ML16341B219
| ML16341B219 | |
| Person / Time | |
|---|---|
| Site: | Crane, Susquehanna  |
| Issue date: | 08/30/1979 |
| From: | Martin J Office of Nuclear Reactor Regulation |
| To: | Mattson R NRC - TMI-2 LESSONS LEARNED TASK FORCE |
| Shared Package | |
| ML16341B218 | List: |
| References | |
| NUDOCS 7910240703 | |
| Download: ML16341B219 (6) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMlSSlON WASHINGTON, D. C. 20555 AUG ~0 1979 NOTE TO:
Roger J.
Ma tson, Direc or TMI-2 Lessons Learned Task Force FROM:
Jim Martin, Accident Analysis Branch Division of Site Safety and Environmental Analysis, NRR
SUBJECT:
CLASSIFICATION OF TMI-2 ACCIDENT
REFERENCE:
Your August 16, 1979 note to Guy H. Cunningham, Re:
Board *(Salem) question concerning class 9 accidents There are at least ten classes of accidents:
classes 1 through 8, class 9 and the set of conservatively analyzed accidents postulated pursuant to 10 CFR Parts 50 and 100.
The double ended pipe break postulate is part of the design bases for the ECCS.
The scenarios postulated in Reg.
Guides 1.3 and 1.4 are part of the design bases for the containment for the site.
The titles on Reg.
Guides 1.3 and 1.4 are misnomers, causing part of the widespread confusion - the titles say "LOCA", but the Regulatory Positions are silent with respect to mechanisms or initiating events.
(Nevertheless, it has always been clear that severe cladding failure and primary pressure boundary leaks would be necessary in order to obtain the source terms specified in the scenarios in Reg.
Guides 1.3 and 1.4.)
In the decade since the accident classification scheme for environmental reports was established (Proposed Appendix D to Part 50), the term "class 9 accident" has developed as a colloquial expression related to the resulting broad cast and adverse radiological exposures of accidents, rather than any specific (or even general) initiating event.
(Although common attention is paid to the core and containment, there is sufficient inventory in the spent fuel storage pool to cause such exposures.)
The upshot of these musings is four-fold:
l.
I don't agree that "the accident at Three Miile Island Unit 2 involved a sequence
. of successive failures more severe than those postulated for the design 'of the ~1ant" (emphasis adde4),
. Although there was a series of failures, the combination of engineered safety features that worked, or partially worked, was sufficient to prevent broad cast and adverse radiological exposures.
2.
I would say the event was close enough to a conservatively analyzed design basis scenario for the containment and it' engineered safety features, to be called that.
In short, it was a design basis accident.
R; J. Mattson AUG S0
>979 3.
The classification is moot.
The major environmental consequence of TNI-2 was that we scared h--1 out of 1.5 million people, or so.
Such a broad cast and adverse consequence is not covered by our regulations,
- guides, or the Atomic Energy Act.
W hbt ~
i td 1 if'i scheme.
Health effects and property damage should be considered The attached table is illustrative of a starting point.
know how to handle the matter of psychological stress.
can't avoid such stress given an appropriate and actual event.
(The way things are going, I'm not sure that we the absence of an initiating event!)
quanti tatively.
I doubt that we He certainly initiating can avoid it in
Attachment:
As stated im Nartin Accident Analysis Branch, DSE Office of Nuclear Reactor Regulation cc: i. Soffer R
ouston
. Kreger D. Nuller
.0 l
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CLASSIFICATION OF Et'lERGENCIES BY SEVERITY OF PROJECTED lllSULT I
CLASSfv'ROJECTED 2
llNOLE BODY DOSE ()Io)
NthS) lib' hd0 bo < Nbb L5oO 5 <$80 / bti 0.5 L.NBD ~ 5
- 0. 05 g llB0 < 0. 5 UE):lB) I )'N I
)Htidehts Hhi'ch l)as'6 5 'deh'r a'nd I'(nnl'nent threat to the lives of illdividUaks.
iii'ciden);s bhi'c4 'pos'e
'h 'clear a'nd imminent threat to the health of ilidivid05)s.
Iutidehts r>hic(i od 0 's4tisticall si'nit'!cant basis,'pose a 'threat tu thd h'eat tli 'op i!i'digi'duels i'n a populatson group in 'the 'long 'teer 11lcidNts Nhic)> dN 5
basis pose a threat to the general
)learnt)l Of 8 )lO>U)a):i'4N 'gib'up i', the long term, but for which speci'fic
- indiV]duals'll the )AU'p3 'ca'n'not be positively identified in the shovt tenn.
Incidents not to b'e 'c)hssified a-emergencies, but for which assessnlentg
)ll'ot'e'ctiv'e 'o'r corrective actions may be deemed advisable ui-desibab)'e.
NOlES:
I l.
Af'I] Hone, or some of these clatjseh iildy.cU'exist i'n tinle and space.
Doses at large'r distances would occUt after a delay due to tl.aVei tilii'e; I
2.
llflo1e body doses include bone doses:
hanrjes for 'other 'organs can be established using ).h't'f'os o'f whole body dose to organ dose (et:u.;
llg(( i's a(io'dt IX of thyroid dose),
unless other evide'nc'e siiggests the use(seaI of,a higher ratio, s
3.
On a statisticall Sitliihcant basIs; Ii)egnant wome'n i'n thel'r first trimeste'r cou'ld be
>(Iie'n't1fieh. as a
sub-group in ttlib e ass.
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