense.'
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- l. August 1979. pursuant to the C mmission's request, a Siting Policy i
Tcsl Force made recommendations with respect Ia possible changes m NRC r:cct:r sitmg policy and criteria.'
currently met forth m to CFR Part 100. As st tid thtrein. its recornmendations
- wsra snade to accomplish famong c thers) the fol!owing goal
t To stka into consideration in sitir.
he nsk assoctzied with accidents beyond t>
design bIsis (Clast 9) by establishir g 5 or Aation
~ dmsity and distnbunon entena.
This mstter is currently before the f
Csmmission.
This and other recommendations that hsva bean made as a result of the invsstigitions into the Three Mile Island i accidir.: tre currently being brought toFethat by the Commission's staff in ths fctm of proposed Action Plans.'
Among other matters, these mcorporate i
! rs' corr.atndations for rulema'aing related is drgradrd rue cooling and core melt l tecidents. ".ne Commission expects to issus dicisions on thaso Action Plans in tha naar future. It is the CommissioWs polscy and im.nt to devote NRC's major i rssources to matters which the Commission believes will rr.ake existmg and future nuclear power plants safer.
and to prevent a recurrence of the kind I ci accidrnt that occurred at Tnree Mile
!sland. e'n the interim. however. and pending completion of rulemaking
, activitiss in the areas of emergency -
l planning, siting criteria. 4.nd design and operationil safety. all of which involve
! considerations of serio:ts accident *
' potsntial. the Commission Im' ds it
! esstntial to improve its procedures for l discribing and disclosing to the public
' the basis foe a riving at conclusions j regrrding the environmental risks due to
( eccidents at nuclear power plants. On
' complition of the rulemaking activities
- in thess arsas. :nd basari also upon the l exprrience gained with this statement of
' intarim policy and g tidance the l Commission mtends to pursue possible changis or additions to 10 CFR Part 51 13 cod 2fy its position on the role of tecidsnt risks under NEPA.
l
'Cf NUREG-cJss "Pianning Basis for the i Deweiopmei4 ef State and Local Govemment l Radenlessed Einergency Response P'ai # m Support
- of I gne Wceer %cieer Power lonia." No=cenber o
l1rs
- Nt; REC 4a:s. Report of the Sihng Pol.cy Task
- occa." August 1978 i
- Detfi NUREC hec. "Acieon Piene for implemwreng Recomrnendeieons of tae P vendent a
' Commsee.on sad Other Seudees o'she T%ti-2 l Acesseson." Decevriber to. te's t
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