ML20202D980
| ML20202D980 | |
| Person / Time | |
|---|---|
| Issue date: | 01/25/1999 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-T-3063, NUDOCS 9902020203 | |
| Download: ML20202D980 (221) | |
Text
- ' cQ ;
.,,m q., ; ? , 27 { ,,-
. .. _...: ,.4.,,, . . . . .. ..;.p..,: . '.)+;_'< ;;. l, ;, .f g. t. , *y_n V' . ., , .._, ;,, , ;..-* A ;. ;'.llq. . y V'. ,,1 stn; b, r. .~..;.... _ e .v <. . g..9.;....._. . .- . : y 6; .;q.
- r.
x.. %...:...
...,. Hs _9.*- e .-
- ..e... .. .
. ,e. 0, -r . 2
- . :.y
.4.. . . . *
. . - . . < . ;'>'.-v.i "n-
- w. 4 -.._.l.. e 1.
,, .. i ., .. . - , :. ;;- _, . g_(;_
, , , . . . .; ... . ,. ., .,c..sw. .,' N_ > =of. ;. a;
., .- k v* .. - . ~.z .; ,Q ;*,, . / e* .
- '.',.,.ys',.-
q . .-
} l- 4
(. q e , " . ' .g ,.:.1,*,;..s..
.'.Q.t, , i ; %m ': . n;,'..' 0. '. .[ . .,.-;g ' i. ',.W.
s
,'j ,; .P .-.g* .. 'f. ).m. , . . . . ' ..
't,
_ . . . ,,p
,.-p, 4' .q ' * . 3 3. -: g l+ f,-
...g..
f '. s ', f3
> .4. <, . f.
..?.
3 v c. 4 .,; .
a .. . ..n..n,r.y,.,. . . . , . . . .
- : t. . > > :x s y:V. , , 2- > . . g.,~s,. 3...;*s
- s. . .
r .e ; . .,v y . ., n .
..... s. . . y g ,. p . 9 . g; . , :..: -
. f. . . .
'ui .-. .? . % m :Q. a ;5. . :.f:[
./l. i.. q . .. . v.'..:<f. . ; %. 4 : ;. : g, :t..... e,L a. _ }.Q Q,.l
- _ ' . ' . . . . . . ... .. ;;' A i . . . . . , . . . . . -. . .. .' R +. .- J. ;. N:5 'lyl}y g .;f.?t.'.o.n[ . ': L.'.
' 'g*:.'.'.f ' :t,.
.. . .h.,.i:' -
, : . ( x% 'j *. +?,:'.. .* A.,fC.. w.,&;.,
j
- ; , _..;,'..o..I....4, m y ..'y;;,......p...V; .;..'.s.. .,5, : .i.,,.'..,e
', -l. ,,,f.'.,. . . , ,
s,. k ' 't'w,sp' .U yy;ll***
i'
,+*.l'..s'.'fs,. ,: . . .: !'o.f . ;'. *p ., .-
."'.s ;;.'.',-,....*:,..r.p';...'...,L,..l.*' 4* ;; ' "l ,-
, . p.
u, ;q_
y- v: . .v.; .up. ., .a..,. .n.
- - .- . . . ., .. t
..s..
'l' U - }, : . g ,. L :. pg . . y.f. , . ,f }g y .O s, .).?. .g,. %
2, .
,.~
. -},... ., ' ' ,. ,: g.. . .~y' .,Q:'..{ Q. {:j:... . ; r. . ,. L.:. } .y Q, ; . ,.;4jf a
- f :p. m..
- 8. ',
f.,v, .c. . ., s .. (._fQ
- }- (?[ . - . 3
,, _ :l.
v.' s . . .;. . .
. . ,.*':'. : . .,, t..,u,, ,3
. . ,. . . v.. -, . s..a- .s:....,-. .-. .s.... . . . . . . . ... . . . . .r ;: .....:.. . x n. .a.
.....,~.-;z, .
. . ;- . .. ~ - . . ,;a . . .
- u. ,.g - l r ..
- 4. : . ., s. :t74.. .Q.w.
.o
-.r . . .,
v . . . ,. .
-(.
.~.. . := . . . . v .,
. c .. ,. * : .,;, 3.,,.
e,e s, .y ;. ~ -.%g ; . y . . .
....,v..
,,
- i.; .
,. q .. a
- 'q y -
.. ,;s. s . ;
.. . _e x . . f; 4 . . .., . l.~
- -, s >
. : ... ; ~ , . ' , -. .' ... .. , . , .
r .. . .y.-
n, . . ,~...
> 4, .e
.: r
- , . . . ; ,;- . -. .g .,
. . . . t; -. c.
.; .. . ...,n . . , : ...,p. . .u . gc ,.v.,....j.
..t, .-
f 1.,.; ,t.n;.n.
.,. . - . .,: t._
..a.7..,$*,.._,..v. . . s. g .
,..s : .
f,.' .
, , . ... ,, u . .v . s..i .
.. f,. .; , . . . ,y . , . .g, L'* .. , , . '. ': ^ :' *,.s_ .,.f.- ..,s*...,'..
s
- , '..] l .-'.? '
- ') . ' h :. ' *b ',?.,;'.'.,.'*s.A. -
- . .,l Il , * ? 'j, . ,* ' .
. ,Ih' ';', !- :: yy --Y ) 's-. -l.;I.f.f: )'s'l':f., ' l' l i ., ',. ,'::.,Q ._- ,.% .N.h, '.,, y f. .. '.l . * *D .[.Q.<.
, , , ,' ;.l'l.l l
. .. v. .'. .' ,: .. V Q %, '1 ' '
v.,~.c..',
e - 5
~ :; * * ., . . . ... .;-
. ; .. . y ,.s j ,, '. ' <
.:2,.'.-__.,. .,['.'.
.M.. : .., ....: '-.n7 ,;. ;- : .- .
.l ' ::.. < - - . .- ;... .-
. :-4
~r 4
- . .;.. ; .j;{.. ... :..... '. . .x. . a , . . . . ; : o ;
-y.
. ..2,. ~. :. .....: ._ ..... s.. ...e. . , . . .; ; ;. .. .- . +,t,-.
, . . . , . :. . {. :>. , ~.;:.;. ;;:.:: ... . ,. s a . .~
. <- .. ,.; ..e : . ,. . ., s.. ... .; . . ;..y~ c, .,.. .;.
.~
- . , .a, n
- :y . .:.:.s'-: . ...q..v .;,. . . . , :....,.
. .. ~.:, , . .a ...,v. .,.. .: p.;; . ;. c;, :4, .. .;
.:.. ;. c.~ , .: :s : 4: . .,.;
,,, , .- . . . , , ,f ' .A [.; s..,. .. . , , , g ....c.
s
. O s l: { \ ; : * ?
v.p*., .- ;,,.- .\.-
.:. ,'.' ... ,.,* ,N. , "*t?',*!.. . '."i
.p , ,'e.* \ .s, J. ;'!la;
.., ~. :: .- ..:
, 'l **?.'Y*
,/:,.'....:.',... . l ;e*l ' *., '. l f, 6i j -l
.- ' .',8!g...a h
- N .?. .q ' ;
- i. ;?
- 4-
.g .e. ,,.e.,"/*
'l "
'. . ;*'.." 9 t. , k. - (,;.L*
. *. ' ;;3 ' ,': . .' * '.'* ' % .,' '!. l5 -
e-
.... , <e.
~;. y. .. ; ., ..
. : r.-y ..,..s . . . ...
, .. ... . e .; ., . ;,: . . .
. .; >. ? .: ,
- - ~.,;<~ Y
. . 9 i . n . ,,..y
- .'- ,, .rg . - -.
...q'.. . .s .l...'S.
a....y* ,; .M. . . r. . _. .
.~..r
,c ',,~f,.
,_..s,3._y.....
e .; ,
). . , .. ; .
. p.s,u.n .r . . ., . ...,,.
.,,...v.,...
. y. , . ,.n .- .... ....., ..u.. ;..: . ,
..y . ...,g. r : . : :.,.. . . > .:.. ..,
- g. - .
. s . .. . . . ...s.,....- . .
. . ,...y.
,,...- .,.-~
.-a..
. ;, ; . <. . ,._ ..:>,:,.,.i. .-
. .-y . ;* . . ,....
. . .. . . . , ..~ ;..~.--
. ..
- n . . . . .. ,:. s . . p . .. . - v,....
s A. ,. % .. . . ,. . ; . .
< . - .. . . . h . . 6:, y._ . , .. ,e. .
.,\,3 -; ;;.. .. . . . . , . A.1, . . . g ..vc.....'.._....n':....n ; v: c . . ., . ..-c1 . :.t::. . , .^' ;. . ' j.. . ...:.. .'*;. ?. ?v. ;.?;. m. . f. . . : .., '.,.
..:...;;p %. . ,;. f- c[.; (. - . 3.v,. ..
, .- ....'.[ . . ? . _ . .:' : . ... . ,.
- l j ' . . ,' ../
}. z .. 'r _ _ ' , Q.: ;.. ... .} . j g;*: f;F. , ,G: ? ;,'. ;;,_. .< ? ... ,J* .1,L <', ;~. :; y . .);f. ,'
..;7
.. . . .'. _. . . . . . .p....... .. :. .. . . .*.. ,..*. .,?..-
c .. ; . < : - + -
- '.. ,,; ; .; .':K.
.;g;.;.-l : . ;-..;3. t z<. q,V. .,';c; ;p.:(~.
'; .. *; _ : <. . . < - y >:
.r.n.; : . '. n."l ..-,: . y, ; . ,._!;. ,.a.....c .::. . .*>. qt ..:::;L-'?. :': u:'.-* y: :.:,i .., .2: - . V., n*.. ;. _ ;. ; . y .. .. :. .n.
_n v ; :':: G t . .. . u .s . .. r. . ; . ..: . .
, , _. ,, -f .j : , . , . . .. , g. , , .,:+......s 1 .
- .. ... s. .n
. :-_. .,. .;.. .a
, ~ ;;. . ' :.~... ..:.. :. : ,V,;. - v '.. )._ . :
1
. . - :. .<; , ' - ... ' . . . . .g. . ; ;j. ;.
- ; '. . . : ' u. : . ;.' >. 9<:.:: /s-&e,.. . ~:-._~.:.z.: . ;; u .* :- mal.n. . ..:..,y, c: - ,: '. -.w'
- n. . , :.; . o. , .. :,(, , _ . * *
- . p
- v. -, .- .. .;,. .,. - : i.;.7 5 . ;. . r...;.i. p< w
.. . ., %. - . . * . :g: .
j,' '. . . ':.: ^ ..'..;,~..,.'.'... ; c. ....-_" e.
- ,._.L..,,-
-:(
y: .;;; ... ;. .,; -'
.- ,: ;. .. : ..+,. ;u - 'i
- - - +.2 o .. ;J : w:.. _,s...s. .:
.'. .. . . ..; . ~ ..u.
.o ...
,,..,.,,.......,,..,.%;.':.n;,,. ,;P.u, . y.Y ,.; ::; . +., .,[,. .'
s . .e
. . ' . . =.,:. . .
..- ..M....... ..' '
t.,. . :y A. ,; ... ., :
, ~ - ..,. , .. .
t... ,-
..,.,,g .. .. g?<...'.=.5,*, m. J y. ( , ...a.
\
. * . = .t.-
g - .;* ..,.t..
+
, p : , ..
,,..,,.q,&....- ..'l,, .,.,.',.>vw p'f.._..,'.,a,...., ..#
.,.'.f,,
. . -. /.; . - , y..,
s.
..h.,,.t , : . , . . . , -
.,,f' . ,. . . ,
. r* .,, 1 , .,.,
,,.c., ... . ,
,..,.,_.,.r. -r , ,. .i
- t. ,. . .
<.. ,, , = , .. <-. ... ..' , . . ...
.Qt ..
,g .. , ,. ; .e , ..
- y
}., , = ,j,.;......, _ . ., , :,
r,. . , . .. ,
- 5. s
.. . ;.3 . j ,,7 ,g . . .,, . , . ,. , - ....;, ,;
, g).y ;, ;,, ;; x, g . .., -g
. -: ' ,..... . . ._ ._ ,. : g , p . .,;...., , .,{,.
.~.. _,< .s
. . -.,....o _ . . ,. ., _, ..;. . . . ~ . . , . ,r._ ..;,.
v., n .
, ;,. t z; ; . .. __,
. _ . , ,., ,- y .,n,...
. . , . , ,.; . . . . .,s.. , . . . .
s .: . <. . : . > 6* .f.-.
'...; .' *. ' . , - .- ..T.; _ . ) . -
= <-' .u.~-*: . . ?;,.,,.*. ;; ' ', .c. :, .,2':-.'. .: .* ., . [* . :*?% *,. ....-;. ' ' , * ' ; G-l . ' . *" ,.-,. 'u:- C c: .: .'.'. . ..:".;',.,......N,*. 1
- ..:_ ;. . . . . , . '. .. .. .. .. .. ., . ,..-Q_..-:;,'.~....:.'.';.;1. _d (s~,s. ,~.-; .l.* , . ::?!.. . . . . '..'.' .- ' . [.(..=...,._.,bV.:
. : -w
..:r..s,, w - + , . . - ' : ?.. .-,.t.., ,'n.u' .,- u.*
- : r. . l lk , , ' . .. .. h
.** A,4. ,, ~ -;.g>.
.,.w ...6 . .~ e. -
.r.
+ ..., ..,.... - . . .;. ' . .. . ; . . . e., ...rc~ ',9.
- u. !. _ p ,,
s.- .W . .<J._..'q
- s .
_,_ ', . , ; ;.e . ,
. . +' ds . . s
.o..
2s.. .. - ..yp*_.... .
..:as
.9g ', _ : o. , [ f.['*! $ f [9 ~ j ' Jh.: . . . _
j . i } [ '.} ' h ~_ ,; -'.,...:.'.j...2g t . .] : . . . . ., , '..-
'f
. , . ) .,W o ' p": . :l ...;[* w M.o.:'f.g u, f:'.,D.
t, _ '
- . . } _.
.l' ,.; .{';[ :i.l:
- * {. . - ' ,,
-
- t ,;]; '-
l ' .\ ,, '. ;. ;,n. { '.j :.. -t 'i \' . .. .; ..',-- ~o d, i f l.. ,v.,. . '.,' ':: *. ,t.g. *., . ?. ,'. ' ': ={
Q. y . ' **
- ;;.3.st' *:';'.i : ; r . :.- ': , _- '.' \.' .
. ' 4. . '
a.'.- \, t'>. ' ... ' - ,.
. . . . - e- y :. . - .
- c. .. a .;..-
. '. Y, . . . .
. y. i N :
- ,. : ,.',.m'...*;._.*..s.n,, , ,. 4.* ... '.. ., r. , ..t ';:. .. **.s.r: ,,' .. . . . . ,f. : : ? *;, T.; ,'.';; Y %...a.V,;.%. , v.
. . . . . . , . . . . . - ,:., . ' . . r- f . ..
. *> . _ - .. . -. '5 ,...s:, ..: ..,;
. ..g;.,: . -: a , c. { :;:jr's
'. . .>, . . ..s...q.,,._ 4.~. *: :7 : : . y . . .; . .i .;.
. .. ,. , i.' ..;:- v -' ';,1...,: ;:.M,., , ,j" ;.::,:. i....t.:;
.s. .:.~. .:..'.V.,..
p '. , ' .";.:w .,
- s'. ;- _
.v
- . .', :, fQ. .
.f. n.' n.: - -
%'; - . ~'*
- g - .,
- . ..}:e.
.m:'*..;n ^*.s : ,. ,. . . . . .
. . , . ::V.a-.
- p. . r......-c;..W. . ;. :V..: ..-.e :. . .. .a.:*,
.e
..s..,
.s.:
- s. ,.. .. -
..;... v. . ..
. . '. y: s. .;. ,
.....%.,.7.-.
s y .-- 2. .3,
.:s
..n,'
s,.,
.y....'...._...,;...,a,t',4
- '..* q .;. , : .r.,.n ! , -.; y ~ ,...:,4
,..=,.,,,c:.s. : gc . .r.
. .. ; :*g ,,; ;. ., -;. .-..f.....c* v r.
9 -
- . \ t,.
_: . .. .i. . - , . . ,
, t e,._
L.,..-...,.,, ) .3
- *;. . . D., j,
- m. c>. a:....:,..,.,,-.h..i.*.,....
. ..sn .
+ : 4 ..o '}.. 7. - Q : .; '. . . . , . f, (i * ,,.; .
9.... 4 -. ' , , , , },.,
- ......; .e.
...y
,,h.,., 4,...,4,....,.!'..g . ..f.1 ,..:..,.. . . . . ,,,
.;f r :+.}.. : :..~...n... ., ,+:.,;.,_..'..
.. : . , .: ? . s
?
. . . . - . .: . , ..., Q; y y. : y. ) . . ...,;. :
. : ;;.-v.;;;- ..-..
. .: .y.f. .
V . c.
4,a---,,.. -?' .' -;.3+
.h- "y, :.:; i.'. ?.;'s., _7:~
r....
- pi.
. . : * , .f, a .
- _, y', q *. ;-; n. ;. . . . * ,. . .
f: _ ; .'.- ._x . ,
- 4,_ . '"1.
- j ;y . .;,. ;;: - < . ;s <;*;
. ,,- _ ,. r .:. , ,.-. r .".. ,;;*.. ;;M,y:. ',. .. .n.. :, ., . . - -.
.; ...j.t
- -.. .. x,
- c, . _.:;s ., ., _ . , ., . ; ; ,..p,'. ..
, - : '3 . , h* o :;, . _ .
g ;<
,. . - . ,,.. . : . * : - ... ', . : 3' ,;." . q:. .:
-. 4:
1 ...;- : .,4 - . L, s
. ;. e . .? '
'.: ' .. ,3,.,.,ff,,.; , - : :q: : ;. .
'..,M
,. 2'-ca..;..,- ..:..,.,.,%
.. s.~;.,..,..v$,-'...._,.; . ._ s.,:
.; 'g", '.
..;.:....*..t
..* ".;,..g.
v
. .: , .:; .. . . .: .i *y .: ;' ,; .:,. ,3.
,.,: ,s'...
..s. .n. . .:-a.r,'. . . .
..- ..g..
.z.....,:,.,.....~~ ,,.\..,:
.._.s.
- . . .
- :,,, :.. ,, : ; :. ,;, :.. . , . , -.y... ,;
t . . . :n '. ." . o.i..j ...":.
n . ;;u ~.. .. : . . .:
3 . . a. :.. :. a. %.,::? ... .. .,v...; y..:. Lv .1, e .:. : , . . q, ...-,_: -:; , .:,
.~. l;;;,. ; . . ;;_.3:,. -.
y
.f_..
, . , . , . .. , !: - '/ ; . ,.
- . .<
- . ... .._;*a.- .. .. :.e. u..:.. .,,'.%.. .
g .
_ [ :. ,, Y ,. }3..*. ,. r.' ,. ,;_ - . g ;; .;y w.
. )n.,.._;.. ;.e :,_ .
._a ': . m.: . _ - .: ,;. ...Q.-
. .y,
- i . . } .+ 1. , ,.'. , s.; [.' ' _- . . . . > ... ; ; . : 1_ . r ..._ _ };:3, r ,. ;
ip ;, , .,
. . , , .,.o,._,
.. ,,... }';f. ~ _ :. ,, ~. l3 9 [; ; ,'; _, . . ,.,., _.
,. _.;;p .Q .
. . . n _ . . ,,yx
. . . . . ... s r. .
.fr
- f'
'I fjf h. , [ .
";.;V . .;.. . u ;. . r .. ..: e.:
-N v 7 ' :,: lY. > ;4. , *. <#.: +&'. ,nb ,N.s.'. .v, ~.a.;; ' q ; - ,b .~.; 4 , .cl..-8.t; Q.:.m: : :.. g.::wc:::e - : .. . ::: ,V.. .:.?. . ?s.+ 9*"..:......'%..3
- . u 2 - l ;;. y ':?.::-, . . ' . . .*
. . . . .- - . : 6<. :. ;n.m. . ., ;- , -
. . , ,. . . . a .A,3..n.. ' L w'- .. :.N: A. .. . . ..: :.>..: .^. ..:q. ;r. ; .m. . . > w
. -' : . ..:s: ., O. .y:,,h .: : v. ,n. v. ;..'n.
.. ).
. , :.; .- , ' ,.?..y.. ..fL. 7.
- . ?.
- : ,- . . .,.,c n . .: .. m .-: ... . .. . a. . ::,.. : ~ . . ::2 . :cn. .:..
. . , . . . . :*, . ..y:y, . O. . F......c.... ..:. ..
. :; ::?.:.; ;.; . < r. - n. ::.gm. :: sy .. .: 4.w:.% = . ,, :
. 2 .. < .a .: .. : ; ; i ,. . o.
.: .y . ,; .t.*:~.. ..,. .. ::. ;r. . p, ,:+.; g q ~..e..n.... y g .3 , e ?. ...s.-:.~....; . . - :.:. .: ; .; ;. .; : . .... e ,,
< g: . i: . .. : : .; . .;: ; -:. a ., . .;
!. ; ..;g. ,;, . , :..a.,......:n:.
. ,,.j;; G, 'l(. '.,. i.: }- l f.N.i. Q ,; .b.N.:'.u,'&,;. .$. : ;. g. , - ... .p >*f M '; f.; };W :a,h, ',f.:l; g.D. -l ,4.H:.4... .):-i1.. (.l ;.,',y Q V..
.'. l,. .l .[. i..*}:: . ', _ s. * -[ .9. *
[, c?'f.%. o -m:. :.!:s 4 ;;* . .
. :: .. w.. .. ... ;?, .q. . ':, <
r j 4. .: +.- . .:
, . .. . - . ? . ' a.' :. . ,, ..
- 5. .
- u.- - .- . 4 . u s
- .: +::x, i..q .> :) .-, m.a:
Y. . ;.s. . .:, ,:;.
~ , ..a:g . 4.:...:..*......,.-, .
.y c.; .. .e..; . ' v . 7v,. . . . :.
- :. . e
<-..\;9 { . 2 v,%. .
r
,.e.
, . , . . . , . . .- . .. .. - .., -.,9._..<
- e
. ;u
. .:..'.._5.,,...,: ,. *- ..,;..,..=). .s
. . . 4... ..r.
- ,, .; . .v.;;,.n ,, *. .
. j.?. '. .,.
. .< . .. , ,...p,. , - ; s.
.-. y ^.7. . ,, , .;.. :s ;.. . .
.; w ,-
. . .,F. ..cy'.* :,
- s. , .
r.,. ,o b-' s .:. . t z. e ;,-v
- ,,,..).y.- ..'.'li.->S*.,..,,;,=....
.,..::_.s,
- s.'
,# .m.
,- f: ; .* :h ~ .. ,. ;
'l,,.,"*\.< .. -:. . *';*1..
. . '.sll:. s'- ; , : . ;. . .i*.-. 9-
'-. . .. : . ..,,..9c._ . $ . : . . .y; ,. ., ; ._
l
. . A. :
- ._.. . . . y .
,- ,,_,k.,,* .' , l'a ^'s_ ;
.e,. .y,,.,.3'.
t, .*. . , . ~ ;. .e.. . . . . 1;, _.._',';;.. .:.. i, : n. .+ . .r,_ . ,..'n.
, , , ei ,' . ' .
._...,,., ., . * *,.> f,., .. ,. ,e s_,,. ..9.,-, . \> . '.,q..
+-
.} - - ,. - .c
.,.r .. ..j, ...,;. 4
. _._ s. , ...;,,, . . . ~ .:, , . . , .
W. .o# ..v : . . ,. . : y * ,,:,.;.,,. -.
..:. n .s - . a. .,. .. . f g .o. , .; ,. % " .
.-.s'..)
.,..v,....v.. , ifc a. ...; .* - .er..,,,,<.....,.g
. . . ' t
..,.":..; . .- .,.'- *, .. ., ._; .,. . ,....-*Tg,,,e..
- -'. -" . , .?.- . .- F..?.',,..- . . , . .' '.,.t.,.,. ,k. a.,,'r.e-
. ' ., *s e . _;,'.. .
- ' .i ' . , . . . ,. ' . .
.r'.' - ' ** .. .
- . .'. ',. *: ' . ^. . . ' . ' _ ,..
'.-[,.7,',.,.,...I..
..e
, *. ,. ,y, j'.
} . ,i ' , { ,. , <. , *.. ' , ,. .s,,. , . ..j s'e .^
,' ' * - . . . , . a- ,, . . .
.,;....:.'"t-, ' ' ,t * [, - . 7 ,., ..((. :. . . ;,.'....] f '. '; . l; *. .. 3, N /' .f. g..f.f . " . . t ,,,,1, ,f,. ..*
'.l
.,,'s *,; ^ :' . 4.,i,:q}.v.s,,,'..
' j ,
.,.c..;..'
- . .,..es..
.,.- r
. ,.'.e ,. ;,' :;,.". .- : .: ' .. *:..- , ! .- ,. j . , .r+ ' . -
J/ ~,n. 8,.; ,.,3,,.. ,- .
, , . . +.*'.f
..,.......4
. t .;.., r.
, . . 4- ., , . ., .p ...f.-- .c p. :.. .
. ;. . . . ;g - : .>. . >;.. .. . ..-; ..
. 5 .
.s- ; j ufe. 4
..-... c .4. . . . . v.,,.. . . . 4,,
.,',a.s
,.;;...,_...,4..., v.. 'g 1
.c...., . 4,. : T. ,. ;
.. .i .. .. : /;,... -,..(a. ,. .;...._.3...v.,....:..
. m
- ...+,- .,,>;;~.;..~..,,....-?. .. . - . .:.. ... ..
,, .. . . :. ,.. .- - ,r ,.,<..,.;;..<... ;. . . . , . , . . c, .>
. c
....,.....u...xn.c... <f . .,.r.;,;; . , ..-
..<,y; . . ...;,,;,,...-..y; e, ,,., .,~.......,....,..t.,.
c .. . ,. ..,.7. ,,
- .,r,.'. .,
.,;,7.,.....,*;,. ; :; . - .. . ', <...:: .. .. , _ , .. , _ ; ; .,
- . ...
- . v;-,..s.7 e . ..;,.,,
- . _,s _ .R.j . < 3: _ y. ,., . . . ., f, .;r;, ,.. .. .,;
e
..,.g.
- , .:y...; :.
.-g.. .,v.,..v,f.,., :...,,.
,. 4
-"- . ..'; - g.
..-..c,.. .e..,.. .,..... .:.1.....t,,..g<...r.
- .- .- , ,: y, . - . . . . . . - .. .. , . . .
, . .:. . . . -L , , . .
.h. .. '. T...
. ' 4 x L ..':-.
,.. s. . . , . ,..;..,.,....,.a..7,.. 3.u.- :. .a. _. . . - ,,...:
4
,c... ., . :
. . , . ..c-,y 9 %.' "..^ . < . , , .: ,, ,{_ .b::. . ..:. y ,,. . .5.
...- . 4, S. r . . *i..' ,..,g,s'.*r ' . g' , . :',,. '
. ' ' . ;- e. . .z'
^- y .:, , .'- . ,. . q ,. u a./.
-*. ,4 . ; ' ; l; -, . .,,;"
,', . . . . . . , ' . ,' ,l*,, - ..
.. . n.
,. *,.:...,.,.;i.,:,,+,;.*',;*.'p* ^. , , . .[,
- , l ,.
.,f
.a .4 .; *- ( . .
Hr .Gl; ." :: . ,:j t2 ,;(. ' :,q , y ' ~'
_.l' \* '
- b :.' 7......'.',.s*,&l,..,.6 .:r. s.:%.. (.
.t G.: .. *j....'i,','.o'*:,.,.,.;,":?y y :
y,,.:. a.a: , .y
,f. .ue . p :;%' t' ** c., ., f. *:. "R.). . ' . ?a i
g
- .....:.... - ' ' .- . . - n .;.t,"._ ;.. . ,- : ,; . u l...y'....',
- *e.T
' F. p:
. ;.;... x, ' ,w.. .;:c :.:;;lq ~:: ,q :.3. A_ i...;w. ..,, l ' ,c . ' .:
, , - .., y . ,.:.v. . -j
.. ; , i, * > .. s..- ; ... ?. : .,. M, ,.
-e..,..
,..:g, z .. ;
- 'v.
- ,. . l'
- 2 . ~. . . ;; ", . .
, . ' , ' .. , . ,.s s
..;..s-
.
- 7'.-- ..>. . S.
. f .
.c , ;.
u 4 r,. ,.
t, . ; ! , , **.i^ ., ._r ;:l.. 0 d;; - .?. T ...!'~ g . ' .' 4
, , ' ,. ' ' . . . ( ' + , ....,.:....N' .s r, 7. + 4. q . '. .
. . . ,. Mr , ..;i . .'.a 9, * . ' , , ..,"f . ,. . n. .
- .. / ,. . j , %- d'a' '*l-- /. =.5".'
.N . .
s..
I ^
8?.J/#J " . "" . .- . ' ;2..+/.- ;-
f
^\..,. 3.... '.i.*'t' 4
.. * '8.- ';l,,'E..'.'~j",^d'.'**..
. i<.'.'. ~ - -
-&; i. '$, .:a* }l $ ; l.. '.g'l %. '-' /.* . '.;. l ' 3 :'. .' h ', ' ; ..
- q^:l,**.;. ',*.? \. .'T . ,;; .';;Y:;H y;. . & ; i f ' . '*,' .?
- l. , . : [_ ', : " _ . [ ,, .l . * *, . ' ' ' ' , . ,l{ ~ ,: - J, ._ :. , . t.. .-Y: a; : f. ;
- .,.,'.",,[..l,..:.-.'_. . . . , , . . . , . .
.- : :.2..-,.'-9.'a,-
,W.? ,t, 4 ,, ;j, a.r . ,. *: , .. .. , , ,
,....::...:..,..4..4..:,.. ,.
- . ,. - . 1. 'e*:., 3 .? . n y. , ..,A. :%=,.,,
^;}y ; :+5::*]:,n
.-.... ~. .
- .-,h-;.. . . . .
- *.-
- . , ,. . .,)j.;; . ; * ; "s%. ,
,w 5 nl', ; . f;,g.r g
- j,a ;
,;._., . ..p -3^
- , . ,, ' . , .' ['_ _ * ,j_- , '. *j~ ',?l_ .,;' .
' _.,';,.'*, _ - _ ' .' ' ; ;l* , .
.. . . .; * , *. [ , ;,
- j.;j . '.,'e,j . .; )* *fg^, f . . ,} }*"\ l. - (,.,,;_- ,, ,**. . , ;l' 4 ,, i., .. . s ..,,. g. .,, .e.) , .. ,, .*
,j';g' ,. l' '? - l * **j [ "'
,[ }M ' . .,
, :. v _ *! y _.. I' ,?[, ' , ; %' :- k. ,J. j * . ' ' , ' ' - ' . , .:
'l) _ f Il . f;. V. ' ' ; . _. ;, '
- s , ./ l
.1. _; ?;)., *[;; y , ; .. ._,;, ; . .; : I f ; a g'.,' , . ', . ,. ,, l _l ;;* .s,
'.k.'.',...'[.,
' '.s.';e . , ,- =%. 4, u.h'f..'* .,<k.--,; Jij.,.s.- ,,. , ;".,.'.,'.'f.y.[fl,'k,.;';,.["..,,.'.',.*;..*".'"; - *
^
2 *
., . '- ;...* ; .: ) p .:. '.
. . . ;::.. ? , -.f rEl-* -*^'ty. , , , . ,, ,, '. . [ J. e ,, ..l4;.* "'s (. ,( '. Cf .# . *i m .',',$ ' .. .,d n .O. p*'N'[ ,#
' . . . . ,' . , ..+. s.;: p. 'A.a 4. ,. .". W ., ,.:7,
.+.
, <;. ; - . , ;. ,; . : c - ;,.,.<:)+. _
~..,*;',. .
~
e, -
. . . . , . ... .. . . . .s. .* - .. :. y. .,. ..*. - - .
,o -
s .. :, . y - , ..,4 % ~ *:.
^' ' ' ' .: ,f Q :.!n} f,Q?:}f&., $,Q .lyg. .ll.*'h. [f::%' .
3* . .y;,
i L _7 _ ' L. L Y'
- '- ).."I'. Q;l *'.l. ,..}:[.._. & ^'al h ' i^ ** '
- ' "':_ UI' -', ? ;' *; . N . . ,c
.'\ l ; _." _ . ' ' _ _
" ,I ,_.. *. . , - ' ,;*9' , ,
. , . ll . * ,% :
Q,*
,f* i'
. .^,' M ",. /;.fi i,,9
- , '.. ':: ', (, f, . , , . . ; . . C ? J . .
. . . . 4{, - ~j ^' - - Y Q .5 [ *: , '/,1
. f.. .;. .,* -
- . f ry o,q L .lg -Q y?";* , f,',), . ". .k-G. ' C' %, ~;- l,. e-: );e s . h*:
[.*'_*. ' ' .':[;1 ._. . ' ,* ' ' . . ir - '
'll.. '*[-
^
m.,_ y' . ' ' ' .j . \ .,-' '. ;>*._ . l: -
- ';: {
> . ;*.y_g y , . . .~
. - g;: . , L ., +- L.. W ,(" .;.u - . ::,' -
- y;';. ^ ' ' l % . _ _l* .Q _ :, , * ,'; ' .#. - ll '.W:;:':;.ly:l l 'LW_ *M ;Q ' .', : '
,1;. ,,;Q ),a.;Q, .sc.i, , .,.:q;',;;_:.{ j o : p;,W&.,y'\ "j?. Q.)y'l.'y *;;;y*; 9
' p , :;p ;.p.",.j * :,;. f . ; : : .:l f. :J : .
,~.i
[ ', y j yq g .;;,q, .ph. ,,Q.j
.,,,:,' , . .. 1;(';,q:_:. -:gy!;:f.. y.R, . t g. '!..d.
. . . , . . p.. ,* ;i.
.y -
.. - ....t,.,.. .s,.1 n .. ., ..* . . .* '; 4 ;- ,,'g
,, , .., ..... a., . . ,
, u.i _
*..q...,'.: . s ':*s . : . s.: uj s
..?', , * . . 2'...f.. r . . }: : .-
*'l'.,:' ".,';.,, .!,. s: ' ;e 3, . l l;, -"., .9 , . ;L: . . "; :.'. . _ . '
,< .L . ' . , . ..!*
, ,;;;, g.fy . AgQ s/. ._,t,. f.p4~?'.h
, ; s '- ; .,
- 9. .,--,-,.q;;: .-. ,._.. _ g . y,.. .' , . .. .,. . .
"; ' . : - ; gi_-- .
, ': ,4;;m:: ':.,; __ _- . , . , . . ,,L. >
- . . n; , ,.':v< s ' l ,L ' _ , ' - {l;;;. ,.y... f_..q :. .;y ps o .vyg Q);;p.;;.l;,
* .. '. i. pw. ,1lg.: l,).g3..; .. }' ,;- :
s _
.: .e, . ,,
. .., , e ;. : . i .
, .v),
^
,.a :
- ; .s t ;, _ . - . . . . ... ; ..
_..,;..,.;:..... . . . a ,, < . ... ?... ;
; s. :.,. ;. b' y .p3 ...l, , .:.tj..y ., ~:, .,p., ::.;.3.. .,,._..;,!q :.. e ;
.g ... .,....;._- ; .;. <.....,....,........cD...-p;.;..,s..,.n.q; ! .._ ... .:. . .,.<,..,..m
;.,0.3, i3. 7.. . . . , ;. , ..3,....,..,.,
gr 9.,, y,y._ . ,.,3: ,;._c ,gg . _ ,;g . .,. , ..y
.l . * -
. , . , . . , - . . . .e;- ; . .. . _.. _.. .,. . . .. ..;_... _
a .. ; c ., _
. ,.;.~.. ,
....m
. ; .. . .- , . }:. . . . ... . ... .t.,
c . g.t_- . s,. :.v._ ~::.... .,.c~q 3,
.3 . ,;,.
.-v
,. .; . a,p._- , n.
. -p s .;.3.,; ,.
.,g ,_. 2., .. .n; ,! (;3. g,,y..+,:.go
..y. _,.
G
6 ' - ,- a 'i *
" i 4w% r,isMW_Wyc x ' M > g; . m 9
QMun 1 na a . w omee w g ,m n n -sxs x, x ; .
.(.
g7 c4 :
+.;.m~ .3' p :spgy:p r ..*.
': s' ,1 n pJa 3.c .w y e? q Q r m)t r_ j;s,,.t
& O *w' v.,f}.
-m.
n Q,v, . a , \pa,- . sv ,
. I a
r k;j n.. _
,. as K -
A :- l,'eih(d 5 + "m.h. L
.y;w ' ? ? m3 3,
- x p
4
- n ,
W %'uwdf,;y j JOFFICIAETRANSCRIPT OF PROCEEDINGS. i m ww- e , r < kMNkh(;s,e man.b pw %v, agmg.mo g%g r ,;h$NUCLEXNEEGUL1TORYECOMMISSION- .s- - _c. ~
?
- t. - A .e y v o -e Y s w^ sr w -z!. ,
4 4 t
.t
+
, >i
? 'f I r . , : . ,,.k^.i, ,..a. . ., .
% > ., *, i
, 7 , _
M. .uSMh{h;h' N W ,%d?,uADyISO.RWCOMMITTEE TON t REACTOR LSI.FEGUARDS d m ' - w T W 9 y< p %g g @%w .g 4.%* -rf-M gi pp:ehM'
~
%M:%
.! - g}i R N.n eq>Q M
.%. .3M .M,a ys;" bl - e 5q g[ %T.
t =:/ 1 5J
%,u t
i 4 i
'$ " ' k, '
'C i
fi: r s
'W
; -- ,Q:: M, .o s;v(,
g y A, y g; p q ' ,m+ . r < > p ,a , yw s
~
,; "p- ," -
,.f
; -p n
L9y&p.s.o;,p;GMjy MQ, % ym p ._ ,w Qy W;Q[n - j& t _, n f,e <>'x
* , a ,3 - - ' , ,
e[-s
' L:q pA w..' y Qa- ,,
m sd, ,. . ,
, u @,
q >- ,3
, u. s .
1 o < r .
. .> 4 ,
f hb b [ . h1 7
\ .x- A ., c., .. .. N ,
ef. 2' i kw m oikx
? '
a h ww. aw xw , ;, v N @sp$es&n%a@s+Y b hmd w nme M y> sw3.P,C. 's:y6
~ ~ -r <
Yg;;LPROBABILISTIQ ~ A. m . RISKiASSESSMENTJ < u' , 1 w< ll l m* ' W ;f
%q. y[: L ' '
.L .0 j w-.. .W h%ylm , . ,;m$s ,& ,
&3,M I. . . . p ~, - -. m, . , , ,%s h
- m. .
c,m Ij w% - ;e e s .,- c ;e "
*~ ,
e .., , $ {. &Eib Y $ v.a: W' k'h hn' ;Y , > O V-' t j {l" ' p-; ;$
'1 f
Zb 7$'MMp @&@f,?? jf:y ' M .b)y ' e' jfC/]W?&ldlQ,$J{M"' + d[; l M c {I:r d ^i t y g % g., +
, 7 p' q' 'p''c ,' 1 J d
c $qm,&Y:+%p;vg Sp 9%e M p xyhN x~ -., * ,L w-.. Q Mb, < > ., e y- 'p m" ' 'v * - h 'w'J ' g v . %m2w x
.%n w' h: 9;Q':t
,j " ,
Qy w' W punm 4:Vf&fW % yS qm.yL @ M ; g,;T Mm?wWJ .saw'i .qhf p yy: iM h. r ' ! m- ' L:.u si WT;%w.' u .
^v ' ~, ' ' ' m a 9 y n'T -~a t w dayd% 7 s&n s,n Fy T
.y. ,i c. m7g qw 4 us .- w c m, - na.
gYh g.k ym A%; s W mig M . 9 , , , m
' 4 sW M6. ,,
c-'-aca ,, r w~ e,f Rw.'n+ 4 s y%, y 3@n W Ny x %p % ep Q u m @u m?W t ;f q,g' M, s v ,~s ukt m: nw c - n.s n. W W M~ sn n + g n"4 -& n hW - ~ n- , ~. mv c . r M w:4
;a' Am o er w
,t
.n c e^- WT M, u L " s @. %bMah,-(MgQDOCket#0;:'$ NN av, 4 ,a%n s M pg',;u <,>:V %,.J ,~ W); , $%as$as%gMGi7FN pQ%@ M;sM W b w w. - e < mA c 7.:h; * >> .
- : ,- +. 7#r< f/?
<A < J "J % ?
.m wm s aw m ;
mm -n ~91. - n %e , > ~ J m
> ~i hh& h.5)ffk *+ f ' L >,jg% > j ' 1! l0l* i f.h%. > ' O ll' 'y
- L, , f Q;{Q A
%% pmA W + ' Wh3 #/WA6
%* M,..;Q.lf ' i
%.. ' yn. c.e b,mn,' ,-
o
,WlW .
^'
V , ^ m , %j ~ 4+%-b:449% tW:dtw%w1;wk Ac%r,s - > . , , - x . m, u- ~ a-y;n
- a. 4 WJ<v.v s ;
Yh Yh h O ~
. Q,,EYh.g,' g A;,
O, % y i -
. h'Y W Byg gj+M ,djWH @h' g~4Qw (< . .
~. t ,.
gp%ggy n Ri @h.hkY:9%e. # a- w v ~-w s 4 - um Hms*s. fA r
-.L+ Ua, F% e ,u gh 'nm.m
%w A O ff 3m n& % ' % W~ PG m ; ,
- M T3 w "'d i' L ~ fy' :N e
f rWo M.h h1ASB-3004635F g' tb-d:u4G.. zM 9( N&m@NhddhdW0rkrOrdeA~ y khbh
- ,w& tn4gme@w ',%p b- g9 rMr NN D M;b , Nh k
g.n,
$'9 m+, ' a < W>
w + >
%m,
, ~ .
w.
+~ -
$~M e
h q a45mn w oufp;s wmmn s wg w -s ~ j r> -; ' ' w m 4te y q 4pp A % p.pp am e m m;m.o.wu wAu se .. n
'1 x
; ry%,. $
e w
< W.; 2 xn,m,.x a4 i
,W -
~
%+:m 7 5 69iNrMW:qg.%%mam fML er < .; M* 7,;W 1
3-M *
' 1** ! r'
't s
8
*'J^ t kgg; djDf'bWi%qp k:b '+
- t ' ?.\
A y&g w; My MMW'k+W Wl% zf y ;u v-
> c 7
+ ,
c F
.'I'. : m v
b- G:<M SW uRmfM;p ~ mib; s4 i
, m; u" ., n'W
,.,.4
,h
. * . ile- i ,c J n.., .s e
t V :. d MmQ,!bg % @W.y-W@( r:.Ws7[LOCAT10Nb 5 Rockillie,MD? '
-m ,
q M,Ws' v - av JWQ~ h - ~*. dM M
/ '
" 4
%' . tfu.& .adbQ-hW c g D ~ W w.. anf,p^- 8 8
~
hML,<pa .iDATE: 4 .iMdadayl ' January 25,1999 ' y$m % w$w o , . PAGES:1 - 195 ' 4 nw-.,
.K /
ay - a A s~ , c p v.t , g ,, o, ,,'<', . 1 ,-.
,.f c Q. s
;s t&.~G
" v. -k h. ,
g, n+. r u 6 ['
- m.):c dd. ,uy.g n "%w:.
/ ,p' )' 3y ,
%M{Qg#,.,k. ppm;n %%UT R.e u' $hM[k;; NkNbk %. . <44g , w , $WANN RILEY & ASSOCIATES, LTD. a 1025 Connecticut Ave.,NW, Suite'1014 s h a au~ q e,ne m-m y
% . ~~ .
-l m- wN h '
4 Ln-5 g " c. g*M -'w an yl.6 V w ' .lY $ O'.
^
u
._' *I amfE s_pamn0 Ne sf l .
t 64 Wl*f y h X kNf, w, j,gs 1 1v. 8. . -u' 'lA>8:0$ pphj lt80 u _c.J$skNe _ m _ , e_ _ x,__ -
. . AT.
F l r
)
i I i i DISCLAIMER UNITED STATES NUCLEAR REGULATORY COMMISSION'S ADVISORY COMMITTEE ON REACTOR SAFEGUARDS JANUARY 25, 1999
-i The contents of this transcript of the proceeding of the United States Nuclear Regulatory Commission Advisory 7' T 3,
- %./ Committee . on Reactor Safeguards,: taken on January 25, 1999, as reported herein, is a record of the discussions recorded i
at the meeting held on the above date.
]
-This transcript had not been reviewed, corrected' ;
1 and edited and-it may contain inaccuracies. ;
s
.N< J*+)
9 - - e , ,- , __ _ . . , . . -
, . . . . . . .. . - - . - . . . . .. . . - - . . - . - . - - . . . - - . ~ . . . . . - . . - l l I'
- l. 1 1, .1 - UNITED STATES OF AMERICA L
l 2 NUCLEAR REGULATORY COMMISSION f' 3- ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4 ***
- 5. MEETING: RELIABILITY AND PROBABILISTIC 6 RISK ASSESSMENT 7: ***
8 U.S. Nuclear Regulatory Commission l 9- 11545 Rockville Pike l 10 Room T-2B3
' 11' -Rockville, Maryland
-12 Monday, January 25, 1999 13 The subcommittee met, pursuant to notice, at 1:02
- 14. p.m.
15 MEMBERS PRESENT: 16 GEORGE APOSTOLAKIS, Chairman, ACRS i
'17- JOHN BARTON, Member, ACRS 18 MARIO FONTANA, Member, ACRS "19 THOMAS KRESS, Member, ACRS 20 DON MILLER, Member, ACRS 21 DANA POWERS, Member, ACRS
- 22. ROBERT.SEALE, Member, ACRS 23 WILLIAM SHACK, Member, ACRS l
.~ 2 4 GRAHAM WALLIS, Member, ACRS 25 l
i .,O ANN RILEY & ASSOCIATES, LTD. l V Court Reporters ,
- 1025 Connecticut Avenue, NW , Suite 1014 'l Washington, D.C. 20036 '
(202), 842-0034
- . . - - . - . - . . - - . - . . . ~ . . . _ _ - . _ . - - . . . . - . - . _ _ . . - - . _ -
2 ;
.1 PROCEEDINGS 2 (1:02 p.m.]
! 3' DR. APOSTOLAKIS: The meeting will now come to
-4 order. This'is a meeting of the ACRS Subcommittee on !
L 5 Reliability and Probabilistic Risk Assessment. I am George ; L6 'Apostolakis, Chairman of the Subcommittee. [
.7 ACRS members in attendance are John Barton -- will 8 be in a few minutes -- Mario'Fontana, Tom Kress, Don Miller 9 will join us soon, Dana' Powers, Robert Seale, William Shack,
- 10 and Graham Wallis.
.117 We also expect Mario Bonaca, who has been selected 12 .as a-new member. He is expected to be appointed to=the ACRS L 13 in the near future.
'14 'ACRS invited' experts are'Mohsen Khatib-Rahbar and
'j 15 .Jeff' Kaiser. 16 The purposeJof this meeting is to discuss the 17 possible use~of frequency-consequence. curves in v p 18 risk-informed decision-making.
$19 The Subcommittee'will not, review proposed options
;20- .to make-20 CFR 50.59,. as was previously announced in the 21' 1 Federal Register. On December 23, 1998, the 22- Subcommittees -- I guess there are two subcommittees --
g 23' DR. KRESS: Singular. DR. APOSTOLAKIS:
- 24 -- singular -- the Subcommittee
; 25' Lwill gather ~informationi analyze relevant issues and-facts i'
y'- ANN RILEY-& ASSOCIATES, LTD. Court Reporters 0 1025 Connecticut Avenue, NW, Suite 1014 !.' Washington,.D.C. 20036 l ,, (202)-842-0034 I L. 4 f Vl w y - v - '=
3
- 1 and formulate proposed positions and actions as appropriate
^
r /\ i, 2 for deliberation by the full committee. v J 3 Michael T. Markley is the Cognizant ACRS Staff 4 Engineer for this meeting. 5 The rules for participation in today's meeting 6 have been announced as part of the notice of this meeting 7 previously published in the Federal Register on December 8 30th, 1998. 9 A transcript of the meeting is being kept and will 10 be made available as stated in the Federal Register notice, 11 It is requested that speakers first identify themnelves and 12 speak with sufficient clarity and volume so that t hey can be 13 readily heard. 14 We have received no written comments or requests 1 m (_) 15 for time to make oral statements from members of the public. 16 This issue of using the frequency-consequence 17 curves at the release level was raised in an ACRS letter -- 18- actually an attachment to the letter -- last July in the 19 context of making 10 CFR 50.59 risk-informed. Since then we 20 have had several discussions among ourselves -- I mean the 21 members -- regarding the usefulness of such an approach. 22 There have been several concerns voiced. We have also had 23 some additional work done by Dr. Kress, so today we will 24- have another opportunity to discuss the possibility of using 25 these curves in a real way and see how the uncertainties I)
\/
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. .. .- ,. . . - . . - . - . . . . . . . - - - .-._ .~. -.-.-. - .- .... -. - . - ...
i f 4 1- that are involved can be handled. () 2 3' In'the. process of learning more about these curves,.I contacted a few friends in Europe and I received 4 information from the Netherlands, how they are doing their l- 5 business, and they are not using these curves, but I was r l , 6 surprised to receive a paper from Switzerland, where they 7 actually proposed to use frequency-consequence curves where I-8 the consequences, the equivalent grams of cesium released, 9 and I read the paper with great interest and I noticed that 10 it was co-authored by several colleagues in Switzerland, the 11 regulatory body there, and several colleagues in the United 12 States. 13 In fact, these colleagues are in Rockville, so I 14 thought it would be a good idea to invite the lead man from () 15 that company, Dr. Mohsen Khatib-Rahbar to come as an invited
)
16 expert and talk to-us about that approach and maybe address 17- ~ some of the concerns that the members have, so I am very 18- pleased that Mohsen agreed to come. 19 -Usually the members desire to know what the l
;20 qualifications are of the speakers, so Mohsen has degrees in 21 Chemical Engineering and Nuclear Engineering from Cornell, a 22 Ph.D. --
i 1 23 DR. KRESS: We-all know him. l . 24' DR. APOSTOLAKIS: Not all. l 25- He worked at Brookhaven National Laboratory for j 1 l l l , i tb ANN RILEYJ& ASSOCIATES, LTD. [ Y\ / . Court Reporters l 1025 Connecticut Avenue, NW,. Suite 1014 Washington, D.C. 20036 (202) 842-0034
. . . . - _ - . _ - _ . . . . _ . .___._m._ . _ _ . , . . . _ . - . _ . _ . . . _ . _ _ _ . _ _ _ _ _ . _ . .
5 1- -about 10 years, where he in charge of the severe accident () 2 analysis group, doing a lot of work for the Nuclear 3- Regulatory Commission of course. He spent a year then at i + 4, the'NRC as a Visiting Scientist, and then since 1990 he has I l 5 been the Presidentlof Energy Research, Incorporated, here in ) 6 Rockville, and he has been very active.-- well, his company l t 7 and he himself have been very active supporting -- providing I 8 -technical support to regulatory agencies around the world <! 9 including our own here; in Spain, Sweden, and Switzerland. L10 So we are very happy that Mohsen could. find the ; i 11- time.and join us and enlighten us -- we really appreciate 12' it, Mohsen. I 13 DR. KHATIB-RAMBAR: Thank you. 14 DR. APOSTOLAKIS: We are also pleased that Mr. l fA 15' Murphy has agreed to come and Mr. Holahan. This is just to 16 exchange ideas, as I said. We are not really going to make l 17' Lany. decisions, although the Subcommittees of course usually 18 do not -
- not usually -- all the time do not make decisions, 19 but'this is really for us to understand what is going on-20 :about these curves.
' 211 Yes,tDana?
22 DR. POWERS: The Subcommittes does need to make a 23L decision on whether to bring this discussion forward to the
~
24 full Committee or not either now or in the future, n
- 2 5.. DR. APOSTOLAKIS: Okay. That is a good point.
s
- ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington,-'D.C-. 20036
.(202) 842-0034
- .. .. . - . - . . . . . - - _ - . . . . - _ .- - ~_-. - . . - - -~ .. _ - . . . -
6 l' Yes. ('g . '
.- ( j. 2- Oh -- Mike actua'.1'r put some comments here for me.
3 Okay. =We will start'with Ur Kress, who will give us some. 4 of-his recent thoughts or the issue and then we will move on
.5 Eto Dr. Khatib-Rahbar.
)
6 .IMt. KRESS: Thank you, Mr. Chairman. I hope no
- 7. one notices my tie.
I 8 (Laughter.] I l 9 DR. POWERS: Anyone that doesn't notice his tie is 10 qualified under the Americans for Disabilities. 11 [ Laughter.] 12 DR. SEALE: I will repeat -- at least the stripes 13 are running in the:right direction. 14- DR. KRESS: With that out of the way, the subject ( lx - 15 ~ I want'to talk about is of course the proposed role of FC
-16 curves, as we call them, in a risk-informed regulatory 17 system.
18 I had put together what we call a white paper for
-19 .the_. committee's use,'just to educate ourselves on these. I !
20 Lam not really. going'to talk about that white paper. It is 21 available if you want to read it. What I.am going to do is
.22 ~use the concepts in the white paper to take it a step
'23 further about, okay, given that, well how do you use these
;24L things and are they useful at all.
-25 If we are talking about their use in a ANN RILEY & ASSOCIATES, LTD.
1- 'I ~ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
' Washington, D.C.'20036 f(202) 842-0034
l l V 7 l l l 1 risk-informed world, risk-informed regulatory system, you 3 6 j; ~) 2 .really'ought to start from the top-down and look at what is l
)
needed for a risk-informed regulatory system, and what you 3 4 have to have is regulatory objectives, 'and of course the l _5 major regulatory objective you might say is protect the j :6 health-and safety of the public. That's not good enough i 7 'because you have to put that in terms that are useful as ' 8 . measurable metrics, and-if you have such terms of measurable l 9 metrics you also have to have something entirely different l 10 to those and that is acceptance' criteria, acceptance values 11 for those metrics, so that is major attributes you have to 12 have to really have a risk-informed system. ' 13 As an example, 1[ mentioned that in 1.174 we had i 14 the metrics of CDF and LERF and plant-specific values were o l (_,) 15 to'be provided and there were definitely acceptance values 16 developed for these and this is the kind of regulatory 17 objective-I am talking about and the kind of acceptance j 18 valves I am talking about, except -- and these were good. i 19 Those were very rational, good objectives. l 1
-20 I personally do not think that CDF and LERF 21: represent the only regulatory objectives and of course that 22 was recognized in 1.174. Also, because they asked for a lot 23- of other things --
24 DR. POWERS: Dr. Kress, isn't'this a situation -- 25 the reason we look at other metrics that we have continued n f I ANN RILEY & ASSOCIATES, LTD.
^
% l' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. . _ . . - _ _ _ . . . . _ _ . _ _ _ . ~ . _ _ . . _ _ . _ . _ _ . . _ - _ _ _ . _ _ . . .. _ . _ . _ _ . .
l- 8 l 1 1 to. chafe under the burden of using CDF and LERF rather than 2, actual risk? l 3 DR. KRESS: No , I don't think that's l-4 particularly -- at least that's not my motivation. I 5 actually think LERF is a very good connector to risk, and so i 6 that's not what bothers me. I just think there are other l I 7 objectives. LERF to me is a surrogate, a pretty good 8 surrogate for the prompt fatality risk -- individual risk
- 9; for prompt fatalities.
10 I just think there are other objectives that we 11 need to deal ~with other than that one, and that that'does H12 not necessarily -- it may but it doesn't necessarily 13 supersede all of the others. I
'14 DR. POWERS: Well, I think that maybe we are j
) 15 saying the same thing. Arguably LERF relates closely to 16- prompt fatality risk.
17 DR. KRESS: Very closely, yes.
'18 DR. POWERS: But we recognize there are other 19 measures that if you did a Level 3 PRA properly you would 20, .come forward with the latents, you would come forward with 21- the property contamination, you would come forward with the 22 injuries. You would come forward with a lot of other 23' . measures and that we see these deficiencies in either the
-24 measures CDF or LERF,.especially if you start thinking about 25L doing cost benefit analyses for regulation. You are not
[ ANN RILEY & ASSOCIATES, LTD. l - Court Reporters ! 1025 Connecticut. Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. _. .. . _ _ _ . _ . _ _ _ _ _ _ _ . . . . _ . _ - - _ _ . . _ . . _ _ _ _ _ _ _ . _ . . _ _ ___.__._..m 9
1 getting all the costs. !
) 2 DR. KRESS': I think'you are hitting on it. In 3 fact, I made a little attempt to list what some of these i 4 .other things might be that we are really as an agency 5 . concerned with, and~a number of these are real risk 6 parameters and I may not have all of them either. This was I
7 .just an example of additional objectives that we may be interested in. 9 Now we are interested in limiting certain risk 10 parameters. We are also interested in doing it in a
~
11- particular way, and that is the defense-in-depth philosophy 12 and I~have also lumped the CDF under that because it is not 13 a real risk metric, but it could be put up here I think, but 14 the idea is in a' risk-informed world there are objectives O,j
- 3. 15 that you want to have acceptance criteria. There are ways 16 you want to achieve these objectives, and I list these 17 safeguards separately. 'Actually, it is just another set of 18 . sequences really. They could be up here, but the reason I 119 L -listed them. separately is I think you would, when'you 20 approach safeguards, you do it differently. You want to
- 21, . lean real heavily on the prevention end, as opposed to
'22 mitigation or --
23 DR. POWERS: Well, I think we lean almost
- 24. exclusively on that --
25 DR. KRESS: Yes, so I have listed it separately [ ANN RILEY & ASSOCIATES, LTD.
\ Court Reporters 1025 Connecticut-Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 l - *y
l 10 1 but it is really just another set of sequences.
)
L sc) 2' .DR. POWERS: Right now it is.done in the ' l %J. 3 relatively primitive way -- 4 DR. KRESS: Absolutely. 5 DR. POWERS: -- of a-design. basis threat and being 6 -able to counter that threat. 7 DR. KRESS: Absolutely. 8 DR. POWERS: And it is an area probably ripe for
.9 rethinking. It seems to me that this is an inventory that 10 when you.are thinking about cost benefit analyses -- in a 11 grander scheme, not in the regulatory scheme -- but in the 12 grander scheme of. things that you want all these things in
.13 addition.
14 I still think the experience of the Chernobyl d h 15 accident'is telling us that injuries -- 16 DR. KRESS: Injuries and --
- 17. DR. POWERS: -- are the various -- society costs 18 that'is non-negligible.
19 DR. KRESS: And I do have injuries on here, and I
;20: .would add another one -- total number of injuries, you know, 21 as well'as individual risk and injury, so there may be other
'22 objectives we'want to add because.I didn't mean.for this to j '23 necessarily be a comprehensive complete list, and in 24; arriving at a risk-informed regulatory system there are also 25 other considerations that are outside of -- different than l
I' O ANN RILEY & ASSOCIATES, LTD. i~/'\ Court Reporters P '1025 Connecticut: Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
11 l 1 .these', things like caps on instantaneous CDF and things like l('~'N l ) 2 time left on the license ought'to be a consideration. It's 3 probably risk equation and I.just listed a couple of those 4 as. examples and my point.with this'is you have to deal with all these in a risk-informed world in some way. 5 l 6 Now my talk today about FC curves is not going to
- 7 tell how to work these others in. I am going to deal with 82 risk parameters and acceptance criterias on them.
9 DR. WALLIS: Do these have to be just 10 radiation-related? 11 DR. KRESS: Yes. 12 DR. WALLIS: I think one of the biggest problems
'13 with Shoreham was the risk that the public imagined or 14 appreciated of trying to evacuate Long Island.
, /,_,,\ L lx / 15L DR. KRESS: !I think you could add things like that 16 into it. It's going to be difficult -- ! 17 DR. WALLIS: That might be far more risky than the 18- actual radiation risk. 19 DR.'KRESS: Yes. Yes, I think you could add .
.20 things like that into it. I am trying to keep it to pure 21 risk' numbers though right now. That's so we can deal with 22' them.
23 -The issue then I am dealing with today is how to 24 incorporate the risk objectives into a risk-informed , 25: regulatory system. . V ( .' ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025' Connecticut Avenue, NW, Suite 1014 ~ Washington, D.C. 20036 (202)- 842-0034
12 i
- . 1 In the first place, we do have to have acceptance I
() 2 criteria, and that is a. subject all its own, I think. For 3' -the moment I am not going to say how to arrive at acceptance 4 criteria. I just want to say we've got to have them. We 5 have to have them before we start a risk-informed system and 6 they need to be there and we have to figure out a way to get i 7 them. -) 8 Then we would have to determine whether any l 9~ particular plant status with respect to these acceptance -- 10 what it is with respect to these. You have to have a way to 11 do that. -Well, clearly these risk objectives I list will 12 come straight out of a PRA. I mean those are things you get
-13 right out of a PRA, a Level 3 plant-site specific PRA.
14 Well, why not just use the Level 3 plant 15 site-specific PRA. That's after all a perfectly rational 16 way to go, and that is what I see proposed by some people 17: :like Bob Christie. 18- Well, there are lots of reasons that I think that 19 is not.a very practical, viable way to go', and in the case
-20 of 1.174 they came to the same conclusion, that the full 21 Level 3 PRA was just too uncertainly, too unwieldy, too --
'22) just too dislocated from the things'you are interested in in 23- ' terms-of the' design of the system.
24 DR. WALLIS: I don't think that is true at all. I 25 think real public risk is in'the Level 3 PRA. [
^s I
\ ANN RILEY & ASSOCIATES,.LTD.
Court Reporters
- 1025 Connecticut. Avenue, NW,. Suite 1014 Washington, D.C. 20036 (202) 842-0034
13 1 DR. KRESS: Oh, there is no doubt about that. (- i /
) 2 DR. WALLIS: The uncertainties don't go away by 3 saying we are going to use the surrogate.
4 DR. KRESS: I understand that and I am going to 5 address that issue. I think it does de-focus though, and 6 that is the problem I have with it. 7 So what they did in 1.174 is develop a practical, 8 utilitarian, convenient surrogate for the prompt fatality. 9 Now it is a surrogate.and I thoroughly believe that, and 10 what I am saying now is that was for the individual risk of 11 prompt fatalities. We also had it for CDF. What I saying 12 is for these other risk objectives we are interested in 13 preserving in a risk-informed regulatory system there is a 14 need to have a consistent way to develop such convenient N._) 15 lower tier surrogates for the other regulatory objectives. 16 That is what we are about today. That is what FC 17 curves are around. We are looking for lower tier surrogates 18 for these risk objectives so we don't have to use a full 19 Level 3 PRA.
-20 DR. WALLIS: You used the word -- I'm sorry to 21 interrupt, Tom -- convenient. Do you mean convenient for 22 the Agency?
23 DR. KRESS: Convenient for the Agency -- 24 DR. WALLIS: Or convenient for the people who are 25 subject to-risk?
- n. ANN RILEY & ASSOCIATES, LTD.
('-) Court Reporters 1025 Connecticut Avenue, NW, Suite.1014 Washington, D.C. 20036 i (202) 842-0034
14 1 DR. KRESS: No , convenient for the Agency -- well, () r"N 2 supposedly we are going to take care of their interests. If 3 we don't take care of that interest we are not doing our 4 job. 5 DR. WALLIS: But if your criterion is convenience 6 for the Agency, that is not really the right criterion. 7 DR. KRESS: But convenient -- but not at the 8 expense of giving us the risk metric. We don't want to do 9 that and in fact clearly -- clearly -- these regulatory l 10 objectives I listed do depend on these things. They depend 11 on the amount of release of different fission products and 12 the timing, but they depend on the site specific parameter. 13 They are in there. They are not -- you cannot do away with 14 those. They are part of the equation and they have to be
,a
( m, ) 15 preserved in this system using FC curves some way. They 16 have to be in there. That is what I am saying. 17 DR. WALLIS: But in picking regulatory convenience 18 as a criterion, you may do things that are very inconvenient i 1 19' for these populations -- 20 DR. KRESS: Well, regulatory convenience may have 21 been the wrong word. I am saying something a little bit 22 more straightforward and easier to do than a full Level 3 23 PRA, but still incorporate those risk parameters some way. 24 DR. SHACK: It's to make it implementable. , 1 l 25 DR. KRESS: Make it implementable -- that's a l s~x. 1 ANN RILEY & ASSOCIATES, LTD.
\/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 L Washington, D.C. 20036 l (202) 842-0034 l
t
f 1 L 1 15 ) l 1' better word. <
\
l [/ Ns 2 MR. HOLAHAN: Dr. Kress? This is Gary Holahan of ' i 3 the Staff. ! 4 I wonder if an alternative to developing new ' l 5 surrogates would be to test whether the design basis i 6 ' requirements or a revised version of'the design basis l
- 7. requirements aren't already good surrogates for_these other '
l 8; objectives. i 9 DR. KRESS: That could be a possibility. I think 10 you may have difficulty doing that, because the way you do 11 thht is you do a PRA at the level 3 and see if the resulting l 12 plant configuration that you 3ot from the design basis 13 accident actually meets the criteria. 14 Now they probably do, and you can probably use O
'(_j 15 that as a basis to say our design-basis concept hasn't been 16 all that bad. It's not -- there's no -- I don't think 17 there's a direct way to do it, though. I think it's an 18 indirect. But it's a thought.
I
- 19. But'the question then before us is how do I
'20 incorporate these things that are part of the risk equation
'21 .and perhaps use F-C curves as surrogates for all of the risk 22- . objectives. That's the subject I'm talking about.
l 23 Well, I'd like to turn -- when I_get to that, I'd i L 24. like tx) turn to some work done by Jeff Kaiser. Sorry he's , L l 25 not here, because he could answer the questions I have about i ?~ ,-{ ANN RILEY & ASSOCIATES, LTD. I
%. Court Reporters l 1025 Connecticut Avenue, NW, Suite 1014 l
Washington, D.C. 20036 (202) 842-0034 l- - -_ _ ,
16 1 these. 'These are just_a couple of examples of some of his () 2 work. And what1these are, and I don't know if you can see , 3 them or not,'because they're copies of copies of copies, 4 what Jeff did was basically took as an independent variable 5 the release fraction or a release of fission products or a , l 6 surrogate for them and varied -- he went to a great number l J 7- of actual sites of actual plants. He used the site-specific 8 populations, meteorology, et cetera. And he varied the 9, emergency response measures over -- from bad emergency j 10 response like no emergency response to reasonable to really 11- good, to see what the effect of the source term, which is 12 fission product release, has on these risk metrics. It's a i 13 conditional risk metric. This is the prompt fatality one, 14 and this is the latent fatality, individual risk. 7T (,,/ 15 And what ycu see -- ignore the lines for a minute. 16 Those are not Jeff's slides. I put these on there. But 17 what you see in the data is it scatters all over the place 18 from site to site and depending on the emergency response 19 measures you have. A big scatter. Look at those kind of 20 . things, especially up here where the release fraction is 21 pretty high. Now that's -- 22~ DR. SHACK: Now what did he -- he went to a
- 2 31 specific site and we see the vertical distribution of dots 24 as he varies the emergency response?
p 25- DR. KRESS: Pretty much. Pretty much it. And of i ANN RILEY & ASSOCIATES, LTD. [\ ~ Court Reporters
- 1025 Connecticut Avenue, NW, Suite'1014 Washington, D.C. 20036 n (202) 842-0034 L
. - - .- ~ - -. - -- . , , , _ . - _ . .
P 17 1 course if-you had a constant kind of energency response, l [f) 2 you'd still get a lot of scatter just from site to site.
^
L 3 But this is why Dana and I have said that using level 3 and 4 atmospheric transport with the big uncertainties -- this by L- 5 the way is not an uncertainty analysis exactly, it's a 6 sensitivity analysis, .and certainly would even make this ) 1. 7 worse. 8 DR. APOSTOLAKIS: Tom, I think we should be very l 9 clear as to what is variable here. Is there plant-to-plant t 10 variability here? 11 DR. KRESS: This is different sites -- 12 DR. APOSTOLAKIS: Different sites. Okay. 13 DR. KRESS: And it's the effect of different j_ 14 emergency response measures. There is no plant except the
- 15. site in here.
16 DR. APOSTOLAKIS: Right. 17 DR. KRESS: Fission-product release is the 18 independent variable. It has nothing -- so, you know -- 19 DR. APOSTOLAKIS: Okay. 20 DR. KRESS: If -- so -- 21 DR. APOSTOLAKIS: So each vertical line represents 22 a site, the points on a line. 23 DR. KRESS: Probably; yes. That's one of the ?[ 24 things I was going to ask Jeff. 25 DR. APOSTOLAKIS: Okay. So the different vertical lp ~k ANN RILEY & ASSOCIATES, LTD. V Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
18
'11 lines or imaginary lines indicate different sites.
( )_ 2 DR KRESS: Yes. 3 DR APOSTOLAKIS: And then along the vertical axis 4 he just varied arbitrarily -- 5 DR. KRESS: No , no. This axis is an arbitrary, l 6 it's the independent -- l 7 .DR. APOSTOLAKIS: Yes, but I mean, if I pick one 8 value say.for the fraction of release. 9 DR. KRESS: Yes. 10 DR. APOSTOLAKIS: The bunch of points -- 11 ~DR.-KRESS: Represent different sites and 12 different emergency response measures. 13 DR. APOSTOLAKIS: And different emergency -- and
. . 14 different sites.
) 15 DR. KRESS: Yes. Yes. If that's --
16 DR. APOSTOLAKIS: So it's not one site. 17 .DR. KRESS: If that site had this release -- 18 DR APOSTOLAKIS: Yes. 19 DR. KRESS: Then you_would get this with different 20 emergency response measures. 21- DR. APOSTOLAKIS: Okay. So -- 22 DR. KRESS: So vertical is both of them, both site 23 parameters and emergency response parameters, which are on
- 24. the vertical line.
, 25 DR. APOSTOLAKIS: Okay. Okay. Okay.
, e ANN RILEY & ASSOCIATES, LTD.
- '-')
( Court Reporters , 1025 Connecticut Avenue, NW, Suite 1014 ( Washington, D.C. 20036 i (202) 842-0034 ' L
19 i 1 DR. WALLIS: Without looking at the likelihood of # } ) 2 the various responses this isn't very useful, because the 3 values go from zero to 1 essentially, except 1 is off the -- 4 DR. KRESS: That's right. , 5 DR. WALLIS: But if the values go from zero to 1, 6 anything is possible, and you haven't told me anything.
'7 DR. KRESS: Yes. This is the nature of the beast, 1
8 i's.what I wanted to get across. But what I'm -- if,
~9 however, one says all right, let's use best-estimate 10 reasonable emergency response measures, then this scatter 11 collapses-to site-to-site variations, which is not very big, 12 not as big as this. And in fact I tried to draw a line. !
" 13 ' ' Now this is not a regression line, it's.an eyeball 14 regression. But.that would kind of represent reasonable is_ 15 emergency response measures.
16 Now you can't see the scatter of the site 17 variation on there because there's no way for me to do that, 18 but we found out with the LERF business in 1.174 that the 19 variation in LERF is only about a factor of 4 for all the 20 sites. And basically this is kind of what they did in 21 1.174. They took a reasonable set of emergency response for 22 all the sites and come up with an acceptable LERF value to 23 meet the safety goal. And this is kind of what they did. 24 So'what this line represents then is a correlation which is 25 a-kind of best-estimate correlation between fission-product
) ANN RILEY & ASSOCIATES, LTD. ~# Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
, - . .. ..- . . . = - - - . . . . - . . - - -
20 1 release and the regulatory objective safety goal, risk 77 2 metric. 3 Now -- and it come right of a exercise of an 4 atmospheric dispersion consequence code. You didn't have to j 5 have a PRA or anything for that. It's an atmospheric
.'1 6 consequence dispersion code. And what I'm saying is for 7 these risk objectives that I list that are in addition --
8 are LERF plus other things, that there is such a correlation E 9- for each one of them that can be gotten in exactly the same j 10 way. 11 Now you could adjust your assumptions on emergency 12 response to whatever you think you want it to be in that 13 .particular correlation. You can actually adjust that. But 14 I am saying that you can develop with such a code a
's 15 correlation, a preexisting correlation for all the sites, 16 for each of the risk metrics.
17 Now -- 18 DR. WALLIS: Tom, could you explain something 19 about emergency response to me?. Is this the responsibility 20 of the State? 21 DR. KRESS: Yes. 22_ DR. WALLIS: Because you might conclude from what 23 you've told us that one should regulate emergency response 24' .very carefully. 2
.5 DR. KRESS: -You might, you might. But anyway my
,N.
t 4 ANN.RILEY & ASSOCIATES, LTD.
\- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
. Washington, D.C. 20036 (202) 842-0034
. . . . . - . - . . .. _ . - - . . . - . - - - . . ... - .-. - ~.- . . , ..
21 l L 1 point is there is a functional' correlation between fission () 2 product release and the risk metrics,.and -- 3' DR. FONTANA: When you choose -- Tom, when you- t 4' choose a.particular value at a fission product release, 5 'you're.also choosing a particular value of the timing of
- 6. release, and the only variable is differences in emergency 7- response? Is.that correct? I t
8- DR. KRESS: That's part of the timing. That 9 timing is built into the emergency response in this case. 10 DR. FONTANA: Oh, it is? 11 DR. KRESS: Yes. It's lumped into the emergency .., 12 response in this case. -So if indeed I'm correct t' tere 13 is a' functional correlation between fission product release, 14 and I'm absolutely sure there is, that one can use and M 1(s_,! 15 . predetermine ahead of time for all U.S. sites, then the
;16 frequency consequence curves are useful, and they are useful :
17' in this way. 18 I showed in the. white paper -- now there may be 19 some discrepancies in how I've used CDF here, so kind of 20 take that with a little grain of salt. But the integral 21 .part is correct. If you want to look at what I call a risk 22 ' consequence metric, that's those lists of objectives I had,
- 23 'and --
24 And find out how one calculates it from an FC
~25' curve, but it is an interval of the full FC curve. And here j ') .
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
, 22 l l 1 I have put it in terms of release fraction. Of course, you
) 2 don't want a release fraction because that doesn't give you 3 the power of the reactor as a function, you would want 4 actual curies, but I just did it in release fraction because 5 --
for convenience in this case. , 6 But what you see is it does have the derivative of 7 the frequency consequence curve in it. It does have this 8 functional correlation in it for that particular 9- consequence, so you have to -- it has that in it, and it has 10 CDF in it some way, and it may be -- it may be built into 11 the derivative or it may be separate, I am not certain now, 12 but it is in there. 13 So, what I am saying is, if you are applied with 14 appropriate FC curves that come straight out of the PRA, it ( ,/ 15 uis a level 2 PRA, and have developed ahead of time these l l 11 6 appropriate functional relationships, then it is an easy i 17 task to develop software that will digitize this. In fact, 18 Bill Shack sent me some digitized values of FC curves. You 19 can digitize them, the slope of the FC curve, and 20 numerically integrate and directly determine from the FC 21 curve that way the status with respect to that risk 22 . objective.
'23 In my mind, this is the way you have to use FC
-24 curves. So I have a bit of a difficulty with I think l
25 Mohsen's talk where he is going to come up with actual lines ANN RILEY & ASSOCIATES, LTD.
. 5- j Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
p 23 !
-1 for the FC curve. I think you have to do it -- you look at '
, . r^) t 4 2 the curve and it is the whole curve that matters, not just
.% / :
L
}
3: different parts of it. I 4 DR. WALLIS: Tom, this is an integral. ) 5 DR. KRESS: It is an integral. 6 DR. WALLIS: So it is very forgiving about the 7' shape of the curve in terms of the result.
~8 DR. KRESS: That's correct.
- 9 DR. WALLIS
- It may well be that if you know CDF 1
10 from LERF, that different curves that look different only l 11 . change this number by a factor of 2. ! 12- DR. KRESS: Could be. I am not sure yet. But I i l 13 am talking now technical rigor. And there may be other ways I 14 'to get around this, I am sure, but I want to be sure we know l 15 what we are doing. So the summary of my talk is that I 16 don't think CDF and LERF are the complete regulatory 17 objectives, and I suggested others that would be on the 18 list. ' 19 The first thing'you have to do is develop 20 acceptance criterias for these, and there is a way to do 21 that, and that is the subject of another talk. I didn't 22 discuss that. But you do have to have these acceptance
-23 criteria or else you don't have a way to operate. And these 24 acceptance criterias might have to incorporate the 25 uncertainty some way.
,/~N l
! ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 c - e
,- -- .- . . . _ _ .. . . . . - . . - _.. - ~ _ .-. - .. - _ - . . - . . .
F 24 j i l' FC curves appear to me to be a way to provide a () 2 3.
~ systematic, consistent, surrogate means for determining a plant's status with respect to all of these risk-related '
4 . regulatory objectives, including LERF, and I shouldn't have i 5 'put CDF on there, because they are clearly not CDF, but 6- including LERF.
~ .'7 DR. FONTANA: Tom, why are you calling it a 8 surrogate? I i
9- DR. KRESS: It is a surrogate, i i 10 DR. FONTANA: Because you can take your allowable I i
.11. ' -- apparently one FC curve is an allowable criterion that 12 you don't want to exceed.
13 DR. KRESS: _ There is no unique FC curve, though,
- 14 : -that will meet your regulatory objectives.
' 15 L DR. FONTANA: I know. j i'
16 DR. KRESS: Okay.
.17- DR. FONTANA: But, presumably, you'have --
18 DR. KRESS: The surrogate is the integral. ! 19' DR. FONTANA: And then to calculate the FC curve l 20- for'a particular -- you go to a PRA, level 3 PRA. 1
.21 DR. KRESS: Level 2. J
.22. DR. APOSTOLAKIS: -Two, level 2.
m i" 23 DR. KRESS: That's why I am avoiding level 3. o L24 That's.my whole objective is to get rid of level 3. 25 DR. FONTANA: Okay. You have got the consequences ANN RILEY & ASSOCIATES, LTD. !' Court Reporters l '1025 Connecticut Avenue, NW, Suite 1014 i ' Washington, D.C.'20036 (202)'842-0034 1 I
25 1- in terms of -- () 2 DR. KRESS: This functional correlation which was 3' developed from what would have been the back end of a level 4 3, but you do that ahead of titi.e. 5 DR. FONTANA: It is necessary for -- 6 DR. KRESS: Yeah, that's what makes it a 7 surrogate. Yeah. You have to have that functional 8 correlation. 9- Okay. And I think one can deal with some of these GL O . objectives such as total deaths, total injuries, you might 11 better deal with those with site-specific regulations that
.12 :- are separate-from acceptance criteria, I don't know. My 13 approach would be to look for ways to do that. So-that was 14 just a side comment, that last bullet, just, you know, for (s
15- what it is worth. 16 That's what I wanted to say about FC curves. 17 DR. WALLIS: .You split the site characteristics 18 from the FC curves. If you just said level 3 -- 19 DR. KRESS: They are in there automatically. i 20 DR. WALLIS: And so a reactor in New. York City and 21 one in Idaho would have completely different allowable FC 22 curves but the same risk, perhaps, if you took the 23 calculation into account. 24 DR. KRESS: You could always go back to level 3 25 and be site-specific and have different FC curves to meet ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
-(202) 842-0034
__ ___.____m _
.- - - _. - .-. . . . ~ -. .- - ._ . . . . , .
2G l? 1L the same objective,1yes. j, 2 L. DR. APOSTOLAKIS: Thank you, Tom. Yes.
- 3 DR. KHATIB-RAHBAR: Let me make a comment on what L
4 Tom has said. 'First of all, if you-are using early fatality 5 'as a surrogate, I totally agree with Tom. If you are going 6 to use latent fatarities, the site-specific differences make
~
-7 Lvery little difference.
18- .DR.' KRESS: Yes, that's right. 9' DR. KHATIB-RAHBAR: What makes a difference is 11 0 really;in the'early. fatalities,.where evacuation'makes a ! 11- . difference and inhalation dose often d'ominates.
'12 DR. KRESS: Absolutely.
13 DR. KHATIB-RAHBAR: When you go to latent 14 -. . fatalities,- when you integrate it out to thousands of miles, f'v
?(,,); : 15 - the uncertainties arriving from, you know, using a straight-16 time plume model, et cetera, --
17 'DR. KRESS: And the.same thing about total L 18' injuries.
'19 DR. KHATIB-RAHBAR: Right. Right. I mean which l20' are integrated in the facts when you are talking about the 21 early fatalities. i
- 22 DR. KRESS: Site variations;really show up in
.23- prompt fatalities.more than even anywhere -- !
DR. KHATIB-RAHBAR: " Absolutely.
;24: Absolutely.
L. by,1 . 25? Absolutely. In fact, we did a study at Brookhaven about
~
'L ANN RILEY & ASSOCIATES, LTD.
Court Reporters
.1025 Connecticut Avenue, NW, Suite 1014 Washington,'D.C. 20036 (202) 842-0034.
1
27 i
~
I five, six years later after Jeff Kaiser's study, which is a [d
\
2 nuclear engineering -- nuclear technology, where we 3 demonstrated, considering all the uncertainties, the 4 uncertainties in the weather, variability dominates. That's i 5 why, as I will discuss later on, I hope that you can be l 6 convinced that you do not go to the level 3 PRA, which sort 7 of supports what you are saying. , l 8 DR, KRESS: You really can bound it or make a best 9 guess for it. 10 DR. KHATIB-RAHBAR: Absolutely. Absolutely. l 11 DR. KRESS: And what is what I am saying. l 12 DR. KHATIB-RAHBAR: Absolutely. 13 DR. APOSTOLAKIS: You mentioned a paper. Would 14 you send us a copy? (h ( ,/ 15 DR. KHATIB-RAHBAR: I will be happy, too. Yes. 16 DR. APOSTOLAKIS: Thank you. Okay. Let's go on 17 'with Mohsen's presentation. You have a comment, Joe? Go 18 ahead. 19 MR. MURPHY: Joe Murphy from the staff. Let me 20 just add one thought for the early fatalities. What we 21 found in 1150, that the number of early fatalities is almost 22 entirely driven by the assumption about evacuation. 23 Basically, if you assume 100 percent of the population 24 evacuates, you will have no early fatalities. If you assume 25 nobody does, you will have essentially the close-in [/l' ANN RILEY & ASSOCIATES, LTD. k.- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 1
, - - .- .- - .. -. . - . - - . - ~ . . - -- .~
1 28 1 population of'one to two miles, you~will have an extremely i II 2 high percentage of that that are under the plume, will have i V L 3 early fatality. So it is almost directly proportional to l 4 .the assumption on an evacuation. 5 DR. KRESS: I agree with that, and I have an l 6 additional comment on that I would like to make. And that 7 is we are fond of saying emergency response is just a 8 defense-in-depth concept, but when it is that important, and
- 9. it is very important to the' LERF value you end up with, to 10 me, it is not really an emergency -- it is not really 11 defense-in-depth, it is part, it is a strong part of.your 12 acceptance. criteria. It couldn't be characterized as 13 defense-in-depth in that case.
14 DR.-APOSTOLAKIS: Okay. Let's go on with Mohsen's
...^
(,,) 15 presentation and then ILam sure we will have discussion, a I
'16 free for all. It is'in the front there someplace.
l 17 DR. KHATIB-RAHBAR: Okay. Good afternoon. I ; 18 guess, before I start, I would like to bring to your
.19 attention one important issue here. As George indicated, my 20: company works with a number of regulatory authorities, !
21 including the U.S. Nuclear Regulatory Commission, therefore, 22 as I have told George, my presence here should not be 23 . construed in any way as me representing the U.S. NRC or any l 24 of'the other sponsors in Europe, and, in particular, my 25 views about the Swiss approach are solely my own and do not pr 1
/ ANN RILEY & ASSOCIATES, LTD.
- j k /1 Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 i Washington,lD.C. 20036 1 l (202) 842-0034 l
l'
, . -. . . .. _. -_ _.~ . -.. . - _ - . - . , .- - . . - - - . .
L- 1 I 29 h 1 represent -- I.am not a representative of the Swiss Nuclear r~. ._
- ():: 2: Safety. Inspectorate here today, I am representing myself. j l 3 So, if-there are any comments, any questions, they l i
4 should be directed at myself rather than these 5; organizations. l d DR..APOSTOLAKIS: Even so, we thought it would be !
- 7. worthwhile to have you here, j 8: DR. KHATIB-RAHBAR: I appreciate it. I am happy 9 to be here.
10 .Let me first give you an outline of what I will l 11 discuss here. I guess this -- the precursor for this was a
.- 12 paper that Chakraborty sent to Dr. Apostolakis about a' paper 13- we gave at the IEA back in 1995 which had the proposed Swiss 14 safety criteria in it. And-I. guess for the first time we
( 15 decided to use the frequency consequence curves in a manner 16 which is a little different than what was used in 17 NUREG-1150, or had been perceived a little bit by others. 18 In the subsequent year, I received some 19 communication from George that he needed some specific 20 issues that he wanted to discuss at this meeting. So I was 21 away last week in Europe, so before I left on Friday the ! 22 following -- previous week, I prepared this presentation, 23 which really consists of two parts, George. J 24 The first part deals primarily-with the issues 25 that!you had raised in your e-mail to me, and the second L I 0,
!( P[.
5-ANN RILEY & ASSOCIATES, LTD. Court Reporters ; L 1025 Connecticut Avenue, NW, Suite 1014 I Washington, D.C. 20036 (202) .842-0034
.I i
30
'l part deals with the Swiss approach. So, depending on your jm 2 interest, I can skip one or concentrate on the other.
() I 3 don't.know-how much time you want to devote to this. But I
- 4. have prepared something equivalent to about 45 minutes worth !
5 of -- i 6' DR. APOSTOLAKIS: I believe you should go ahead 7 with.the full presentation. I appreciate that you -- the 8 fact that you put extra effort to respond to my questions. 9 .DR. KHATIB-RAHBAR: First of all, let me say -- !
\
10 the first question, I guess, or issue that, George, you l 11 raised, was -- What do these curves represent? If you look 12 et a typical frequency consequence curve, forget about the 13' consequence measure, what it is, in this case it is 14 cesium-137, but it doesn't matter. These curves represent l (. '15 really several regions. If you don't mind, I will stand 16 because I can - - 17 DR. POWERS: You need a microphone.
-18 DR. APOSTOLAKIS: You need a mike. Theron.
~
.19 DR. POWERS: While you find a microphone --
20 DR. KHATIB-RAHBAR: I can stand closer to the 21 microphone, that's okay. 22 DR. POWERS: It strikes me that it does matter 23 that you have plotted 137 across.the bottom because -- l
- 24. DR.~KHATIB-RAHBAR: Yeah, we can address that, l
- 25 . yeah.
? i I
'l ANN RILEY & ASSOCIATES, LTD.
hs J Court Reporters
,1025 Connecticut Avenue,-NW, Suite 1014 l -Washington, D.C. 20036 l (202) 842-0034-l
- ~ -
. _ . - - -. . . _ _ . ~ . ~ . - . - , .
31 1 DR.' POWERS: -- when people -- 0 () 2 3 DR. APOSTOLAKIS: 'Can we wait for'just a second then, I am sorry, for him to put a mike on so the recorder 4' can -- ) a 5: DR- POWERS: Well, I am just going to give a 6 speech, I wasn't going to ask him a question. j 7 DR. APOSTOLAKIS: Well, if he interrupted you, l i 8 though,- and.the recorder wants to take everything down. 9 DR. KHATIB-RAHBAR: Okay. I can sit here. That's 11 0 Efine. Don't worry.
.11 DR. APOSTOLAKIS: Okay. Go ahead now. Yeah.
12 DR. POWERS: Well, I mean the fact is that if we 13 look at a reasonable consequence code, it will typically 14 include 66 isotopes, I think.
-( 15 DR. KHATIB-RAHBAR: Fifty-four, yes.
16~ DR. POWERS: Some, like that. 17 DR. KHATIB-RAHBAR: Rif.it. 18 DR. POWERS: For some sites I think we have done 19 96 or'something like that. It strikes me that we have to 20 then wrestle with the idea that we have not got one 21 frequency consequence curve, cnr two, or three, but 54.
-22 DR. KHATIB-RAHBAR: Yeah, I will address that 23 ' issue a little bit later, if you don't mind. Let me first 24 address what I want to say, then I will come back to your 25- point, if you don't mind.
ANN RILEY & ASSOCIATES, LTD. O,~~J'
. Court Reporters 1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
i 32
. . t 1 What I.want to show here, this curve really
() 2 ' represents what I call three regions. The fat region, and 3 the fairly sharp' region here, and the intermediate region. 4 What does fat region' represent is really that the -- most of 5 _the current lightwater reactors have a curve which look like 6 this. By.and large, most of the severe accidents are 7 mitigated by the existing design. This is what they call 8 the defense-in-depth region. That means most. accidents, 9 most of1the severe accidents are mitigated by the i 10 containment. You are getting very, very low releases for 11 most of the accidents. I don't want to point this at you. ; 12 MR.'MARKLEY: If you would like to stand, j 13 'DR. KHATIB-RAHBAR: This is too complicated. 14 DR. APOSTOLAKIS: We thought:you could handle it,
/~h
(, ) 15. Mohsen. 16 DR. KHATIB-RAHBAR: You would be surprised', 17 George. 18 Okay. And then in this region, the uncertainties 19- on the releases are -- the consequences are enormous. As 20 you can see, essentially, if you look at this curve, this 21' horizontal region'shows, essentially, the width of the l 22 uncertainty band. It goes over several decades. You are ; 23' talking about as much as six or seven decades. But on the 24 other. hand, if you look at the upper bound releases in this 25 region, given the uncertainties that exist, they are not []
%/
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
-Washington, D.C. 20036 (202) 842-0034
,. .r . _ _ . . . _ . . _ _ - _ _ _ . _ _ _ _ . - ._ _ _ _ . . . _ . .
-],
33 l' that significant, consequentially, okay. I 2 However, in this region, this is where, even l 3 .though the frequencies.for these accidents in this region 4- are very small, but the consequences are enormous. So, in 5 terms of a risk, even though the overall frequencies.are 6 low, you get oftentimes a large fraction of the total risk 7- of severe accidents coming from this region. These are P 8 primarily events which involve bypass of the containment,- .,
'9 steam generator tube rupture events, event V, V sequences, '
10 et cetera. Thank you. 11 Now, this is what I call in this region, what I 12 call the vulnerable region, the containment vulnerable 13 region. So region B~is somewhere in between. These are 14 events which typically result from early containment 7~g (,) 15 failures, steam' explosions, direct containment heating, et 16 cetera. Ek) if you are going to be talking about what we are
- 17. going to do, what we are going to be preventing, we have to l J
18 -consider the fact that as you go up in consequence, the 19 frequencies become very low, the uncertainties and 20 . frequencies become very significant, but the uncertainties 21 and consequences become relatively narrower. 22: On the other hand, the_ upper bound consequences 23 are very significant. So if one wants to deal -- talk about 24 severe accidents and consequences of nuclear reactor 25' accidents, really very large in terms of a public mind, the L l - /~'\ ANN RILEY & ASSOCIATES, LTD. ~ ksI Court Reporters p 1025 Connecticut Avenue, NW, Suite 1014 l -Washington, D.C. 20036 L (202)l 842-0034 4 l !
34 l' ' issue is really mostly what we are dealing in this region
- e
) '2 here. Okay. Society as a whole, when you are talking about 3 contamination area, you are talking about huge land 4 contamination, we are talking about releases of this 5 magnitude.
( 6 Another way put, this is for a typical study we 7 have done for a European power plant, which is a -- this is 8 boiler water reactor with a Mark 3 containment. This is a I L 9 real curve. In this case, the release is percent of core 10 inventory. As you can see, this shows, this region of the 11 curve, most of the releases are due to areas where 12 containment is relatively intact. Release is occurring 13 because of design basis leakage from the containment, and 14 for this particular case, early containment venting with
~() 15 suppression pool being a factor.
16 DR. WALLIS: So the TMI is somewhere way down in 17 there. 18- DR. KHATIB-RAMBAR: TMI Is somewhere down here. 19 It is actually, if you go --
'- 2 0 DR. WALLIS: It is negligible.
21 DR. KHATIB-RAHBARi It is very negligible, 22 . exactly. In fact, I wish I had brought up the figure which 23 I had compared the releases between TMI with these plants. 24 It is somewhere down~in this line. 12 5 : MR. KAISER: So those are individual -- ANN RILEY & ASSOCIATES, LTD.
\ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l 35 1 DR. KHATIB-RAHBAR: These are individual (m. ( 2 contributions to this curve.
)
3 DR. APOSTOLAKIS: You have to speak to the l 1 4 microphone, Jeff. 5 DR. KHATIB-RAHBAR: That is correct. This shows, 6 -for this particular plant, we had, I believe, 20-odd release , 1 7 categories. 18 DR. WALLIS: And Chernobyl is right on the 1 9 righthand. 10 DR. KHATIB-RAHBAR: Chernobyl is actually down 11 here. 12 DR. WALLIS: Right. 13 DR. KHATIB-RAHBAR: Somewhere up here. Exactly. 14 MR. KAISER: Aren't you comparing a complementary
?
s ,/ 15 cumulative distribution function with individual accidents i 1 16 on the same plot?_ Isn't that -- 17 DR. KHATIB-RAHBAR: It is. But it is, this is a 18 CCDF. 19 MR. KAISER: Yes. ; i 20 DR. KHATIB-RAHBAR: Complementary cumulative 21 distribution. All this shows, these are the contributions l l 22 to this, which is really, this is the integral curve ; 23 essentially. And this shows that -- where the different 24 contributions to that part of the curve is coming from. In 25 this end, actually, the CCDF and the frequency are really . O, ( ) ANN RILEY &.A." CIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
36 1 one'and the same-thing. () 2 3 DR. APOSTOLAKIS: And just'for the record, they i are not reallylCCDFs, they are not -- they are not 4 complementary cumulative distribution functions, I don't
- 5. 'think. They are just curves showing the behavior of the "
61 frequency of exceedance, right? 7 DR. KHATIB-RAHBAR: Why do-you say they are not? 8 DR. APOSTOLAKIS: Well, they are normalized, it 9 doesn't go to one,' does it?
'10. DR'. KHATIB-RAHBAR: Well, this is -- I can 11 normalize for'the-core damage frequency, then it goes to i
12 one, yes. 13 DR. APOSTOLAKIS: Well, then.it is a different 14 curve. But it.is a distribution really of the frequency. es g < ( ,/ . 15' DR. KHATIB-RAHBAR: That is correct. The 16 Jdistribution of the frequency, absolutely. Which'I can 17- normalize it with frequency, I can get a relative frequency 18 in'a sense, rather than a probability, per se, depending on 19 which school of. thought you come from. l 20 So, well, all I am trying to show is in this 21- . region, the bypass events and' things dominate, and this is
'22 the region where you have some chance of containment
-23' failure.
24 DR. WALLIS: Well, they must be probabilities 4 L 2'S because they haven't happened. b ' ANN RILEY'&' ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue,~NW, Suite 1014
. Washington, D.C. 20036
. (202) 842-0034 o
, .. , - , , . . , , n. .,.
I: 37 l 1 DR. KHATIB-RAHBAR: So, to restate, in the region
) 2 A, even though the uncertainties in releases are very large, 3 'nevertheless, the contribution to risk, even the upper bound 4 level, are not sigaificant. If you look at the overall 5~ risk, the contribution coming from, you know, releases l-l
'6 resulting from leakage from the containment, overall, l
7 risk-wise, Lit is significant, but in terms of the
- i. 8 consequence-wise, it is an insignificant contribution.
L 9 DR. KRESS: But when you talk about risk, you are 10 talking about what? l 11 DR. KHATIB-RAHBAR: Product of the two. 12 DR. KRESS: Prompt fatalities? 13 DR. KHATIB-RAHBAR: No, I am generally talking 14 about latent fatalities.
) 15 DR. KRESS: Latent fatalities.
16 DR. KHATIB-RAHBAR: Latent, generally. What I 17 will be addressing here is mostly latent. I 18 DR. KRESS: But it could be possible that they
'19 might be significant with respect to, say, land 12 0 contamination or --
L 21 DR. KHATIB-RAHBAR: Latent fatalities are l'
-22 non-contamination, Tom. In terms out they are correlated --
l 23 DR. KRESS: They are one to one, almost, yeah.
~ 24 DR. KHATIB-RAHBAR: One to one ration, just about.
l H25 DR. KRESS: How about total injuries, for example? l
'"A ANN RILEY & ASSOCIATES, LTD.
-) Court. Reporters 1025 Connecticut Avenue, NW, Suite 1014 l Washington, D.C. 20036
- l. (202) 842-0034 i
l' l
q 38 1 DR. KHATIB-RAHBAR: Total injuries, again, latent () 2 3 total injuries integrated over, let's say, 50 years, they are also very similar, but early fatalities are not. What 4 is affected by inhalation dose will not be. Noble ~ cases 5 dominate inhalation. Okay. But actinides and cesium, et i 6 cetera, will dominate the latent injuries, et cetera. ! 7 DR. KRESS: Cesium, strontium, and actinides.
<8 DR. KHATIB-RAHBAR: Strontium-90 and barium-140, 9 exactly.
10 DR. WALLIS: It would be very useful if you also 11 showed the probability curve and not the integral, and then 12 the probability times consequence, which would really 13' indicate'-- illustrate.your conclusion here. 14 DR. KHATIB-RAHBAR: Yes. Actually, I should have () 15. brought one in. I have a curve like that, but since.the-16 focus is mostly on the FC curves, I did not want to --
- 17 ' DR. WALLIS: Your FC curves are a bit misleading.
18 They are log scale, you have to look at the extremes to 19 figure things out and so on.
- 20. DR. KHATIB-RAHBAR: That's correct. That's why I .
21 tried to put the other figure to show you, really, you need 22 to plot frequency versus consequence if you want -- 23 DR. WALLIS: And frequency times consequence. 24 DR. KHATIB-RAHBAR: And times the consequence,
.25 exactly, which is really the risk.
O A). s ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
39 1 .DR. APOSTOLAKIS: So just as a point of n j- 2. clarification, when you say that the uncertainties in 3- release are very-large,-you mean on the abscissa. 4 DR. KHATIB-RAHBAR: That is correct. I will show 5 you'. 6 DR..APOSTOLAKIS: So that is really the aleatory 7 part. 18 DR. KHATIB-RAHBAR: Precisely. 9 DR. APOSTOLAKIS: That's what --
~10 DR. KHATIB-RAHBAR: Precisely.
11 DR. APOSTOLAKIS: Okay. Okay. That's clear. 12 DR. KHATIB-RAHBAR: Yeah, these are the 13 uncertainties in this region here. Okay.
- 14. On the'other hand, the region V and C, the.
M ( ,) 15 uncertainties of releases are much-smaller, however, the 16 contribution to risk are more significant because of 17 consequences, you know, the releases are a lot more 18 significant. You are talking about kilogram quantities 19 rather than microgram quantities.
- 20. Now what are these uncertainties, because the 21' . question was asked also what are the uncertainties and what 22 confidence do we have in their quantification? This is the 23~ part of that curve which I was showing you with the
'24- horizontal-line essentially.
'25 What you see here, these are a number of discrete
/N- ANN RILBY & ASSOCIATES, LTD.
' Am lL Court Reporters 102$ Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
40 l' 1- release conditions. That means a number of ways you can () 2-3 fail your containment. On this x axis here you see release
. quantity as a percentage of total core inventory, initial 4- core inventory. 'These bands, the ones which are relatively
- 5. narrow, oftentimes,.as you can see here, there are a number 6 of them, RC1, RC3, RC7, and a few others. These represent 7 the early. containment failure and containment bypass 8 scenarios.
L 9 I have listed a few things. This is, for example, 10 for this plant this is the uncertainty in release. In this 11 case I believe this is for cesium iodide or cesium hydroxide 12 -- they're very.similar -- for a bypass event in a boiling 13 water reactor. This goes from about 2 percent to as much as
- 14. nearly 40 percent of the entire core inventory. So about an 15 order of magnitude.
- 16. But the upper bound is very significant. As you ,
i 17 go down in terms of the level of release, the uncertainties 18 become greater, which is also explainable, because you're 19- talking about smaller numbers, you're talking about the 20 agglomeration processes for aerosols, which are very 1 21 . difficult to quantify. Leakage through very small parts is '
- 22- very difficult to quantify. So the uncertainties grow as
- 23 'you go later and later and later in containment failure time
- 24. ' basically. Okay? So the uncertainties become horrendous 25 when you're talking about conditions where containment does <
O ' ANN RILEY & ASSOCIATES, LTD. k- ' Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
41 1- not fail or if it fails very late.
..,R 2 DR. WALLIS: Essentially they go to zero on the
( [ 3- left axis. 4 DR. KHATIB-RAHBAR: Exactly, because the tail end i , 5 goes to zero. But again if you look at the upper bound of ' 6' these releases, they are manageable, they are not that 7 significant. .So when we are talking about putting criteria 8 on, requirements.on, I think for these we need to look at 9 'the upper bounds. We are really not going to try to 10 regulate the tail of this distribution here.
- 11. DR. APOSTOLAKIS: Now the RC states are what --
11 2 DR..KHATIB-RAHBAR: These are release categories. 13 They are discrete ways you can fail the containment. 14 DR. APOSTOLAKIS: Are these the accident 15 progression bins of the 1150 study? In other words, it l 16 ~ concludes the whole accident sequence up to and including 17 containment failure. l 18 DR. KHATIB-RAHBAR: Precisely. Yes. 19 DR. APOSTOLAKIS: And then you are telling us what 20 the consequences of these -- okay.
~21 DR. KHATIB-RAHBAR: Associated'with those release 22 categories. Exactly.
23- DR. APOSTOLAKIS: Okay. 24 DR. KHATIB-RAHBAR: Given a way you can fail the 25 containment. p
, 4 ANN RILEY & ASSOCIATES, LTD. ~\ /'
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 ~
42 l l 1 DR. APOSTOLAKIS: Yes. l r~g j t 2 DR. KHATIB-RAHBAR: In this case, given that you
%J
- i. 3 can have a bypass, this is the uncertainty in the release.
l l 4 DR. APOSTOLAKIS: Okay. l 5 DR. KHATIB-RAHBAR: What are the uncertainties and 3 l 6 what confidence do we have in their quantification. Let me l 7 continue. In general the subjective uncertainties are S quantified using expert judgment, because there is no other l l 9 way. If you're talking about probabilities, you are talking 10 about expert judgment. And to the extent possible, models 11 -- some of these could be incomplete. But by and large 12 there is a model for just about everything which I have 13 discussed here. But the degree of completion of the model l 14 depends on the process. And of course to the extent
,/
Is_,- 15 possible, one uses test data. 16 Even though it's difficult to demonstrate in my 17 view, however, in my personal view, the extent of 18 uncertainties are probably overstated, simply because, as it l 19 relates to release of volatile fission products, cesium, 20 tellurium, et cetera, the upper bounds often involve nearly 21 100 percent release. I mean, you cannot get any worse than
'22 that even if you tried.
23 So because of that I think the releases are -- by 24 and large the uncertainties are relatively overstated. 25 Again, I cannot prove it, because it's opinion. But on the
-(n)
'/
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 l Washington, D.C. 20036 (202) 842-0034 l
l 43 1 other hand, if you look at both NUREG-1150s and the studies
/m
( NJ
) 2 that we have done -- I think these are the only two types of 3 studies which have included the uncertainties -- by and l
,1 4 large I think the uncertainties are pretty much overstated. I l
5 DR. APOSTOLAKIS: Now I looked at a few of the l 1 6 papers you sent me -- not in detail I must say -- but I did 7 look, and you do state what you say here also in the papers 8 that, yau know, you have to use expert judgement, and I 9 agree. And then there is a quantification of the parameter ! I 10 uncertainties. I 11 DR. KHATIB-RAHBAR: Yes. I i 12 DR. APOSTOLAKIS: Now it seems to me that in . level I 13 2 PRAs what is really important is the model uncertainties, 14 the assumptions we make about how the phenomena will O is,) 15 progress, and I am not sure that your earlier paper for 16 nuclear science and engineering addressed those. 17 DR. KHATIB-RAHBAR: No, it did not. 18 DR. APOSTOLAKIS: It did not. 19 DR. KHATIB-RAHBAR: That paper only focused on 20 parameters. 21 DR. APOSTOLAKIS: On parameters. Now your second 22 bullet applies -- I mean, does the second bullet address 23 that concern a little bit by saying look, when in doubt, we 24 assume that the whole thing is released? 25 DR. KHATIB-RAHBAR: Just about. Yes. [a}
\>
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
_ _ _ . . _ _ . . .._ _ -.._._,_.....-. _._ ._ .._.._.m._ _ . . _ _ _ _ _ _ _ _ , - _ _ _ _ I. 4 44 l it i 1 ' DR. APOSTOLAKIS: So I don't have to worry about l] 2 model uncertainty in this context? l
-3 -
DR. KHATIB-RAHBAR: Exactly. In this context, in { 4- the uncertainties that we have quantified, in a sense the 1 l 5- model uncertainty has been included. i
'6 Give you an example. -
In the paper you refer to,
.7 which is'bssed.on an old suite of computer codes developed 8 by the NRC, rebay position phenomena, which is a process L
L 9' when' volatile fission products sit on the surface, because u 10 they have decay heat, they can heat up, and because as the ili temperature increases, they can be volatilized again,.and 12 they can be released. In that particular model, this (
-13 process was'not physically modeled, okay? So even if we f.
14 vary the parameters over five orders of magnitude, .since the l
"#"Y
((,j zo model was not there, we could not see the effect. But it i 4 16' turns'out what'that process does, it actually narrows the 17 uncertainties, because it increases the lower-bound 11 8 ' releases. The upper-bound releases are close to 100 percent 19 already. 20 So what that rebay position process does, it 21 -actually brings up the releases which were lower in L 22 -qdantity. So in effect somelof these unmodeled processes i T 23 tend to narrow the uncertainties rather than necessarily 24' ' widen then. Okay? So from that perspective in the numbers
.25 ina have here, we have allowed for rebay position processes,
- h. JANN RILEY & ASSOCIATES, LTD.
N . Court Reporters
. 1025 Connecticut Avenue, NW, Suite 1014
-Washington, D.C. 20036 (202)'842-0034 i
i 1 45
'l processes which are not easy to model or were not at least 2 at that time, and in a sense what uncertainties we represent
[%)Y 3 here do cover some of these unmodeled phenomena. 4 However,.given these uncertainties, narrowing the 5- uncertaintiesuin my view are not expected within the 6 reasonable time and resources that we have available. 7 Therefore, any use of risk curves should encourage ways of 8 circumventing, okay, the potential impact of uncertainty. 9 DR. APOSTOLAKIS: If we go back to your slide 2 -- 10 DR. KHATIB-RAHBAR: The outline? 11 DR. APOSTOLAKIS: No. y 12 DR. KHATIB-RAHBAR: Slide 3? ; 11 3 DR. APOSTOLAKIS: ~Oh , I'm sorry. I'm sorry, 4. 14 Yes, number 4. FC' curves and uncertainties. b d _15 DR. KHATIB-RAHBAR: Yes, the actual curve? 16 DR. APOSTOLAKIS: Yes. 17 DR. KHATIB-RAHBAR: Um-hum. 18 DR. APOSTOLAKIS: So what are we to understand . I 19' from your discussion a few minutes ago regarding the bands 1 20 that you are showing there, 95th percentile, 5th percentile? 21 Are these realistic? Are these conservative, optimistic, 22 the fifth percentile curve is not so well understood, but 23 the 95th is pretty good? Wnat is your message? 24 DR. KHATIB-RAHBAR: The message is that this 25 uncert 4
- band in'my view is very wide.
ANN RILEY & ASSOCIATES, LTD. \s) Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
46 1: DR. APOSTOLAKIS: -Which -- 2 .DR. KHATIB-RAHBAR: The upper bound, the 95th )
- 3. percentile.
4' .DR. APOSTOLAKIS: Yes?
'5. DR. KHATIB-RAHBAR: Okay, in my view is relatively 6 conservative.
7 DR. WALLIS: It looks suspiciously like a factor 1 8= of'2, if you look at the axis and the -- ) i 9 DR. KHATIB-RAHBAR: About'here? ' 10 DR. WALLIS: Yes. 11 DR. KHATIB-RAHBAR: It's about an order of 12 magnitude. 13- DR. WALLIS: Goes'through 2. 14 DR. APOSTOLAKIS: No, from the mean. ( 15 DR. WALLIS: .2 and .5.
.16 DR. KHATIB-RAHBAR: Yes, exactly. ~It's about a ;
i 17 factor'of 2. Yes. Yes. Right. - Just.for this case it's a 18 case-of cesium-137, okay? But, yes, what I'm saying isLthe Z 19 upperJbounds are relatively conservative. I-mean, I'm 20 talking about releasing,-you know, most.of these actions j
~
- 21. close~to1 100 percent of cesium in the vessel.
- 22 DR. APOSTOLAKIS: Okay. ,
- 23- DR, KHATIB-RAHBAR: Experimentally, I mean, FIPA's
- 24. experiments.have measured releases of those magnitudes.
-25 DR. APOSTOLAKIS: No, but there are two different t, ANN RILEY[& ASSOCIATES, LTD.
Court Reporters
'1025 Connecticut Avenue,.NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 w w m v w f % s--
47
' issues ~here. I think you have; addressed the question of the
~
.1
(_)y '2 uncertainty in the horizontal axis there.
.3. DR. KHATIB-RAHBAR: But you do release quantity, 4 .right.
5 DR. APOSTOLAKIS: You release quantity. And you 46 told.us that when in doubt, we assume the whole thing comes 7 out.
- 8. DR. KHATIB-RAHBAR: Correct.
9' DR. APOSTOLAKIS: So that would tend to make your 10 ' curves flatter; right? 11 DR. KHATIB-RAHBAR: Exactly. 12 DR. APOSTOLAKIS: Flatter.
.13 DR. KHATIB-RAHBAR: Right. That's why they're
.14 larger than they~probably should be.
_) '15 DR. APOSTOLAKIS: Okay. Now, if I select, though,
- 16 say 10 to the 100th grams of cesium --
17 DR. KHATIB-RAHBAR: Right. 18 DR. APOSTOLAKIS: And -I cg> vertically, now that 's 19 a different kind of uncertainty.
-20 DR. KHATIB-RAHBAR: This is the uncertainty in the
-21 frequency --
22- DR. APOSTOLAKIS: In the frequency. 23 DR. KHATIB-RAHBAR: Right. 24 DR. APOSTOLAKIS: And what -- the argument you
.25; just'gave us --
ANN RILEY & ASSOCIATES, LTD.
%- ~
Court Reporters-1025 Connecticut Avenue, NW, Suite'1014 Washington, D.C. 20036
.(202) 842-0034 L
s
._ _ . - . _ _ . _ _ ._ ._. _ _ _ _ _ . . . _ ___ m . _ . _ _ _ . _ _
48 1 DR. KHATIB-RAHBAR: Was only on --
) '2 DR.'APOSTOLAKIS: Does not necessarily apply.
3 DR. KHATIB-RAHBAR: No. That's only for the 4 consequence. l 5 EDR . APOSTOLAKIS: So how do you -- so you have 4 6 another argument then supporting your assertion tilat the I 7 95th percentile curve is conservative with respect to the 8 frequency now? 9 DR. KHATIB-RAHBAR: With respect -- no. With 10 respect to the consequence -- I'm only focusing right now on 11 the consequence. 12 DR. APOSTOLAKIS: Okay. So what you're saying --
'13 DR. KHATIB-RAHBAR: Only on the consequence.
14 DR. APOSTOLAKIS: Is that the curves are flatter 15 than they ought to be. 1 16 DR. KHATIB-RAHBAR: Right. Right. 17 DR. APOSTOLAKIS: But you are not saying anything 18 about -- 19 DR. KHATIB-RAHBAR: The width of this -- l 20 DR. APOSTOLAKIS: The width -- l 21 DR. KHATIB-RAHBAR: No. No. 22 DR. APOSTOLAKIS: Okay. 23 DR. KHATIB-RAHBAR: Because the width actually is 24 not very meaningful. This shows a total uncertainty core 25 damage-frequency here. It is meaningful from that O ANN RILEY & ASSOCIATES, LTD.
%/ Court Reporters 1025 Connecticut-Avenue,. NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 ,
1
i i l j' 49
'l ' standpoint.
( 2 DRI APOSTOLAKIS: Yes. L 3: DR.'KHATIB-RAHBAR: But these are really I' h- ~4 exceedence frequencies. They are not the actual , 15 Lfrequencies. Okay? l
. 6 DR. APOSTOLAKIS: But this was one of the l R 57; concerns, because in a regulatory framework, that
~
]
uncertainty also in fact if you look at what Tom presented 3 8;
)
i L. 9 that'would play a role -- l 1 10 DR. KHATIB-RAHBAR: Sure. 11
'l DR. APOSTOLAKIS: The uncertainty in the frequency ;
i l '12' curve. l l ' 13 DR. KHATIB-RAHBAR: Sure. 14 DR. APOSTOLAKIS: So that's where it seems'to me . If~~\ l l V 15. -- l16 DR. KHATIB-RAHBAR: Let me talk about the 17L uncertainty - j i ) 18- DR. APOSTOLAKIS: Well,-on the other hand -- no, I I l ! 19" ;would'certainly let you continue, but I'm trying to
-20 understand a little better what's going on.
2 11 The question that I'm not sure anybody has 22 ' addressed is if I.am very conservative on the aleatory.part, 23L .in other-words, I make the curves flatter than they ought to L. '24 I be,-how would that affect my uncertainties in the epistemic 25; .part, which is the frequency of the releases? I don't think
- r. ANN RILEY & ASSOCIATES, LTD.
k s)/ s Court Reporters 1025 Connecticut. Avenue, NW, Suite 1014 o Washington, D.C. 20036 L (202) 842-0034 LR , (.
.- , , - =
50 , 1- anybody has any thought -- [) 2 DR. KRESS: I don't think the two are related. 3_ DR. APOSTOLAKIS: No , but if I'm very conservative 4 this way, I mean, . horizontally -- 5~ DR. KRESS: Oh,1you're talking about making an 6 acceptance criteria of some sort. l 7 < DR. APOSTOLAKIS: Yes. Yes. Yes. Yes. How does 8 that affect my acceptance? Because if I know -- if I look j 1 9 'at the curves in Region C, right, where for example Mohsen 10- has 10 to the -- let's say 6 10 to the 4th, okay, somewhere 11- in there? And I know from the argument Mohsen just gave me 12 that I really should not be there, that maybe that's an 13 artifact of the calculations that I have assumed more stuff 14 is being released under conditions that really is -- that is N '15 really justified -- so the fact then that.I have uncertainty 16 about the frequency.of that release is -- what does that do l 17 to my acceptance criteria, since I know that I'm already
'18 conservative?
i 19 DR. KRESS:
~
Well, you see the problem you're 20; -having is the problem I've wrestled with pretty hard, and 21 that is these acceptance criteria which were generally
-22 risked. things, prompt fatalities or land interdiction or 23 something are almost universally expressed as an expected 24 value, a mean.
25- DR. APOSTOLAKIS: Yes.
- [~)h ANN RILEY & ASSOCIATES, LTD.
[s / - Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 L Washington, D.C. 20036 l (202) 842-0034 o [
1 51 1 DR.IKRESS: What we're looking at here is 2 basically a hidden probability -- it's a cumulative l A(} 3- distribution function, which is a,one-to-one correlation. 4 So when you're looking for an expected value, it's an
'5- integral, and when.you're talking about a metric that's an 6; integral'of this, you don't know how to deal with it.
7 DR. AFOSTOLAKIS: It's a double integral.
\
8- DR. KRESS: It's a double. 9 DR. APOSTOLAKIS: It's an integral horizontally 10 and vertically. 11 DR. KRESS: Well, it's not, it's a single -- 12 DR. APOSTOLAKIS: Sure, because you have to 13 eliminate all the uncertainties. 14 DR. KRESS: -Yes, when you're talking about l) (,j 15' uncertainties it may be a double. j 16 DR. APOSTOLAKIS: That's right. 17 DR. FONTANA: Excuse me, let's see if I understand 11 8 this. I came down from Mars and.I got a job with Energy 19 Research, and I have to do some calculations. And I say I. 20 calculate a reactor accident, and I get a certain 21 probability of a certain hole occurring or some failure. 22 Okay. I get a certain probability, and I look across this
- 23. curve, and that tells me that the release for that 24 particular accident. expands let's say 10 to the 1 to 10 to "25 .the minus 4, 10 to thes4, is.a big uncertainty in release.
.O ANN RILEY & ASSOCIATES, LTD. ' \~/ ' .
Court Reporters 3 1025. Connecticut. Avenue, NW, Suite-1014 Washington, D.C. 20036
+ '
(202) 842-0034
- m. . . _ ~ . _ . _ . . _ _. -. . . . ..._._
l 52 l 1 Okay, now let poke in another department. And now
) 2 .I want to say I_can now accept a release of let's say 10 to 3: the minus 3 -- 10 to the plus 3 of cesium. And that means )
L 4 that the acceptable probabilities are that vertical band. L l 5- DR. KHATIB-RAHBAR: The frequency exceeds -- l 6 DR. FONTANA: Am I understanding this right? 7 DR. KHATIB-RAHBAR: Yes, the frequencies, all it ! 8 says - how do you read this curve, really, that's what it 9 boils down to. This shows the frequency of having a release i 10 greater than 1,000 grams -- 11~ DR. FONTANA: Yes. 12 DR. KHATIB-RAHBAR: Of in this case cesium-137 is L 13 of the' order of 10 to the minus 6 per reactor year. L 14 DR. FONTANA: Yes. 15 DR. KHATIB-RAHBAR: Frequency of exceedence. ; j l 16 DR. FONTANA: That is working from what is 17 allowable-to whether the plant is meeting that. In other j 18 words, if I am doing an accident analysis, I'm going to get ; 19- a probability of a'certain failure, I'm going to calculate 20 some releases. 21 DR. KHATIB-RAHBAR: .Right. 22 DR. FONTANA: If I pick a probability and look 23 across this curve, it looks like I've got a wide band of -- 24- DR. KHATIB-RAHBAR: Of releases. Sure. 25- DR. FONTANA: Of releases. l t b L O
- 3 ANN.RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
_. . . . _ ~ - . . ~ . .__.._..._.._._.-...._____...._m__. . . . _ . . . . _ _ _ _ . . m l'
.53 l
1: '1: DR. KHATIB-RAHBAR: Sure. This curve shows you i '2~ the: uncertainties both in release quantity and the frequency
- 3- . both. . -
4 .DR. FONTANA: ,Okay.
'5 DR. KHATIB-RAHBAR: Right. Absolutely.
- - 6 DR.,,FONTANA: I just wanted.to see if I 7 understood.
8 DR. KHATIB-RAHBAR: This is one -- essentially a L 9- good'way to show both uncertainties. In the release
.10 frequencies this is the total core damage frequency o
I 11 uncertainty, okay? And1this is for a given,--you~know,
^
12 depending where you are at in this region, this is the 13 uncertainty in the quantity of release. All it shows you, 14 as you're going to lower and lower frequencies, the D n
\ ,)
% 15 . frequencies are becoming.more uncertain, and that makes 16 sense. - Why? Because these are mostly, let's say, steam 17 generator tube. rupture events, initiating events, but that
'/
j -- 18. : depends.-- > 19 DR. WALLIS: I think you're saying that CDF is
- 20 pretty in good shape, it's within a factor of 2. - LERF is
, f 211 awfully. uncertainty.
-22 ' DR. KHATIB-RAHBAR: Precisely.
L23. DR. WALLIS: How youfget that: steep cliff.
*24 DR. KHATIB-RAHBAR: Exactly. Exactly.
'25< - DR. WALLIS: Depends on lots of uncertainties.
fN ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington,.D.C. 20036 (202) 842-0034 e <w , m --:wp. se--,-g
54 1 IMt. KHATIB-RAHBAR: Frequency points. Absolutely.
}}.
( j 2. DR. WALLIS: You can put it anywhere between 10 to 3 the minus 8 and 10 to the minus 6. 4- DR. FONTANA: I've got another thought, too, and I 5 know you can't draw a curve like this, but if you drew it on 6' linear terms rather than log terms, you'd get a curve that 7 would look like this -- 8 DR. KHATIB-RAHBAR: Um-hum. 9 DR. FONTANA: And'it would probably make it a 10 little easier to see conceptually. 11 DR. APOSTOLAKIS: I'm sure that would help the 12 people who will read the transcript. 13 Joe Murphy had that comment before. Yes, there
- 14. are several comments. Joe has been trying to say something 15 for awhile.
16 MR. MURPHY: I just want to point out that what 17 we're trying to do -- I agree with what Mohsen has said, but 18 understand that we were comparing on the horizontal, you're 19 comparing the uncertainty in an integral-to the uncertainty 20 in the scalar. If you want to compare them on an-equal 21 basis, 'you have to differentiate the curve.
-22 DR. KHATIB-RAHBAR: Yes, you've got to put just 2
.3 frequency versus consequence, as was indicated earlier.
24 MR. MURPHY: And it is good information there, but 25 the broadness of that horizontal line, recognize just the X) (
\'E ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 x
~ . .. _. _ . . _ _ . _ _ _ _
55 1 broadness of'the integral and not of the differential. The g3
.. (N . ).
2' differential would be much smaller. ; 3 DR. KHATIB-RAHBAR: This is what I can show you by 4- that,;just showing you this is the width, it's just right i 5 there. 6 DR. APOSTOLAKIS: 'Ye s , yes. Yes, yes, yes.
;7 I think what you're saying -
yes, let's go back l l 8 to1the'other - LI think what you're saying, Mohsen, is 1 9: 'really that you feel that the 95-5th percentile curve is 10 reasonably conservative -- 11 DR. KHATIB-RAHBAR: In terms of consequence. 1 j l 12 DR. APOSTOLAKIS: But the mean in the 5th 13 percentile a more realistic analysis would move down. 14 That's really'what you're saying. It wouldn't be so flat, j f3 (/ 15 It would be steeper. 16 DR. KHATIB-RAHBAR: Yes. This curve would be 17 steeper. 18 DR. APOSTOLAKIS: The mean of the 5th percentile. 19 DR. KHATIB-RAMBAR: It will be steeper.
~20 DR. APOSTOLAKIS: Now we had --
f 21 DR. KHATIB-RAHBAR: Well, the 95th itself could 2 2 .- also be steeper. 23 DR, APOSTOLAKIS: Yes, but maybe, since it's an
-24 upper bound --
25' DR. KHATIB-RAHBAR: .In a sense the mean, George, [ ANN RILEY & ASSOCIATES, LTD.
\~< - Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
7 - 56 1 .the'mean --
- D. ) 2 DR. APOSTOLAKIS: I understand.
3 DR. KHATIB-RAHBAR: In these types of things -- 14 DR. APOSTOLAKIS: Is driven -- 5 DR. KHATIB-RAHBAR: Is very close-driven by the 6- upper bound. 7 DR. APOSTOLAKIS: You're right. You're ri 3uc. 8 DR. KHATIB-RAHBAR: It'makes no difference. 9 DR. APOSTOLAKIS: You're right. Well, it would -- 10 anyway. But -- 11 DR. KHATIB-RAHBAR: Because he was talking about 12 difference between zero to 1. I mean, the mean -- 13 DR. APOSTOLAKIS: I got the message; yes. 14 DR. KHATIB-RAHBAR: Is going to be much closer to O) (_ 15 1 than to zero. 16 DR. APOSTOLAKIS: Yes. So even the 95th you are 17 saying -- 18 DR. KHATIB-RAHBAR: Precisely. 19 DR. APOSTOLAKIS: Would go down. That's already 20 conservatism built in. 21' DR. KHATIB-RAHBAR: Absolutely. 22 DR. APOSTOLAKIS: Jeff?
-23: MR. KAISER: Yes, I guess I'm a bit puzzled about 24 the. interpretation in the horizontal of that as an 25 . uncertainty in the magnitude of release. If you had a set ANN RILEY & ASSOCIATES, LTD. '\ '=
Court Reporters
'1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
-...__._____.__.m._-. ._ _ _ _ _ _ . _ , . _ _ _ _ _ . _ _ . . _ . _ _ _ _ _ . .
57 1 offi'ndividual! accidents and it happened that, let's say, y~~. b 21 .between about 1-and 10 to the 3 curies you had no accidents
- V(
3: at-all, wouldn't that lead to a curve that looks something 4 ;like'this?~
-5 DR. APOSTOLAKIS: Maybe your previous. transparency 6 explains that,ithe one you just put up there with the 7- _ release categories.
8- DR.-KHATIB-RAHBAR: This~one here?
, 9 DR--APOSTOLAKIS:
. Yes. Maybe we can put the -- is 10 that what you mean, Jeff?
-11. MR. KAISER: Yes. '
12- - DR. APOSTOLAKIS: So where would you have no 13: accident ---releases. 14 MR.. KAISER: If you happened to have none -- you yO ,j-c L15 go back to the other' slide we were just looking at. 16- DR.LAPOSTOLAKIS: I'm sorry. 17 DR. KHATIB-RAHBAR: Which one do you want? This
.18- one?
19 DR'. APOSTOLAKIS: You mean the flat part. l
'20 MR. KAISER: Yes. The flat.part could be --
21' DR.-APOSTOLAKIS: Sure.
'22 MR. KAISER: Reproduced if there were no accidents
~
I23 at all. 24- DR. APOSTOLAKIS: Yes. 25 ' MR. KAISER: In that interval with the slant. So [' ' ANN RILEY &' ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
' Washington, D.C. 20036 (202) 842-0034
. . =- - . , .
1 l 58 1 in other words!it may have nothing to do with uncertainty on ( ) 2 the magnitude.of release. 3 DR; APOSTOLAKIS: It may not. You're right. 1 i 14 You're right. l 1The other things --'I'try to differentiatec-- S-6' DR. KHATIB-RAHBAR: Let me make sure I understand s 7 'that point. What'you were talking -- the uncertainty is The head and'the tip -- I mean the bottom and the tip 8 this. j 9 of.this thing right here. Okay?' In the quantity.of'
- 10. release.
Ill- DR. WALLIS: Your artist has drawn one which 12 actually goes down to the left, which is impossible. ) 13 DR. KHATIB-RAHBAR: What is. impossible? j 14 DR. WALLIS: Because you're having negative j
- ) [15 releases around the middle of that --
16 DR. APOSTOLAKIS: Well, that may be'an --
- 17 DR. KHATIB-RAHBAR: Down here?
18 ' DR. WALLIS: .No, in the middle, underneath -- 4. - .19 .DR APOSTOLAKIS: Well,-the curve goes up a little 20- : bit --
, -21 ' DR . WALLIS: Underneath the 95th --
22- -DR.'APOSTOLAKIS: Where it says "mean." 23- DR. WALLIS: It goes down to the left. 24_ DR. APOSTOLAKIS: But that's an artifact of -- 25; DR. KHATIB-RAHBAR: Yes, this is an artifact of W i [ L ANN RILEY & ASSOCIATES, LTD. ON- i _ Court Reporters-f: 1025 Connecticut Avenue, NW,' Suite 1014' Washington,_ D.C. 20036 (202) 842-0034' d' y , - # .-- ., ._ - .
59 1 'the graph. ( 2 DR. APOSTOLAKIS: No, but let's not forget, as I
.3 forgot when I was differentiating by hand, that this is a 4; logarithmic scale. So the fact that it's flat there does 5 not mean that there are no accidents, because -- if the v '
]
~ \
, _6 frequency were flat, the frequency itself, then that means 1 1
'7 you are not contributing anything, right?
l 8 So the fact -- if I take the curves that Mohsen is j 9 showing _as real, then there are accidents all over'the 10
~
place,,because the fact that the logarithm is flat doesn't 11 mean anything. ; I 12 DR. KHATIB-RAHBAR: As this one shows. i 13 DR. APOSTOLAKIS: As this one shows. That's l 14' right,
\_/ 15 DR. KHATIB-RAHBAR: This is the whole idea. As
- 16 this one shows, there are accidents all over --
\l7 DR. APOSTOLAKIS: But Jeff's point was good in 18 general. If.there are no accidents there, then you will see 19 the frequency itself being a lot, not the logarithm.
12 0 DR. WALLIS: No, the frequency would be zero if 21 .there were no accident. 22 DR. APOSTOLAKIS: No, because it's cumulative. 23 The. density will be zero. 24" MR. KAISER: The density will be zero, but this 25 'would.be flat.
/
/
/
l'~%\ ANN RILEY & ASSOCIATES, LTD.
/
y 7'
/
, Court Reporters ,
1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
.- - . - _ ~ . . - .-. ~ ~. _ ~ - - . . . ~ -
. . - . . . - .- . . ~ - - . - . . - _ - .. _
l 60 1 ! 1- DR...APOSTOLAKIS: Yes. l 2 MR. KAISER: But you'd still have the 95th, the ) l l 3 Sth and the mean, separated. ; 4 DR. APOSTOLAKIS: Yes. 5 MR. KAISER: But you would not be entitled to take f 6 the, you know, the gap between two extremes as an l
~
1 l 7 uncertainty'on magnitude.of release. ) 8 DR. APOSTOLAKIS: Right. l l 9 MR. KAISER: It doesn't necessarily mean that. So 10 .I think we should be careful not to assume -- l 1 L 11 DR. APOSTOLAKIS: Yes. i. 12 MR. KAISER: That it does mean that.
.13 DR..APOSTOLAKIS: Yes. Actually the cumulative in i 1
14 general is not the best way to communicate these results. l s_f)
- 15. It's the PDF that -- that's why PDFs were invented. But --
16 DR. KHATIB-RAHBAR: Yes, but in.a sense, though, l -17 the cumulative in a sense is also nice that it shows you the L 18 flatness of the curve is -- L 19- 'DR.~APOSTOLAKIS: Sure. But it's logarithmic, and 20 -that's, you know -- 21 MR, KAISER: We could talk about some more
-22 numbers. Right.
23 DR. WALLIS: It must be flat'at both ends, because t> 24: itlis' logarithmic.
- 25. DR. KHATIB-RAHBAR: -Sure.
f'- ' ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
-(202) 842-0034
. . . . . . . _ _ .. . . .m. ._ _ . . . _ _ _ . . _ . _ _ . . . _ . _ . ~ _ . . _ _ _ . .
l l. t 61 1 DR. WALLIS: You can't get away from it. l ( 2' DR. KHATIB-RAHBAR: But it's how flat it is in the 3' middle that's what matters, really. 14- DR. WALLIS. It's how curved it is that matters. 5 DR. APOSTOLAKIS: Dr. Shack has a question. I Ei DR. SHACK: As a way of characterizing risk, in my ) 7 -simpleminded view I look at'CDF and LERF as a way of pinning : 8 the horizontal part of that curve and then going out 9 somewhere and saying I'm going to force this much of the i 10 curve to be so low at that'LERF value, and then are we -- I 11 guess the question is how much more information do I get -- l 12 when I've pinned the flat part and I've pinned that part at 13 -the LERF, how much variation can I get in the curve? Am I 14- 'really getting any more information out of the whole curve l D w.) 15 than I am by pinning those two points? l 16 DR. KHATIB-RAHBAR: Yes, you are, because it is
- 17. telling you in a given plant if-you're looking at whether 18- the likelihood that youJcan in a sense for these fission
'19' products,; conditional probability or the probability of j 20 releasing fission products is really a spectnm of 21- conditions that can lead to release of fission products. On 22 the one hand you-have those which are very-large releases, 23' bypass events, et~ cetera, but you can have a number of other 24 scenarios where your containment can fail, you know, under
- 25. different conditions. So it is giving you the spectrum of v-L
! .f
- ( . ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 l Washington, D.C. 20036 (202) 842-0034 i
i
)
l 62
]
1 conditions that your. containment can fail, and it's showing ! 1
) 2 the effect of mitigation, how it's spread out. It is really
(, 3 not either the containment fails or it doesn't fail. There j t 4 is something in between. That's all it's telling you. I 5 But in terms of overall magnitude of release,.you 6 are absolutely right, what is really dominating is that LERF ; t 7 -- releases part of it. ; 8 DR. APOSTOLAKIS: Okay. Let's go. j .9- MR. KAISER: Could I ask something? ' 10 DR. APOSTOLAKIS: Sure,. 11 MR. KAISER: Because if it so happened that we had 12 accident sequences in which we=could define exactly the l 13 ' amount of cesium released,-so there's no uncertainty on 14 those amounts, but we had some uncertainty on the
' O lV l15 frequencies.
16 Wouldn t the -- you have taken it away. Could you 17 put it back? ) 18 DR. KHATIB-RAHBAR: Need it again? 19 MR. KAISER: Thanks. I mean one that would-still 20 look exactly like this even if there was no uncertainty on I 21_ the magnitude of release.
- 22. DR. KRESS: Yes.
23 - DR. KHATIB-RAHBAR: The curve itself would look 24 exactly like this, right -- one of these curves. 25 MR. KAISER: So it proves my other point. How can
)
l LI T -ANN RILEY & ASSOCIATES, LTD. b- # Court Reporters 4 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034-ll
, .~. .
l~ \ 63 l l- ! l' you interpret it this way, as an uncertainty on magnitude of l' I l 2 release? I don't think you can. [ 3 DR.'KRESS: You can't. l 4 MR. KAISER: No.
- 5 DR. APOSTOLAKIS
- No. All these uncertainties 6 like how much is it released if I have a release category 7 .and so on have to be converted to uncertainties and L .
L .8 frequencies when you produce these curves. l' 9' MR. KAISER: Exactly. j l 10 DR. APOSTOLAKIS: Because the release-or the j 11 consequence here is the independent variable. 12 DR. KRESS: Yes, it has-no uncertainties -- I 13 DR. APOSTOLAKIS: It is the independent variable. j 14 You enter the figure'that way. 15 MR. KAISER: Precisely. l 16 DR. APOSTOLAKIS: You say 10 grams -- 17 MR. KAISER: Right. l
'18 DR. APOSTOLAKIS: -- now tell me what you know 1 l 19 'about it.and what you know is you go up and say it will be 20 . released with such and such a frequency and the frequency is 21 uncertain.
l t p 22 Now when you produced it in the-PRA, it doesn't h 23 mean you did it that way. You did it in fact the way that 24 Mohsen showed us. You have the release categories and you
- 25. 'have uncertainty on this, and then there has to be some l
l , ANN RILEY & ASSOCIATES, LTD. l L' Court Reporters i L '1025 Connecticut Avenue, NW, Suite 1014 j L ' Washington, D.C. 20036 l (202) 842-0034 l
-. -. - _ - . - _ ~ .. - _- - . . . ~ . ._~ . .
L ( 64 1 process there that converts it to this, because I have seen [ /~
'( j. 2 curves where~they talk about both the uncertainty on release i
l 3- and frequency, which is of course wrong. 4- DR. KRESS: And of course you cannot talk about 5 the frequency of a specific release because these are
~6 cumulative complementaries.
l 7 DR. APOSTOLAKIS: Sure -- or greater. l
- 8 DR. KRESS: It is greater. It makes it even .
9 harder to deal with the-curve. 10- DR. POWERS: George, I guess I understand your 11 interpretation which says that I am going to use release as 12 an independent variable until you asked questions about this 13 figure. 14 You could turn the figure by 90 degrees and
- 15' Alternatively say I will take the frequency as the 16 independent variable and ask questions about the uncertainty 17 in release.
zl8 DR.-APOSTOLAKIS: No. I don't think you can do 19 that becauseLof the way that these curves are produced. 120 DR. POWERS: Well, what I know is that the 21 frequency of any given is an uncertainty-and having 22 specified that any given sequence that the release one
-23 calculates to be associated with that sequence is an 124 uncertainty, so in fact'what you are plotting here is the 25 product of two.rather uncertain quantities which are not 9' ANN RILEY &. ASSOCIATES, LTD.
. Court Reporters 1025 Connecticut Avenue, NW, Suitefl014
' Washington, D.C, 20036 .
(202) 842-0034 4
+ ,
_m._ . ___ _- _ . .m- _ ..._._ ..._. ___ _.. _ ..._._ __._.__ __._ _. h 65 11 independent of each otheri () 2 DR. APOSTOLAKIS: We are becoming way too
' technical now, but the.way the curves, the three curves that !
4- Mohsen is showing there are. produced, say, from the , i 5 simulations is su'ch that you cannot really do what you said, j t [L4 6 E fix a' frequency and say, ah,-with this fcequency here is my l 7- uncertainty in the consequences, because if you put back -- , 8' those two areLthe most' popular transparencies I guess. L 9' Can I go up there? I i l 10- DR. WALLIS: I think you could, George, but you l E 11. would end up with different percentile curves. l p 12 DR '. APOSTOLAKIS: Yes. 13 DR. WALLIS: You could do it, but you-would end up
-14' .w ith different. percentile curves.
L\ 15 DR. APOSTOLAKIS: You would have a different
-16 curve, a different. figure.
17; , DR.' POWERS: I think Graham is probably right but 118' -having been in the business of producing such curves, I
-19 ;think the way they get produced in fact allows you to switch 20- ,back and forth.
t
- 21. DR. APOSTOLAKIS: For example, here, in this i 22 figure, the PRA itself will give me the RCJ and it will give ]
23: meLthe. frequency of.the RCJ, right, for each one? y 124 . DR. WALLIS: With uncertainty. 25 DR. APOSTOLAKIS: Yes, with a curve. It is a ANN RILEY & ASSOCIATES, LTD. L Court Reporters L 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 , (202)'842-0034 l I' T ' = 7 mi - 'umiw--wI u d w M r - T m- de
- _ _ . _ . - - . . . ~ . . - - _ - . - -.. - - - - . - - --. . . - --- - . _ .
66 1 curve. Then I would, to generate the frequency-consequence t A) 2 curve I would enter this figure, say, at 10 to the minus 3 3- percent of core inventory, okay, or greater if you want, and i 4 I I.have to go vertically now and see how I intersect the d I 5 horizontal bars that Mohsen has up there and every time I 6 intersect I get the amount and I get the corresponding 7 frequency _from the probability distribution of the frequency 8 ~ of RC 10, RC 11 and so on, and then I have to take some sort 9 of a convolution to come up with a. frequency. 10 In other words, I am converting a figure where the 11 release is not an independent variable to one where it is, i 12 DR. WALLIS: Oh, but George, really you have got ' 13 an ellipse there, you have got an ellipse with uncertainties 14 in both axes and you can take your convolution, cut it
) 15- horizontally or vertically and integrate. It doesn't
'16 ' matter.
17 DR. APOSTOLAKIS: Yes, but then you can produce 18 curves like the ones Dana wants, but it will be different 19 curves. I can do it that way. Gareth? 20 .MR. PARRY: I am not sure this is going to help, l 21 but -- 4 22 DR. APOSTOLAKIS: Unlike the previous comments, 23 'eh? J
.24 [ Laughter.)
25 MR. PARRY: But I suspect that what these bounds <-(p) . ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue,ENW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 \ /
67 , lI ^here-that are called uncertainty bounds are, they are a ,() .2. combination of -->and you raised the term so I am not afraid
- 3. to-use.it -- of both aleatory and epistemic elements, which.
L4 means'-- because these are results from a particular type of 5- accident.and the underlying conditions in that accident i i
-6 'could be variable'so that this may have some frequency --
7 DR. APOSTOLAKIS: Which is this now? , 8 .MR. PARRY: Let's-take RC1. RC1 could have an 9 element embodied in that, what is called an uncertainty
,10 ' band, of what is really'a-frequency of an accident,-so this 11 is an uncertainty and embodied within a frequency )
i l 1 12= distribution,.I think. I 13 DR. KHATIB-RAHBAR: No. No, not'at all. In fact, j i
-14 if I were'to put this graph'up and take away the uncertainty j L
I) J15. in frequency, I would find the pinch point right -- 16 everything collapsed - - 17- We.may be talking about different frequencies. 18 DR. APOSTOLAKIS: You are saying it is called 19l epistemic. Good.
. 2 0,. DR. KHATIB-RAHBAR: For this particular case, 21 yes -- no, for the frequency.
12 2 DR. APOSTOLAKIS: Yes. 23 DR._KHATIB-RAHBAR': If I take away the frequency I 24 . uncertainty these two will collapse right at the V Sequence 125 point. All it shows is.the uncertainty V Sequence which is i
- . ' ANN RILEY.& ASSOCIATES, LTD.
Es Court Reporters ,' 1025 Connecticut Avenue, NW, Suite 1014-Washington,-D.C. 20036 (202)~ 842-0034 L i
1 4 68 1 Event V Bypass in this region. If you don't have a { 2 frequency uncertainty, okay -- on a vertical axis these two 3 will collapse.
.4 MR. PARRY: So your V Sequence is so precisely l 5 defined that all the parameters associated with it are --
6 DR. KHATIB-RAHBAR: If you take away the frequency 7 uncertainty. 8 MR. PARRY: Which frequency uncertainty? I am not , 9 talking about the initiating event. I am talking about
- 10. other things that underlie that which could be -- I don't l 11 exactly where the --
-12 DR. KHATIB-RAHBAR: Stochastic type issues.
13 MR. PARRY: -- where the leak is, for example. l 14 DR. KHATIB-RAHBAR: Stochastic type issues. O ( ,/ 15 MR. PARRY: Which is what I am saying right, and 16 those issues then should really be treated as aleatory and 17- not epistemic and they complicate the things. 18 DR. APOSTOLAKIS: We have got the same problem I 19 with the Army's -- what is it? -- incineration of chemical 20 munitions, right? 21 Imagine that you create these curves with Monte 22 Carlo simulation or Latin hypercubes. A single simulation, 23 'in other words a single set of input variables, no epistemic s 24 uncertainty -- you know, you selected the variables -- will : 25! result in one curve that will show the aleatory uncertainty [ ANN RILEY & ASSOCIATES, LTD. Court Reporters - 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C.20036 (202) 842-0034
_ . _ _ _ . - . - _ _ . _ - ~ . _ _ _ _ . _ _ . . . _ _ . . . . _ . . _ _ . _ . . . _ _ l-l 69 l' on'the cesium released. If there was no aleatory u () 2 uncertainty you would get one point, so get a curve. The 3 uncertainty horizontally, as Mohsen said earlier,.because of 4: the uncertainty, you know, the aleatory part. L .51 The fact that you have epistemic creates a family. 6 of. curves. They are not unsure. 7 The. problem with that is that when you say 95th 8 percentile, this curve that Mohsen is showing connects all l 9 'the 95th percent. percentiles of the.various -- of the 10 spaghetti curves, okay? This is not what you would get by
-11 using 95th percentiles for all the parameters, right?
12 MR. PARRY: Right. 13- DR. APOSTOLAKIS: Okay, so it is a pointwise 14 derivation but this is really becoming too detailed now. It () 15 . forced me-to introduce additi'onal technical terms.like 1-6 spaghetti that have not been explained.
'17 I think --
11 8' EDR . KRESSi Fettucini. 19- DR. APOSTOLAKIS: Why don't we agree that the i
- 2 0 ~ uncertainties we are talking about here are really between 2 11 .the 5th and 95th and the message that Mohsen sent us is that 22: 'in-his belief the 5th percentile curve should be steeper 23 .than it is, okay? -- and he also claimed that the 95th
.24- percentile curve should also be steeper, therefore driving 25- the mean, but perhaps not as much. I think that is the 5
' '[ *
' ANN RILEY & ASSOCIATES, LTD. !
, /' Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014
' Washington, D.C. 20036 (202) 842-0034
~. . . - . .- . .-
- - . - ~ . . . - _ .- ..
70 l 1 message he is sending, because otherwise we wi2' spend the r~g V a 2 whole afternoon discussing the Monte Carlo stuff, okay? i I 3 DR. KHATIB-RAHBAR: Other questions? 4 DR. APOSTOLAKIS: Let's go on. 5 DR. KHATIB-RAHBAR: I don't remember what I was 6 going to say next. 7 DR. APOSTOLAKIS: You said you had two parts in 8 your presentation. 9 DR. KHATIB-RAHBAR: I am not even through the i 10 first part yet. 11 DR. APOSTOLAKIS: Okay. When you are through with 12 the first part, maybe we can take a short break. L13 DR. KHATIB-RAHBAR: Okay. E14 .The next question is what to use as the q
) 15 consequence measure. In my mind the problem of nuclear 16 accidents really is the catastrophic potential for 17 -contaminating a very large area of land for a very long I
-18 time -- the Chernobyl accident is given a point in time.
- 19. DR. APOSTOLAKIS: So it is not risk?
20 DR. KHATIB-RAHBAR: The risk is of ground 21 contamination depending what risk measures -- 22 DR. APOSTOLAKIS: Well, I know, but I mean -- 23 DR. KHATIB-RAHBAR: It's the risk of heart
-24 attacks. Land contamination is of concern because of health
-25 effects.
l l b'- ANN'RILEY & ASSOCIATES, LTD. Court Reporters 1025: Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 L L
, . .- . - . . . ~ . . . - . . _ ~ - - . . . . - - . .- . . . . ~ . . - . ,
c 71 1 DR.=WALLIS: It is not the land. It's the land if
<~s '
Q 2 used'by humans. 3 DR. KHATIB-RAHBAR: By humans, absolutely. 4 Especially in Europe where land is relatively scarce, the i 5 population'in terms of density is fairly high, so land l J 6 contamination, useful land contamination becomes more 1 1 7 significant. 1 1
- 8. Prompt fatalities could often be mitigated by l 9 offsite. emergency counter-measures. Again, in the case of l
)
10 Switzerland, for example, the offsite emergency l 11 counter-measure often involves sheltering. All Swiss homes 12- are equipped with a basement.which was designed as a fallout 13 shelter, so during an accident most people vertically-i 14 . evacuate. They go'down to the basements. ()
. "h A, s 15 As a result, if you do away with the cloud l
I 16 passage, typically the early fatalities are relatively i 17 small. 18 ' DR . KRESS: How viable is that option in this 19 country? 20 DR. KHATIB-RAHBAR: In the U.S.? That is another 21 issue. Actually we looked at it a number of years ago for - 22- the NRC. It is viable. 'It is relatively viable.
-23 DR. APOSTOLAKIS: So let me understand your first 24' bullet. I am still trying to digest it. If it were up to 25 you, you would revise the safety policy statement of the r
O ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
72 1 Commission'--
~~
I. 2 DR. KHATIB-RAHBAR: Absolutely. 3 DR. APOSTOLAKIS: -- contamination -- 4 DR. KHATIB-RAHBAR: Absolutely.
~5' DR. KRESS: And you would --
.6 DR. KHATIB-RAHBAR: I will come to that:later.
7 DR. KRESS: And the mean value of the acceptance 8 -' values'on prompt fatality would be without evacuation but 9 sheltering-instead? That's an interesting thought. 10 DR. KHATIB-RAHDAR: Because you would actually H11 eliminate one large uncertainty by doing it that way.
.12- DR. WALLI':S There is also the catastrophic 13 potential of wiping out a source of useful energy because of 14 the reaction to the accident and that is a catastrophe too.
15 DR. KHATIB-RAHBAR: Yes. I haven't looked at that 16 yet. 17 DR. SEALE: Few people do.
'181 DR. FOWERS: Your last point is an endorsement of
,; - ,19 hormesis. 20 [ Laughter.) 21 DR. KRESS: That is supposed to be uninhabited. 22 DR APOSTOLAKIS: Uninhabited, yes. A very 23' unfortunate place to have -- 24' DR. KHATIB-RAHBAR: This source is actually
, :25 -incorrect. Coming on the plane-on Saturday I looked at this b\ /L ANN RILEY &' ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
' Washington, D.C. 20036 (202)-842-0034
L 73 1 and I came to my office trying to dig out this source to
) /2- , bring you a copy. I realized this is not the correct paper, u 3 where this thing came from. I can dig it out for you.
L i l 4 DR. APOSTOLAKIS: Yes, if you could. Okay, 5- thanks. 6 DR. KHATIB-RAHBAR: 'The issue is if you take l i 7 one-half a gram of Cesium-137, you spread it uniformly over ! 8: one square kilometer, it makes the area fully unhabitable l 9- for essentially a very long time. Chernobyl is a point in j 10 time. 11- DR. KRESS: That is a release fraction of what, 10 12 to the minus 20? 13 DR. KRATIB-RAMBAR: A very, very small quantity. 14 Very, very small quantity. (\
'( ,)- 15 DR. KRESS: That end of the curve could be 16 important way down there on the release fractions.
l 17 DR. KRATIB-RAHBAR: Well, this is very ideal. I
.18 mean it's taking half again a gram and spreading it 19- uniformly is the point.
20 DR. KRESS: It is indicative though of what small L 21 releases can do to you -- 22 DR. KHATIB-RAHBAR: But the release fractions 23 could be much greater if you went to backup. This issue, a 24- -few years ago when we were debating this, it came up. This , .25 does not mean half a gram released from the reactor. I ANN RILEY & ASSOCIATES, LTD.
.(N./O) . Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 '
(202) 842-0034 L l
74 1 DR. FONTANA: It says there was 165 kilograms of
/
r~m 2 cesium. Q.)) 3 DR. KHATIB-RAHBAR: That's correct. You have got 4 a total of 165 kilograms in the reactor typically, for a lot 5 of power reactors and when you are talking about half a 6 gram, this is what is on the ground if you uniformly spread d 7 that. 8 DR. APOSTOLAKIS: What do you mean by totally 9 uninhabitable? 10 DR. KHATIB-RAHBAR: In other words, you cannot use 11 that land for a long time. 12 DR. APOSTOLAKIS: You cannot drink the water, 13 underground water, you cannot send your cows there. 14 DR. WALLIS: I think it is worse for grazing rs () 15 animals. 16 DR. POWERS: I think that water problems arise 17 with cesium contamination One is that it does get 18 preferentially uptaken into plants. The other one is a 19 really interesting one that does arise in the Chernobyl 20 accident, where it goes onto pine needles and one 21 subsequently has forest fires. It migrates. The hot spot 22 moves around on you. It's kind of fun. Moths pick the 23 stuff up and they transmit it and then tend to go from tree 24 to tree and things like that, so you have some interesting 25 transmission with cesium. O ANN RILEY & ASSOCIATES, LTD. ( J' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l 75 1 But I think deep groundwater is by and large very [%.J j' 7 poorly effected in some soil types. Now, there are -- I can 3 find soil types where it is egregiously effected, but deep l 4 groundwater is slow to effect because of the high absorption 5 potential of cesium. By the time cesium gets to the ground 6 water aquifer, it has decayed several half-lives. 7 DR. APOSTOLAKIS: So the half-life he has there, B what is the half-life? 9 DR. POWERS: It is 12 or 13 years. ) i 10 DR. KHATIB-RAHBAR: Yes. A typical cesium-137 is l 11 about a 30 year half-life, this is in days, 10,000 days, l 12 11,000 days, 30 years.
)
13 If you look at this table, this comes up from, I l 14 guess, one of these original -- 54 dominant radionuclides. ,
/s
( ,) 15 These are just a few typical ones.for a typical pressure 1 1 16 water reactor. 17 This is the inventory in becquerel, what is the 18 fuel for a typical PWR which has been running equilibrium 19 cycle timeline. 20 DR. WALLIS: It is a very interesting calculation 21 to spread that over the world and to look at grazing 22 animals, and look at the standards for becquerels in meat, 23 and you come up with a horrific conclusion about how you 24 can't eat these animals. It is not too difficult a 25- calculation. I) ANN RILEY & ASSOCIATES, LTD. (_) Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 l
........-_._.._.__.,____.m _ _ _ _ . _ , _ , _ . . . . _ _ . . _ . _ . _ - . - . _ . _ . .
76 1 DR. KHATIB-RAHBAR: First of all, let's focus on-() ,2-
-3 noble gases. In terms of the overall inventory, as you can
. .see, the total inventory for a typical reactor is dominated
.4; by noble 7 gases. But noble gases oftentimes have a very, 5 very'short half-life. For example, you keep the 6 ' containments closed for about 12 hours, you can decay-
- 7. roughly ~ half of your noble gases. That's why, when they 8 . talk about'early fatalities, what really dominates early i
9 fatalities are noble gases. And if you can do away with 10- noble gases, you have done away with a large portion of your 11 .early fatalities. This dominates the inhalation dose. ; i 12 'Okay. l 13 The same for iodine. 14 DR. KRESS: Isn't there a pretty sizable fraction 15- due to the I-131, though?
.16 DR. KHATIB-RAHBAR: Yes, I am coming to 17' iodine-131.
18 DR. KRESS: Yes, but for prompt fatalities, too. 19 DR..KHATIB-RAHBAR: Yes, I am coming to the next
. 20l item,' iodine group. The iodine group, you know, this is 21 ~ typically about five radionuclide -- radioisotopes.
22 Iodine-131, you know, if-you look at it in terms of the 23 overall. Becquerel, 134 dominates, but'it doesn't have a 24 : substantial half-life, it decays right away. So the one ; 25, 1which reallysis significant is iodine-131, which has an i r O -ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington,.D.C. 20036 (202) 842-0034 w 4
_ _. _ _ . . . . . . _ . _ _- _ ___ _ . . _ _ . - _ _ _ . _ . ~ . . _ _ _ .. 77 1 eight-day half-life, you know, or one-day half-life here. 2 DR. APOSTOLAKIS: That is what. Farmer used, richt?
- (s_ -
'3 DR. KHATIB-RAHBAR: Yes.
'4 DR. POWERS: Understand, however, you can get some 15 misleading things out of this. For instance, 132 half-life 6 really doesn't count, it is the tellurium-132 half-life that 7 counts here. -
8 DR .- KHATIB-RAHBAR: Yes. 9 DR. POWERS: Okay. So the fact that 132 goes away 11 0 very_quickly, but it is.only being generated -- 11- DR. KHATIB-RAHBAR: I am just looking at first 12 order type effects, yes. -9 13 DR. POWERS: That is the first order effect.
.14 DR. KHATIB-RAHBAR: Yes, but tellurium, again, is ID' 4s_)- 15 not a significant concern.
16 DR. POWERS: It is because it produces the 132 17 iodine that you have to worry about it.
' 18 DR. KHATIB-RAHBAR: Tellurium --
I 19 DR. KRESS: It decays. ; 20 .DR. KHATIB-RAHBAR: It decays, yes, it decays to 21' iodine-132, that is correct. But, again, if you look at it, 22 really, what dominates again on this first order, this is 1
-23 not complete, this is only a few of them, cesium sticks its 24 ugly face out. Okay. That is really what dominates.
-25 And there are other things, for example, rs i f ANN RILEY & ASSOCIATES, LTD.
\/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 I
. -. - - - . - .~ - . . - . -. . ~.. -~ . __ .. .
78 l' strontium-90, barium-140, these are significant risk factors j 2' in terms --'because strontium goes into the bone marrow. ) 3 Barium-140 is also the same. So these tend to be very ; t l 4 .significant. ' 5 Quantity of release, if you look at the mass 1 c 6 quantity of release, you have for a typical PWR about 7 170-odd kilograms of cesium, but you have tons of things { 8 -like plutonium and other things. Okay. 9 So, again, this gives another credence why cesium i 10 is more.significant. Again, if you'can deal with the early I 11 counter-measures-with. iodine issue, I think the iodine issue i ! t 12 totally goes away, b'ecause that is really -- the concern 1 13- .with iodine is primarily it gets into the milk and goes into 14 the thyroid. And if you can, for example, dump the milk for O;,, 5, 15 several days and come up with some counter-measures for 16 iodine, you can do away with the effects of iodine 17 ~ altogether. I 18 It still does hang on, there is a contribution I 19: from' iodine. In fact,-the calculations that we did, there's 20 -about a 10 percent contribution from iodine, latent i 1 21 -fatalities. It is not altogether eliminated, but its l 22' significance becomes much smaller. i 23 DR.'APOSTOLAKIS: So, let me understand this, what u..
- 24 .you
- are.saying is that early fatalities are dominated by L 25 iodine?
r R ' i ANN RILEY & ASSOCIATES, LTD. , ~ %~ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 L t ?
. ~ -
79 1 DR. KHATIB-RAHBAR: They are dominated by things . I 1 2 like noble. gases and iodines, right. j V. 3 DR. APOSTOLAKIS: Yes. Okay. But we can do 4 -something about them?. 5 DR. KHATIB-RAHBAR: To mitigate their impact by l 6 emergency actions or different counter-measures that we can 7 take. 8 .DR. APOSTOLAKIS: Well,- in essence, what you can [ 9 'say then is that'you are using the release of iodine and 10 , noble gases as a surrogate goal for early fatalities, but i 11 you are confident you canldo something about it. 112- DR. KHATIB-RAHBAR: Yes. 13 DR. APOSTOLAKIS: Which is the same thing for 14 cesium for latent. So you are not really using only the (,/~T) 15 cesium' frequency consequence curve, you are using both. 16 DR. KHATIB-RAHBAR: We.are -- in the curves that 17 we have', the concept of equivalence which is developed is on 18 the basis that we have looked at 54 risk dominant L19- radionuclides. l201 DR. APOSTOLAKIS: Okay.
'21 .DR. KHATIB-RAHBAR: And we have determined the I 22 latent effects of different radionuclides in this family of 23 54 radionuclides, and we have said, if you release 100 L24 percent'of~ strontium-90, how much would that be. equivalent 25 to in terms of mass if.you convert it back to cesium?
l O\ : ANN'RILEY & ASSOCIATES, LTD. l ' [ks' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202)-842-0034
80 1 DR. APOSTOLAKIS: But this only for latent? O 2 i k' ,) DR..KHATIB-RAHBAR: This is only for latent. 3 DR. APOSTOLAKIS: So what I am saying is if I read 4 your paper with the Swiss, without talking to you, I get the 5 ; impression that you are only using cesium. 6 HDR . KHATIB-RAHBAR: No, it says cesium equivalent. I 7 DR. APOSTOLAKISi The equivalent, equivalent. But 8 ~ this is for latent. But now, after talking to you, I also 9- know that you can write another paper for iodine and noble j 10 : gases for the early releases, but you simply don't worry too 11 much about it because you are confident'that you can do j 12 some, you can manage it. 13 But,.in essence, you are using both. You are not 4 14 neglecting early fatalities.
- i fm) 15 DR. KHATIB-RAHBAR:- No, we are not neglecting it, 16 'but we focus, as I said.
17 DR. APOSTOLAKIS: You are focused on latent. 18 DR. KHATIB-RAHBAR: The issue, cesium issue is 19 latent effects. The issue, is my view, is not early 20 effects. 21 DR. KRESS: Not only that, George, with the 2:L possible acceptance of noble gases, you can probably 23~ correlate the release of the volatile fission products. So E 24 that if you pegged the cesium, you probably also know what
'25 the iodine is.
l i
~\s-[ l
~
ANN RILEY & ASSOCIATES, LTD. Court Reporters ' 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
-(202) 842-0034 i
i i h 81 1 DR. KHATIB-RAHBAR: Yes. 2 DR. KRESS: So that if you just use cesium,'you y 3 can incorporate it as the iodine part of it, actually, 4 because they are. correlated. Now, there is.a little problem 5 with noble gases doing that because it is not a good -- not 6- as firm a correlation,-but there is even a correlation
- 7. there.
8 DR. APOSTOLAKIS: So you are -- I mean they are 9 not independent. 10 DR. KRESS: They are not independent, that's 11 right. 12 DR. KHATIB-RAHBAR: Yes. That is a very good 13 point Dr. Kress brings up. The cesium, iodine, nobles 14- gases, even tellurium, to some extent, are essentially 15 correlated by roughly correlation coefficient.close to one. 16 DR. KRESS: Yes, it is close to one. 17 DR. KHATIB-RAHBAR: Close to one. The reason that 18 the release to environment for noble gases is overly
.19 correlated, in the sense, because noble gases do not retain, 20 they just escape.
21 DR. APOSTOLAKIS: So let me' understand this. 22 DR. KRESS: .That's why it is a little problem with
.23 'that.
24' DR. KHATIB-RAHBAR: Precisely. 25 DR. APOSTOLAKIS: Are you claiming then that all I ANN RILEY & ASSOCIATES, LTD. N Court Reporters 3, 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. - - . - . - . - . .. -. . - - .- . . - . . . . - - . - ~ . - _ _ . - . . - = - . . . . . _
82 1 : have'to worry about is cesium equivalent? DR. KRESS: I 2 I think you could probably do it with
./ .
3' - just cesium. .Maybe you need two of them, maybe you need 4 cesium and something for -- cn maybe.the actinides. 5 DR. KHATIB JRAHBAR: Yeah. What we have done --
- 6. .IHl. SEALE: On cesium, he is smart to know what er 7: the correlation is.
8 DR. APOSTOLAKIS: Yeah. But he says equivalent, l 9 . so, I assume he is smart enough to come up with that. l l 10 DR. KHATIB-RAHBAR: Yeah, the equivalence has not 11 been developed. Let me give you the weights, this is for 12 particular calculations we had done. The iodine
.n 13~ contribution was 10 percent, cesium is not 1, it is .6, 60 )
i =14 ' percent, tellurium'is about 1 percent, Dana. Strontium, ) r~ 15 barium is a factor of roughly 2, 1.7. 16 DR. APOSTOLAKIS: Percent of what? 17- DR. KHATIB-RAMBAR: This is just the weights. The 18 contribution essentially to latent fatalities, if you look 19- at it. If I were to derive the cesium equivalents, as I 20 said, I would take all the inventory for these 54
, 21T radionuclides released into the environment and try to see q 22- how raany latent f atalities they would cost over a period of ,
123- 50: years, I forget, integrated out. And then you find out l 24 ' how many -- how much in terms of mass of cesium would they 25 correspond to, per radionuclides, and I can' weigh it O: ANN RIL.EY & ASSOCIATES, LTD. As / Court Reporters 1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 t y - - -
83
.1 -according to dose. Okay. So the weighting factor that I
! ,<*"g - ,'( > 2 get the contribution to the essential latent fatalities, t ' %/ 3 there is some from iodine. As I said, it is roughly about 4 10 percent. E '5 DR. KRESS: You just multiply the cesium
'6 fatalities by --
7 DR. KHATIB-RAHBAR: Precisely. 8 DR. KRESS: Divide it by .6, basically.
'9 DR. KHATIB-RAHBAR: Right.
10 DR. KRESS: Then you cover the others. And that's 11' the way you would handle it, sort of.
'12' DR. WALLIS: Would you tell me how many fatalities 13' you come up with when you make this calculation?
- 14. DR. KHATIB-RAHBAR: I don't have the number, it is
- (
( 15' thousands, thousands. 16 DR. WALLIS: It is thousands? 17 DR. KHATIB-RAHBAR: Thousands, yes. 18 DR. WALLIS: It is not hundreds of thousands? l 19 DR. KHATIB-RAHBAR: Hundreds of thousands, I 20 forget. 21 DR. KRESS: It depends on the release. 22' DR. WALLIS: It-is a large number of people. 23- DR. KHATIB-RAHBAR: Sure. When you integrate it 24 over a 50 year period to thousands of miles, of course. L .25 DR. WALLIS: I think you need to tell us these i
.g-
- / ANN RILEY & ASSOCIATES, LTD.
-J' Court Reporters
-1025 Connecticut Avenue; NW, Suite 1014 Washington, D.C. 20036
'(202) 842-0034 l
b ,
84 1 numbers, because that tells us how important it is. 2 DR. KHATIB-RAHBAR: What numbers?
~3 DR. WALLIS: Are we dealing with a thousand people 4 or;100,000 people?-
5 DR. KHATIB-RAH'BAR: Oh , in' terms of numbers, those
- 6. numbers are readily available, I mean 1150 gives you those 7 ' numbers, that is~whylI didn't want to things'that are l 1
8 .already available. I mean'1150 has those numbers, you can 9 look in the appendices. 10 DR. KRESS: You don't want to look at just the 11 . deaths in absence of the probability.
'12 DR. KHATIB-RAHBAR: Frequencies.
13 DR. WALLIS: Now, George put some words in your 14 mouth, he said you were confident that you could handle l
- 15. these sort of immediate fatalities with emergency measures.
'16 DR. KHATIB-RAHBAR: By and'large.
17' .DR. WALLIS: Now, I am not confident that the 18 emergency measures will work. You'are relying upon a whole 19 lot'of societal' things to happen, people to respond to 20- .something they have never seen before, with a lot of
~21 uncertainty about what is going on. I think that is not 22 something you can rely on.
23' DR. KRESS: You might tell somebody to go down to , , x24 their basement'and'they will say, I am getting out of here. 25 DR. WALLIS: If you think about Three Mile Island, l-
'l ~
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014' Washington, D.C.-20036 L (202) 842-0034 L
85 1 there was a lot of confusion about shall we evacuate, shall I r~ ' l 2 we not evacuate? Is it serious, is it not? What is going lR )s i 3 on? 4 DR. KRESS: A lot of uncertainty. l 5 DR. KHATIB-RAHBAR: The whole concept of emergency j 1 6 actions is controversial, you are absolutely right. But I 7 what I personally -- personally promote is sheltering 8 concept, because I think sheltering is cheap. 9 DR. KRESS: It is the least uncertain. 10 DR. KHATIB-RAHBAR: It is least uncertain, and you 11 can demonstrate that. 12 DR. WALLIS: Or it could be handled if there were 13 proper plans and everybody did what they are supposed to do. 14 DR. KHATIB-RAHBAR: Yeah, it just doesn't work (~
'; ,) 15 that way, unfortunately. When you are talking about 16 relocations of a large number of people, especially in the 17 high population areas, that is not easy.
18 DR. WALLIS: It is difficult enough without any 19 nuclear accident. 20 DR. KHATIB-RAHBAR: Now, what to use as a 21 consequence measure, to continue. Off-site consequences, 22 fatalities, land contamination, et cetera, require level 3 23 PRA. This involves even additional and greater 24 uncertainties. In calculating those types of weights, those 25 uncertainties are als.o inherent in there. Let me not l T ANN RILEY & ASSOCIATES, LTD.
'N_ l Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Nashington, D.C. 20036 (202) 842-0034
. . - . . _ . _ _ _ ~ - . _ . . _ . . . _ . . . _. _.
86 l 1 mislead you. Those are there, as you pointed out.
) J:
s
~2 But you are not -- since you know this is i E 3~ uncertainty, an uncertainty that you are going to add on top 4 of other uncertainties, and the.quantification of these 5 uncertainties are even more difficult --
I mean there are l 6 studies'done, I think some that NRC has recently sponsored,
- 7 some European. commission has' sponsored, and some we have 8 done a number of years ago, and, by and large, the l
, 9L ' uncertainties and risk are going to be dominated, if you
-10 want to do a level 3 PRA, by off-site consequences. Weather
- 11 variability itself is significant. Population variability 12 'is very.significant. Emergency action factors are.very 13 significant.
14 So that is a complication I would rather one would ( 15. not-deal with. You have not totally gotten away with it, 16 with the concept that we have introduced, but we are not 17 requiring additional calculations and additional burdens on 18 somebody to demonstrate. [_
- 19, DR. WALLIS: It is. interesting, all the things
~
20 that really matter are not in something as simple as CDF. DR. KHATIB-RAHBAR: Release fractions alone, I 2'2 L again, are not adequate.
'! 23 DR. APOSTOLAKIS: They matter from the uncertainty
;24 l point of' view, because if you don't have core damage, I
$7 25; ' m e'a n ~ ~- '
ua- ' 0;N ANN RILEY-& ASSOCIATES, LTD.
\_sk Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
-Washington, D.C. 20036 (202) 842-0034
, , -J 1 l' a, . ~l . E _ - - - - - - _ -
. . . ~ . ~ .. . , _ . _
i 87 l l DR. FONTANA: As-far as we'ather goes, the wind I ll' V 3 2 direction, for example, really isn't an uncertainty, 3 because, in principle, you could do the calculation for 4' that. 5 DR. KHATIB-RAHBAR: But rain is, for example. , 1 Again, given lot' hot spots are driven by rain, how many 1 6
'7 rains do you.put in your weather bits, and that is very -- ]
l 8 DR. FONTANA: That is --
- j. 9 DR. POWERS: But I think Mario might argue, maybe l 10 -you would argue, that if an accident were to occur, you i 11 would know exactly what the wind direction is, and you would l
12 know what the -- whether it was raining or not. You would 13 still have the other uncertainties, what the magnitude of l 14 source term was. 15 DR. KHATIB-RAHBAR: You know that for 20 16 kilometers. When you are talking these numbers into 2,000 17- kilometers, that is nonsensical, absolutely nonsensical. 18 DR. WALLIS: It makes all the difference in the l 19 world. The Chernobyl plume didn't have to go to Scotland. i 20 DR. KHATIB-RAHBAR: Actually, they measured high l- 21. concentration of, for example, plutonium near Sweden for o 22- 'Chernobyl. But if you had to use existing models, they L
- 23. would not predict a single -- in grams of plutonium, or b 24 micrograms of plutonium in Sweden.
b L :25 DR. POWERS: When you say use existing models, 'tO ANN RILEY & ASSOCIATES, LTD. . (.~) Court Reporters l 1025 Connecticut Avenue, NW, Suite 1014 l -Washington, D.C. 20036 L (202) 842-0034-l l-
;. 88 1 'models of what?
,2 . DR. KHATIB-RAHBAR: By using the straight line
'aV.
plume models, MACCS, CRAC. 3 4- DR. POWERS: Now, I think if you used -- the 5 trouble with those_models is that they are really fairly 6- localized models.
.7 DR. KHATIB-RAHBAR: Yeah, but they are integrated 8 up to 1,000 kilometers, though. They are applied,-
9 unfortunately, to very large areas. 10J DR. POWERS: When you apply things like AIRREG, do 11 'you get plutonium in Sweden?
-12 DR. KHATIB-RAHBAR: Sure. You have to update the
-13 weather -- all the way-during its trajectory and follow'the-14 mountains and all the pathways. I mean if-you again look at-s
(
~
15 lthe AIRTEC calculations, they are subject to other 16 uncertainties which, you know, is a ball game in itself. I 17 mean there is -- you cannot avoid that. I mean that is
- 18 there, but that is hidden somewhere else. I mean you have 19 to put in eddy diffusivity parameters into those codes.
20 -DR. WALLIS: I think you want to make sure you
.21 don't have a hot' plume, too, so that it doesn't go up.
22- DR. KHATIB-RAHBAR: It can rise, exactly. There 231 ~are ebulliency effects you have to consider. There are q 24 niany, many factors in here which are not straightforward to 25 ' calculate. So all I am saying is, why burden it with that, ANN RILEY & ASSOCIATES, LTD.
.\- Court Reporters
-1025 Connecticut Avenue, NW, Suite 1014-
. Washington, D.C. 20036 (202) 842-0034 o
II '
- .i,-____ _
I 89 1 if possible? 7
) L2' DR. KRESS: If you can incorporate all those
-3 ' uncertainties appropriately in the acceptance criteria. :
1 I L 4 DR.~WALLIS: So I think what you are saying is i ! 5 that.the real consequences are dominated by things that are l'
< 6 difficult to figure out,-so let's forget them. ;
j 7 'DR. KHATIB-RAHBAR: No, I am not forgetting them i I L 8. ' altogether. I am saying'let's not burden the process with j 9 rgoing through those types of exercises.
)
< 1 10 DR. KRESS:
l You have to incorporate them somehow H l ' 1 ilu 'in'your acceptance criteria. l ,s l 12 DR.~KRATIB-RAHBAR: Yes. , 13 DR..KRESS: And you have to do it in a bounding ' L ' 114 sense ~. l "15L DR. WALLIS: But when you are telling the story to , 11 6' 'the people who are going to-be effected, you have got to 1 17 level with them and say there are'these things which are 18- major actors like emergency response, really major actors in j i 19 determining how many people are going to be hurt. l 20T DR. KHATIB-RAHBAR: Right. I mean that's -- 21 DR. SEALE: The details of emergency response is ! 22 site-specific. And I think at this point we are trying to-t 23' find out what the general principles are rather than
- 24; - emphasizing the. fact that you get a different answer for L25 Palo Verde whether or not the Santa Ana winds are blowing )
t ANN RILEY & ASSOCIATES, LTD.
\- -
. Court Reporters j 1025 Connecticut Avenue, NW, Suite 1014 '
Washington, D'.C.'20036 L , . ,
'(202) 842-0034 i p
- p
~. , ~ .- - . -.. ~ . . - . . . . -. - .~ . -. .~..
90 1 towards Southern California. And I think that is the reason l 2 that you don't go into these other things at this point, you 3 do.have to have a site-specific element in it, but I think 4 it is premature.
.5 DR. KRESS: That is exactly what I.said. For l 6 example, if you will excuse me a minute.
7 DR. KHATIB-RAHBAR: Please. l 8 DR. KRESS: Now, that Jeff is here, I love to show ' 9, his. curves, but when I showed this curve from his work, I
- 10 intended this line that I drew on there to represent 11 reasonable emergency response measures. You could very i 12- .well, if you are daveloping an acceptance criteria,.you
.13 could very well 5g) this line which is basically no
- 14. evacuation and no emergency asponse at all. And, of 15 course, that makes your acceptance criteria very strict, but 16 you have covered everything then. And-I say that is where 117 you incorporate these uncertainties, somehow, in this 18 correlation function of your acceptance criteria.
19 DR. APOSTOLAKIS: I suggest that we let Mohsen i finish the first part and perhaps when we come back, -- l 21 IMt. KHATIB-RAHBAR: Let me finish the first part. 22- DR. APOSTOLAKIS: -- we will have an opportunity 23 to -- 24 DR. KHATIB-RAHBAR: Yes, let me finish with this, L 25 and then I think we should take a break. 1* j: l i
'l ANN RILEY & ASSOCIATES, LTD.
A~<#' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 l Washington, D.C. 20036 (202) 842-0034
_ . _ . _ . - - . . . _ ._m_._ __ -. ..m_. _ _ _ _ . _ - _ . _ _ _ _ , 91 1 Release fractions alone are not' adequate because
)
~
2 they do not account for reactor size.
'3 .The impact of short-lived ~ radionuclides can be 4 ~ mitigated byLemergency response measures, so if you look at
.5 an attribute which actually satisfies nearly all of these, I 6 think release activity, Becquerel, cnr equivalent. mass 7 equivalent of.' cesium-137,.in our view appears to be a
.EF . reasonable measure of the consequences. So that would be
- 9. the: response.
10 DR. APOSTOLAKIS: And that would be only one? 111 DR. KHATIB-RAHBAR: No , as I said, I would -- in 12 fact, in some of the more recent studies they use release 13 activity, in~ terms of Becquerel, which includes everything.
-14 But'.the question, it's much-more difficult to come up with
' acceptance criteria for Becquerel, perhaps, as~it w 11 be if
~
15 16 you have to use a release quantity. 17 DR. KRESS: But in principle it's about the same. 18 DR. KHATIB-RAHBAR: It's the same thing, really. ! 19- But some peopleitake easier to the mass quantity rather than
.20 Becquerel quantity.
21 DR. KRESS: I would have used curies, myself. 22 DR. KHATIB-RAHBAR: Oh , curies. - Yes. , i 23 DR. POWERS: I spend a decreasing fraction of my 24 ' time associating with people of the chemical persuasion, and 4 25 they grow uncomfortable with focusing on a single kind of D ANN RILEY & ASSOCIATES, LTD.
'k > Court Reporters
,, ~1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 r
i
, m
92 ! 1 radionuclide, for a lot of reasons. It seems to me that if [/I
'L 2
3 I were to generalize for them what you've said, what you've said is that you really only have to understand the 4 particulates coming out of the plant, that we can handle the 5 gases. 6~ DR. KHATIB-RAHBAR: No, not necessarily, because-
- 7. cesium is not necessarily particulate matter. I mean, I 8 think -- I mean --
l 9- DR. POWERS: When is cesium not -- l'
' 10 DR. KHATIB-RAHBAR: I'm talking about the being 11 ! volatile, particulates in the sense as you look at TIID 12 14844 where there are refractories of that nature,>no. Yes, 13 . particulate, it's an aerosol matter. That's correct. But 14 it's volatile. It's a volatile aerosol. Volatile aerosol.
' 15 ' DR. POWERS: When is it a volatile?
- 16 DR. KHATIB-RAHBAR: Cesium is a volatile species.
17- I mean, you can evaporate it at a few hundred degrees.
' 18 DR. POWERS: Yes, and a few hundred degrees is 1
L 19 located'where? 20 -DR. KHATIB-RAMBAR: In'the atmosphere'it goes and
= 21 condenses into aerosols.
L 22 DR. POWERS: I think it's an aerosol shortly after i j 23 emerging from a core. p1 24 DR. KHATIB-RAUBAR: Right. It. condenses. It 25 approaches. temperatures more than -- l 1 .-
-( ANN RILEY & ASSOCIATES, LTD.
-s : . Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 l-(202) 842-0034 s
e y
l l: 93 1 DR. POWERS: -It bears no resemblance to a volatile 2 species once it moves away from a hot -- and that if -- if there were other radionuclides that behaved as badly as 3 4 cesium, and there are certainly people that have advocated
~5 that.we've omitted one, it wouldn't change your point at all 6- if you said " particulate" instead of " cesium."
7 DR. KHATIB-RAHBAR: Okay. Excluding noble gases, 8 ' essentially. 9 DR. POWERS: Wnat you're excluding is both noble 10 gases and the gaseous forms of iodine, whether it's I2 or 11 methyl iodide.
.12 DR. KHATIB-RAHBAR: Yes. but as I said, don't --
13 in the analysis we have done, we have credited iodines. We 14 have not recognized whether iodine is as a gaseous form or (_) 15 it's a particulate form per se. We have like a 2-percent 16 fraction being in a gaseouu form. So there is some 17 contribution from gaseous iodine in there as well. But it 18 does credit iodine. It does have some contribution from 19 gaseous iodines. 20 All I'm saying is that we should not include 21 ~ overwhelmingly iodine and/or noble gases. We should 22 dominate early fatalities. We should focus on latent 23 fatalities and contribution from iodine, whether it's 24 gaseous or particulate, is smaller than what it would
- 25 contribute to early fatalities.
L[ \s - ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
-(202) 842-0034
i 1 94 l 1 I don't know what I said on particulates per se.
,y : 2 DR. POWERS: Well, I guess I'm a little confused (J
m 3 with what you've said. You have a line here that says 4 reactivity of cesium-137 appears to be a reasonable measure 5 of consequences, yet in your own studies you've added in l 6 iodine. 7 DR. KHATIB-RAHBAR: Cecium equivalent. Cesium-137 ) 8 equivalent is what we're using always. Did I have just 9 cesium-137. 10 DR. POWERS: You have mass equivalent. You have 11 release activity or mass equivalent. 12 DR. KHATIB-PAHBAR: Mass equivalent. That's -- 13 mass equivalent, sure. 14 DR. POWERS: Okay. So the equivalent applies to
,~.
() , 15 both mass and activity. I do understand that. 16 DR. KHATIB-RAHBAR: Absolutely. Absolutely. 17 DR. POWERS: Yes. 18 ~ DR. KRESS: When you look at the safety goals, 19 prompt and latent fatalities, which I view as something like 20 acceptance criteria, prompt fatalities dominate. Have we 21 chosen the wrong safety goals? Because we could just show 22 -- forget the latent fatalities. The prompt fatality safety 23 goal will dominate almost all sides. Maybe once in a while 24 they don't. It depends on -- 25 DR. POWERS: That's only because of the way you i
; ANN RILEY & ASSOCIATES, LTD. \_)i Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l !, 95 )
-1 use your consequence -- your. transport modeling. If you ;
l n f) 2' didn't do-that, if you didn't narrow the plume down l < 3 artificially, then you would find that the latents i 4 dominated. . 5 DR. KRESS: Maybe. It depends on population 6 distribution. 7 DR.' POWERS: It clearly does, but the thing that ; l 8 -you can affect when you integrate overall sites, the thing ; i [ 9 -most at your command to affect is how narrow you make that 10 plume. And at least what we-find from the uncertainty 11 studies that the NRC has sponsored is we may be artificially ) 12 -- may have. artificially narrowed that plume in ways we , l 13 shouldn'tLhave, and we're deriving a whole lot, a bunch, out - 14 of. intuition we gain from those artificially narrowed
/~)'T i
\~ 15L plumes.
l
. 1 46 DR. KRESS: You'could very well have a good point.
17 DR. WALLIS: Well, the message I'm getting is that 18 the latents dominate. When you're talking about hundreds of H 19 thousands of latents, it's very difficult to get 100,000 20 prompt fatalities. You have to work pretty hard to do that. 21 DR. POWERS: I think he was talking about in the 22 case of -- 23 DR.'KRESS: I'was talking about the safety goals i 24 which are individual risk. You're talking about totals.
- 25. DR. WALLIS: That's silly. i ll ANN RILEY L ASSOCIATES, LTD.
Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 ; (202) 842-0034 l ?
i ! l l L I t 96 ) 1 DR. KRESS: Well, that's right, that may be
) 2- another silliness we ought to -- i 3 DR. WALLIS: That's the lunatic who stands around 4 the plant during an accident.
l 5- DR. KRESS: No, it's not him. , l ' l 6 DR. WALLIS: Says come get me- l I 7 DR. KRESS: No , it's an average over the l l
- 8. population. 'But that may be another thing about acceptance l 9- -criteria you need to look at. Total deaths may be a better 10 thing to look at.
l l 11 DR. POWERS: It is certainly my understanding that 1 l 12 when we look at prongs for accidents that progress slowly ' 13 enough that the evacuation plans can be implemented, that 14 .they are dominated by the. inefficiency of those evacuation f . 15- plans. ~ Undoubtedly there is a certain number of lunatics, 16 but mostly, you know, the conventional wisdom, 10 percent 17 just never get the word, you know. I think that's more of a 18 concern than lunatics.. I i 19 DR. APOSTOLAKIS: Okay. Maybe we can take a break 20 now. By the way, does the staff plan to say anything or
- 21. just participate in the discussions? Do you want some time L
22 for presentation, Gary? 23 MR. HOLAHAN: I don't believe we do; no. 24 DR. APOSTOLAKIS: Okay. So just general 25~ discussion. ANN RILEY & ASSOCIATES, LTD. Court Reporters 102R Connecticut Avenue, NW, Suite 1014 [ Washington, D.C. 20036 (202)'842-0034 I
97 1 And,.Jeff, I understand you will do the same
. N's i
- %d
) 2 MR. KAISER: I don't have a presentation.
3 DR.=APOSTOLAKIS: 'Just participate. 'Okay. So 4- we'll continue with Mohsen's presentation at 10 minutes 5 after three.
-6 [ Recess.}
7 DR. APOSTOLAKIS: Well, let's reconvene. We are 8 on the record'now. I 9 'Before we start maybe I should say a few words 10 about our other invited expert who joined us a little ) i 11 . earlier. -Jeff Kaiser is a Vice Presidentoat SAIC. He is j l
'12 managing the process industry programs. He'has a Ph.D. in i
13 Elementary Particle Physics from the UK. 14 The reason why he is here is because in his past (n_):15- he has done a lot of work on Level 2 and Level 3 PRAs. In 16 fact, Dr. Kress used some of your curves -- or not curves, 17 points, I guess, figures. I 18 DR. KRESS: Figures. j 19 .DR. POWERS: Scattered ions. l 20- DR. APOSTOLAKIS: Scattered ions. Okay -- and 21 Jeff has also worked on the development of atmospheric 22 . dispersion and consequence models, both for nuclear and the
; 23' chemical industries, so thank you very much for coming.
24 Jeff, we appreciate your willingness to come. 25 So -- we go back to Mohsen now, to his second
' \~-
[m[ ANN RILEY & ASSOCIATES, LTD. 1 Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. ... . . . . .. - . . . _ - . - - ~ . . -
98 1 'part. L2 DR. KHATIB-RAHBAR: Okay. There are a number of 3' other issues that were raised in communication with Dr. 4 Apostolakis. One was are the accidents outside of the core , 5- considered. 6 In the studies we have done, we have looked at 7 shutdown and other modes of operations but in terms of 8 frequency-consequence curves, we have never, at least I have 9 never'seen any shutdown studies that have gone beyond 10' calculating the fuel damage frequency -- in other words,
'11 releases have never been computed, to'my knowledge.
12 Therefore, the answer to this is no. They have 13 not been considered. i 14 Should they be included? Should, in other words,
,O 1% _/
15 frequency-consequence curves include other than full power [16 operational modes or operational modes, shutdowns,
'17' refuelling, et cetera? And the answer to that is yes, a 18- qualified yes. By qualified I mean there are a number of f ~19 other issues one'has to deal with when you are going to i 20 non-power operational modes, but I think by and large the L 21' uncertainties associated with those other issues are not in 22 -my view any more significant than what we are dealing with
[ '23 currently. i i 24 'There are other issues, for example, issues such 12 5 as air ingress can cause revolatilization of otherwise If ANN RILEY.& ASSOCIATES, LTD.
\~s Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
i l ! 99 l l l l 1 non-volatile fission products, lithiura being one of them, i eS l i 1 2 but again I think that they could be dealt with. They are LJ 3 not any more difficult at least in my mind than full power ! 4 . operational mode. 5 DR. KRESS: Let me ask that question a little 6 differently. Are PRAs configured in such a way that you can l 7 actually do a shutdown risk that is -- evaluation? 8 DR. KHATIB-RAHBAR: They have done them, yes. 9 They have been -- 1 10 DR. KRESS: They look at any sequence or any plant 11 configuration -- 12 DR. KHATIB-RAHBAR: Yes. I'll give you an 13 example. We have look at one kind of plant in Europe. They 14 have looked at 35 different configurations -- all the ; L/N ; (_ ) 15 coafigurations they could think of. I 16' DR. KRESS: Do you ascribe a certain amount of 17 time to which those configurations are in -- 18 DR. KHATIB-RAHBAR: They are all in different 19 timeframes, exactly. 20 DR. KRESS: And is there vari ation of that 21 timeframe for -- 22 DR. KHATIB-RAUBAR: Yes, yes. 23 DR. KRESS: -- for Monte Carlo on that? 24 DR. KHATIB-RAHBAR: No, no. It's not Monte Carlo 25 on that but what you have to do is -- that's what I mean l-l
/ ) ANN RILEY & ASSOCIATES, LTD.
i i/' Court Reporters I 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
-. - . . - . - . - - - - . . - - - - . _ . . - . . - . - . - ~ ~ - . ~ ~ - - - -
100 7 1 Lit's a qualified yes -- a number of issues have to be
'2 considered. How do you calculate these releases? How do 3 'you integrate them, over what-period-of time, et cetera, but 4 I don't.think -- You know, I have not done it but I do not )
5 -- think'they are insurmountable. That's something that you l El can. deal with. '
- f. '
7 DR. KRESS: Well, one shutdown's --'well, 1
- 8. something like another one but not exactly, and you have to 9- have that~ variation in there some way.
,10 DR. KHATIB-RAHBAR: Absolutely. Every plant looks
~ 11- "different. It's very procedural driven.
12 DR. KRESS: Juld you can't do it for past 13 shutdowns. You have to do-it for future shutdowns so it I _14 almost'hasLto be a Monte Carlo simulation of some. kind, it ' L 15~ seems to me like -- if you are going to~do.a proper shutdown L16 ' risk assessment. '
)
17- DR. KHATIB-RAHBAR: Monte Carlo simulation -- 18 maybe I don't -- ; 4 - 19 DR. KRESS: Monte Carlo simulation of plant 20L configuration' states and. times at the states. . 21L DR. KHATIB-RAHBAR: But those are known. You know i
.the time-you have different shutdown states,.because you do
~
.22. l
.23- -them.very often. ' They are not uncertain'in a sense. l i24- DR. KRESS: Yes, but it_ matters -- it matters :
125 whether the state.is -- say, this piece of equipment is out i fL j ANN:RILEY &' ASSOCIATES, LTD. - Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
.i
, a
101
,m 1 now and another one is out now, whether they overlap or f j 2 whether the one precedes the other. Is that the sort of 3 thing you think you can handle without --
4 DR. KHATIB-RAHBAR: They are all considered, 5' absolutely. 6 DR. KRESS: -- without a Monte Carlo? 7 DR. KHATIB-RAHBAR: Without a Monte Carlo they are 8 considered. Maybe I am missing, maybe I am not answering 9 your question -- I don't understand the question properly, l 10 but I think those are configural issues. 11 DR. KRESS: I just think it is very difficult to 12 use the PRA event tree methodology as is to do a shutdown 13 risk assessment, that's all -- that the technology has to be 14 improved.
._ / 15 DR. POWERS: But I got the impression the point 16 was that the challenges that you bring up, which I think are 17 very real, are simply because the order that you do things 18 and what-not is not known in advance.
.19 DR. KRESS: That's right. That's part of it.
20 DR. POWERS: The shutdown evolution is not done 21 often enough that you can anticipate 99 percent of the time
~
22 I am going to do this first and this second. There are some 23 things that you can and some thinge that you can't but I i i 24 thought the speaker's point was none of these things are 25 insurmountable and defy the current technologies.
,a
?#I' ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025. Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 t
[- L i Lf 102 u U' ' L 1 You can -- we do Monte Carlos all the time with I l' (M/ 2 PRAs nowadays. It is a relatively routine. thing to do. g 3 'DR. KRESS: But my point was I thought you needed l L '4 to do a Monte Carlo to do it properly. I l 5 DR. POWERS: You think-it's essential -- arguable, l 6: We have had speakers come before this group'and within this L 7 group.that have-argued that there are major challenges with i I , 8- the treatment of human performance and success criteria in > i i 9' shutdown PRAs. I don't.think that they would argue withlthe 10 proposition that these are not insurmountable things. They 11 just said they had to be done. I 12 DR. KHATIB-RAHBAR: Exactly. They have to be l 13 dealt with, absolutely. 14 DR.' POWERS: And there may be some substantial tLk l15 methodological developments-that have to occur here to make 16 is relatively routine to do shutdown PRAs, routine in the ; i
~
17 same sense'that-it is routine now to do an operational PRA. l l j 118. I'think that the " Monte.Carloness" that might be , i 19 required that you talked about becomes feasible simply I
'20- -because ou'r' computing power is going up so much.
21 DR. KRESS: I think it.is definitely feasible. I J22 'just don't think that PRAs are configured in a way to do it. 23 DR. POWERS: I don't think that people -- well, 2 4' ' let's say'up until October I didn't think people had looked 25- 'at-that. Now we are evidence that people have looked at E l i. j' ANN RILEY-& ASSOCIATES, LTD.
- l. -Court Reporters l_ lv26 cuinoctirit Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
, 1, , , -u--.. 1- ,-,-,.i,
l: 103 l L 1 doing Monte Carloness on PRAs for other purposes, but they ()' 2_ have implemented it, so it seems to be doable. 3- .This question of success criteria I think-does l l 4 come up, because I think that the success criteria for- ! '5 shutdown' accidents are different than they are for real ; 6 accidents when the containment barrier is not in place. 7 I think they are identical'if the containment 8 ' barrier is'in place, but I think they are not when the 9' containment is open. l 10 DR. WALLIS: Now Chernobyl did not occur in a 11' power operational mode. It wasn't really a shutdown 12 either -- tinkering mode. That maybe is the most. dangerous l 13 where something, an unusual mode is entered.
'14 DR-. KRATIB-RAHBAR: Yes, there are different modes' i 15 andLof course there are methodological issues which do come i
- 16. into play.but the issue is you have to balance your 17 uncertainties. Are the uncertainties going to be driven by 18 lack of-data or are.the uncertainties going to be driven by
- 19. modelling these types of complex overlaps that you refer to, 20 et cetera.
21 But what I am focusing here again is mostly on l 22 phenomena, things like success criteria that Dana put his 2:3 finger on. i 24 DR. KRESS: Or on your first bullet -- part of the l l 25- motivation for that question was spent fuel pools. F j 1001 RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
. Washington, D.C. 20036 (202) 842-0034
104 , 1- DR. KHATIB-RAHBAR: Yes. - L: fs v ( ) 2- DR. KRESS: And things like resins and waste 3 products that release small amounts of radioactivity which 4: normally aren8tzin PRAs but might be incorporated into FC 5- curves. They could be and I think part of that question is
- 6- are those, is it feasible to incorporate those and have they
.7 'ever been incorporated in FC curves?
'8 DR KHATIB-RAHBAR: To my knowledge they have not 9 been incorporated. I have not seen one, but I think it is 10 feasible and it can be done.
11 DR. KRESS: Particularly the spent fuel pools. 12 DR. KHATIB-RAHBAR: Absolutely. The spent fuel 13- pool has been looked at in a large number of studies and 14 that is some in-fact we know most about in at least in 15 lightwater reactor business -- at least in Europe I know 16- they have looked at them. In the U.S. I don't know, except i 17 for a couple I know of, but I don'+ know that many have been l 18 done. 19 Here again the phenomena of the uncertainties -- 20 there are a few issues which do come into play but I contend 21 they are not any more difficult than the issues we already
- 22 are supposed to deal with. By and large the containment is L
'23- open oftentimes. We don't have the same containment loading i 24- challenges.that we have to deal with typically. Oftentimes
[ 25 the' reactor pressure vessel head is in fact removed, but t i-ANN RILEY & ASSOCIATES, LTD.
\' Court Reporters
- 1. '1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 o
i
\
105 1 there are other processes. The air factor is in there, G t
) 2- natural convection _ processes come into play, et cetera, that
'3 Lyou have to deal with, but I think given the uncertainties 4 that we are currently putting on these risk curves, these
- 5. . will not-be any larger than what we are currently dealing 6 with.
7 Now'let's come to the core of what I am here for. 8 It's a paper which we presented several years ago at an 9 agency-IEA meeting which dealt with the proposed Swiss risk 10 criteria, safety criteria. b 11 4 These criteria is composed of two parts, one for 12 existing power plants and then for the newer generation 13 plants -- if there'ever will'be a new power plant built in 14 Europe.
'k_s 115 The core damage frequency including all external 16 events -- this again at that time we did not think of 17 ' shutdown modes _or other modes of operation. This was only
-18 power operational mode but including all external events is
- 19 to be less than equal to 10 to the minus 5 per reactor year.
20 ' Frequency release is greater than 10 kilogram 21 equivalent of Cesium-137, gram equivalent again -- I would
- 22 like to underline that. It should be much less than 10 to H23' the minus 6 per reactor year.
24 This was put into a exceedence frequency 25- consequence curve of the nature we have been discussing this
;m
~
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025LConnecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
106 p.- i l' . afternoon,:which is of this format. This is the total core l ~ }n}. 2 damage frequency of 10 to the minus 5. l 3 I'll-give you a little background how we selected l t 4' these ' breakpoints :ba the curve. That might be of interest
- 5. to you. This~ number here, this release corresponds to 6 approximately the. maximum release you would get for an 7 equivalent Swiss PRA or BWR during a severe accident when 8 filter containment venting system was actuated. All the 9 -Swiss plants-are required to have -- have been backfitted 10 with'a filter containment venting system, and for a boiling 11 water reactor you have an additional filter on top of the 12 suppression pool. These are typically Venturi type filters.
13' So this corresponds to releases which-are by E14 design required. In other words, with these filter is -15 containment venting systems filters are supposed to perform 16 to'certain criteria, and.this is essentially like a design , 17 criteria roughly. 18 DR. KRESS: I have a little trouble following a --
-19 'this is what-I would call an acceptance criteria that is 9: 20 -derived on the basis of what you could possibly get out of 21 the reactor. That seemed to be the wrong direction to 22- : approach an acceptance criteria.
23 I don't care what you can get out. I want to know r _. 24: what-is acceptable'for.some other reason, and perhaps the 25' -criteria that went into the general design basis for the l^ l l A - Q-l ANN'RILEY & ASSOCIATES, LTD. Court Reporters ! 1025 Connecticut Avenue, NW, Suite 1014 f w Washington, D.C. 20036 (202) 842-0034-
,- j'~'
107 1 filter had that incorporated in it so it had to be this good l . 4(~)j 2 because this is what we accept, and then I would say okay, 3 that is all right, because you got it by a round-about way. I i 4 But it ought to be stated in such a way that this ]
- 5 is what is acceptable for some reason or other. l 6' DR ~. KHATIB-RAHBAR: I understand where you are 7 coming from. I agree with you, but I think the discussions 8 on how to arrive at this'-- how we looked at what is l
l~ 9 acceptable from a societal point of view -- you know, what 10 about an engineering point of view? Can we design a system 11 in which we have a high degree of confidence that give you 1
.2 releases of decontamination factors of that order, et i
13 cetera, et cetera. I agree -- that should not have been the
, 14 basis for selecting this type of a criteria but I am just l ' (,cN
(,l. 15 . telling you how this whole thing evolved. 16 DR. KRESS: Yes.
' 17, DR. KHATIB-RAHBAR: Whether I agree with it or not 18 is another issue.
19 DR. APOSTOLAKIS: But'the 10 to the minus 5 though 20 in the frequency does what Tom says. 21 DR. KRESS: Yes. 22! DR. APOSTOLAKIS: That is what society in 23 Switzerland felt was acceptable. 24 DR. KRESS: Yes. 25 DR. KHATIB-RAHBAR: But I guess what Tom is saying (\~' )-- ANN RILEY'& ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 L Washington, D.C. 20036 ll (202) 842-0034 W
. - - - . - . . ~ . . - - ~ - - - . - . - - . ~ - - . . _ . - . - . . _ , . . . - . , _ - -
108 is)this. number --
~
j1 C 2 DR. SHACK: That's an ALARA concept there.
'3 DR. WALLIS: 'Right. I also sense it's a flat '
l
. >4 curve. .You'are caying that all these accidents are at the
'5 maximum because there.is nothing below that to make.it keep "6 going up.
t 7 DR. KHATIB-RAHBAR: All it says is that most of
'8f ithe accidents are -- ,
9L DR. WALLIS: 'Are at that point. 10- DR. KHATIB-RAHBAR: -- of this point, exactly. l
-11 -! DR. WALLIS: Most of the accidents, right, i 12' DR. KHATIB-RAHBAR: In fact, yes. I mean the 13- previous-curves showed that most of the severe accidents are
~
14- mitigated by the containment. , h
'\s ,/ 15-DR. KRESS:
Look -- point of question. Suppose -- ; 16 -now this is an acceptance curve. Now suppose an actual 17 reactor, plant configuration comes in so that it started at , 18 below 10 to the minus 5 and sort of' paralleled that curve, 19 but'went.through'the line up there about 10 to the minus 1 l
.20 tand'then dipped back down. Is that an unacceptable -- I 21 'mean how does one decide?
22 DR. KHATIB-RAHBAR: No, that's a good point. No , u- . 23- I know where you are coming from. I agree, but again you , 24 have!to. recognize that all of these criteria are developed ! 25: iwith something in mind.' l j-.
- ("
.t ANN RILEY & ASSOCIATES, LTD.
- h Court Reporters 1025.' Connecticut' Avenue, NW, Suite 101'4 C
Washington, D.C. 20036 (202). 842-0034 l: l ', j. i
l 109 ) If you go back to the U.S. NRC safety goals, look 1 L 1 j () 2 3-at WASH-1400. It'is basically what the technology allowed
~and you could calculate it in WASH-1400 in 1985.
l 4 DR. KRESS: There is a basis of truth in that, l L 5 yes. !' 6' _DR. KHATIB-RAHBAR: I mean I don't know if.that is 7 exactly what happened ~but if you go and take WASH-1400 and i 8' put the numbers'on.a curve, that is what you come up with, l 9 and I'think you, I agree with you in an ideal world you 10 should not keep that in mind but you look at something which 11 is achievable 1 12 If I set the safety criteria at the level where I i 13 could not demonstrate it and I could not achieve it, it's l l 14 worthless. .In fact, this part of the curve -- l J['\j (_f 15 DR. KRESS: It's not worthless. It is not j l l 16 worthless if it is a real true acceptance criteria. You I 17 would shut everything.down -- you don't do it.
-18 '
DR. KHATIB-RAHBAR: I mean demonstrating a , 1/:' O 19) . criteria at'this level is impossible.
'20 DR. KRESS: Oh, I understand that. That is a l 21' different issue, yes. I agree with that, because we are 22- having that same trouble in 50.59, yes. You can't go beyond 23 your tools for deciding these things.
24- DR. KHATIB-RAHBAR: Right, and then this level DL 25 here, which is 10 kilograms release, this corresponds to L h $ ANN RILEY & ASSOCIATES, LTD.
?
li k- Court Reporters ti 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 841-0034
110 L 1 approximately 6 percent inventory for a large power reactor. ( ) 2 'This again is typically what you would get for early ) 3 ; containment failures, steam explosions, direct containment ' 4 heating, type failure.
' 5l We said any releases greater than this should have 6 .a frequency much less than 10 to the minus 6.
- 7. '
DR. KRESS: Based on what? 8 DR. KHATIB-RAHBAR: The idea was that -- 9 DR. KRESS: That is a large release and 10 to the 10 minus 6 is a magic number-for large releases? f 11' DR. KHATIB-RAHBAR: This was based again on the 12 same philosophy. No question about it. 13, DR. KRESS: Okay. 14' DR. KHATIB-RAHBAR: Okay? Somewhat ad hoc.
}%,) ,15 DR. KRESS: I have a bit of a problem-with that 16 kind cf acceptance criteria, although, you know, it's very 17- practical.
-18 DR. KHATIB-RAHBAR: But again you have got to look
-19 at the history. If you look at the IAAs, the INSAC
-20 standards, it.somehow follows the INSAC.
21- DR. KRESS: Yes, I know there is a history behind 22 that.
;23 DR..KHATIB-RAHBAR: Behind this whole process, so
-24 the idea was not to really re-invent the numbers here, but 25 try to say how we --
p. [ ANN RILEY'& ASSOCIATES, LTD. 3 )- L'^ Court Reporters l '1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0024
111 q P 1 DR. KRESS: To say that they should be consistent. I 2 DR. KHATIB-RAHBAR: Exactly.
'D 3 DR. KRESS: Be consistent with values of --
'4 DR. KHATIB-RAHBAR: Precisely.
5 DR. KRESS: -- that are deemed. acceptable for some 6 other reason. 7 DR. KHATIB-RAHBAR: Precisely. 8- DR. KRESS: I understand. 9 DR. KHATIB-RAHBAR: We did not want to re-invent 10 the wheel here, so this has been set at 10 to the minus 5, 11 an acceptable number -- 12 DR. MILLER: 10 to the minus 6 -- 13 DR. KHATIB-RAHBAR: 10 to the minus 6 is being a l14 large release. In a sense we define a large release, okay? 15 This corresponds to something on the order of 10 percent 16 -cesium or iodine. 17 IMt. KRESS: Now probably this could not be at all 18 ' consistent with the U.S. safety goals. It may be more 19 severe because it looks like it is. 20 DR. KHATIB-RAHBAR: It is more severe. 21 DR. KRESS: Yes, it looks like it is much more 22: severe.
- 23 DR. KHATIB-RAHBAR: It is a lot more limiting.
J24 DR. KRESS: .Yes, a lot more limiting.
-25 DR. KHATIB-RAHBAR: This in fact -- I will show /
ANN RILEY & ASSOCIATES, LTD. kc ~ . Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 4 . . . . . .
. . - ~. ... ~ . . -.- - .. ~. .. . . - - - .. .- .
- - . . ~ - . - . . ~ _
l: 112 1 l' 'that later. It is very limiting. j&
)- .2 DR. KRESS: So it is like almost redefining-the L 3 safety goals.
i l 4 DR. KHATIB-RAHBAR: Much more restrictive safety 5 goals. 6- DR.-KRESS: Did you intend this for new plants ! l ' !- .7 or - 8 DR. APOSTOLAKIS: Let me understand what that l 9- means. If-you calculated a LERF at an acceptable. level -- l' 10 DR. KRESS: It would be a lot more than 10 to the q
-11 minus 5.
12 DR. WALLIS: Where is LERF for this curve? ! L 13- DR. APOSTOLAKIS: LERF is an average value. It is
- 14. not here,'right?_ It's the average of the larger release --
15' but,-no, it could be here? 16 DR. KHATIB-RAHBAR: Basically this I would say --
- 17. - 'it's about here.
18' DR. KRESS: But LERF is basically a conditional 19 early containment failure, as we defined it, but if you 12 0 ~ wanted to know what the prompt fatality value,-individual ! 21 risk of prompt fatality was from this curve, which this LERF 22 .is supposed to be surrogate for, it -- you would have to 23 ' integrate thisocurve with this functional relationship for f24 the prompt fatality versus fission product release that 25 Jeff's curve has inherited. !i I y- ~ ANN RILEY &. ASSOCIATES, LTD.
- -- Court Reporters i^ '1025 Connecticut Avenue', NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 0 <
i
- . - . . . . - _ . . . . . . - - . . . - ._ . . - . - . . . . . - . - - _ . - - . , _ ~ -
113 l' It's a convoluted interval between the two. So J>$ 2-
~
V: 4 it's not obvious just looking atLit just to know that 3 functional relationship is such that this level, 10 to the 4 minus 5 going down'at this point of fission products, you 5' :know that's going to be well below 10 to the minus 5. 6 DR '. KHATIB-RAHBAR: So in other words, about 10 1 7 percent inventory of cesium with iodine for a large power 8 reactor would approximately correspond to one early 9 fatality, roughly. 10 DR. WALLIS: So where'is LERF? Do you have -- 11 DR.-KHATIB-RAHBAR: So if you take.that as being a 12 definition of LERF, I don't know what-it is in ACRS's mind,
.13' this is about it.
14' DR '. APOSTOLAKIS: Well, but Tom, based on what l - E15 - Mohsen just said, I'm not sure that your conclusion was i 16 .- correct. .Or maybe - .he says, Mohsen says, that LERF is L 17 .about where you have the second knee. So it's 10 to the L ~ l 18 minus 6 for a release of 10 to the 4th or greater. Like L " l 19 that is indeed correct. In the U.S. goals, I am not saying-20~ anything about the straight line that he has beyond 10 to 21 the 4th. We don't have that. We don't have regulations 22 there. l
- .23 DR. KHATIB-RAHBAR: You don't go exactly.
24 DR. APOSTOLAKIS: Right.
-25 DR. KRATIB-RAHBAR: This is as far as you go.
1; ibs/ ANN RILEY &' ASSOCIATES, LTD.- Court Reporters 1025-Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
- .~ , - - - . .. . ._ - _ . . . . . . . - . _ ~ . . . . ~ . ~ .
i 114
-1 DR. APOSTOLAKIS: For that part we don't. We only
[ '2- have that point where the knee is. Now your formulation l
.3 earlier showed that the whole curve affects --
4' .IMt. SHACK: The question is if you bring that knee 4 .5 low.enough, does that force everything good enough? 6 DR. APOSTOLAKIS: .But wait a minute. Wait a
.7- minute.
,8 DR. KRESS: Yes, it definitely could. Yes.
1
!$ DR. APOSTOLAKIS: No. I think they're regulating 10 more, but I'm not sure whether they are more stringent, the 11 criteria are more stringent.
1 12 DR. KRESS: I guarantee you that's more stringent 13 than 10 to the minus 5 LERF. 14 DR. KHATIB-RAHBAR: It's'much more stringent.
.-[Y -y ,) 15 DR.'APOSTOLAKIS: Than 10 to the minus 5 what?
16 DR. KHATIB-RAHBAR: LERF. 17 ' DR. APOSTOLAKIS: Oh,.LERF. Well, yes, it's 10 to j l 11 8 .the minus 6. :l
-I 319 DR. KRESS: All.right, that's also much more -- I i
l
-20s Dthat's also more constringent than prompt fatality 421 individual risks go.
22 - DR. APOSTOLAKIS: But it is conceivable, though,
'23: ;that in'an'American plant you could have that little piece
;24h[ f of the last segment of the straight line, in the real
- 25 assessment now, not the criterion, having, you know, larger ANN RILEY & ASSOCIATES, LTD.
Os Court Reparters 11025 Connecticut Avenue, NW, Suite 1014
-" ^
m Washington, D.C. 20036 (202) 842-0034-9 . ,.
, ~ . . . -.- - - . . - . . - , . . - _ . . . - . - . . .-. . ....- . -... - .-.
4 115 11' . scope or smaller. f
- ! .- DR. KHATIB-RAHBAR: Farther.
\_ /. I 3 DR. APOSTOLAKIS: Yes, I i
4 ' DR . KHATIB-RAHBAR: I'll have some examples for -- ! 5 DR. APOSTOLAKIS: And then that would affect the 6 fatalities, would it not? 7 DR. KRESS: Yes. It's an integral. 8 DR. APOSTOLAKIS: And we are not regulating that. 1 9 DR. KRESS: Anything that affects the area under l
~ 10 the curve.
11 DR. APOSTOLAKIS: Are we regulating that part, 12 Gary? 13 MR. HOLAHAN: Well, I think -- no, nature is 14 regulating the total amount ~of -- O
.Q .'15 - DR. APOSTOLAKIS: That's correct.
16 MR. HOLAHAN: Cesium, and that's what establishes l 17 the end point. 18 DR. APOSTOLAKIS: So 10 to the 5th is a total. 19 MR. HOLAHAN: It's total. Well, you know, more or e 20 ~1ess. Yes. 21 DR. WALLIS: But the point is LERF.is not obvious
- 9. - 22 from an American curve. ;
; '23 DR. KRESS: No.
- [ 24 DR. WALLIS: There isn't a kink like this in it.
li , 1 lFg, - 25 .DR. APOSTOLAK1S: Well, don't use a curve at all. i
/ ANN RILEY & ASSOCIATES, LTD.
-- Court Reporters 1025 Connecticut Avenue,1NW,. Suite 1014 Washington, D.C. 20036 (202) 842-0034 x
116 1 DR. WALLIS: I always have problems knowing when I \_/
) '2 see an F-C curve how to relate i t to this LERF which we talk 3 about.
4 DR. KRESS: It's related to the slope of the 5 curve, its actual position on there, and convoluted with the 6 health consequences. Just look at it and say it. 7 DR. WALLIS: It's complicated, especially since -- 8 DR. KRESS: There is no unique function of this 9 that gives you a LERF value. 10 DR. WALLIS: Most of these curves get vertical -- 11 DR. KRESS: Yes, it makes it even more -- 12 DR. WALLIS: And you don't really know where you
-13 are at all.
14 DR. KRESS: It's hard. But the nice thing about ( ) 15 that vertical is it's going down to low frequencies in a 16 hurry. 17 DR. KHATIB-RAHBAR: And then this by and large is 18 also an extrapolation as well. That so far is -- 19 MR. KAISER: Well, this curve will have to get 20 vertical'somewhere. 21 DR. KRESS: Yes, it has to. It it's a cube of the 22 -- it has to go to zero. 23 DR. WALLIS: Are you telling us LERF is not very 24 real? l 25 DR. KRESS: I mean, there's no way around it. l (' 'g ANN RILEY'& ASSOCIATES, LTD. k _/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
117 1 You're right. All-those curves will go to -- 2 DR.-WALLIS: (W Are you telling us LERF is not very 3 real?. 4 DR. APOSTOLAKIS: The question is how quickly do 5 they go. ( 6. DR. WALLIS: Is it that part of the curve is not 7 .very real? 8L .DR. KHATIB-RAHBAR: This part of the curve is not 9 very real. 10 DR. APOSTOLAKIS: And in our regulation we don't 11 .specify how quickiy. 12 DR. WALLIS: And LERF is probably not very real,
.13- :either.
14 'DR. KRESS: It's inherent in our LERF criteria. 15 -DR. KHATIB-RAHBAR: I need to know what LERF is in 16 yourfmind before I can say it is or it's not. 17 DR..WALLIS: .I don't know. That's what I'm trying
.18 .to figure out.
19- MR. HOLAHAN: I'm not sure'I agree with Dr. Kress,
- 20. ~ which is a dangerous thing to do, I know, but.I think LERF 21 is-pretty -- the LERF definition's pretty close to the knee 22= of that curve.
23 DR..KHATIB-RAHBAR: It is about here?
'24 MR. HOLAHAN: Yes.
25 DR. KHATIB-RAHBAR: That's what I. thought it was. P ANN RILEY & ASSOCIATES, LTD.
\u- Court Reporters 1025; Connecticut Avenue, NW, Suite 1014 Washington,.D.C. 20036 (202) 842-0034
. . .~. .- .- . . . . .- .- . . _ . - . . . . _ . . .
l 118 l 'l- MR.-HOLAHAN: Yes.
~
'2 DR. SHACK: It is the frequency of a given large 3 release.
4 MR. HOLAHAN: Yes. DR. SHACK: It depends on how you define the large
- 6. release.
7 MR. HOLAHAN: Yes. 18 DR. SHACK: But once you've done that, then you've
.9 pinned that point.
10 MR. HOLAHAN: And whether it's 6 or 10 or 20
'11 percent of the core, it's somewhere near that knee.
12 DR. KHATIB-RAHBAR: Now let me tell you how we 13 arrive at this one. This actually -- this point here is a 14 lot more uncertain. The idea here was that we knew -- ,[ 15 demonstrating any numbers -- numbers of 10 to the minus 6 16 - are fairly difficult to demonstrate, let alone' demonstrating 17- numbers of 10 to the minus 8 level. It's impossible. Okay? 18 In other words, this is the area where incompleteness of the 19- PRAs come into' play, other uncertainties come into play, et
. :2 0 cetera.
21 But this was important to put in here to 22- . demonstrate that we want : to get' releases which are f airly 23- large, as l'ow as< practically possible. So the meaning in 24: this part.of the curve is nothing more than qualitative 25 indication that we like to make sure that the releases f% ANN RILEY & ASSOCIATES, LTD. Ih Jf r Court Reporters 1025-Connecticut Avenue, NW, Suite 1014-Washington, D.C. 20036
;,: (202) 842-0034-
-;( c'
_ ,_ . . - . . _ _ _ _ _ _ . . . _ _ . _ _ . _ . _ . . . . _ _ . _ _ _ _ _ . . .._m__. _ - - _ , n . 119 1 : corresponding to anything greater than 10 grams of cesium ' () 12, 4 equivalent is.as. low as practicable. '
'E DR. APOSTOLAKIS: So if you did a PRA for a Swiss 4- reactor, and I know they have PRAs for all their units, and m
~5 \your F.-C curve happened to cross that straight line there
)-
6' ind go'above it,'and then you realize that, you know, it J
-7 would take $2 billion'to bring it down, you would say it's 8 okay.
, 9 DR. KHATIB-RAHBAR: Yes. I'll come to that.
10 DR. APOSTOLAKIS: So these are not criteria then. ' 11 These are -- i 12 DR. KHATIB-RAHBAR: These are not speed limits. 13 'These are not -- these are not -- 14- DR. APOSTOLAKIS: So it's proposed safety goals. l15 DR. KHATIB-RAHBAR: These are not going to be 16 interpreted as speed limits. 17 DR. APOSTOLAKIS: They are goals. 1 l 1
- 18_ DR. KHATIB-RAHBAR: These are just goals. These 1 i
19 are aspiratory targets that you want to meet. E20 DR. APOSTOLAKIS: Okay. 21 DR. KHATIB-RAHBAR: But how you meet them is
- T 22 'another issue. I'll come to that a bit later.
23 DR. APOSTOLAKIS: And this pink line is intended
/, ; ., y
~24 to-be used'with.a mean value?
t 25~ DR .- KRATIB-RAHBAR: I'll address that to you in a
- [' ANN RILEY & ASSOCIATES, LTD. I
~ Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) '842-0034 4
- w. s __ 4 . ._-_ . . , . _ . . _ . . - . . _ _ . . _ _ , _ . _ . .
. . _ . . . . - . . _ - . _ . _ . - . . _ . _ . _ .. . - . - . . _ . . . ~ . . - _ . . . . _ . . _ . . _ _ . _ _ . _ _ . _ .
120 11 second. 2' MR. KAISER: Can I come back? 3- DR. APOSTOLAKIS: Sure. Yes. l 4 MR. KAISER: Mohsen has said that this criterion
'5: .is. considerably stricter than, say, the safety goals are.
6 DR. APOSTOLAKIS: Well, he didn't quite say it 7' that way. 8 DR. KHATIB-RAHBAR: It could be -- yes, it could 9 be more strict for some, .yes.
- 10. MR. KAISER: So my question is, was that done with 11 careful thought? You know, you've-decided that the criteria
.12 that-exist previously are too lax, and that-something more 13 strict is needed.
- 14. DR. KHATIB-RAHBAR: No, at the time when we
-15 . started doing this, there was really no definition for l .
l 16 larger early release. If you go back to U.S. NRC ' 17' requirements -- L18 DR. APOSTOLAKIS: If they're still discussing it, ; 19, 'what's large early release? 1 20 ' DR. KHATIB-RAHBAR: An interpretation of large . . 21 early release has always been subjective in nature. At the i, time NUREG-1150 was done,'this was interpreted as one early 22 2'3 . ' fatality. In fact', the question was we'll be back here even
'24 without the bad' case. Then later on, people started talking L .-- s l 2 '54 'about in terms of equivalent release quantity. Ten percent
/9
\ 'J ANN RILEY & ASSOCIATES, LTD.
. Court Reporters 1025-Connecticut Avenue, NW, Suite 1014 l Washington, D.C. 20036 (202):842-0034 o
ll
1 121 l' 1L .may be a good number. And the reason we came up with 10
.()
2 . percent, because that was somewhere lower than bypass 3 ' scenarios. It was something we could live with. But there L l 4 was.never a clear indication what the large early release 5 criteria ~in'the U.S. was, nor was th'is for European or REA
- j. .6 standard. So when we started talking about this in~1985, i
f-7- there were no criteria for large early release. Okay? ! 1 8 So we came up with something that we thought we 9 could support. _In:other words, there was some basis for it, .) 10 you know,.the basis for this part of the curve, as I told 11 you, is essentially a design standard preventing system, and _ ' l 12 this is the large early release criteria. We said anything ; i 13 greater than this will be total catastrophe. Okay? l 14 . Radiologically. This is. bad, as is. This is fairly bad. '
~
I __15 DR. KRESS: All right. -Pegging the two points 16 . determines the slope'of that flat part. What determines the 17 slope of the part beyond -- 18 DR. KHATIB-RAHBAR: As I said, this was relatively 19, _ arbitrary. ' 20 DR. KRESS: Just an arbitrary slope. 21 DR. KHATIB-RAHBAR: This was very arbitrary. This 122 can go as-high as the entire core inventory if you draw down 23 in frequency.
.24- DR. APOSTOLAKIS: You have a risk-aversion factor 251 Lof~two there.
'/) \~/
' ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202)-842-0034 L.
. _ ~ . . . ._ _ _ _._. . _ _ _ . . - _ . - . _ . . _ . _ _ _ _ _ . - . _ . .
L i 122 l l' RDR . KHATIB-RAHBAR: Right. All this part of the ; r= i- %
'f _
- 2. curve shows --
.3- DR. APOSTOLAKIS: Minus 2. Which .is re ally pretty 4 stringent. In' fact, there was a study yearc, years ago down
,5 5- at UCLA that showed that no industry could survive, could be L 6 accepted if you had an aversion factor of minus-2.
.7 DR. KRESS: Yes. That's one reason I asked, is 8 that risk aversion. ,
9 DR. APOSTOLAKIS: Yes. Yes. It's really 10 difficult to'-- . 11 DR. KRESS: Is there some valid reason for 12 choosing that slope?
- 13 DR. KHATIB-RAHBAR: Yes,.the idea is that you --
~
- 14. basically I think that for future designs you wantEto
?
.f~y ! J- 15 prevent - in particular for future designs you want to 1
M16 prevent releases of this nature by design, recognizing you
$7 could not demonstrate this number on'pbobabilistic levels.
11 8 So you have.to do it'deterministically by eliminating by l l 119 " design.
, i :
20 DR. KRESS: Where is your view - you're a pretty l l 21' good PRA guy -- where-is your' view of where that level is
'22; that PRA gets -- you're really isn't the noise of PRA? Is 23- .it.on this frequency curve part? Is it like 10 to the minus
? 2 4 .- 7, dozyou-think?
l
- 25~ DR. KHATIB-RAHBAR: I would have a difficulty with l i
?/~NI ANN RILEY.& ASSOCIATES, LTD.
D(~) Court Reporters g 1025 Connecticut Avenue, NW, Suite 1014 l- Washington, D.C. 20036 l -(202) 842-0034-L - l
123
, 1- numbers below 10 to the minus 6, to be honest with you.
'2 DR. YRESS: See, this I think is a significant 3' point that I've tried to make in relations to the 50.59
" ' .4- problem, where, you know, if you tried to use PRAs to define 5 what's risk-significant or not, if you start getting below '
6 those numbers, you're in the noise where PRA are basically 7 useless to you. And that's why I asked you -- O!! 8 DRu KHATIB-RAHBAR: Many things matter in this --
, -9 DR. KRESS: Because I was considering it like 10 10 to the minus 6 to 10 to the minus #1 also.
11 DR. KHATIB-RAHBAR: In fact, that's one reason why 12 this line's for one thing, a thick line. 13 DR. KRESS: Yes. 14i DR. KHATIB-RAHBAR: These.have to be interpreted j 15 not as ore speed limit that you can exceed. Furthermore, 16 they are also to reflect the fact that in particular when 17 you go down in frequency -- 18 DR. APOSTOLAKIS: You'just scored some points 19 Lhere. 2
' 0_ MR. KAISER: Can I go back to my question about --
21 ER. APOSTOLAKIS: Sure.
, 22 - MR. KAISER: How this compares with other criteria 23 'that,are out there? I spent;some time looking at the i
24 chemical industry, and as you know, there are requirements 25 in law in places like the Netherlands and the U.K. and other i et^j ANN RILEY & ASSOCIATES, LTD. Aw/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 1 +
l 124
- 1) places, and one of the big difficulties is in trying to
) 2 understand whether the criteria that are proposed in these.
- 3 different places are really the same or whether there are 4 enormous differences between them, because they're couched
(- -. 5 - in very different terms. 6 -And I think one warning or one: caution we should l 7 bear in mind is that it's nice to throw up these curves 8- here, but'what if you do a curve like that and then you find 9 that it's four orders of magnitude more stringent than some r 10 other criterion that people have been pretty happy with for 11 a long time like an individual risk, for example? Why l 12 should you suddenly ratchet these criteria by four orders of
-13 ' magnitude?
14 DR. KRESS: That's really a good question. [f%(,,) 15. MR. KAISER: Yes. L 16 DR. APOSTOLAKIS: .W ell, and that question has been
- . E17- of concern to this' committee. Core damage frequency, for 18 example, a goal of 10 to the minus 4 reactor year, is more
- 19. ' stringent than what you would. derive.by working' backwards c20 from.the individual risk criterion we have'now and some p .21 : reasonable numbers for1 containment performance.
b 22- FMR. KAISER: 'Right.
- 23. DR. APOSTOLAKIS: So then this ius new policy.
-24 That's what you're saying. It's not just a surrogate 251 anymore.
r . . jax\
; ANN RILEY & ASSOCIATES, LTD.
UN J f" Court Reporters 1025 Connecticut 1 Avenue, NW, Suite 1014
- j. Washington,:D.C. 20036 L (202) .842-0034 i.. . "
l $ @ I
. _ . . _ .. . _ . . . _ . . . . _ _ _ . . ~ _ . . . . _ . . . _ . _ _ - . _ _ _ . _ ._ _.
l 125 I
- l. . .
- j. 1 MR. KAISER: Yes, it might be --
-O i
( J- 2 DR. APOSTOLAKIS: It's new policy. 3 MR. KAISER: It might be, yes. If you're not l 4 . careful,-you might still -- i .5 DR. APOSTOLAKIS: So you have to be -- 6 ' MR. KAISER: Ratchet everything. )
- 7. DR. APOSTOLAKIS: That's correct.
8 MR. KAISER: And of. course the consequences of
'9 that to an industry can'be very large.
10 DR. APOSTOLAKIS: Now the Swiss -- 11 MR. KAISER: Yes. 12 DR. APOSTOLAKIS: The way I understand it do not 13 have goals at the risk level, individual versus societal. 14' Do they? 15 DR. KHATIB-RAHBAR: No. That's correct. No. 16 DR. APOSTOLAKIS: So this is their criterion. 17 DR. KHATIB-RAHBAR: These are equivalents. Right. 16 DR. APOSTOLAKIS: This is it. 19 DR. KHATIB-RAHBAR: This is it. 20 DR. APOSTOLAKIS: This is the highest level goal 21L . they have. 22i ' DR.-SHACK: Proposed.
]
123 EDR. APOSTOLAKIS: Yes, proposed. 24 MR. KAISER: Proposed. 125 DR. KHATIB-RAHBAR: Now let.me address that issue. I { ' ANN RILEY'& ASSOCIATES, LTD. l [h / Court Reporters
;1025 Connecticut Avenue, NW, Suite 1014 l
o)g Washington, D.C. 20036 4 . (202)- 842-0034 t v * ./ e A -
i l l l 126 1- This is a~very good point. The criteria which have been --
)f 2_ release criteria which have been used by different 1
l 3 organizations in the U.S. or elsewhere, which is 1 4 safety-health criteria, early-fatality criteria, we debated
- 5 that extensively, and it was decided that there is no 1- 1 i
l 6 interest to -- societally to look at the health issues 7' because especially when we talk more latent fatalities, land 1 8 ' contamination is.what matters, okay? They were talking l _9- about the fact at Chernobyl, the fact that you have done the 10 contamination as much as you could possibly do, so the j 11 contamination levels are at the level chat you cannot go and
~
12 occupy the land in that area or use it for anything for 1 13: many, many years to come. 14 So it was recognized if there was an accident in 15- ' Switzerland, _and all the powerplants are within about a
- 16 50-kilometer area, they're located in one area, if you stand .
17 on a hill, there's an accident in one' place, that entire 18 area around Zurich is going to be totally uninhabitable for p -19L many,-many years to come. So talking.about the health 20: criteria-or the. fatality criteria in my' view is not very 21 meaningful -- land contamination area which can be so severe 22 'for a'very small' country, it doesn't matter anymore --
- 23: DR. FONTANA: It's defined as uninhabitable L 12 4 because you can't grow crops on.it or because you can't i
25: stand.on it?' I ' 2\ 2 ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025~ Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 l (202). 842-0034
i 1- , 127 i' 1 DR. KHATIB-RAHBAR: All of the above. [%_J.b 2.. DR.'KR6SS: You get sick and die. .
.'3 :DR. KHATIB-RAMBAR: All of the above. Essentially !
~4' all;of the above. l
'5 DR. FONTANA: And it kills you somewhere before I i
6' you'normally would die'.
-7 DR. KRESS: 'Unless you're out age.
8 DR. KHATIB-RAHBAR: It is something socially that 9 you're going to -- I mean rigb' now we.can probably argue 11 0 for many years.how many peopla will die as a result of L11 Chernobyl, but we know how much land we cannot use today, 12 . Society understands that much easier, I think.
'13 DR. KRESS: 'Mohsen, I had on one of my curves a 14 list of potential -- I call them regulatory objectives, that-15 included land interdiction, injuries, death. There's no way L 16 with that many objectives in mind, there's no way you cannot .
1 17 have a set of csnsistent criteria, I think. Some of them I i
'18 re-going to-dcminate over others. And in my mind and a '
11 9- co_ple of the other ACRS Members who will remain unnamed, L 20: the only common metric that we can come up with among those i o I [ 21' things, believe it or not, is dollars. ]
- l. 22 Land if we set a dollar limit on what we're willing 23 to accept for nuclear power, then you could.put that same l ~
p 24 ' dollar limit on'every one of those metrics and come up with H2 5 - a'value for it, and one of them may dominate over.-- the .~ 1.[ ANN RILEY & ASSOCIATES, LTD. Court Reporters l' 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 L (202) '842-0034 L 4 h, - , ..
- - . , , , - -m, , , - ,
I 128 1- value~of the acceptance criteria you get for that may be the
/ 2 one that sets the stage and dominat.es, but it seems to me 3 like that's the only real consistent way because you have to 4 have;a common metric if you're going to compare all of these k 5 3 acceptance. Is that --
6 DR. KHATIB-RAHBAR: .'t understand. Yes. 7 DR. KRESS: So, you know -- 8 .DR. KHATIB-RAHBAR: You could turn actually land 9 -- dollars. 10 DR. KRESS: And what you're saying about land 11 interdiction for many years. 12 DR. KHATIB-RAHBAR: It's the same thing. It's the 13 same thing.
'14 DR. KRESS: 'It's going to cost a lot of money.
'g_,f ; 15 DR. KHATIB-RAHBAR: Precisely. That's all 16 economic --
. :L7 DR. KRESS: That's probably why it would be the 18 'one that would dominate.
19 DR. KHATIB-RAHBAR: Abso]utely. 20 DR. APOSTOLAKIS: Well, you know, that's why -- 21$ DR. POWERS: I wonder if I could come back to your 22 previous viewgr.tph -- 2 3'- DR KHATIB-RAHBAR: Certainly.
- 24. DR. POWERS: And even one that you used before 25 then. But maybe I'll just recall --
[' ANN RILEY.& ASSOCIATES, LTD. h_s)/ - Court Reporters
'1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202)- 842-0034-E l
E 129 : 1 1 DR. KHATIB-RAHBAR: Which one? This one? f f 2 DR. POWERS: Let's start with this one. [
-3: DR. KHATIB-RAHBAR: Okay. !
4- DR. POWERS: You've -- let's turn to your second !
.5 . knee. !
6 'IMt. KHATIB-RAHBAR: This one. Okay? 7; DF. POWERS: ;Out there. If you look at a previous
'8 viewgraph you~used in which we got releases up to that j 9- magnitude,'they'seemed to all be. associated with some sort
, ' 10' of.a catastrophic. failure or a bypass, if you get that.
11- DR.:KHATIB-RAHBAR: Um-hum. I j i
' '12 DR. POWERS: Could you impose the same effect of j 13 this curve by saying I.shall reduce the frequency of those 14 accidents that result in early containment failure or bypass
() 15 below whatever number that you picked here? That would have p 16 the same effect? 17 'DR. KHATIB-RAHBAR: In other words, this is a risk ! '18 ' ; factor.you're. talking about. 11 9 DR. POWERS: Yes. 20 DR. KHATIB-RAHBAR: You either reduce the 21 . consequence or the frequency or both. l-I 22. DR. POWERS: Um-hum. l: h 23. DR. KHATIB-RAHBAR: Absolutely. You can do either i
'24' onerto satisfy the same.end.
i . 72 5 DR. POWERS: There is no concern on your part that jO ANN FILEY & ASSOCIATES, LTD.
. \, / Court Reporters I 1025 Connet.icut' Avenue, NW, Suite 1014 Washington, D;C, 20036
- (202) 842-0034
- . . . . - - . - - - . - . . - .. . . - . . _ . . - . . . ~ . . - . . .
130
- 1. there are accidents other than early containment failure or
..g p) 12 bypass that could give you numbers like this.
3 DR. KHATIB-RAHBAR: There could be some shutdown 4' sequences. Some of them could lead to that. 5 DR. POWERS: Let's leave out shutdown. Let's -- t 6' that's only -- that's only -- , 7 DR. KHATIB-RAHBAR: This curve does not recognize 8 particular! accidents -- 9 DR. POWERS: I understand that, but'what I'm 10 ~ asking is, could we replace this curve by having essentially 11 a containment failure criterion, that is, if you take bypass 12 as a failure of one_part of the containment, you just simply
.13 don't allow --
14 DR. KHATIB-RAHBAR: Um-hum. m k,) 15 DR. POWERS: The frequency of containment failure 16 to exceed some limit. 17 DR. KHATIB-RAHBAR: You can, but there's a problem 18 with that, because when.I'm putting -- venting in there I'm l 19 already failing containment. I. don't like to -- do not 20' particularly like the containment failure criteria, because 21 what: matters is what you release into the environment. 22' .Those'are subsidiary criteria you can derive'from this, no 23- question about:it, but because venting is one mode of ;
- 24. Lcontainment failure, leakage is one mode of containment 25 failure, I would prefer,. because there is always a O.
ANN RILEY.& ASSOCIITES, LTD.
-%2 Court Reporters 1025 Connecticut Avenue, Ini, Suite 1014 Washington, D.C. 20036 y ( 202) 842-0034
. __. ___ _ . ~ ~ .__ _ _ _ . _ _.__m . _ _ .._.m _ .m m _ _
i- . L 131 i: l' ' conditional probability of 1 that you have failed your . ( ); - 2' . containment, by not.failing it, you have a certain release, - i ( 93 design-basis release.
~
h '4 DR APOSTOLAKIS: So if'we go'back to your ' L L
'5 .viewgraph with the. release categories --
- 6 DR. KHATIB-RAHBAR: Right.
7 DR APOSTOLAKIS: If you can pull that up. If you p "8 udo what Dana just suggested, then you'are just dealing with - [ .9' the frequency of the categories on the vertical axis, and l 10 'you are ignoring your bars. Is that correct? , 11- DR. KHATIB-RAHBAR: I don't know.
.12 DR '. APOSTOLAKIS: Let's go back to that.
13 DR. KHATIB-RAHBAR: Maybe Dana can explain that 14
~
himself. I don't understand it. ' t
'\ 15- This.one, George?
16 DR. APOSTOLAKIS: Yes. Yes. See, on the right.-- l- '17 DR. KHATIB-RAHBAR: Righti p 18 DR. APOSTOLAKIS: That's why I asked earlier. Are
- 19; .these the accident progression bins?' On the right, te. RC1, i-L 20 2, 3.
I L 21 DR. KHATIB-RAHBAR: Yes. Right. Right. j 22 DR. APOSTOLAKIS: These are the accident i !~ '23' progression bins. 'You have -- in some of them you have ! p L24 ' failed the containment. Right? I n25 DR. KHATIB-RAHBAR: Yes. These are all the ones i
.I ) 1001 RILEY &' ASSOCIATES, LTD. l Court Reporters j
- 1025.ConnecticutrAvenue, NW, Suite 1014 _ i I Washington, D.C. 20036 .
(202) .842-0034
,r- --. __ - - - . , _ - . - . , . _.
- ~ .. . . . . . ~ . . - . . . - _ . - . - - - . - . , . - - - . ~ . . . . .
l_ 132I i 1 with containment -- yes. ; () 2_ 'DR. APOSTOLAKIS: Okay. Now if I do what Dana
.said, and deal'only with'the containment frequency --
3 ' 4 failure frequency -- then I'm saying I will take all the RC 5 from 1 to 21 and I will make sure that their frequency is i 1 6 less than a number. 7 DR. KHATIB-RAHBAR: Is that what you mean, Dana? 8 DR. APOSTOLAKIS: Well, that's a containment. 9 DRl POWERS: 'Yes. 10 DR. APOSTOLAKIS: So the'information then I'm not 11 using is the information you have in the figure. 12 DR. KHATIB-RAHBAR: On the quantity released. 13 DR'. APOSTOLAKIS: The quantity of release. s.
. 14 DR. KHATIB-RAHBAR: Yes.
O
. (_) 15 DR. APOSTOLAKIS: That's the difference.
16 DR. KHATIB-RAHBAR: Right. But you could do that. i 17 I mean, there is nothing which prevents you. But I said the ' 18 -reason I personally do not like it, because you're 19 restricting'it. I 20' DR. APOSTOLAKIS: So by using the curve that you 21 showed us, you are using all the information -- :
- 22 ; DR. KHATIB-RAHBAR: Precisely. It's all there.
! i
~
23 The conditional. probability could be derived from that if L ~ 24 -you wanted to. We could extract that information for you.
'25 DR. POWERS: Okay. What we conclude from this
.<~~.
1 i- ANN RILEY & ASSOCIATES, LTD. b Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
~
,~ k *, r
.- .. -. .. -- - . . ~ . . . . - . . . - - . - . - . . - . - . . . -
133 1 discussion is that-by restricting the frequency of -- the l ( 2 . conditional frequency of containment failure we're being
, 3 somewhat more conservative than when we'useithe curve.
A 4 Now-I have learned something very important. { 5~ DR. WALLIS: Well, surely you.could have a i 1 6 containment failure with no core damage. You could have a 7 LOCA that let's steam out but doesn't let any fission
- 8. products out.
9 DR. KRESS: I don't know of any reactors that , 10 would do that. The design criteria is such that they won't 11 do that. 12 DR. SRACK: It still seems to me that if you do ) i 13 that or you pin'the LERF, the real question is whether that 14 curve can have some funny shape out at the high end so that, k 15 you know, .I mean, by pinning two points on a curve, you l 16 clearly don't define the whole curve. 5: 17 DR. KRESS: You don't define the curve. 18 DR. SHACK: But in reality are all the curves of 19 such shape that by pinning those two points, you've 20 ' essentially done everything that you've needed to do. I 21' mean, is it really -- are there -- if you pin that point, 22 are there changes that you would allow people to make that , 23 would suddenly tail that end of the curve way out? In other .
- 24 - words -
25 DR._FONTANA: A good example, Bill, was -- let's ANN RIL2Y & ASSOCIATES, LTD. TN A . Court-Reporters
'1025' Connecticut' Avenue, NW, Suite 1014 Eashington, D.C. 20036 (202) 842-0034
134-1- say for -- well, 10'to the 5th is all the cesium there is, (), -2 okay? -So that. puts that You're talking about PRAs, you're 3 going to be talking about 10 to the 8th, minus 8th, hyphen 4 10 ,' doesn't make any difference. So there's no point l , 5' fooling around below that point. 1 6 DR. APOSTOLAKIS: 7 DR. KRATIB-RAHBAR: You could do that; sure. 8 DR. APOSTOLAKIS: Well, that's a containment -- l
- 9. If you don't like 10 to the minus 4 and 10 to the 10 minus 6 and you want to reduce that, then you have got to 11- put a curve on the other part of that curve. You can't have i
12 a straight line anymore because you are reducing that i 13 ' allowance unnecessarily I think. i 1 14 Your two point argument is for a straight line but
'15 -if you reduce that point too far you are going to have to 16 put a curve on it.
.17 DR. SHACK: No, I'm saying all the curves have a 18 certain shape and so when you pin them by two points you
.19 .have essentially fixed the curve.
j ,; 20 DR. KRESS: You know, the reason all these curves p
, 21'- have a, shape is.because they are cumulative -- the 22 complementary distribution function -- and all it says is 1
23: most probability density functions for fission product 24 release look a lot alike for the plants.
.25 DR. SHACK: But what am.I gaining for looking at
[ j ANN RILEY & ASSOCIATES, LTD.
- \- / Court Reporters 102E Connecticut Avenue, NW., Suite 1014
-Washington, D.C. 20036
-(202) 842-0034 a x
I 135 1: the whole curve over the two points?
) 2' 'IIR . APOSTOLAKIS: In other words, Mohsen, if I 3L - take the CDF and the LERF, am I capturing 99 percent of the 4 informati'on you have there so I don't have to worry about 5 the. actual shape of.the curve, of the criteria?
6: DR. KHATIB-RAHBAR: I think you are, but the way-7- 'weLapplied this curve , and I.will show it later on, is
-8 important because we-want to --
.9 DR. APOSTOLAKIS: The management part.
10 DR. KHATIB-RAHBAR: -- ;o focus on when you start 11- putting certain actions tx) try to. meet this criteria where 12- are you getting the benefits? 13 When you only focus on large early releases, you 14 only focus on one part of:the probicm, not the entire O V 15 problem. 16 DR. KRESS: I think that is a good point. i 17 DR. APOSTOLAKIS: So maybe we should let him go on
- 18. ' and --
19 DR.-KRESS: Well, I wanted to make one other 20 . point. l 21 ,When you fix this curve, you in essence have fixed 22- the PDF and what you are saying -- I am putting a
- 23 - regulation, a speed' limit on PDF. I think that is a
'24 difficult thing to do because.PD 'is sort of inherent in the 25- ' nature of the beast.
ANN RILEY &' ASSOCIATES, LTD. ! [~'N s Court' Reporters 1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 4 4 V F
136
- 1. My point earlier was if you do have a set of
- 2. criteria, set of objectives that I listed on mine, what one i
3- could do is say, all right, let's take the curve that you 4 get from a plant -- is it acceptable with respect to all of 5 those, and what one would have to-do is do this integral 6 with respect'to each one of these functional relationships
'7 that I got from Kaiser's exercise, and then convert that 8 integral, which is a risk consequence, convert that into a 9- dollar cost and you add up the dollar cost of all of them i
i 11 0 and-then you have an acceptance level on the total dollar 11 cost, and if you exceed that you have exceeded your speed 12 limit and if you don't, you're acceptable.
.13 That was my concept _that I was trying to get 14 across and I am not sure I did.
) .15 You only do that --
I mean you can't do that with 16 individual little curves. 17 You have to do it for all of~them. You have to 18 'have all of these functional relationships but the 19 only common way that -- 20 -DR. SHACK: But you are doing that to set the l 21' acceptance value then. ! 22 DR. KRESS: I set-the acceptance value independent 23 c, - all that. This is.to see if you meet the acceptance 24- value and it is'the sum of the costs of all of them, and 25 then.my acceptance value is a dollar cost, and it may be the ANN RILEY & ASSOCIATES, LTD. ('- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 w s
l 137 1- one part of this when one of these things dominate that () 2 ~ dollar cost and the others add a little bit but -- and then
-3 it probably would be the land interdiction would dominate 4 the dollar. cost mostly, and if you -- except if you set the '
i ; 5- curve so that it has to meet that one, probably the other 6 .ones don't add ~a whole lot but they add some, and it would 7 be a total dollar cost would be my acceptance limit. 8 This was my concept on how to do a truly
'9 risk-informed regulatory system incorporating all of the 10 :NRC's--regulatory objectives, and-then you have to worry i
'11 'about how you do it, how you do it with defense-in-depth and o 12 how you incorporate other things,~so there are different 13 beasts you have to worry about.
~
14- DR. APOSTOLAKIS: Let me suggest something because l
\ 15 some of this stuff is interesting and I want to discuss it i
16' in' detail but why don't we limit our questions to questions l 17 of clarification and let Mohsen finish, and then open up the
- 18. . discussion on more general subjects because what he just r
;19 said, for example, that the curves are important when you-
,. , 20 consider risk management is something that we should see V L 21' first before we talk about the value of the curves and their i 221 equivalents with LERF and CDF, so I suggest we limit our n ! l23 questions to those'of clarification and let you finish, and l " 24 then we open it up to anything that -- A
- 25' DR. KHATIB-RAHBAR
- -It is up to yvu, 1
7 ANN RILEY & ASosCIATES, LTD. 7; Court Reporters
'1025 Connecticut Avenue, NW,. Suite 1014 Washington, D.C. 20036
) (202) 842-0034 s 4
._ .._ . . . . - _ - . _ _ _. . - ~ _ . . . _ . _ _ . _ _ . . _ - _ . _ _ _ . . . _ _ _ . . . - . - _ .
4 4 . 138 1 ~DR. APOSTOLAKIS: Yes. Okay.-
?~
.f 2' DR. KHATIB-RAHBAR: For existing operating 3 reactors, it is proposed that to conform to the criteria at
'4 the mean level of exceedence frequency through cost benefit
- 5. backfits, how will utilities --
6 DR. WALLIS: Clarification. When you say cost 7 benefit, that means that'you have to put a price on an
'- 8 s incremental CDFLor LERF or whatever you are measuring,-got 9 to put aidollar price, otherwise you can't do a cost benefit
- 10 analysis.
' 11 DR. KHATIB-RAHBAR: That is a totally --
-DR. WALLIS: So.you must put a price on these 13 safety measures. Thank you. !
14 DR. KHATIB-RAHBAR: That has not yet been I,Q.- A,,/ 15 : actually'-- we debated that extensively. We have'not yet 16 addressed that issue. l 17- DR. WALLIS: Otherwise it is just invoking cost
- 18. benefit ' --
19 DR.'KHATIB-RAHBAR: Absolutely. 20 DR. WALLIS: -- as a phantom. 21 DR. KHATIB-RAHBAR: Absolutely. That in itself is 3 . 22 a very complex issue.
- 23 DR. SHACK: But it gives you a way to look at 2-4 relative measures, even if you don't know exactly what 251 ' dollar to put on it if one gives you more bang for the buck.
ANN.RILEY &. ASSOCIATES, LTD. Court Reporters . 1025 Connecticut-Avenue, NW, Suite 1014 Washington, D.C. 20036
- (202) 842-0034 y -
p 1 -w -
- w. 4 ..-~,y -,
u +
139 1 DR. WALLIS: I don't buy anything when I don't
) '2 know exactly what dollar. There's a pricetag. You don't 3' buy a car'at the fuzzy price --
l= '4' DR. FONTANA: Yes, you do. 5 DR. WALLIS: When you write your check, you don't 6 write a fuzzy check. 7 DR. APOSTOLAKIS: You don't use thick lines. 8 DR. KHATIB-RAHBAR: . One major emphasis of this 9 whole criteria development was that to try to encourage 10 utilities to reduce'the uncertainties, to really circumvent 11 the uncertainties through procedure and/or low cost 12- . modifications. In other words, instead of spending millions 13 of dollars trying tx) say what the uncertainties are, you
'14 have to do thin'gs that do not get you in a situation where hQ -15 these uncertainties become important.
16 DR. WALLIS: Aha. 17 DR. KHATIB-RAHBAR: That is an important thing to 18 keep lin. mind. I will address that a little bit later -- 19 what I mean and how that could be achieved. t20' So in terms of a procedural thing, this is how
~
L ' 21 ' this whole thing'is perceived. If you come to the top here, 22 if the conditional complementary distribution. function at 95 23 percent level, it exceeds the proposed safety' criteria -- L 24. DR. KRESS: Let me ask you about that. How did
!25; 'you; arrive at.this 95 percentile number?
e p-
~ ANN RILEY & ASSOCIATES, LTD.
i' N-) . Court Reporters 1025 Connecticut Avenue, NW, . Suite 1014 L . Washington, D.C. 20036 L (202) 842-0034 r e- Fm ,- '-r'u -- - -- 1-r
p.. . ... .-~.-.- .. _ .. . - - .- _- . - - _ - _... - - - .~ . -. .. .-. . - - - . . ! i l , i 140 1 DR. KRATIB-RAHBAR: The' idea here was to try to l ( ); 2- relate something which is relatively conservative --
}
.3 1DR.'KRESS: You are. operating only on the i
- 4. uncertainty with this? .There's two degrees -- you could l
5; operate on.the mean value and the uncertainty. 6- These'CCDS tend to be, the PDF its derived from _ 1 7 tend toLbe' log-normal and the 95 percentile means the best 8 you'can do was about four times the mean, which seems like
- 9. that is almost negligible in PRA space. ;
.10 I am concerned about.using a 95 percentile of an 11 existing' curve as a.-- I don't consider that a different,
'12 really a different level of safety -- hardly -- in PRA. i 13 . space.
14 DR. KHATIB-RAHBAR: All I am saying-is the mean is i 15' a good indicator of uncertainty really for these things.
'16 When you are~ talking about numbers between zero to one, your
- 17. mean is fairly high. You are close to the upper bound'of 18 .the uncertainty. .For all the fission product releases you
-19 are going from-10 to the minus 5 to one so I don't care what
'20 kind of distribution you put on that, your mean is going to 21 .be fairly.high. It's a very gpod indicator of the
- 22. . uncertainty that'you have in your process.
pc , 23 , All.this thing is saying is that I am putting in a
.o 124 .slightly higher confidence on the number I am using. That's ,
12 5- .all. r ANN-RILEY & ASSOCIATES, LTD.
- -- Court Reporters a 1025-Connecticut-Avenue, NW,.Saite 1014 Washington, D.C. 20036 L< (202) 842-0034
^
,_ 141 1 DR. APOSTOLAKIS: Well, actually, what it says is j 2 later. It says that if both your mean and the 95th are 'I 3 above --
4 DR. KHATIB-RAHBAR: Then you are okay. 5 DR..APOSTOLAKIS: -- then -- no, above. 6 DR. KHATIB-RAHBAR: Above -- oh, I'm sorry. 7 DR. APOSTOLAKIS: Then you consider backfits and
'8 1so on.
9 DR. KHATIB-RAHBAR: Other things. 10 DR. APOSTOLAKIS: Otherwise you consider cheaper 11 things, procedural changes -- 12 DR. KHATIB-RAHBAR: The one idea here is to use 13 this process -- 14 DR. APOSTOLAKIS: That is what he is saying. () ,15 ' DR. KHATIB-RAHBAR: -- to encourage either i 16 reducing the uncertainties through modifications, procedural 17 changes, et cetera, so that you can get away from this whole 18 large uncertainty issue. 19 DR. KRESS: Well, you know, what I was looking at 20 with this is I was viexing it as equivalent to kind of what 21- they do in 1.174 where they have those regions and if you 22 are above, say, on CDF, you are above'10 to the minus 4, you 23 kind _of start worrying about it, or above 20 to the minus 5 24 you worry about it. Once you approach-10 to the minus 4 you 25 get more concerned. a-ANN RILEY & ASSOCIATES, LTD. []J x- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
1 l 142 1 That is kind of what these two regions are. You
<w (JI
~_
2 have defined two regions where you are be! Tinning to worry 3 about it, and what I was saying is they used an order of 4 magnitude difference in 1.174 and you are using a little i 5 factor when you use the 95 percentile. ! 6 DR. KHATIB-RAHBAR: Yes. It is p<.obably a factor 7 of 2 or 3. I 8 DR. KRESS: Yes, and that bothers me. I have j l 9 trouble discriminating a two or three factor with PRAs and 10 that's what is bothering me about it. 11 DR. KHATIB-RAHBAR: I understand what you're 1 12 saying. You are talking about uncertainty at least in order 13 of magnitudes typically -- 1 i
, 14 DR. KRESS: Yes.
e~ ,1 N) 15 DR. KHATIB-RAHBAR: -- rather the factors of two 16 or three. 17 DR. KRESS: Yes. 18 DR. KHATIB-RAHBAR: But on the other hand, these 19 are the type of things we compute -- I mean knowing the 20 state of knowledge today, this is what we can come up with 21 in terms of uncertainties. I mean I agree with you. These 22 i are driven by many other factors. 23 Anyways, if you come essentially outside this 94th 24 percentile, no action is necessary. You'are below that so 25 it's not a problem. However, if your CCDF at 95 percent
. / ~.
/ i ANN RILEY & ASSOCIATES, LTD.
V Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. - - . .- . . _ . - . . . ,, . . . - . . - - . . - - . ~ . ~ . ~ . .-. ^^' s ,
f '
)
.143 1 level' exceeds the criteria,'then you see whether your mean
\
[/
.s-2 . exceeds this criteria or not. If the mean does not exceed 3 the criteria,Lthenzyou will evaluate some procedural 4- modifications -- you know,' accident management actions, et 5 cetera.- 1 6 .DR. KRESS: _A little clarificaticn on your 95th. ,
l 7 Is that the 95-95 or is that the 95th percentile on the ) 8- mean?
-9 DR. KHATIB-RAHBAR: 95th percentile on the means. '
10 DR. KRESS: It's not the 95-95, okay. 11 DR.~APOSTOLAKIS: No, no, it's the curve -- you 12 know, the log-normal' curve you mentioned -- the uncertainty
~
13 on the frequency of this or greater release. 14' DR. KHATIB-RAHBAR: On the greater releases, ' ('{},j 15 right. l 16 DR..APOSTOLAKIS: Typically log-normal shaped. l l
'17 - DR, WALLIS: This doesn't help until you say how 18 beneficial they have to be before they are worthwhile i 19 implementing. You can't just say beneficial. You have to 1;
[ l 20 say -- 21 DR. KHATIB-RAHBAR: -- by how much. 22' DR. WALLIS: What they need to be before you do 23 them because otherwise you just say it's infinitesimally
- 24. ' beneficial, therefore I.must do it.
25 DR. KRESS: Two thousand dollars, two thousand [ ANN RILEY-& ASSOCIATES, LTD.
- \__ . c Court Reporters 1025 Connecticut Avenue, NW,' Suite 1014
. 2 84 b34 i
-. . ~ ~ . .. .. -.- .. .- .- - . . - . - ~ - . .- - ..
144 i 1- dollars per manrem. l t () 2
.3.
pict. 're . DR. KHATIB-RAHBAR: This is just a qualitative 4 DR. WALLIS: A 50.59 thing again. 5 DR. KHATIB-RAHBAR: This was just to think ahead 6 if you wanted to implement such a system, what are the type 7 of processes you have to go through, and the idea here was
.8 ,to distinguish amongst two things, one is things which are
'9 cost beneficial, what those cost beneficial factors are --
10- DR. WALLIS: Finding what's beneficial may turn
^
11 out to be-as much of a problem as deciding what is safe. 12' DR. KHATIB-RAHBAR: I agree. 13 DR.'APOSTOLAKIS: Also, this is not PSA-based. It 14 -is PSA-informed really, isn't it? 15~ DR. KHATIB-RAHBAR: Define what is PSA-based.
- 16. DR. APOSTOLAKIS: Based means that -- what based 17' means is that you will do all thrae things looking only at 18 the risk numbers, and I bet you you are not going to do 19; that.
20 DR. KHATIB-RAHBAR: No.
;21 DR. APOSTOLAKIS: Okay, so it is informed. You 22l are going to look at what's' driving them -- yes?
.23 DR. KHATIB-RAHBAR: I don't know what is meant by 24 ;riskL--
25 DR. APOSTOLAKIS: Based means only.the results of , []
.\ /
ANN RILEY & ASSOCIATES, LTD. Court Reporters
~1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C.'20036 (202) 842-0034
. . ~ ~ ~ . - . - . . . _ ~ ~. .. .. . ~ . - ~.
145 1 1the PSA.
~ 2- - DR '. KHATIB-RAHBAR: 100 percent,on the risk -- no, M(f 3 :they're not.
4 DR. APOSTOLAKIS: And also I don't believe that 5 the intent here is that, you know, you compare with the 6 95th -- yes/no? s 7 LR. KHATIBkRAHBAR: No, it's 'not. 1 1 8 DR. APOSTOLAKIS: It's -- well, these are fuzzy ! l
'9 rules really.
10 DR. KHATIB-RAHBAR: Precisely. t 11 DR. APOSTOLAKIS: Okay. 12' DR. KHATIB-RAHBAR: This is, as I will again show 13 through the example, the idea here is not to treat these -j i 14 lengths as absolute lines.
.r O _15 ' ~DR. APOSTOLAKIS: Sure.
f j 16 DR. KHATIB-RAHBAR: This is just to provide some 17 guidelines. If a power plant exceeds these criteria -- ! 1 18 IHl. SEALEi -- leaky pipes, in other words. ! 19 DR. KHATIB-RAHBAR: Right -- to encourage the 20 utilities to come up with ways to circumvent some of these 21- issues rather than -- in fact, by and large a lot of the 22 decisions -- the venting decision was made before even this
- 23 thing 7was put into place.
- 24 If you want to justify any cost beneficial basis, 25 I$1000 per manrem averted, a venting system probably would
- 9 ANN RILEY & ASSOCIATES, LTD.
L (\_s/ 1 Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 4 -m-p _
1 146 1 not be cost beneficial. You know, these venting systems 2 i[wd } have cost millions of dollars to install, and the benefit 3 you get from them for example depends on the plant. For l 4 large dry containment it may not be very significant for ' 5 some cases. 6- But that is not the issue. The idea is that some 7 of the changes'because societally they were considered to be 8 things that people wanted to have done and there were some 9 technical bases for them it would give an additional degree 10 of comfort to the society if they were implemented 11 regardless of cost. That is an example. Venting is one 12 example. ; 13 DR. FONTANA: Dollars per manrem can be kind of 14 misleading because it should be dollars per the what does it ('v ; 15 cost to recognize the surroundings -- it's a totally I 16 -different number. 17 DR. KHATIB-RAHBAR: Even that. Even that, for the 18 venting even that will become very difficult. 19 DR. KRESS: There was some argument that that 20 number included that at one time. 21 DR. APOSTOLAKIS: Okay. i 22 DR. KHATIB-RAHBAR: Okay. 23 DR. WALLIS: I think you should have sort of a 24 stock exchange where the price per manrem goes up and down 25 depending on what we know and what people think. O ANN RILEY & ASSOCIATES, LTD. () _. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036-(202) 842-0034
. -. . - . - . . . .- . . - - . . - ~ . . - . . ...- - .-.. . . . - - .. . . . ,
147 1- DR. KHATIB-RAHBAR: Of course for future reactors
}
( . 2 it is to be at the'94 percent level, as indicated.
'31 DR. APOSTOLAKIS: Let's go to your risk management 4 texercise.
5 DR'. KHATIB-RAHBAR: Let's look at some
'6 applications for some plants.
7 Again, there are four plants, five units in 8 Switzerland. The two smaller, older units -- one GE boiling 9 water reactor, one Westinghouse two-loop PWR, a BWR 10 MARK-III, BWR-6 MARK-III.and the German KWU plant. 11- DR. APOSTOLAKIS: And they all.have detailed PRAs, 12 ILunderstand? 13 DR. KHATIB-RAHBAR: They all have done PRAs during 14: shutdown, yes.
) 15 DR. APOSTOLAKIS: Including shutdown?
16 RDR . KHATIB-RAHBAR: Shutdown, right. 17- These are typical risk curves that one comes up l 18 with for these plants. These are three of them only shown 19 here. We have the last one just completed but I don't have 20 :the curve here. l I 21 Again~, these are a combination of apples and 22 oranges. Let me explain a few things for you. 23 The black line here represents the Westinghouse 24 plant, the Betsnau plant. This curve includes the risk l. 25 -associated with internal. events and external events, I d
/~'\ ANN RILEY &' ASSOCIATES, LTD.
(_) Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C.'20036 (202) 842-0034
148 . I 1 everything, seismic, floods, fires, everything is included. 2 For this particular plant, I believe this is J) 3 Millerburg, which is a boiling water reactor. This is a 4 small reactor. This excludes fires, but it does exclude -- 5 include earthquakes, and aircraft crashes. 6 DR. APOSTOLAKIS: Why do they exclude fire? 7 DR. KHATIB-RAHBAR: It was not -- the utility l l 8 study had the fires in there. So this part, this is the l l 9 evaluation that went by the Inspectorate. 10 DR. APOSTOLAKIS: Oh. 11 DR. KRATIB-RAHBAR: They found problems with the 12 fire, so the fire was excluded from the analysis that they 1 13 performed. And the yellow line is the -- one, which is a ' l 14 boiling water similar to Grand Gulf, and this curve is
, j 15 internal events only. Okay. This does not have any 16 external events at all.
17 DR. WALLIS: It seems incredible that with 18 something as vague as PRA you get absolute coincidence of 19 CDF with three curves. 20 DR. KHATIB-RAHBAR: It is interesting. But, 21 again, as I said, they are different size reactors. This, 22 for example, this reactor is about three times -- 23 DR. WALLIS: But it looks so unusual as to wonder i 24' why it happened that way. 25 DR. KHATIB-RAHBAR: Yes. Well, I guess it is not ( ~'} ANN RILEY & ASSOCIATES, LTD.
/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
" 4 149 1 unusual, in this endLof it, you just study the containments.
? *
'] j 2 DR '. APOSTOLAKIS: But'why is it 10 to the minus 5 3 andinot, you know, some spread? 4, DR. KHATIB-RAHBAR: Because all the reactors have 5 been.backfitted substantially, that basically the backfits 6 that they have done, they have brought them to them level of 7- current designs, which are typically 10 to the minus 5. 8'. DR. WALLIS: So they aim for 10 to the minus 5. 9- It is not just fortuitous. I 10 DR. KHATIB-RAHBAR: Because they have been 11 1 backfitted by and large to satisfy those types of m
-12 requirements.
13 DR. POWERS: They are cumulative distribution 14 functions that get pinned,'for that reason, on that side and ( 15' .get pinned by. fission. product release physics on the other 16 point. And, as we all know, all.high entropy distributions 17 are about the same. And then we plot them on a log scale, 11 8 so they.really look coincident at this point. 19- DR. KHATIB-RAHBAR: No, no, no, that's not true, 20 because, actually, we have done a comparison with about five
~
21 or ten different plants, all over the place. 22 DR. POWERS: What's not-true, that they are 23' plotted on a log scale? 24 DR. KHATIB-RAHBAR: No, no, no. They are all over
'25 the place.
ANN RILEY & ASSOCIATES, LTD.
\'- Court Reporters 1025 Connecticut ~ Avenue, NW, Suite 1014 Washington, D.C. 20036 _
(202) 842-0034
l 150 } 1 DR. POWERS: They are plotted on a log scale.
=
2 There is no controversy that they are plotted on a log 3 scale. It is uncontrovertible that they are on a log scale. 4 DR. KRESS: I would definitely agree with that. 5 DR. KHATIB-RAHBAR: What is -- what is the A problem? 7 DR. APOSTOLAKIS: Mohsen said that -- I mean if 8 they did these PRAs, say, 20 years ago, then the flat parts 9 most likely would not be around 10 to the minus 5. 10 DR. KHATIB-RAHBAR: Not at all. Not at all. 11 DR. APOSTOLAKIS: What you said was that in the
+
12 last several years the Swiss have passed requirements or 13 regulations -- 14 DR. KHATIB-RAHBAR: This plant, the core damage 15 frequency, the first time it was done, it was up here. 16 DR. APOSTOLAKIS: Okay. 17 DR. KHATIB-RAHBAR: As I said, they have gone 18 through about $200 million worth of backfits to the plants 19 to bring them to the standards of modern PWRs or BWRs, and 20 from modern BWRs and PWRs, that is where you are at. 21 Believe it or not, that is where you are at. 22 DR. POWERS: And that is what fits that side, the 23 other side gets fixed by physics. 24 DR. KHATIB-RAHBAR: The other side is really fit 25 by this line here, which, as I explained. ANN RILSY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
151 e 1 DR. POWERS: It is-physical --
- )-% : 1
. 2 DR - KHATIB-RAHBAR:
. It is a consequence, 3 absolutely.
4 DR. KRESS: And the black line then would have to 5 have'something done? *
- 6 DR. KHATIB-RAHBAR: Yeah., we will talk about the 7 black.line in the next figures. ,
l 8 IMt. KRESS: Okay. 9- DR. KHATIB-RAHBAR: Now, even these older plants 10- are.very similar to, in terms of risk, to some of the most 11 modern plants. 12 DR. APOSTOLAKIS: So the earlier regulatory l 13- decisions were not based on these curves? 14 DR. KHATIB-RAHBAR: No , they were not. They are
?\
]( )I 15 not. Absolutely. But I mean just, it is coincidental after 16- the make the modifications in areas. For example, some of 17 these plants, one of them did not have an ECCS system, an
- 18. ' accumulator system'.
19 DR. APOSTOLAKIS: But did they have the PRAs when 20 they proposed-these changes? , 21 DR. KHATIB-RAHBAR: They actually did the y 22 modifications recently. 23 DR. APOSTOLAKIS: Okay. So then the coincidence 24 'is --
. 25 DR. KHATIB-RAHBAR: But these are not coincidental !
.[/I,
\_
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. . . . . . - - . . - . . . . - . . - . - - ~ . . _ - . . . . . _ - . - ~ . - ~ . . . . - - . . .
I 152 1 .from that point of view, yes. Now, let's look at : hat black () :2 3 line, this is the Betsnau, the PWR one. percentile curve. This is the 95th r This is the 5th percentile and this is 4 the.mean. I guess you had asked, George, that you were l 5 amazed that our uncertainties are relatively narrow compared 1 6 to-what you have seen before. 7 DR. APOSTOLAKIS: Yes. 8 DR. KHATIB-RAHBAR: I think if you look at these, 9 comparing it probably to NUREG-1150, the uncertainties are 10 wider because the 1150, my understanding was all the data 11 ;was generic data, which they used in the 1150 PSAs. These 12 plants,.by and large, are using plant-specific data, they 1 13 have extensive databank, l 1 14 DR. APOSTOLAKIS: And this is -- p. d 15 DR. KHATIB-RAHBAR: This is based on 16 plant-specific data. 17 .DR. APOSTOLAKIS: This is a complete PRA external 18 events? 19 DR. KHATIB-RAHBAR: This is a complete PRA,
;20 including everything -- excluding for power, not other 21- modes.
22 DR. APOSTOLAKIS: Not shutdown? L ? 23 DR. KHATIB-RAHBAR: It does have a shutdown study, 24' but these curves do not include the shutdown. And the other 25 factor is that there is some -- of course, in general, the i
)
O ~ ANN RILEY & ASSOCIATES, LTD. k/% Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 l j' l- l l l
- - ~ . ~ . - . . . . - . . _ . - . . . - . - - - - . . - . . . - . - _ - - - . - . . . -
153 1' seismicity for Swiss plants has been found to be
'\
[d 2 : problematic. The. uncertainties are not properly reflected 3 in the seismicity curves.for Switzerland, so that is being 4 reassessed. 5 DR. APOSTOLAKIS: Okay, 6 i DR. KHATIB-RAHBAR: With the exception of that, 1 l 1 7 you do expect slightly narrower uncertainties here as ' 8 compared to 1150, for the reasons I just stated. But, by 9 and large,.if you put the 1150 numbers, they are not that l 10 far apart, they.are probably about here. They are not that l 1 11 much narrower than NUREG-1150. In fact, there is a curve in 12 the paper I sent you, it has a comparison. For the boiling l A
. 13 water reactor it will be even wider than 1150 in terms of 14 uncertainties.
() 15 Here you find that the 95th percentile level
]
16 definitely exceeds the criteria, and the mean level down 1 1 17 here, of course, does exceed it substantially. There are a f 18 number of procedural modifications, not modifications -- 19 accident management actions which have been developed for [ ~20 Westinghouse. 21 DR. APOSTOLAKIS: We are following in your 22 previous block diagram. 23 DR. KHATIB-RAHBAR: Right, 24 DR. APOSTOLAKIS: In the region where the 95th is 1 25 above, but the mean is almost okay. I i 1 i,
%' ANN RILEY & ASSOCIATES, LTD.
, s,) Court Reporters 4 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 ; (202) 842-0034 - I
154 1 DR. KHATIB-RAHBAR: Almost okay. So now we are A
! ; 2 going to look at procedural modifications, which is really 3 accident management actions. These are like Westinghouse 4 Owners Group procedures, if you look at it for a typical 5 PWR, okay. Additional water to degrade a core, manual 6 depressurization of reactor cooling system, steam generator 7 isolation, early isolation of steam generator during a tube 8 rupture accident, additional fire water to a damaged part of 9 steam generator, recovery of containment isolation early, 10 cavity flooding, et cetera, et cetera, you go down the line.
11 These are some of them, if not all or most of the 12 Westinghouse Owners Group, what they call SAMGs, severe 13 accident management guidelines. 14 DR. WALLIS: So what you are telling us is that f^ . 's )N 15 there is considerable flexibility. If you change the 16 regulations, we can change how we run the plant to meet 17 them. 18 DR. KHATIB-RAHBAR: What? 19 DR. WALLIS: There is considerable flexibility, 20 that is very nice to know. It is not as if you are locked 21 into having to have a high CDF, there are things you can do 22 to bring it down. 23 DR. KHATIB-RAHBAR: You can do, exactly. The idea 24 here is to, again, to see how -- which part of the curve 25 these will benefit the most and which one of them are going [\) \/ ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
155 1 to'be beneficial. So if you took these actions and put -- 2 u'se a risk model, the PRA model, and basically calculate the 3 effect, this is what'you find. 4 DR. KRESS: Cumulative. 5 DR. KHATIB-RAHBAR: This is the same thing, 6 cumulative, right. This is all of them, this is all of.the 7 actions considered together. In fact, it turns out what 8 brings this part of the curve down is the things which can 9' eliminate or reduce the. releases from bypass events, steam 10 ' generator tube ruptures, additional water, for example. 11 This bought you essentially DF of a 100 right here. 12 DR. WALLIS: Is it true to say that all these 13 procedures are thermal-hydraulic in nature? 14 DR. MILLER: I thought everything was. 15 DR. KHATIB-RAHBAR: All fission product, really, 16 aerosol in nature. This sends out really more aerosol
-17 physics than thermal-hydraulics, really.
18 DR. POWERS: Aerosol physics is 19 thermal-hydraulics. 20 DR. KHATIB-RAHBAR: Not quite. 21 DR. POWERS: It is simply two-phase flow. Yes, it 22 is just two-phase flow. 23 DR. KHATIB-RAHBAR: Everything is thermo-dynamics 24 from that standpoint. 25 DR. APOSTOLAKIS: Is the recovery of containment ANN RILEY & ASSOCIATES, LTD. d Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
- - . . - - - . . . . . - - - . . . _ . - . - . . - - . - ~ . .
l i 1 156 l 1 isolation a thermal-hydraulic issue? () '
'2 DR. KHATIB-RAHBAR: No, that is basically a way 3 for:the operators to recover the isolation early, 4 primarily.-'-
j 5: DR. APOSTOLAKIS: So not everything is
- 6. thermal-hydraulic.
7 DR. WALLIS: This is like losing a valve? 4 I 8 DR. KHATIB-RAHBAR: This is AC power recovery. l
- 9. DR. WALLIS: Like losing a valve or something?
]
10 DR. APOSTOLAKIS: I don't know, that was his V-5. 11 DR. KHATIB-RAHBAR: Yeah, this is recovering AC l 12 power, essentially. I d 13 DR. APOSTOLAKIS: Let me change the question, give 14 it'a different flavor. Does this mean, if all of them are
) 15' thermal-hydraulic in nature, that this is the weak link in 16 the plant, thermal-hydraulics?.
17 DR. WALLIS: No , these are cures, George. These
- 18 are cures.
19 DR. SEALE: Removable heat capacity, George,
- 20. DR. APOSTOLAKIS: Let's not pursue this.
21- DR. KHATIB-RAHBAR: So all this shows is that even 22L though, again, you are exceeding these lines -- 23 DR. WALLIS: No, I think it is very interesting, 4 i 124 the solution to a PRA problem is thermal ~ hydraulic.
= 25. DR. KHATIB-RAHBAR: If you look at the .h.
5-/ ANN RILEY & ASSOCIATES, LTD. S Court Reporters 1025~ Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
~
(202) 842-0034 ! 1 I i
f 157 1 uncertainty -- 2 DR.' APOSTOLAKIS: You have to remove the heat, i 3 right? There must be something there. 4 DR. POWERS: Well, I mean I think it is a truism, , 5' if Sna could do -- if we had good, keen, physical insight, we i 6 would not have to do PRA, except possibly for a certain 7 amount of aleatory uncertainty, right, George? If our 8 epistemic uncertainties were zero, -- l 9 DR. APOSTOLAKIS: Yes. 10 DR. POWERS: -- then we would only be handling the 11 aleatory part,'right? 12 DR. APOSTOLAKIS: That's right. 13- DR. POWERS: If our insight was perfect, there 14 _w ould be no aleatory part. k 15 'DR. APOSTOLAKIS: There would be no aleatory part, 16 that's correct. 17 DR. KHATIB-RAHBAR: I don't have the 5th 18 percentile shown in figure'because this was not very 19' relevant. But if I had looked at considering these, all the 20 actions, there was an overall narrowing of the uncertainty 21 band around the mean value, and this is really to 22 demonstrate that-there are procedural things we can do even ,.2 23 you are not-narrowing the uncertainty, but you are 24 : circumventing areas'where you can get into high uncertainty. j 25- DR. APOSTOLAKIS: You didn't really do much to the L ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut' Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
158 1 core damage frequency. (j 2 DR. KHATIB-RAHBAR: No, core damage frequency was 3 not changed. , 4 DR. APOSTOLAKIS: Okay. 5 DR. KHATIB-RAHBAR: The core damage frequency, 6 because we did -- with the exception of recovering of AC 7 power in a couple of cases, by and large, -- 8 DR. WALLIS: You are just mitigating it once it 9 has happened. 10 DR. KHATIB-RAHBAR: Yeah. That is precisely it. 11 So this is how, again, a plant which falls outside the 95th 12 percentile can fulfill this requirement. 13 But to summarize, if there is such a summary, in 14 my mind, I think FC curves can represent the common risk fh (_) 15 metric for all sources and all modes of operations. It is 16 just a question of semantics and also having to do that. 17 And the' curves should not be treated as speed limits but as 18 indicators for safety optimization more so than anything. 19 Uncertainties cannot be expected to be fully 20 eliminated, at least not in the foreseeable future. 21 DR. WALLIS: I am going to ask you how you 22 optimize, unless you have some value function like dollars. 23 DR. KHATIB-RAHBAR: Yes, that will have to be 24 done. Absolutely. And, as I said, an example I have at the 25 very last figure which shows how I propose that would do / 'N ANN RILEY & ASSOCIATES, LTD. ks Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
i 159 l
' I 1 such an optimization.
() 2 3 optimization. DR. WALLIS: It tells you where you need to do 4 DR. KHATIB-RAHBAR: Where you -- right. 5 DR. WALLIS: How do you do it? < t
', 6 DR. KHATIB-RAHBAR: What you' define as your cost ,
7 benefits criteria, et cetera, of course, are still issues to 8 be addressed, no question about it. You know, there are -- 9- some people have: drawn the parallel within this and the l 10 radiation protection requirements. And I personally do not, 11 but some have done so. But you definitely will need'to have 12 a cost indicator before you can -- some cost standard:before 13 you can do this. I 14' But the idea.here is that if the risk is way too l "i
;)- 15 high, it falls way outside of these curves, this is an area R16 where they call -- risk is not acceptable, you have to do )
17 something. 18 DR. APOSTOLAKIS: You are changing all the
-19 acceptable -- acceptance criteria because you are going an ;
1 20 . order of. magnitude higher. 21- DR. KHATIB-RAHBAR: This is just an example. 22 DR. APOSTOLAKIS: So this would be a different 23 ' formulation of what you showed earlier. 24' DR. KHATIB-RAHBAR: Exactly. Exactly. 25 DR. APOSTOLAKIS: Okay. ANN-RILEY & ASSOCIATES, LTD. ; 4 sl Court Reporters j 1025 Connecticut Avenue, NW, Suite 1014 ' Washington, D.C. 20036 (202) 842-0034 1
+ . . . - . _ _. - -
160 ; 1 DR. KHATIB-RAHBAR: If you take that back to t'h. 2 somewhere here. 3 DR. APOSTOLAKIS: Yeah. 4 DR. KHATIB-RAHBAR: But in my own mind, if I want 5- to look at an optimization process where I am not going to 6 treat this as a solid line, -- 7 DR. APOSTOLAKIS: Right. 8 DR. KHATIB-RAHBAR: -- I would look at the region 9 over which I am going to make some changes. 10 DR. APOSTOLAKIS: Is this part of the Swiss 11 proposal? 12 DR. KHATIB-RAHBAR: No, it is not. 13 DR. APOSTOLAKIS: This is Mohsen's proposal? 14 DR. KHATIB-RAHBAR: This is my own, right. I\ () 15 DR. POWERS: If we think about how institutions 16 behave, will they, in fact, attempt an optimization or will 17 they, in fact, say I have this amount of money that I am 18 willing to devote to this activity, how much can I do for 19 that? I mean I think that is how most agencies -- most 20 institutions behave, that they really don't do an 21 optimization, just because it is so difficult to do. 22 DR. KHATIB-RAHBAR: Yeah, but the British, for 23 ' example, have adopted such an approach. If you look at the 24 British way, the way they are approaching this whole -- 25 DR. APOSTOLAKIS: NEI is proposing something
/ \
ANN RILEY & ASSOCIATES, LTD.
\
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 .. . ~ . . .
. _ . . . . . _ . . _ . . . _ . . . . _ . _ _ . - _ _ _ _ _ . _ _ . . _ . _ _ . _ ..___m-.__ _
l 161l 1- similar here. I guess the words are not the right ones, [ (s_/ '2 risk - 'instead of_ optimization, maybe you can say increased 3 regulatory concern. So now they have a motivation for doing ' 4 'something. 5 DR. KHATIB-RAHBAR: But the process which is -- , 6 DR. APOSTOLAKIS: Yes. I understand the spirit of ,
'7 it.
t 8 DR. KHATIB-RAHBAR: It is really the same thing. l 9 DR. APOSTOLAKIS: Now why isn't this beautiful 10 stuff'that you proposed, you described here, accepted by the
\
11 Swiss Nuclear Regulatory Authority? ' 12 DR. KHATIB-RAHBAR: That is a question you are l'3 _ going to have to ask -- fi 14 DR. APOSTOLAKIS: Why are they still discussing ! 15 it?' I mean are there any obstacles on the way? .l 16 DR. KHATIB-RAHBAR: No , I think there are a number 17 of issues like'the ones, I guess, Dr. Wallis raised. They
'18 have to do with defining a lot of these other terminologies 19 which are significant. You know, how do you do cost
~20' ' benefit? What are some of these other aspects you still 21- have to define?
1 22- DR. APOSTOLAKIS: The practical implementation. L 23 DR. KHATIB-RAHBAR: The practical implementation
- 12 4 of it which will drive this thing. And the other factor is 25- _that, by and large, even though this has naturally been i L 1
. 1 i -
\-#
I; ANN RILEY & ASSOCIATES, LTD. ' Court Reporters 1 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 l (202) 842-0034 l i
.. . . .- - -. ~. . - . - - . . . . - _~ .- . .
162 1 applied on a plant-specific, plant-to-plant basis, they [/) s._ 2 think they are fairly confident, by and large, they can 3 satisfy these requirements. As I have shown you, by and ' l 4 large, they do. fall within the criteria on limits. 5 So in areas where they have already exceeded those 6 they have already made decisions a priori to modify the 7 plants and make the changes necessary. As I said, some of 8 these plants had fairly high core damage frequencies before 9 the modifications were instituted. So -- 10 , DR. APOSTOLAKIS: Yes. Actually one of y- _ goals 11 had to do with core damage frequency. You say it had to be 12 less than 10 to the minus 5 per year. 13 DR. KHATIB-RAHBAR: Right. I 14 DR. APOSTOLAKIS: Now when you showed the curves, 15 .you focused on the consequences really, because even after 16 the procedures, the 95th percentile was higher than 10 to 17 the minus 5. So they intend to look at that separately, or 18 is that acceptable? 19 DR. KHATIB-RAHBAR: Yes, they're actually still -- 20 they're looking at some of those core damage frequency 21 figures. As I said, there are a number of things which 22 still have to be done to complete those studies. 23 DR. APOSTOLAKIS: Right. 24 DR. KHATIB-RAHBAR: And they will await -- at
'25 first we wanted to see what could be -- what benefits could
- /~N ANN RILEY & ASSOCIATES, LTD.
(' ') Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
163 1 be~ realized if we just looked at the consequence end of the () 2 picture:to see whether'indeed these numbers are totally out 3 of whack and they're too conservative and no plant-can ever 4 meet them,.or they are something that with reasonable 5 actions and reasonable things you can bring these plants 6 into a realm that.you think they ought to be at.
'7 DR. KRESS: Can I see your last example curve?.
8 Now that you've already put it up. 9 DR. KHATIB-RAHBAR: This one here, the example? 10 DR. KRESS: Yes. 11 DR. KHATIB-RAHBAR: Yes.
,. 12 DR. KRESS: There is some level down there where 13 that line -- in a straight line across there all the way and 14 still be risk-negligible, right?
15' DR. KHATIB-RAHBAR: Sure. 16 DR. KRESS: Yes. That being the case, I envision 17' a series of curves starting with a straight line, and as you 18 go up -- 19 DR. KHATIB-RAHBAR: You can -- 20 DR. KRESS: It's getting steeper and steeper. 21 DR. KHATIB-RAHBAR: Yes. 22 DR. KRESS: And I was surprised as you got -- 23- DR. KHATIB-RAHBAR: Yes, this --
, 24 DR. KRESS: It suggests --
25 DR. KHATIB-RAHBAR: This is just, yes -- O -ANN RILEY & ASSOCIATES, LTD. k- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 I i.......... -
. m__ -
_.____._a
164 ; 1 DR. KRESS: Symbolic.
- D
;.(} 2 DR. KHATIB-RAHBAR: This is symbolic. Not look at 3 the numbers per se. I'm just trying to show the process of 4 what you should go through. I should have actually not put 5 .any numbers on any of these. It's just to show the process 6 that one needs to go through and how these types of criteria 7 should be treated more so than --
8 DR. KRESS: That's'what I thought you meant.
- 9. DR.'BONACA: There was another on the summary 10 ~ slide.
11 DR. APOSTOLAKIS: Mario, can you speak to -- ! l
.12 DR. BONACA: Yes, the third bullet. Could you --
11 3 no, no, no , the summary. slide. 14 ' DR . KHATIB-RAHBAR: The summary slide. I'm sorry.
) 15- DR. BONACA: Yes.
16- DR. KHATIB-RAHBAR: I'm going to have to find it. 17 DR. BONACA: Juet expand a little bit on the third 18 bullet, safety criteria. ; 19 DR. KHATIB-RAHBAR: On this one here? DR. BONACA: Yes. 21 DR. KHATIB-RAHBAR: Uncertainties cannot be 22 expected to be fully eliminated. 23 DR. BONACA: Yes. 24 DR. KHATIB-RAHBAR: I was talking about this tail 25 of the distribution really, the tail of the exceedence as ~
?! ANN RILEY & ASSOCIATES, LTD.
)s / Court Reporters
.1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C.-.20036 (202) 842-0034 y - -
165 1 frequency curve. I'm saying in this region it's going to be () 2 3 very difficult-that we can demonstrate with a high confidence deterministically that we can tell them with some 4 confidence that release is 5.6 percent cesium, okay? And 5 eliminate all that certainty altogether. All I'm saying is 6 we have to divide it away by design or by procedures to 7 overcome-that issue. That's the whole idea. 8 DR. BONACA: Okay. 9 DR. APOSTOLAKIS: So in other words instead of 10 analyzing and talking about it forever -- 11 DR. KHATIB-RAHBAR: Precisely. 12 DR. BONACA: Do something. That's basically it, 13 do something. Right. 14 DR. KHATIB-RAHBAR: Yes. f t,
,) 15 DR. APOSTOLAKIS: Well, now the floor is open to 16 general discussion.
17 Joe, do you have anything to say? 18 MR. MURPHY: Always. 19 I think there's one factor where I -- I think I 20 agree with just about every technical fact that Mohsen said, 21 but there's one area where I'm not sure I agree with him, 22 and that has to do with the need to set a criterion for 23 interdicted land. The reason for this is that there is a 24 very clear playoff between societal risk in terms of 25 person-rem and interdicted land. And what we really should (s \~- e
- ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
166 1 do is tryLto optimize both. And if'I could use a blackboard S O s.) 2 or something -- 3 DR. KRESS: There :Us a slate up there. 4 MR. MURPHY: I want you to know one of the 5- highlights,-just as an aside when I put this on, the pastor 6 .of my church left his mike on when he left the church and
~7- proceeded to comment on some other people while he was still '
8; wearing the mike, and it got broadcast all over. 9 If I -- when I do a PRA for each accident 10 sequence, I get -- and all the way through level 3 -- I get 11 a certain amount of contamination that is released. It 12 comes down, it is a certain amount of material is released
- 13. at a place out on the ground, whatever. 'From that point on 14 the' question is what dose do I get, how contaminated is the D
'i s_,/ 15 land, and what do : do with it.
16- What it-amounts to is that if I take the societal 17 risk in person-rem, and the interdicted land area -- 18 DR. KRESS: A person-rem meaning if there was
~19 somebody standing there?
g 12 0 . MR. MURPHY: Actually, yes. The actual dose that 21- I would expect from the PRA making the various assumptions I 22- have about evacuation -- 23 DR. KRESS: Oh, okay. 24- MR. MURPHY: And nonevacuation. D 25 DR. KRESS: You are putting in evacuation. I \ ANN RILEY & ASSOCIATES, LTD.
\-s!; Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
-167 l' MR. MURPHY: Yes. What it comes out as is that 2 for a.given amount 1I have a tradeoff. What I'm saying is I
? 3' have a certain amount of material on the-ground. I can n. 4 either not clean it up and let people return to it, in.which ! 5 case I get'very[high person-rem, or I can clean it -all up, = ,
.6 and which I.get'no-person-rem,.but I get a tremendous amount i 7 of. integrated area - .of interdicted area. And the nature 8 of this for the limit of stuff we did at the draft of 9 .NUREG-1150, we didn't do it'.or the final, and so the models 10 are not quiet exact, but I think the general pattern is the 11 same, is that you get a curve linearly'that looks like.that.
'12 It's continuing dropping.
13 And'what'we really want to do is find the null 1 14- point, the minimum. And then we can either set a criterion 15 on societal person-rem or-we can set a criterion on. 16 interdicted area,' but we don't need both. 17 DR. WALLIS: You are assuming that all areas are 18 equal? There are some areas that people love more than 19 others. 20 MR. MURPHY: In terms of my ability to do a 21 calculation today, I'm assuming that, and I grant you that 22 .that's a bad assumption. I have a way that we've accepted 23 already of monetizing person-rem, and that's $2,000
- 24. person-rem discounted. In terms of -- I can also convert 25: the interdicted area to dollars, and in fact the codes that 1
ANN RILEY & ASSOCIATES,.LTD. A- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
- -(202) 842-0034
.. . . - . . . . . .. - . . . ~ . . . - - . _ - . - - . . ~ . - - . . - . - - - - - . - - - , .. . _
i 168 1 1 we used in NUREG-1150 supposedly can do that. It looks at I \ 2 'the land around the plant and in terms of what the products V
'3 'are, whether it's city or farm, if it's farm, whether it
)
4 grows grain-or wheat or peanuts or whatever.
~
Those are 5- built _into-the code, and they try to monetize. The problem 6 is those codes, the economic model in those codes, has not 7 ~been updar.ed for I guess at least ten years. Some of the 8 ex-Brookhaveners in the room may remember when that was 9 done. 10 The models themselves as they are now have _ 11 . deficiencies, and the updating of that economic model will , 12 take a bit,of work. But, yes, you really ought to take a 113 city is worth more than farmland, and you should take that . 14' into consideration. But there's a basic randomness to this
) 15 that Mohsen identified earlier.
16 DR. WALLIS: I think it's more than that, too. 4 17 Are you going -- the Swiss don't want Switzerland to become 18 interdicted completely. I mean, this is their whole nation. 19 MR. MURPHY: Well, I understand. 20 DR. WALLIS: And there are small States that might 21 feel the same way. 22 MR. MURPHY: Well, clearly. But you don't want 23 everything interdicted, but by the same token, you don't 24 want a high person-rem dose. So it seems to me that because 25- you have this general pattern, what you really want to do is [- .
. ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036
- (202) 842-0034
+g * -+e 9 m m g-. -m m - --
169 1 -find a limit, and then set a societal risk on one or the 2 other. J 3 I am more confident in my ability to calculate 4 person-rem than I am interdicted land area because of the 5 fact.that I have an outdated economic model. And for that 6 reason I would tend to pick the person-rem. But you could 7 do it either way. And there's a balance, because certainly 8 I don't calculate person-rem all that -- as well as I would 9 like to yet either. Person-rem calculations -- Jeff knows j 10 more about this than I do -- but my recollection is that 11 about 50 percent of the' person-rem dose in a PRA comes from
- 12. distances greater than 50 miles. Of that within 50 miles, 13 'better than half of it comes beyond 20 miles.
14 Now there's a problem in that at least in terms of ('")
.q,j '
15 the max code that we use, in that it's a unidirectional
\
. 1
. 16' model. . And'if you look at statistical data on wind j 17 persistence in the United States, just looking at the whole 18 map, you. find that the median for wind blowing in one
'19 direction, looking at -- oh, I guess there must be 40 or 50
- 20 points on the map that's in the old Meteorology and Atomic 121 Energy, is on the order of three to four hours. And with a 22 reasonable wind speed of five to six miles an hour, about 23 average, taking a calculation out more than 20, 25, 30 miles
.24 in one. direction probably doesn't make sense. But the model
-25 we have right now does.
.O
\s-(
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 l
- . . . . . _ - . . - . . - - ~ . - - _ . - - . . - . _ _ _ . _ - . . . - - . . . . . . . . - . _ .
I 170
- 1. 'Now why_does it? Well, there have been attempts
, 2. to build other models along that line, but the problem is 3 the lack of downfield data in the wind field. Even'if you 4 have good data at the site and you know that the wind
'5 changes direction'at.the site, and there are'some models 1
6 that then take the plume further on down and bend it the 7- :same way. 8 DR. KRESS: Joe? 9 MR. MURPHY: That data doesn't necessarily agree. 10 DR. KRESS: Being able to plot one parameter
.11 versus another like this implies to me that there is a third 12 parameter that they're both correlated by that is varying 13 along this curve. Is it what, fission product release? If 14 I go from the left -- if I follow that curve from the left ]) 15 ' side to the right, what is varying?
16 MR. MURPHY: This is essentially for the same 17 . beast. I take one accident and I release -- I let nature do 1 18 its thing,'if you will. I have a release at 10.to the 8 ; 19 curies of cesium, and it goes out and it gets dispersed by i 20 the' wind, and some of it comes down and some of it doesn't. 21 DR. KRESS: But you've got one -- one point -- 22 MR. MURPHY: Now once it is down -- 23 DR. KRESS: That gives you one point, though. ~ 24 DR. SEALE: No.
- 25. DR. FONTANA: No, he's saying is that he can --
J
\ ANN RILEY & ASSOCIATES, LTD.
[~/.
\- .
Court Reporters 1025. Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l 171
-1 :you can interdict more area --
- ( 12; -MR. MURPHY: Once it is.down, I'have one point 3 'now, if you will, one physical specimen. Now I say what'is
- 4. the dose.to the.public? Well, the' dose to the public 5 depends on whether there's any public there to get a dose.
6 .If:I interdict all the land, there's no person-rem. The 7- people are gone, because the dose to the public in terms of 8 the long-term effects -- 9 DR. KRESS: Okay. Now -- 10- MR. MURPHY: Comes from ground shine. Hardly any 11 of it comes from the cloud. And so if I get them out before , 1 12 they;have down shine-and then don't let them back, which is ; 13 what interdicted means, I'll go all the way down to'zero on ): 14 person-rem. By.the same token, if I say I don't want to ! ' (D)- 15. interdict an acre, I may have some very high person-rem. 16 DR. KRESS: So.this basically -- yes, I 17 understand. ' i
- 18. MR. MURPHY: And what I'm saying is what we really 19 should do is -- and the curve does look something like this.
20 It's an L-shaped curve. 21 DR. WALLIS: But you're talking as if you can 22 decide. I think of so many historical situations where 23 l groups of people have been willing to fight to the death, 0 '24 all'of them, in order not to be interdicted from their area. 25 MR. MURPHY: That's true, i' 4-
- O ANN RILEY & ASSOCIATES, LTD.
l bs/ Court Reporters D 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. . - . . . ..~ .~ ~ _ - - ~ . . . - - . . . - - . . - . . - - - . - . . - - . - - . - . . . - . _ . - ..
172 1 DR..WALLIS: So there's some human values here () 2 3 which you can't just -- MR. MURPHY: From a technical standpoint it makes 4 sense to do this, but then there's the political standpoint, 5 and this is a : policy decision. And it should have broad 6 stakeholder input. 7 DR. KRESS: You see this though to me says given I 8 have an accident, this is a decision on what do I do. It's 9 not an acceptance criteria related to these F-C curves. It 10 has ~ver/ little to do with it, it seems to me,
' ll- MR. MURPHY: It's both.
12 DR. KRESS: It is? L 13, MR. MURPHY: For a given accident, as it's in 14 progress, somebody's going to have to decide when to 15 interdict. We have guidelines that are out there now. EPA 16 has guidelines on this. Those guidelines were set by doing
- 17. this kind of a calculation using the WASH-1400.
18 DR. KRESS: Restating my question, it has nothing 19 to do with the design of the reactor. 20 MR. MURPHY: It doesn't until I get to setting a 21 ~ criterion here that's not in terms of person-rem or 22 . person-rem per year, and then the basic core damage 23 frequency plays in.
'24 DR. SEACK: Well, you get families of curves
'25 depending on -- so that there is a curve for a reactor. And ANN RILEY & ASSOCIATES, LTD.
(* -[' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
173 1 it would be affected by the design in a sense. fx t i 2 MR. MURPHY: Yes, y/ 3 MR. HOLAHAN: Dr. Kress, I think what you would 4 like to do is have some socially acceptable point, and then 5 find out what reactor design and emergency plan and all that i 6 stuff would draw a line through that point. 7 DR. APOSTOLAKIS: Before we go on, I have to leave 1 8 at this point, but the discussion will go on. Dr. Kress 9 will chair the rest of the meeting. 10 DR. KRESS: Before you leave, George, what would ) 11 you like to accomplish today, or did you want to put it off 12 till tomorrow in terms of what to carry over to the main l 1 13 meeting or -- j l 14 DR. APOSTOLAKIS: Well, one thing is what Dana A ( ,) 15 raised there, we want to brief the Committee --
)
16 DR. KRESS: Are we deciding that today or 17 tomorrow? 18 DR. APOSTOLAKIS: Tomorrow is a different meeting, I 19 actually. It's on a different subject. So today. j 20 DR. KRESS: We need to decide -- 21 DR. APOSTOLAKIS: Today. Yes. 22 DR. KRESS: That's what I need to do before we l l 23 close. l l 24 DR. APOSTOLAKIS: Yes, and maybe get comments from 25 around the table. Actually I had a question myself, but ANN RILEY & ASSOCIATES, LTD. \s ' Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 1 (202) 842-0034 l
174 1 there is no time. I mean, developing subsidiary goals from l [~') 2 the curves. Because if you want to use these things in ;
\_- ;
3 50.59, you definitely have to go below this. But that's for 4 something else. I 5 So thank you very much, Mohsen. This was an l 6 excellent presentation. I appreciate your coming. In fact, 1 7 thanks both to Dr. Kaiser and Dr. Khatib-Rahbar for agreeing 8 to come here as invited experts, which meane they were not 9 paid. So we do appreciate this. 10 And now you can go on with the discussion. 11 DR. MILLER: And they're not off the hook yet. We 12 will ask them some more. l 13 DR. APOSTOLAKIS: And we'll ask them some more. 14 Yes. Thank you. 1 (N i
) 15 MR. MARKLEY: -I'd just like to make one point.
16 There is no briefing session to the full Committee. Since 17 this is an ACRS initiative, it's really sorting between what 18 you want to do, so staff's not bringing something forward to 19 talk about, nor are invited experts bringing something for 20 you to consider. This has been offered for your 21 information. 22 MR. HOLAHAN: My suggestion would be that this and
.23 many other papers and meetings would be background for 24 sometime later in the spring, whether it's, you know, 25 somewhere between probably March and June, when Mr. Murphy ANN RILEY & ASSOCIATES, LTD.
[] (_/. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
_ .__.. . . _ - _ . . . _ _ _ _ _ . . - _ _ _ __._ _ .m.._ . . _ . _ _ . . . _ . . _ . . _ . . 175 1? brings the where do'we want to go with the safety goal paper i l b
'O 2- around. I'm'sure --
3 DR. KRESS: This does sound like a safety-goal 4 issue.
> i 1
, 5 MR. HOLAHAN: Right. Yes, I think it is. It's i 6- what should the safety goal look like and how should you use 7 it, and I think -- in my mind, there's no - .I don't see any 8 direction action from this absent,'you know, some thoughts 9 on where we ought to go with safety goal. j 10 DR. KRESS: Well, I was in my mind relating this 11 somewhat to the considerations one ought to have in mind 12 when one risk-informs Part 50 -- J 13 MR. HOLAHAN: Um-hum. l 14 DR. KRESS: Because we're talking about how to 7 g.
- ( j/ 15 risk-inform regulation. So it may have some relevance to 16- that also.. I don't know how to work it into that.
17 MR. HOLAHAN: It could, although I have to confess 18 that;I've been thinking of risk-informing Part 50 like 1.174 e 19 with, you know, LERF and CDF. 20 DR. KRESS: See, the problem I have with that is 21- .1.174 has things in it like you will meet the strictures of 22 the current regulation, which are mostly dose strictures -- 23- MR. HOLAHAN: Yes. 24 DR. KRESS: And then -- but you're going to change 25 the. regulation. I ANN RITEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 r- j+ 4
176 1 MR. HOLAHAN: Yes. () '2 DR. KRESS: And it's sort.of a circular argument 3 to~say meet-the regulations when we're going to change the 4 regulations, and it's these dose criteria that I worry 5 'about. And this was my attempt to attack that part of the 6 problem, although I like the idea of the thinking of 1.174.
'7 But that was'the_ problem I had with it. That's why I 8 thought'this might be relevant in that part of 1.174.
9 I MR. HOLAHAN: i think it can be relevant in that
'10 context.
.11 ,
Since I happen to be talking, why don't I -- my 12 observations from a meeting like this are not that I'm 13' _ inclined to take the regulatory process to, you know, 14 . frequency consequence curves, because I think there are a () 15. : lot of, you know, practicality and stability and 16: understandability issues, that we're already changing things 17' maybe,:you know, about as fast as they can be changed 18 without being sort of chaotic. But in my mind these sort of 19 studies and this sort of discussion helps identify areas in 20 which the requirements we have and the criteria and 21 approaches that we're thinking of may be either well
. 22' calibrated or poorly calibrated with respect to, you know, 23 overregulation or underregulation.
24' So at the moment I don't -- I'm not enthusiastic 25 about establishing a whole new regulatory paradigm, but it's ANN RILEY & ASSOCIATES, LTD. '( ~ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
177 1 a good testing mechanism to see where the things that we're n
/ \ 2 currently doing are in some way, you know, out of V..
3 calibration. And I think -- so the insights from some 4 generic studies like this in my mind are more valuable than 5 an idea that everybody ought to go off, do such analyses, 6 and make regulatory decisions based on them. 7 DR. WALLIS: How about the long-term view, Gary, 8 though? I mean, you're saying that today you have to do 9 what's practical. That's true, but I think you also ought 10 to have some idea of where t'me Agency might want to be 10, l 11 20 years from now. 12 MR. HOLAHAN: I think I'd like to make that 13 decision after I learned how good or how poorly, you know, 14 the deterministic set of regulations and something as simple () 15 as core damage frequency and large early release, you know, 16- how good a job they do. 17 And then whatever residual dissatisfaction you had 18 would be the driving force for changing the next 10 or 20 19 years. But I wouldn't want to change it just because it's 20 intellectually, you know, more -- 21 DR. BONACA: Yes, I have a question in fact 22 regarding -- probably on the same issue, Mohsen, which has 23 to do with what is a contest of this application in 24 Switzerland. What I mean is that if I look at 50.59, it 25 doesn't accomplish a risk evaluation in itself. However, it
\ ANN RILEY & ASSOCIATES, LTD.
[~'/ (- Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
178 1 accomplishes other things that are important too, which is ( ) 2 . closure and commitments and things of that kind. 3 And the question I'm having is I don't understand 4 to what this process is applied in Switzerland. Is it ( 5 applied to any change that is made, and in that case, and if 6 6 we transfer to a risk-based decision, how do they accomplish
..7 other issues such as closure and commitments and maintaining.
8 documentation and all of that-kind of stuff?
.9 DR. KHATIB-RAHBAR: Yes. In terms of specifics, I 10 don't.believe that they have really gotten that far in 11 developing how far they are going to apply such a thing.
12 But one of the requirements that they have by law is that 13- their powerplants have to stay current with the currency of 14 .the art and technology. That means that the -- this is a
) 15! moving target in a sense, that as you improve the 16 ' technology, you have to improve the plants.
17 So the plants are --'they go through a periodic 18 safety review there every ten years, every. plant is reviewed fl9 . f rota bottom up, completely. And.there is no such a thing as 20 a 30-year or a 40-year license life. So the license life
-21 could be indefinite theoretically. So such a process is to 22- be. applied to see how you can -- and essentially how good is 23: _. safe:enough and how safe is safe enough, and then as this
-24. technology evolves, how you improve your plants over the
- 25- . ten-year period, how do you measure relatively speaking. So
. ANN RILEY & ASSOCIATES, LTD.
O- ', Court Reporters
+
.1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
i i I 179 1 insofar as' specific changes, I' don't believe they have.
' : ;js s 4
-2' gotten that far to address that issue.
^u./
3 DR. SEALE: But presumably.the assumption is that : i
. i l 4- if they maintain consistency with the state of the art and l
5' the technology, that plant is a reasonable candidate for an 6 ' extension of its' lifetime regardless of how old the concrete . j l 7 .happens'to be. l i 8 DR. KHATIB-RAMBAR: That's correct. That's an ! 9 implicit assumption. i l 10 DR. MILLER: So in a way they' measuring e 11 cumulative changes over that ten-year period and seeing if i 12 that's moved them toward a safer reactor, so to speak. 13 DR. SEALE: Well, and they're also adjusting the 14 configuration of the plant. k 15 DR. KHATIB-RAHBAR: It's mostly, yes, the plant 16 configuration which is changing as a function of time. For 17 example, after Three Mile Island there was a number of major ; 18 changes made to the plants. After Chernobyl, there were 19 additional changes made. And now, as these older plants are L20 coming for their evaluation, ten-year-period evaluation, 21- they're making. additional changes. Some of them, in fact, 22 if you look at them, they probably are more suited than even 23 - some more modern plants which are currently under
.24 ' construction in some of the other countries, in the
,, 25 neighboring countries. L 1 I ANN RILEY & ASSOCIATES, LTD. , Court Reporters L 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
180 ! 1 But the idea is that you have to be able to change (G t 2 your level of safety to improve your safety with time, 3 because technology allows you to do that. And that is the 4 basic concept behind this ten-year evolutionary process. 5 DR. MILLER: Dr. Seale -- 6 DR. KHATIB-RAHBAR: I'm sorry? 7 DR. MILLER: Dr. Seale said that was 8 configuration. I assume that was a combination of j 9 configuration and equipment. 10 DR. SEALE: Both. 11 DR. MILLER: So I'm in the area of INC -- you 12 mean, configuration, you mean both. 13 DR. KHATIB-RAHBAR: Yes, both. Yes, both, both. 14 For example, this is one area they're going to for example (-~\ i s , ) 15 to some digital INC, and they're looking at that as one way 16 where technology has changed and made things perhaps better, 17 perhaps worse. And you have to look at it. 18 DR. MILLER: The challenge is to prove it's 19 better. 20 DR. KHATIB-RAHBAR: Yes. 21 DR. MILLER: I'm sorry, Mario? 22 DR. FONTANA: My thought was at some point the 23 capability of the plant to meet current technology would not 24 be possible. 25 DR. KHATIB-RAHBAR: As it's currently configured I)
'\j ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. .20036 (202) 842-0034
181 l
'l :and' designed. But they are changing them. !
2 DR ., FONTANA: Lo';k into'the future --
- 3. DR. KHATIB-RAHBAR: It's possible. It's possible.
4 -I don't know. j
')
5- DR. FONTANA: Haven't hit it yet.
)
6- DR. KHATIB-RAHBAR: But'in general, I mean, if you
- 7. look at some of these older plants, they have made major ;
l 8 changes. For example, all-the plants are required to have a 9 : totally independent redundant shutdown heat-removal system. s 10 DR. MILLER: Filter vents.
- 11. DR. KHATIB-RAHBAR: Filter vents. In other words,
~
12 these plants are de facto designed against, you know, other 4~ 13 factors, external factors, other than just accidents. 14 DR. FONTANA: Well, I was thinking, it was kind of () 11 5 an absurd' case, like a whole new material for pressure q 16 vessels that makes all these problems go away Well, you 17 can't -- 18- DR. KHATIB-RAHBAR: That's true. There are !
' 19 certain boundary conditions you cannot change. Absolutely.
l 20 DR. SEALE: Gary, I know you had your hand up. 21 MR. HOLAHAN.: Going back to Dr. Kress' question, 22' 'about if the only thing you really believe is PRA, how can 23 you have~-- in effect, how can you have a risk-informed 24' process, because everything that the PRA tells you isn't 125 :im.portant, some of those you're going to keep. And how are ANN RILEY & ASSOCIATES, LTD. ON Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
- _ .... _ . _ __.__.._m _ . . _ _ - .._ ..._.. _ _ _-______ _._, _ _...._ _..
182 1 you. going to decide which ones to keep. [s. 2 I think there is some information you can draw 3 from these-sort of studies to help you with that. The first 4- thing you can do is you can certainly identify existing 5 requirements or systems or whatever that are irrelevant to ' 6 risk. And, you know, to land: contamination or whatever you r 7 decide are the metrics that you're interested in. 8- And I think even though you're going to keep, you 9' know, some defenses, almost by definition contrary to what 10 the.PRA would tell you to do, you can identify where those j 11 additional' margins are much greater than the uncertainties 12' involved. And I don't mean -- I mean the real, total i 13 uncertainties, where you have to really think about what ! L 14 you're modeling and, you know, as well as the parameters. . (b 15 And I think.that if the purpose of (, 16 defense-in-depth and safety margins is to cever for.what you , 17 really don't know and what is not modeled in the'PRAs. 'Then 118 I think.it is legitimate to go back and test your , 19 defense-in-depth engineering margins against what the PRA
- 20 tells you you know really well on what you don't know so L
L 21- : well. And you' keep those things that you are not so 22 . comfortable.with,_and you let go those things that seem to [ 123 be irrelevant or have, you know, orders of magnitude margin l 24-- .- more-than.is necessary. p 25; DR. FRESS: Good thought. That complies with my I i $ .. ; ANN.RILEY~& ASSOCIATES, LTD. ' (.
- Court Reporters 4
=1025 Connecticut Avenue, NW, Suite 1014 r Washington, D.C. 20036 (202) 842-0034
. . . . . - ~ . - . . . - - .- --- . . _ _ - - - . - . - _ . _ . . . . ~ . . - . -
I 183 l. L 1 thinking about defense-in-depth ought to be utilized in a
.[s } -2 manner that tends to minimize your uncertainty. And'what
- 3. you are saying is you look at places where uncertainty is i
4 very hard, and there you keep defense-in-depth, and I think j 1 L 5' ' that is a good concept. j [6 I like the proposal that Gary made that -- we have 7 got'most of the committee here now. It just seems like we 8 don't really gain much by having a presentation or more ) 9 - discussion at the-next meeting at all. ! l 10 DR. SEALE: -Yeah. l 11 DR. KRESS: And that we can utilize this as l 12 background material for thinking about -- I think we ought . 13 to use in thinking about risk-informing Part 50, too, but 14 mainly for changing the safety policy statement. And so I () 15 can't really, at this time, see the need for, say, asking 16 Mohsen to come back to the meeting and make a presentation. 17 MR. MARKLEY: The other benefit you have is that 18 you are going to be meeting with the Commissico,and they may 19 ask what your current thinking is since you put this in a
'20- . letter on 50.59.
21 .DR. KRESS: Well, the problem with it is most of 22 this is not really relevant, in my mind, to 50.59. But you 23 are right, that probably will get asked. 24 DR. MILLER: Are we going to tell -- that should ! i 25- be our response to the Commission, we have decided it is not i. E[' ANN.RILEY & ASSOCIATES, LTD. L:' Court Reporters . .1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 (
184 1 . relevant? () 2
-3 DR. KRESS: Well, I don't want to speak for the Committee and George is making'that particular part of the
'4 talk. But I would like, at this. point, to ask if there are 5 ~ other members that want to make some comments or'ask 6 question; 7 DR. SEALE: 'I have a question. We haven't heard 8 very much from Jeff, and I would like to ask him one in.
9 particular. 10 DR. KRESS: Oh, wonderful. Wonderful. We have 11 heard quite a bit from him, though. 12 DR. SEALE: Well, but not nearly as much as our 13 more vocal members and Mohsen. When George introduced you, i
- 14. he'made'the comment, Jeff, that you were in charge of PRA i 4
); 15 ' application for' process industries, is that --.did I hear 16 that correctly?
17 MR. KAISER: Yes.
- 18. DR. SEALE: One of the difficulties we have 19~ :l occasionally when.we talk about the flexibility of PRA or 20, the application of PRA to other topics, or to things that l 21; are as yet unsatisfactorily covered in the existing PRAs, is 22 the= idea that somehow we have a limitation because our --
p 2 31 Lthe PRA methodology that we generally find used in the
,24 nuclear industry is, to be redundant, the nuclear industry's
' version of the PRA methodology. And, undoubtedly, in the' l
'"[^' ANN RILEY'& ASSOCIATES, LTD. Court Reporters 1025' Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202).842-0034 p p<
r 185 , IL -other industries that have applied PRA kinds of -- or PSA ( ; 2 kinds of methodology to analysis of their problems, they + 3 have had to have inven_1) at least one or two things that 4 aren't on the radar screen of the nuclear industry. 5 DR. MILLER: And probably eliminated a few that ' 6 are. 7 DR. SEALE: Yes. And I realize,- and you are a , 8 better judge of this than I am, that is probably a topic 9 that'could last at least as long as we have been here today. 10- But recognizing that, could you perhaps, and you don't have 11 to mention it right now, but if you could tell Mike what 12 some references or places we might go to get ourselves more 13 up to speed on what some of the other applications of PRA 14 have been. I think you get the idea of what I am driving f ( L15 at. 16 MR. KAISER: Yes. I think I would say I don't 17 think you will find, at least in the chemical and 18 petrochemical and petroleum industries, that they have done > 19 sophisticated things that the nuclear industry doesn't do. 20 I.think it is more a case of them doing much more quick and . 21 dirty PRAs or QRAs, as they call them, quantitative risk 22 assessments. For example, very often they will simply do 23 . point estimate risk assessments. Spend some time thinking 24 about the values of the individual parameters that go into 25 it, but, in the end, they will just select one of those ( ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
. ~ _ _ . _ - . _ _-
l 186 l 1 parameters and then generate a single CCDF or a societal
') 2 risk or something like that, and then use that to make %)
3 decisions about where they are going to put their dollars to 4 reduce risk. l 5 DR. SEALE: Okay. So this is an input to a cost 6 benefit assessment then that they might do? l 7 MR. KAISER: Yes. 8 DR. SEALE: I guess some thoughts on how they 9 discipline that cost benefit analysis might also be I 10 interesting, because, you know, we talk about $2,000 a 11 person rem, but that is -- well, undoubtedly, there are 12 other considerations. 13 DR. POWERS: There is another point that you can't 14 let slip by, and that is the frequency with which societal,
,y
( ,) 15 as opposed to individual risk is used in the process 16 industry as a criterion. j 17 DR. SEALE: Yes. 18 MR. KAISER: Yes. Well, they do use both, there's 19 no doubt about that. I can dig up some applications. i 20 DR. SEALE: We would certainly appreciate that. ; 21 DR. POWERS: Where they have, in my experience, 22 you find that societal risk frequently gets used when you 23 are looking at protecting workers in a facility. And when 24 you think about societal risk in that concept, you find that 25 it has a complementary nature to the individual risk in
. ' ') \_/
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l T. : t- 1 l- . 187 ! l
,11 exploring the space-of safety. I haven't thought about it j
[
) 2 in the grander public arena, but, certainly, among workers 3 .within a facility, you create two dimensions in looking'pt 4 safety when you look at'both societal and individual risk, p '5. MR. KAISER: . However, I would say most industries i l.
2 6 that I know would not use: quantitative risk assessment for
-7 the workers. They use process safety-management to ensure I' "
8 -that'their workers are safe, and that is entirely a-l . . L 9 qualitative endeavor. It's very rare in my experience for a l10 Mobil or an Exxon to use a'--
- 11' DR. POWERS
- Go to Dupont. You get to use it in
'12 spades.
13 MR. KAISER: Yeah. At a Dupont commercial site or 14- a Dupont Savannah River place. , I
) E15 DR. POWERS: My only familiarity with it is -- and 161 Wilmington.
l'7 MR. KAISER: Wilmington, Delaware. 18 DR. POWERS: Yes. ! 19' MR. KAISER: Okay. f' 120. DR. MILLER: .Well, they use it down at Savannah 12 1 ' ; River, though. ' 22 DR. POWERS: Well, that is a relatively modern, I , 23 Emean relatively new innovation at Savannah River. ; 24- DR. MILLER: Dupont has been out of Savannah River
-25' _for quite sone time..
C ANN RILEY & ASSOCIATES, LTD. Court Reporters L 1025. Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
-e---- e 2 ---.',e. b - a- +. o.w-,- , y . = ~ -.r=- r,.-- , - - . - - -
l l 188 1- DR. POWERS: Yeah.
- 2. DR. MILLER: But they were using it before they
'v['I 3 left.
4 MR. KAISER: Right. 5 DR. KRESS: Are there other comments from the members, that they would like to make before we -- I guess i 6 l 7 you have all commented out. i l 8 DR. MILLER: Well, I think the only. comment I
]
9 would make is I agree with apparently what you said early
- 10. on, and others, I don't see a relation of this with --
.11 applied to 50.59, and it was very valuable for me to better 12 l understand what is going on. I agree with Gary Holahan that -
13 it gives you a good context to look at the LERF and the core i 14 damage frequency, but I don't -- I think it is a way before A 15 ( ) it is a practical situation to even -- when you look at 16 risk-informed Part 50. But I don't see how it is sensitive 17 enough for a 50.59 application.
'18 DR. KRESS: That's my problem.
19- DR. MILLER: Of course, I had the same opinion of ; 1 20- core damage frequency, too. The two are related, obviously. 21 DR. FONTANA: If you look at the FC curve, and you
~
22 'look'at the lefthand side of it, and you start thinking of 23 50.59, it doesn't help you much because the allowed
]
24 probability doesn't go up. If you use 50.59, I don't think 25 you have -- the way lefthand side of the curve is just. I O ANN RILEY & ASSOCIATES, LTD. (_/ Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 4
189 l L l l 1 think, Tom, you didn't discuss it much, but your ) [ 21 relationship on relating the FC curves to steam generators, 3' I thought that was a very good job. I think it helps to l I 4- correlate'these and rationalize them.
- j. 5' I also feel that land interdiction really ought to
' l: l 6 be calculated independently and added up. I think it is j
-7 potentially so important, and I know there is a lot of I 8 emotion involved there.
9 DR. MILLER: So you wouldn't agree with Joe Murphy i 10 said then? l l 11 DR. KRESS: And what I said, yeah, you calculate 12 it independently and add up the costs along with the other 13 costs. You would put it on a common metric. ! 14 DR. FONTANA: But.I think, basically, that the FC
.n 15 ~( )
curves are a very good concept There is a tendency to get 16 balled up with uncertainties, but I.think the way you are 17 proposing to try to get around that looked pretty good. 18 DR. MILLER: It does handle -- it does give 19 uncertainties a better context than just the core damage 20 frequency. 21 DR. KRESS: Any other. comments? E 22 DR. WALLIS: Well, I have a comment. When ways of 23 doing engineering become mature, they get taught. Now, what 24 you presented here is sort of the level of research and 25 development and advising governments and that sort of thing, L [ \ ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034 l
_ . . _ _ _ _ . . _ . _ . . . . _ _ . _ . . _ ~ . . _ . - _ . _ _ _ _ . . _ _ . ~ . _ _ . _ ~ 190
.1 but, eventually,.this gets taught to people as this is the l-() 2 3
Lway it is.done,oor this is the way that you as professionals
'will be doing things in-the future. And I wonder how far 4 along this is evolving to the kind of thing that appears in i.
5 classrooms and'. students learn.to do it this way, and, L 6' . eventually, they will be hired by people like the NRc. I L , 7' DR. KRESS: I didn't know there were any more
- i. 8 students.
l: 9 DR. WALLIS: Because that eventually has happened. l 10 -If something becomes a worthwhile way of doing things in i !. 11 technology, it becomes taught and becomes practice. Has i 12 -this evolved to that point? 13 DR. MILLER: That sounds like a challenge.for 14 ' engineers. i
) 15 'DR. WALLIS: Are universities teaching this stuff 16 'as being the way to do things?
17 DR.TMILLER: No, the challenge would be to -- 18 DR. WALLIS: Does George teach it as the way to do 19' things.at MIT? 20' DR. MILLER: George, naybe. i 21 DR. KRESS: Only national laboratories can do 22: that. L23 DR. WALLIS: So, as far as you know, it is still 24' at the sort of research level?
- E., .
i 125 DR. KHATIB-RAHBAR: I have no idea what they are lt L3 ANN RILEY & ASSOCIATES, LTD. i; .%- Court Reporters r; 1025 Connecticut-Avenue, NW, Suite 1014 E Washington, D.C. 20036
-(202) 842-0034 l'
!: ;v ?-
+ - . --,- - -
m ._ __ . _ . _ _ - . _ _ _ _ _ _ _ _ _ _ _ _ _ . _ - _ _ _ . _ _ _ _ _ l l 191 1 teaching. l i.:< x i ()
/ 2 DR. SEALE: I have another concern about'all of
! 3 'this. In the present environment, if a plant gets shut'down 4 for six months by the NRC, it is dead, almost certainly. 5 Now, maybe if it is a station that has two or three other 6- : plants with it, and they can keep a cash flow up that will . L. ! 7 ~he.lp take care of people to do the things that are necessary 8 and so on, maybe it isn't quite that bad, but it is close to 9 that. And those kinds of events are over here on that part' q l 10 of the curve that we haven't talk about at all today, that 11 flat part there, that mesa, if you will, that vast 12 wasteland, that whatever you want to characterize it as. We l 13 haven't talked about that at all. 14 And if I look at the methods we are using for PRA,
,r k 15 they don't just tell us a hell of a lot about what is 16 happening there either. And I am just concerned that as we ,
17 talk about changing regulations and going to risk-informed 18 methodologies and so forth, and we don't have the 19 methodology to evaluate risk where it is most likely to have
'20 severe impact, are we really serving the industry well, I
- 21 mean in the sense of -- and the public?
22 DR. KRESS: I think that is a real good point, 23, Bob. I don't agree with you that it does not incorporate it 24 in the curve. I think the PRAs can address those things. 25 My feeling is, you know, I had these other considerations on g
;(U) ANN RILEY & ASSOCIATES, LTD.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014
. Washington, D.C. 20036 (202) 842-0034
192 1 one of my lists, and one of them is time risk. I didn't [)
\~/
2 lift it, I had time left on license, but actually I mean 3 time at risk. And I think that can be used as one of the 4 gauges. 5 DR. SEALE: Well, I will share -- 6 DR. POWERS: I don't think that the comment is 7 accurate, though. That we have been looking today 8 exclusively at the integral measures that come from a risk 9 assessment and those attract our attention. But the truth 10 is that those regulations that we have been risk-informing 11 call upon looking at the differentials, that is, looking at 12 things like the risk achievement worth and the risk 13 reduction worth. We have not spoken of those using this FC 14 curve as the object function where you are getting the ((,) 15 differentials, And it is in those regions that are used in 16 the regulations. 17 For instance, you can use it in the maintenance 18 rule to decide what are the important systems components and 19 structures. There are a variety of applications for those 20 used, and it is not in a wasteland, it is on the 21 differential of those curves where these things get applied, 22 and it is built into our regulatory philosophy, that when we 23, degrade elements of the defense-in-depth, that is 24 significant to us and the quantification of it comes in the 25 differential of these curves. We just haven't talked about (9
/
- /
ANN RILEY & ASSOCIATES, LTD. Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034
l 193 1 .it.
] 12 DR. KRESS: I think.you are basically right and 3 that is one reason I like to retain the concepts of things 4' like LERF and complementary -- or conditional containment I
5 failure problem and CDF, because those things tend to be 6- ' amenable to a differential evaluation, whereas, these FC 7- curves, you are" going-to have a little problem when you talk 8 about -- l 9 DR. SEALE: I think that is why Gary is not all 10 that enthusiastic about FC curves, or at least one reason. 11 DR. KRESS: Yes. That is why.I like to retain
.12 - these things,-too, as part of our system.
13 DR. BONACA: Yes. .Just one observation. It seems I 14 to me that this approach that you presented seems to me l 15- appropriate for -inacro decisions. By macro, I mean where you
- 16. are talking about measure changes that can be really looked l 17- at favorably or unfavorably at the high level, which means, i
18 you know, talking about putting in a filter vented 19 containment, that definitely would be a decision, even
'20 smaller changes probably. But to me, that doesn't preclude, !
21 'however, the value of PRA in the just day-to-day engineering 22 used, you know, in a much more limited framework of the 12 3 : decision you make as part of an engineering analysis.
=24 Another thing that, you know, supporting this
- 25. approach here, should exclude our encouragement for the ,
.- ANN RILEY & ASSOCIATES, LTD.
' s.
Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington, D.C. 20036 (202) 842-0034-
194 1- other-application, which, really, it is almost complementary
-2 to'--
3- DR. KRESS: YeF, this is almost an additional
.4: complementary.
5 DR. BONACA: That's right. This is really -- 6 DR. KRESS: It doesn't necessarily -- it may bring
-- 7 'some consistency to these other things if you do it 8 properly.
9 DR. BONACA': That's right So,-I mean, you know, 11 0 I don't think that -- if we say that this. is not applicable 11 today to 50.59, we don'_t wan't to use it, in that -sense, it 12 doesn't discount, in my mind , still, the value of 13 encouraging use of PRA in more engineering type of , 14 applications,'as we have seen, extensively, and they are 15: being done today. So, anyway, that is my perspective there. 16 DR.~KRESS: With that, .what I think I will do is
- 17- add my thanks to the valued experts who 'did a really good 18 discussion and we are really pleased that you were able to 19~ come, plus the staff. I was very glad you could come and
'2 0 )- . valuable comments and valuable discussions, and we really 21 appreciate it. So, with that, I think I will adjourn this-
. 2 2. -particular meeting.
~23_ Tomorrow is ' a dif ferent meeting, right, so I can y
_24- . adjourn. ! 25 .DR. SEALE: Start at 8:30?
/ ANN RILEY & ASSOCIATES, LTD. '( '1 Court Reporters 1025 Connecticut Avenue, NW, Suite 1014 Washington,_D,C. 20036 (202) 842-0034
- a-p * ,- *
. ,. .. ... . . . . _ . . .....____..__...-_..__._.-...._..__...._..__..._.....m,_.._
l t i: i 195 i' ~ ll . 1.. DR. KRESS: 8:30, yes- . So this meeting is now.
-2; a'dj ourned . .
c -3; [Whereupon,'at 5:07 p.m., the meeting was concluded.] 5
"( . g- 1
- 7 r l o )
i 8 i j- <
.9.
L10-I i 11 s ,' 12 ! i
. 13 1 14-t i i
16- , 17: i l
- 18
- 19 ...
20 21
' 22-23
- 24. -
l 25' 1 L i 8 IN( ANN RILEY & ASSOCIATES, LTD. ' (/ .. Court Reporters
' 1025 Connecticut Avenue,'NW, Suite 1014 b; . Washington, D.C. 20036 (202) 842-0034 l
y 7 y - -,.eg w --
.m.. ___ . _ _ . . . _ _ . . - _ . . _ _ . . . . _ . _.._. __
REPORTER'S CERTIFICATE p This is to certify that the attached proceedings
/^s I
( ). before the United States Nuclear Regulatory Commission in ) l the. matter of: j i NAME OF PROCEEDING: MEETING: RELIABILITY AND l. ( PROBABILISTIC RISK ASSESSMENTT l 1 DOCKET NUMBER: 1-H PLACE OF PROCEEDING: Rockville, MD l. were held as herein appears, and that this is the original
); transcript thereof for the file of the United States' Nuclear
[ Regulatory Commission taken by me and thereafter reduced to typewriting by me or under the direction of the' court reporting company, and that tne transcript is a true and I accurate record of the foregoing proceedings. ; l N (bv,e
-y -
Mark Mahoney [ Official Reporter 1 i l Ann Riley & Associates, Ltd. l i L v 1 I ?
INTRODUCTORY STATEMENT BY THE CHAIRMEN OF THE
'. SUBCOMMITTEE ON RELIABILITY AND PRA 11545 ROCKVILLE PIKE, ROOM T-283 ROCKVILLE, MARYLAND JANUARY 25,1999 The meeting will now come to order. This is a meeting of the ACRS Subcommittee on Reliability and Probabilistic Risk Assessment. I am George Apostolakis, Chairman of the Subcommittee.
ACRS Members in attendance are: John Barton, Mario Fontana, Thomas Kress, Don Miller, Dana Powers, Robert Seale, William Shack, and Graham Wallis. Also in attendance is Mario Bonaca who has been selected as a new Member. He is expected to be appointed to the ACRS in the near future. ACRS Invited Experts are: Moshen Khatib-Rabbar and Jeff Kaiser. The purpose of this meeting is to discuss the possible use of frequency-consequence curves in risk-informed decisionmaking. The Subcommittee will not review proposed options to make 10 CFR 50.59 risk-informed as was previously announced in the Federal Registeron December 23,1998. The Subcommittees will gather information, analyze relevant issues and facts, and formulate proposed positions and actions, as appropriate, O. for deliberation by the full Committee. Michael T. Markley is the Cognizant ACRS Staff Engineer for this meeting. The rules for participation in today's meeting have been anr$ounced as part of the notice of this meeting previously published in the FederalRegisteron December 30,1998. A transcript of the meeting is being kept and will be made available as stated in the Federal Register Notice. It is requested that speakers first identify themselves and speak with sufficient clarity and volume so that they can be readily heard. We have received no written comments or requests for time to make oral statements from members of the public. (Chairman's Comments-if any) In the ACRS report dated July 16,1998, I offered a proposal for the development of a risk-
- informed framework for 10 CFR 50.59. Dr. Kress has pursued this idea further and developed a proposed White Paper on the use of frequency-consequence curves. We will proceed with the meeting and I call upon Dr. Kress to discuss the subject White Paper.
}
l tQ 1 l l' i PROPOSED ROLE OF FREQUENCY-CONSEQUENCE (F-C) CURVES IN
- A RISK-INFORMED REGULATORY SYSTEM T. S. Kress o ACRS 1
l lO l Presented at R&PRA SC Meeting January 25,1999 Washington DC LO o i
- m. . . ,
O THE MAJOR ATTRIBUTE OF A RISK-INFORMED REGULATORY SYSTEM IS THAT IT MUST HAVE ACCEPTANCE CRITERIA ON THE [ RISK] METRICS THAT REPRESENT THE AGENCY'S REGULATORY OBJECTIVES IN 1.174, THE AGENCY PROPOSED ACCEPTANCE CRITERIA ON CDF AND LERF. PLANT SPECIFIC VALUES FOR THESE WERE TO BE SUBMITTED BY THE LICENSEE BASED ON HIS PRA. I HAVE NO PROBLEM WITH THIS......BUT I DO NOT THINK THAT CDF AND LERF SHOULD REPRESENT THE ONLY NRC REGULATORY OBJECTIVES O 2
.-. . . . - . - - - . . . . - - - _ - - . - . - _ _ - - _ ~ - . - - - . _
i O l I BELOW ARE SOME SUGGESTED REGULATORY OBJECTIVES THAT COULD ALSO REPRESENT A POTENTIAL DEFINITION OF " SAFETY": 1 I. RISK PARAMETERS (ACCEPTANCE CRITERIA ARE NEEDED):
- 1. INDIVIDUAL RISK OF PROMPT FATALITY
- 2. INDIVIDUAL RISK OF LATENT FATALITY l
- 3. TOTAL FATALITIES
- 4. LAND INTERDICTION
- 5. INDIVIDUAL RISK OF RADIATION INJURY '
- WORKERS
- PUBLIC l
II. DEFENSE-IN-DEPTH PROVISIONS (RECOGNIZING THAT THERE ARE INHERENT UNCERTAINTIES ASSOCIATED WITH PRA RESULTS): , Q l. 2. ACCEPTANCE CRITERION ON CDF BARRIERINTEGRITY
- 3. REDUNDANCY / DIVERSITY [ REACTOR PROTECTION; ECCS; LONG-TERM COOLING]
- 4. EMERGENCY RESPONSE III. SAFEGUARDS.
7 IV. OTHER CONSIDERATIONS
- 1. CAP ON INSTANTANEOUS CDF
- 2. TIME LEFT ON LICENSE O 3
O THE ISSUE IS.....HOW TO INCORPORATE ALL THESE OBJECTIVES INTO A RISK-INFORMED REGULATORY SYSTEM. WE MUST HAVE ACCEPTANCE CRITERIA ON EACH
+
- WE MUST THEN BE ABLE TO DETERMINE ANY PARTICULAR PLANTS' STATUS WITH RESPECT TO THESE ACCEPTANCE CRITERIA O CLEARLY A PLANTS' STATUS WITH RESPECT TO THE RISK METRIC ACCEPTANCE CRITERIA CAN BE DETERMINED DIRECTLY BY A PLANT / SITE SPECIFIC PRA....
HOWEVER..... IN THE CASE OF 1.174 FOR PROMPT FATALITY RISK, THE AGENCY DEEMED THAT FULL LEVEL-3 PRA USE WAS TOO UNWIELDY / UNCERTAIN FOR REGULATORY EFFECTIVENESS THEREFORE........ (d' 4 1
._. - J
O l 1 I IN 1.174, -LERF WAS DEVELOPED AS A PRACTICAL, UTILITARIAN CONVENIENT SURROGATE FOR THE PROMPT FATALITY QHO. l THEREIS A NEED TO HA VE A CONSISTENT WAY TO DEVELOP SUCH CONVENIENT [ LOWER TIER] SURROGATES FOR THE OTHER REGULATORYOBJECTIVESI O. : WOULD F-C CURVES BE USEFUL FOR THIS PURPOSE 7 5
'O t
l CLEARLY, REGULATORY OBJECTIVES RELATED TO PROMPT FATALITIES, LATENT FATALITIES, TOTAL DEATHS, AND INJURIES DEPEND ON THINGS LIKE... THE AMOUNT OF RELEASE OF DIFFERENT FISSION PRODUCTS THE TIMING OF RELEASE Q
- SITE-SPECIFIC ' ATMOSPHERIC DISPERSION PARAMETERS POPULATION AND DISTRIBUTION AROUND THE SITE EMERGENCY RESPONSE MEASURES l HEALTH CONSEQUENCE EFFECTS l
6 u f~
.._ y _ _ _
I 1-
. i.-', - - - . . . _ _
~
4 I msles seems teug of aero __ g.3 ,
+
1 1 * ! r .- , * '. S ,,-s . . s ; 4 1 1 , l A l I .
- 3 s.-. . .
1 ,
\
to-* tr; i- Q3 to 4 4 se " e u44 44 m-> 4
.g ,
w a s. ce sie n ause mism j l l Figme 1. Im Preheminy of Early Fatahry 1 l
- - _ - . . l
/ T U - - - - _ . --
as .
,o-a .
I -3 . ,.., 3 ,.. I . , , t ,,.s . .. l i.- * . 1 gso-*
~ l is-* ir' ie-* io-8 so-a ,o-i .. .i l ce m hacen Figwe 2. Irukvidsal Prebutsisy of t.asent Fatality l
s l l~ 1 l
. . . . _ - . - - . _ - - - - . - . - - _ . . - . - . ~ . - _ . - - - - -
l + 0 l l BY PROPER EXECUTION OF A CODE LIKE MACCS, USING APPROPRIATE ASSUMPTIONS ON EMERGENCY RESPONSE, I PROPOSE THAT , CORRELATIONS CAN BE DEVELOPED FOR MOST OF THE REGULATORY l OBJECTIVE METRICS AS FUNCTIONS OF CERTAIN FISSION PRODUCT ., RELEASE.*
- e. g.
l l Fi -+ CORRELATION FOR INDIVIDUAL RISK OF PROMPT FATALITY F2 -+ CORRELATION FOR INDIVIDUAL RISK OF LATENT FATALITY O F3
- CORRELATION FOR INDIVIDUAL RISK OF INJURY F4 -+ CORRELATION FOR LAND INTERDICTION
- I USE RELEASE FRACTION IN THIS EXAMPLE BUT ACTUAL CURIES WOULD BETTER ACCOUNT FOR DIFFERENCES IN INVENTORY 8
. - - s IT CAN BE SHOWN' THAT THE PLANT STATUS WITH RESPECT TO THE CORRELATABLE OBJECTIVE METRICS IS RELATED TO BOTH THE F-C CURVES AND THE CONSEQUENCE FUNCTIONAL CORRELATIONS RC,= -fon GF-GCDRy,zp,yg(p,y d(RJ)
O IF WE ARE SUPPLIED WITH APPROPRIATE F-C CURVES AND HAVE DEVELOPED THE APPROPRIATE FUNCTIONAL RELATIONSHIPS, THEN SOFTWARE WILL BE EASY TO DEVELOP AND USE TO DIGITIZE THE SLOPE OF THE F-C CURVES AND NUMERICALLY INTEGRATE TO DETERMINE THE PLANT STATUS WITH RESPECT TO THE VARIOUS ACCEPTANCE VALUES.
- SEE MY WRITEUP ON F-C CURVES 9
O
SUMMARY
CDF AND LERF ARE NOT THE COMPLETE REGULATORY OBECTIVES OF NRC. OTHERS WERE SUGGESTED ACCEPTANCE CRITERIA ARE NEEDED ON THE REGULATORY OBECTIVE METRICS F-C CURVES APPEAR TO BE A WAY TO PROVIDE A SYSTEMATIC, CONSISTENT [ SURROGATE] MEANS OF DETERMINING A PLANTS g STATUS WITH RESPECT TO RISV.-RELATED REGULATORY OBECTIVES (INCLUDING LERF AND CDF) SOCIETAL REGULATORY OBECTIVES (SUCH AS TOTAL DEATHS AND/OR TOTAL INJURIES) CAN ALSO BE REPRESENTED AS F-C SURROGATES. THESE, HOWEVER, ARE LIKELY TO BE VERY SENSITIVE TO SITE CHARACTERISTICS AND MAY BE BETTER SUITED TO BE DEALT WITH VIA APPROPRIATE SEPARATE REGULATIONS LIMITING SITE POPULATION. O 10 i
O RISKANAL YSIS AND REGULATORY SAFETYDECISIONS Presentation to: Advisory Committee on Reactor Safeguards Meeting of the Subcommittee on Reliability & PRA January 25,1999 By: Mohsen Khatib-Rahbar Energy Research, Inc. (ERI) P. O. Box 2034, Rockville, Maryland 20847 mkr-eri@ radix. net Ooinions exoressed here in are solelv mv own & do not reoresent those of ERI soonsors O
~
OUTLINE - . Frequency - Consequence (F-C) Curves What do these curves represent?
, What are the uncertainties and what confidence j do we have in theirquantification?
What to use as the consequence metsure? OtherIssues: 0 - Are accidents outside of' core" considered?
- Should they include other than power operational modes (e.g., shutdown)?
- Is the knowledge-base available?
m PSA-Based Regulatory Decisions n Summary JO 1
.l O
F-C Curves: What do these curves represent? \ F-C Curves exhibit "three regions"(Power Operations Domain): r - A" vervIarce uncertainties in consequences & smaller I uncertainties in accident frequency: " defense-in-depth region"(Containment Effective) j
- C"smalleruncertainties in consequences & verylarae l y!) uncertainties in accident frequency: ' vulnerable region"
.ai (Containment Bypassed)
- B'in-between "potentially vulnerable region"(early
;3 containment challenges due to severe accidents) l g
w O, F-C Curves & Uncertainties
. . . . . . . . . wAwassesummuuawamps 1E-04
-[ "A" 5th Percentile :
.,el 1E-05
.A "B" l fMI 1E-06 Niean
,C ,
k 5th Percentile
.] 1E-07 '
" l 1E-08 l 1E-02 1E-01 1E+00 1E+01 1E+02 1E+03 1E+04 1E+05 '
l Cs-137 Released to Enwonment (g)
-l li g1 l 2
1 O ; Contribution ofradiological release modes
, a > , ., . ,
O n=== a== emuso
,e . - . - .
l te , r
=
{ io* - h" Contasment
, Leakage & Eas4 Conta all i ,e , vent!"e s e S venting 'o 0 Q B[< s j
'",e is is is is ik is is i 1
n.m. m . .: c.. m.im
+ l O ;
-C Curves: What are the uncertainties and what onfidence do we have in their quantification?
"A" even though uncertainties in release are very large, nevertheless,
, x contributions to risk (even at upper boundlevelnot as significant) j n "B & C" uncertainties in release are
' smaller; however, contributions to risk are more significant 3
(.2
.?
3
I O F-C Curves: What are the uncertainties and what confidence do we have in their quantification?
, . , - .... \
.--m, - act .7. l
. - - - . . . -.c..... ,
~~- n -e.....
;-== . , ..
-c......
-c.....
. . ; . . -c.....
. . .. . -c,....
. . :. .. - oc. ....
. . . . . - ne. ...
. . .. . . - oc, . . . ..
,, . :. . * .C11 3...
. :: .. - .C12 1...
. .e - .C13 4.2
- - - - C14 0 ..
_ - - - - RC1. ..1.
. . :: . . . .C1 14.7.
., -- - .C20 0.3.
. i .a - . Cat 0.7.
4 s4 4 4 4 4 4 4 4 4 '
..i....i..c......,,
O F-C Curves: What are the uncertainties and what confidence do we have in their quantification? Subjective uncertainties quantified using expert Judgement, and to the extent possible, models (albeit some could be incomplete), and test data
$s Even though difficult to demonstrate, but, the N extent of uncertainties are probably overstated, l .
especia!!y, as relates to release of volatile fission
$. products (upper bounds often involve complete 0 releases and low retention in RCS & containment) 1 a Narrowing of uncertainties not expected within a y, reasonable time and resources; therefore, any
' use of the risk curves should encourage ways of y% circumventing potentialimpact of uncertainties l % vi l O 4
i i O i What to use as the consequence measure? i Problem of nuclear accidents is the catastrophic potential for contaminating a
- large area fora long time l n Prompt fatalities could often be mitigated by j off-site emergency counter measures l l .
m Forinstance,1/2 gr of Cs-137 spread l } uniformly over 1 km2 makes the area totally inhabitable (Health Physics 98, No.1, l . 21,1995) l j 4
- 1 lO i
i l What to use as the consequence measure? l (Cont.) \ Nuclide Halflife (days) Inventory (Ba) 2!!;ll: <2o xa am
$: 't!
,. 1::lll !!; i:llll: 33o kg =" xa lid lIl'!I :::
l'!;lf: Tvolcal PWR & {sl b C113400 MW(tn 'cuan
'7d cl:l$ !!' ' U'lI s 1e5 kg ali cs
. (s 137 10990 0 24s80
e 9 0 01 0 94510 " t'!' '!!.0 ::::lll eo xg J:%' !!,'9 ti!;!?;-
- Rs.104 369 1 07:10
,C 4 2:44 3 39sl0 170 kg all Ce
' N 241 5333 0 2s io
gj . J 600 kg all Pu g.j O 5
i e What to use as the consequence measure? (Cont.) l Off-site consequences (fatalities, land contamination, etc.) require level-3 PRAs (involving additional & greater uncertainties)!
" Release fractions alone not adequate (do not account for the influence of reactor size)
J n Impact of short lived radionuclides can be M mitigated by emergency response measures Therefore, release activity or mass eaulvalent of Cs-137 appear
$ as reasonable measures for consecuences y
e OtherIssues Are accidents outside of " core" considered? d Most shutdown studies have been limited to hjh calculation of fuel damage frequency (!.e., j %d releases have not be assessed). j n Should they include other than power Gf operational modes (e.g., shutdown)?
'f Yes (Qualified).
1 a is the knowledge-base available? h Few new issues arise (e.g., air ingress); however, 8 for the most part, problems (phenomena) less uncertain l e 6
i lO ! PSA-Based Regulatory Decisions Probabilistic safety criteria (i.e., safety goals) should be viewed as economic and social optimums. a Risk reduction well below these aspiratory targets impose great economic burdens.
.. ; a Exceeding these criteria significantly,^could havelarge economic and social consequences resulting from accidents.
[ (Source: D. Ward. Decutive Conference on Risk-Based Reaulation. Washinaton. D. C.1994) 3
'E O
Pro osed Swiss Probabilistic Safety Criteria Core damage frequency (including external events) < 10-5 peryear h Frequency of releases greater than 10 kg-equivalent of Cs-137 <<10-6 peryear id
! Source: Proceedinas ofIAEA Symoosium on Advances in Doerational Safety of NPPs. Vienna. 4-8 Sectember 1995}
O , 7
1 l O Proposed Swiss Probabilistic Safety Criteria asummus - (Cont.) .. . 1E 03 -
== Proposed Safety Cnteria 1E4M l
$ 1E-051M 1E-06 i i 1E-07 .
I E 1E-01 1E+00 1E+01 1E*02 1E+03 1b+04 7 1E 05 1E+06 Cs.137 Equivalent Released to Environment (g) O Existing Operating Reactors Existing operating reactors proposed to conform to critoria at the "mean" level of exceedance frequsncy through cost-beneficialbackfits a However, utilities should thrive to reduce uncertainties thrcugh procedural and/or low-
\ cost hardware modifications.
I N l il. 8 ;
l S lO l ProposedSwiss Approachfor ! Risk-Based Safety Decisions ! i~ - s .=g.p:: , ! - .mhr--. x _ m g i W ,- _, iO 4 i ! Future Power Reactors . . i Future power reactors proposed to conforrn to l criteria at the "95-th" percentile level of f
' exceedance frequency.
i a These reactors expected to circumvent I , severe accident uncertainties by design, achieving a much higher degree of safety. O 9 i
O Application to Existing Plants (Cont.) 1 E-03 , i i f f 1E-04 l E l IE454 I E 1E-00 l
' - KKL 4 1E 07 t -KKs f ! -KKM %*
{ . -Propi, sed Safety Cntena 3 { 1E-08 m -"- ^ ~ - "'- "- "- "- ' ' " - "- ~- - 1E-051E-041E-031E-021E 011 10 100 1000 100001E5 1E6 Cs-137 Equivalent Released to Environment (g) O Application to Existing Plants (Cont.) 1E43 1 1E44
-.g ,,, -
};j 1E46
'J 5 . -KKs-sw 1E47 : -KKs-95%
- a=KKs44ean m .
- Proposed Safety Cntere
~ ~ - ^ ^ ^ - "- " ' - ^ ^ - "'- - - - - ^ " - ^ " - -
1E48 1E45 1E44 1E43 1E 02 1E41 1E@ 1E41 1E +021E@ 1E *041E@ 1E@
% Cs-137 Emmvaient Roomsed to Erwronment (g) 74 O
10
, 7. - - --.
O I l ! Example ofProceduralModifications l l InfI vfddition ofwater to degrading core Inf2 ManualRCSdepressuri:ation Inf3 SG isolationfollowing SGTR Inf4 Addition offire water to damgedSG Inf5 Recovery ofcontainment isolation Off Caviyflooding hf2 Afanual venting hf3 Rewvery ofCHR Of4 Alanualalignment offire water to sprays Combined Combined efects O Im act o Procedures 1E43 , i 1E44 ! 1E45 1E46 r 1E47 j -MKB-95%(SAM) t : -KKB4Asan (SAM) l = Proposed Safety Critena
~ ~ ~ - - - '- " - - - -
1E46 1E45 1E 04 1E43 1E 02 1E41 1E+00 1E+01 1E+02 1E+031E+041E+05 1E+06 Cs-137 Emsvaant Reinased to Erwronment (g) O ri
l L i O1
SUMMARY
F-C curves can represent a common " risk metric" for all sources (and all modes of operation) a F-C curves should not be treated as " speed limits", but as' indicators for " safety I optimization" a Uncertainties cannot expected to be fully eliminated: however, use of safety criteria :
- shouldpromote ways in which uncertainties j are circumvented! l O'
Example 0.001 g Risknot acceptable
! 0.0001 AS j Riskacceptable
,,g, 2
after optimization
.N 0.000001
- 2. g i 1E47 Riskis negligible 8
0.1 1 10 100 1000 100I)0 1000001000000 f* Cs.137 (equivalent) rekased to environment (g)
#1 0
12}}