2004-09-21 Natural Aerosol Event Detection and Characterization
SIGNIFICANCE DETERMINATION PROCESSRisk Evaluation 1 ~Natural Event Natural Event August 23: 5.8...
22
International Atomic Energy Agency SIGNIFICANCE DETERMINATION PROCESS ~ RISK EVALUATION & SAFETY SIGNIFICANCE DETERMINATION IAEA Workshop Sft G l d IRIDM P Safety Goals and IRIDM Process November 11-15, 2013 See Meng Wong, PhD U.S. Nuclear Regulatory Commission [email protected]
Transcript of SIGNIFICANCE DETERMINATION PROCESSRisk Evaluation 1 ~Natural Event Natural Event August 23: 5.8...
Inte
rnat
iona
l Ato
mic
Ene
rgy
Age
ncy
SIG
NIF
ICA
NC
E D
ETER
MIN
ATIO
N P
RO
CES
S ~
RIS
K E
VALU
ATIO
N&
SA
FETY
SIG
NIF
ICA
NC
E D
ETER
MIN
ATIO
N
IAE
A W
orks
hop
Sf
tG
ld
IRID
MP
Saf
ety
Goa
ls a
nd IR
IDM
Pro
cess
Nov
embe
r 11-
15, 2
013
See
Men
g W
ong,
PhD
U.S
. Nuc
lear
Reg
ulat
ory
Com
mis
sion
See
-Men
g.W
ong@
nrc.
gov
Pre
sent
atio
nO
utlin
eP
rese
ntat
ion
Out
line
N
RC
sig
nific
ance
det
erm
inat
ion
proc
ess
gp
(SD
P) a
nd d
ecis
ion
crite
ria
R
isk
eval
uatio
n an
d sa
fety
sig
nific
ance
de
term
inat
ion
N
atur
al e
vent
Im
prop
er m
aint
enan
ce o
f Em
erge
ncy
Cor
e C
oolin
g S
yste
m (E
CC
S) r
ecirc
ulat
ion
line
valv
e(s)
2
Sig
nific
ance
Det
erm
inat
ion
Pro
cess
(SD
P)
~O
bjec
tives
Obj
ectiv
es
To
char
acte
rize
the
safe
tyor
secu
rity
sign
ifica
nce
ofTo
cha
ract
eriz
e th
e sa
fety
or s
ecur
ity s
igni
fican
ce o
f in
spec
tion
findi
ngs,
usi
ng b
est a
vaila
ble
risk
insi
ghts
as
appr
opria
te
To
pro
vide
all
stak
ehol
ders
an
obje
ctiv
e an
d co
mm
on
fram
ewor
k fo
r com
mun
icat
ing
the
pote
ntia
l saf
ety
or
iti
ififi
tifi
dise
curit
y si
gnifi
canc
e of
insp
ectio
n fin
ding
s
To
prov
ide
aba
sis
fort
imel
yas
sess
men
tand
/or
To p
rovi
de a
bas
is fo
r tim
ely
asse
ssm
ent a
nd/o
r en
forc
emen
t act
ions
ass
ocia
ted
with
insp
ectio
n fin
ding
s
3
Sig
nific
ance
Det
erm
inat
ion
Pro
cess
(SD
P)
~O
verv
iew
Ove
rvie
w
Dev
elop
insp
ectio
n fin
ding
s
“Gre
ater
than
min
or”f
indi
ng
Gre
ater
than
min
or fi
ndin
g
Iden
tify
perfo
rman
ce d
efic
ienc
y
C
hara
cter
ize
sign
ifica
nce
(initi
al s
taff
asse
ssm
ent)
S
cree
n to
Gre
en
Det
aile
d ris
k ev
alua
tion
usin
g S
PA
R m
odel
s
O
btai
nlic
ense
epe
rspe
ctiv
eson
risk
sign
ifica
nce
O
btai
n lic
ense
e pe
rspe
ctiv
es o
n ris
k si
gnifi
canc
e
Reg
ulat
ory
conf
eren
ce
Fi
naliz
est
aff’s
sign
ifica
nce
dete
rmin
atio
nFi
naliz
e st
affs
sig
nific
ance
det
erm
inat
ion
Is
sue
final
det
erm
inat
ion
lette
rP
idl
tit
4
P
rovi
de a
ppea
l opp
ortu
nity
Sig
nific
ance
Det
erm
inat
ion
Pro
cess
(SD
P)
~C
riter
iafo
rMak
ing
Dec
isio
n C
riter
ia fo
r Mak
ing
Dec
isio
n
D
ecis
ion
crite
ria
Cha
nge
in:
•C
ore
dam
age
f
ΔCD
F <
1x10
-6
frequ
ency
•La
rge
early
re
leas
e fre
quen
cy
1X10
-6≤
ΔC
DF
< 1X
10-5
1X10
5Δ
CD
F1X
104
qy
B
road
rang
es1X
10-5≤
ΔC
DF
< 1X
10-4
4ΔC
DF ≥
1x1
0-4
5
Ris
k E
valu
atio
n 1
~N
atur
alE
vent
Nat
ural
Eve
nt
A
ugus
t 23:
5.8
Mag
nitu
de (1
1 m
iles)
at s
hallo
w d
epth
R
eact
or tr
ip &
LO
OP.
All
four
ED
Gs
(1H
, 1J
& 2
H, 2
J) s
tart/
load
ed
Coo
lant
leak
obs
erve
d on
Uni
t 2 E
DG
“2H
”, S
BO
ED
G s
tart/
load
ed
6
A
fter i
dent
ifyin
g le
ak, E
DG
2H
was
repa
ired
and
mad
e av
aila
ble
(6 h
rs)
Ris
k E
valu
atio
n 1
~Fa
ilure
due
toN
atur
alE
vent
Fai
lure
due
to N
atur
al E
vent
Fairb
anks
Mor
seD
iese
lGen
erat
ors
Die
sel G
ener
ator
s (M
odel
38T
D8-
1/8)
Ris
k E
valu
atio
n 1
~R
ootC
ause
Roo
t Cau
se
Roo
t cau
se e
valu
atio
n on
ED
G g
aske
ts fo
und
evid
ence
of:
ga
sket
toga
sket
inco
nsis
tenc
ies
inco
mpr
essi
on
gask
et to
gas
ket i
ncon
sist
enci
es in
com
pres
sion
clea
r ind
icat
ions
that
faile
d ga
sket
had
bee
n in
the
proc
ess
of
mov
ing
tow
ard
failu
re fo
r som
e tim
e
fil
tlik
ld
ti
itili
tll
tibl
ldi
t
failu
re m
ost l
ikel
ydu
e to
initi
al in
stal
latio
n pr
oble
ms
lead
ing
to
mov
emen
t ove
r tim
e
8
Ris
k E
valu
atio
n 1
~P
erfo
rman
ceD
efic
ienc
y P
erfo
rman
ce D
efic
ienc
y
Sel
f-rev
ealin
g, A
ppar
ent V
iola
tion
(AV
): fa
ilure
to e
stab
lish
and
mai
ntai
nE
DG
mai
nten
ance
proc
edur
esas
requ
ired
byan
d m
aint
ain
ED
G m
aint
enan
ce p
roce
dure
s as
requ
ired
by
Reg
ulat
ory
Gui
de 1
.33,
App
endi
x A
, Sec
tion
9, P
roce
dure
s fo
r Per
form
ing
Mai
nten
ance
C
ontra
ry to
the
abov
e, fr
om J
une
2, 2
010
until
Aug
ust 2
3,
2011
the
licen
see
faile
dto
esta
blis
han
dm
aint
ain
adeq
uate
2011
, the
lice
nsee
faile
d to
est
ablis
h an
d m
aint
ain
adeq
uate
E
DG
mai
nten
ance
pro
cedu
res
P
roce
dure
did
not
pro
vide
ade
quat
e gu
idan
ce fo
r ins
talla
tion
of th
e ga
sket
whi
ch re
sulte
d in
the
failu
re o
f ED
G 2
H to
pe
rform
itssa
fety
func
tion
onA
ugus
t23
2011
9
perfo
rm it
s sa
fety
func
tion
on A
ugus
t 23,
201
1
Ris
k E
valu
atio
n 1
~E
xpos
ure
Tim
e E
xpos
ure
Tim
e24
10 M
ON
THS
1520
hours)
1015
Time (h
RA
SP H
AN
DB
OO
K, S
ec. 2
.4,
Com
pone
nt R
un F
ailu
res,
Σ(ru
n tim
es) >
PR
A m
issi
on ti
me
(24
hour
s)
192
188
5
Run
1.57
1.77
1.63
1.53
1.92
1.62
1.57
1.88
1.65
1.68
1.72
0.82
0
10
Ris
k E
valu
atio
n 1
~In
fluen
cing
Ass
umpt
ions
Influ
enci
ng A
ssum
ptio
ns
Li
cens
ee
NR
C
Exp
osur
e Ti
me
•28
day
sba
sed
on ro
ot c
ause
ev
alua
tion
findi
ngs
E
xpos
ure
Tim
e•
10 m
onth
s ba
sed
on ro
ot
caus
e ev
alua
tion
findi
ngs
C
omm
on C
ause
Fai
lure
•S
houl
d be
trea
ted
as
inde
pend
ent f
ailu
rew
ith
nom
inal
com
mon
cau
se
C
omm
on C
ause
Fai
lure
•S
houl
d be
trea
ted
as a
failu
re
with
pot
entia
l for
com
mon
ca
use
to o
ther
ED
Gs
C
redi
t for
var
ious
pr
obab
ilitie
s•
Add
ition
al c
redi
t for
ope
rato
r ti
C
redi
t for
var
ious
pr
obab
ilitie
s•
Lim
ited
addi
tiona
l cre
dit f
or
tti
actio
ns•
Low
er v
alue
s fo
r com
pone
nt
prob
abilit
ies
& c
omm
on c
ause
•A
dditi
onal
cre
dit f
or re
cove
ry
oper
ator
act
ions
•Lo
wer
val
ues
for c
ompo
nent
pr
obab
ilitie
s &
com
mon
cau
se
not j
ustif
ied
11
curv
es•
Add
ition
al c
redi
t for
reco
very
cu
rves
doe
s no
t affe
ct re
sults
Ris
k E
valu
atio
n 1
~O
utco
me
Out
com
e
Fina
l SD
P C
olor
W
hit
(Uit
1)&
Whi
t(U
it2)
i“l
t
Whi
te (U
nit1
) & W
hite
(Uni
t 2),
i.e.,
“low
to
mod
erat
e” s
afet
y si
gnifi
canc
e (in
tern
al a
nd e
xter
nal
even
ts)
Fa
ctor
s
Exp
osur
e Ti
me
& C
omm
on C
ause
Fai
lure
Pot
entia
l
Mul
tiple
redu
ndan
t sou
rces
of e
mer
genc
y A
C
pow
er
12
Ris
k E
valu
atio
n 2
~In
spec
tion
Find
ing
Insp
ectio
n Fi
ndin
g
Im
prop
er m
aint
enan
ce o
f EC
CS
reci
rcul
atio
n p
plin
e va
lve(
s)
Key
PS
A/S
DP
asp
ects
•Im
porta
nce
of v
alve
in d
iffer
ent L
OC
A s
cena
rios
•P
oten
tial f
or c
omm
on c
ause
failu
re o
f red
unda
nt
lva
lve
•P
oten
tial f
or h
uman
act
ion
to o
pen
valv
e
13
Ris
k E
valu
atio
n 2
~E
CC
Sre
circ
ulat
ion
line
valv
efa
ilsto
open
EC
CS
reci
rcul
atio
n lin
e va
lve
fails
to o
pen
Valv
e B
fails
to
open
due
to
wat
erin
trusi
onin
EC
CS
trai
n B
in
oper
able
Wha
t eve
nts
will
requ
ire V
alve
A o
r B
to fu
nctio
n?w
ater
intru
sion
in
valv
e op
erat
or
p
Can
Val
ve B
be
open
edin
time
if
How
like
ly a
re th
e op
erat
ors
to o
pen
How
like
ly a
re
thes
e ev
ents
?op
ened
in ti
me,
if
need
ed?
Valv
e B?
Will
Valv
e A
func
tion
How
like
ly is
Val
ve A
14
if ne
eded
?y
to fa
il du
e to
a
com
mon
cau
se?
How
like
ly is
Val
ve A
to
fail?
Ris
k E
valu
atio
n 2a
~E
CC
Sre
circ
ulat
ion
line
valv
efa
ilsto
open
EC
CS
reci
rcul
atio
n lin
e va
lve
fails
to o
pen
Valv
e B
fails
to
open
due
to
wat
erin
trusi
onin
EC
CS
trai
n B
in
oper
able
wat
er in
trusi
on in
va
lve
oper
ator
p
How
like
ly is
Val
ve A
W
ater
intru
sion
als
o
15
yto
fail
due
to a
co
mm
on c
ause
?fo
und
in V
alve
A
oper
ator
Ris
k E
valu
atio
n 2a
~In
fluen
cing
Ass
umpt
ions
Influ
enci
ng A
ssum
ptio
ns
Li
cens
ee
NR
C
Low
hea
d sa
fety
inje
ctio
n pu
mp
wou
ld•
be s
tarte
d w
ith V
alve
B
Lo
w h
ead
safe
ty in
ject
ion
pum
p w
ould
•no
t be
star
ted
with
Val
ve B
in
dica
ting
dua
l pos
ition
Va
lve
B h
as a
mod
erat
epr
obab
ility
of b
eing
re
stor
ed
indi
catin
g du
al p
ositi
on
V
alve
B h
as a
low
prob
abili
ty o
f bei
ng
rest
ored
rest
ored
•su
cces
s pr
obab
ility
of lo
cal
man
ual a
ctio
ns
Va
lve
A ha
s
rest
ored
•su
cces
s pr
obab
ility
of lo
cal
man
ual a
ctio
ns
V
alve
A h
as•
low
rand
om fa
ilure
pro
babi
lity
•no
incr
ease
d pr
obab
ility
of
com
mon
cau
se fa
ilure
•lo
w ra
ndom
failu
re p
roba
bilit
y•
incr
ease
d pr
obab
ility
of
com
mon
cau
se fa
ilure
16
Ris
k E
valu
atio
n 2a
~O
utco
me
Out
com
e
Fina
l SD
P C
olor
S
ubst
antiv
e sa
fety
sig
nific
ance
Y
ello
w
In
fluen
cing
Fac
tors
Ti
me
fram
efo
rreq
uire
dop
erat
ion
Ti
me
fram
e fo
r req
uire
d op
erat
ion
Lo
w re
cove
ry p
roba
bilit
y of
firs
t val
ve
Com
mon
cau
se fa
ilure
pro
babi
lity
of s
econ
d va
lve
Co
oca
use
au
ep
obab
yo
seco
da
e
17
Ris
k E
valu
atio
n 2b
~E
CC
Sre
circ
ulat
ion
line
valv
efa
ilsto
open
EC
CS
reci
rcul
atio
n lin
e va
lve
fails
to o
pen
Valv
e B
fails
to
open
due
to
wat
erin
trusi
onin
EC
CS
trai
n B
in
oper
able
wat
er in
trusi
on in
va
lve
oper
ator
p
How
like
ly a
re th
e op
erat
ors
to o
pen
Man
ual o
peni
ng
requ
ires
exte
nsiv
e w
ork
Valv
e B?
How
like
ly is
Val
ve A
N
o w
ater
intru
sion
18
yto
fail
due
to a
co
mm
on c
ause
?fo
und
in V
alve
B
oper
ator
Ris
k E
valu
atio
n 2b
~In
fluen
cing
Ass
umpt
ions
Influ
enci
ng A
ssum
ptio
ns
Li
cens
ee
NR
C
Rec
over
y fo
r ope
ratio
n of
Va
lve
A an
d B
for M
ediu
m
LOC
As
shou
ld b
e cr
edite
d
N
o re
cove
ryfo
r ope
ratio
n of
Val
ve A
or B
Med
ium
LO
CA
s sh
ould
be
cred
ited
•A
dequ
ate
time
is a
vaila
ble
to
perfo
rm re
cove
ry a
ctio
ns
Va
lve
B h
as a
mod
erat
epr
obab
ility
ofbe
ing
•A
dequ
ate
time
is n
ot a
vaila
ble
to p
erfo
rm re
cove
ry a
ctio
ns
V
alve
B h
as a
low
prob
abilit
yof
bein
gpr
obab
ility
of b
eing
re
stor
ed•
succ
ess
prob
abilit
y of
loca
l m
anua
l act
ions
prob
abili
ty o
f bei
ng
rest
ored
•su
cces
s pr
obab
ility
of lo
cal
man
ual a
ctio
ns
Va
lve
A ha
s•
low
rand
om fa
ilure
pro
babi
lity
•no
incr
ease
d pr
obab
ility
of
com
mon
caus
efa
ilure
V
alve
A h
as•
rand
om fa
ilure
pro
babi
lity
•in
crea
sed
prob
abilit
y of
co
mm
onca
use
failu
re
19
com
mon
cau
se fa
ilure
com
mon
cau
se fa
ilure
Ris
k E
valu
atio
n 2b
~O
utco
me
Out
com
e
Fi
nal S
DP
Col
or
Low
to m
oder
ate
safe
ty s
igni
fican
ce
Whi
te
In
fluen
cing
Fac
tors
Ti
me
fram
e fo
r req
uire
d op
erat
ion
(tim
ing
of R
WS
T dr
ain
(g
dow
n an
d de
plet
ion)
Lo
w re
cove
ry p
roba
bilit
y of
firs
t val
ve
Mod
erat
e co
mm
on c
ause
failu
re p
roba
bilit
y of
sec
ond
valv
e
20
Con
clus
ions
Th
eS
DP
resu
ltpr
ovid
esa
supp
orta
ble
basi
sfo
rTh
e S
DP
resu
lt pr
ovid
es a
sup
porta
ble
basi
s fo
r m
akin
g a
high
qua
lity
risk-
info
rmed
dec
isio
n fo
r ap
prop
riate
regu
lato
ry re
spon
se to
iden
tifie
d lic
ense
e pe
rform
ance
def
icie
ncie
s
SD
P ev
alua
tions
illu
stra
te th
e im
porta
nce
of
pha
ving
real
istic
, up
to d
ate
qual
ity P
SA
s
21
The
End
Que
stio
ns &
Ans
wer
s…..
22
