ineerin overview of spent fuel pool neutron absorbing

12
Overview of Spent Fuel Pool Neutron Absorbing Material Degradation Emma Wong Nuclear Reactor Regulation/Division of Engineering Steam Generator Tube Integrity and Chemical Engineering Branch Public Meeting on Neutron Absorbing Material Degradation 1 Public Meeting on Neutron Absorbing Material Degradation October 4, 2012

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Page 1: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Ove

rvie

w o

f Spe

nt F

uel P

ool

Neu

tron

Abs

orbi

ng M

ater

ial D

egra

datio

n

Em

ma

Won

gN

ucle

ar R

eact

or R

egul

atio

n/D

ivis

ion

of E

ngin

eerin

gg

gg

Ste

am G

ener

ator

Tub

e In

tegr

ity a

nd C

hem

ical

Eng

inee

ring

Bra

nch

Pub

licM

eetin

gon

Neu

tron

Abs

orbi

ngM

ater

ialD

egra

datio

n

1

Pub

lic M

eetin

g on

Neu

tron

Abs

orbi

ng M

ater

ial D

egra

datio

n

Oct

ober

4, 2

012

Page 2: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Ove

rvie

w

•S

afet

y S

igni

fican

ce•

Mat

eria

l Typ

es•

His

toric

al Is

sues

•R

ecen

t Eve

nts

•S

taff

Obs

erva

tions

•S

taff

Obs

erva

tions

•N

RC

Que

stio

ns•

NR

C A

ctio

ns•

Kno

wle

dge

Bas

e

2

g•

Sur

veilla

nce

Met

hodo

logi

es

Pic

ture

: Spe

nt F

uel P

ool

Page 3: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Safe

ty S

igni

fican

ce

•P

reve

nt th

e oc

curre

nce

of a

ny in

adve

rtent

cr

itica

lity

even

tsin

the

SFP

criti

calit

y ev

ents

in th

e S

FP•

Neu

tron

abso

rbin

g m

ater

ials

hav

e a

dire

ct

impa

cton

safe

tyim

pact

on

safe

ty

–U

nide

ntifi

ed a

nd u

nmiti

gate

d de

grad

atio

n po

ses

acr

itica

lity

and

safe

tyco

ncer

na

criti

calit

y an

d sa

fety

con

cern

–C

halle

nges

com

plia

nce

with

NR

C s

ubcr

itica

lity

requ

irem

ents

: 10

CFR

50.

68 a

nd G

DC

62

•N

RC

sta

ff ha

s id

entif

ied

this

issu

e as

po

tent

ially

saf

ety

sign

ifica

nt

3

Page 4: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Mat

eria

l Typ

es

•M

ost p

opul

ar a

t US

pla

nts

Al

iB

Cbi

dC

t–

Alu

min

um B

oron

Car

bide

Cer

met

•B

OR

AL®

–N

on-m

etal

Mat

rixC

ompo

site

s–

Non

-met

al M

atrix

Com

posi

tes

•B

oraf

lex

•C

arbo

rund

um–

Met

al M

atrix

Com

posi

tes

•M

ETA

MIC

®

•N

ew M

etal

Mat

rix C

ompo

site

s–

Bor

tec®

4

–A

lcan

Com

posi

teP

ictu

res:

BO

RA

L® c

ross

-sec

tion

and

Bor

tec®

mic

rogr

aph

EP

RI R

epor

t TR

1013

721

Page 5: ineerin Overview of Spent Fuel Pool Neutron Absorbing

His

toric

al Is

sues

•B

oraf

lex

(197

0s-1

980s

)–

Sili

ca p

olym

er m

atrix

deg

rada

tion

–IN

s: 8

7-43

, 93-

70, 9

5-38

GL

96-0

4: M

aint

ain

5% m

argi

n

•B

OR

AL®

(198

0’s)

–B

liste

ring

& b

ulgi

ngg

gg

–IN

83-

29

5P

ictu

res:

In-s

ervi

ce s

hrin

kage

and

Bor

afle

x re

mov

ed fr

om S

pent

Fue

l Rac

ks a

nd B

oral

Blis

terin

gE

PR

I Rep

ort T

R10

1372

1

Page 6: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Rec

ent E

vent

s•

Car

boru

ndum

, Pal

isad

es 2

008

–S

tuck

fuel

asse

mbl

ies

Stu

ck fu

el a

ssem

blie

s–

BA

DG

ER

test

ing

foun

d up

to

70%

degr

adat

ion

EP

RI R

epor

t TR

1013

721

to 7

0% d

egra

datio

n

•B

OR

AL®

Blis

terin

g–

Blis

terin

g•

Sea

broo

k 20

03•

Bea

verV

alle

y20

07B

eave

r Val

ley

2007

•TM

I 200

8–

Bul

ging

6

ug

g•

Sus

queh

anna

200

9P

ictu

re: C

arbo

rund

um m

icro

phot

ogra

ph a

nd e

xam

ple

of B

oral

blis

ter a

nd b

ulge

Page 7: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Rec

ent E

vent

s (c

on’t)

•B

oraf

lex

–Tu

rkey

Poi

ntU

nit3

2010

Turk

ey P

oint

Uni

t 3, 2

010

•A

real

den

sity

was

less

than

the

licen

sing

bas

is•

Inef

fect

ive

impl

emen

tatio

n of

cor

rect

ive

actio

nsp

•In

effe

ctiv

e in

iden

tifyi

ng a

nd m

itiga

ting

degr

adat

ion

–P

each

Bot

tom

Uni

t 2, 2

010

•P

anel

s de

grad

ed b

elow

the

TS re

quire

men

ts•

Inef

fect

ive

impl

emen

tatio

n of

cor

rect

ive

actio

ns•

Mon

itorin

g an

d m

itiga

ting

the

degr

adat

ion

not a

dequ

ate

–IN

12-

13

7

Page 8: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Staf

f Obs

erva

tions

–S

urve

illanc

e pr

ogra

m im

porta

nt to

det

ect

onse

tofd

egra

datio

non

set o

f deg

rada

tion

–E

ffect

iven

ess

of s

urve

illanc

e m

onito

ring

prog

ram

sim

pact

man

agem

ento

fthe

SFP

prog

ram

s im

pact

man

agem

ent o

f the

SFP

–E

ffect

ive

oper

atin

g ex

perie

nce

eval

uatio

n ca

n l

dt

lid

tifi

tile

ad to

ear

ly id

entif

icat

ion

–U

nkno

wn

degr

adat

ion

mec

hani

sms

and

rate

s co

uld

resu

lt in

redu

ced

subc

ritic

ality

mar

gins

.

8

Page 9: ineerin Overview of Spent Fuel Pool Neutron Absorbing

NR

C Q

uest

ions

•M

ater

ials

in e

ach

SFP

and

mon

itorin

g m

etho

d•

Mon

itorin

g an

d m

itiga

ting

the

mat

eria

l de

grad

atio

n•

Deg

ree

of a

ccur

acy

of in

-situ

neu

tron

atte

nuat

ion

mea

sure

men

ts•

Sur

veilla

nce

inte

rval

s to

mon

itor d

egra

datio

n•

Mat

eria

ldeg

rada

tion

affe

cton

the

criti

calit

y•

Mat

eria

l deg

rada

tion

affe

ct o

n th

e cr

itica

lity

anal

ysis

9

Page 10: ineerin Overview of Spent Fuel Pool Neutron Absorbing

NR

C A

ctio

ns•

IN 0

9-26

, LR

-ISG

200

9-01

, upd

ate

to G

ALL

(N

UR

EG

1801

Rev

2)an

dIN

12-1

3(N

UR

EG

180

1 R

ev 2

), an

d IN

12-

13•

NR

C e

valu

atin

g m

ater

ial d

egra

datio

n m

echa

nism

ssu

rvei

llanc

ete

chni

ques

and

mec

hani

sms,

sur

veilla

nce

tech

niqu

es, a

nd

pred

ictiv

e m

odel

ing

Lit

tk

ld

b–

Lite

ratu

re k

now

ledg

e ba

se–

Con

firm

ator

y re

sear

ch o

n th

e su

rvei

llanc

e th

dl

met

hodo

logy

–C

onfir

mat

ory

rese

arch

on

the

surv

eilla

nce

inte

rval

ad

equa

cy

10

adeq

uacy

Page 11: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Kno

wle

dge

Bas

e•

Cur

rent

NR

C s

tate

of k

now

ledg

eC

omm

erci

alan

dde

com

mis

sion

edS

FPs

–C

omm

erci

al a

nd d

ecom

mis

sion

ed S

FPs

–Li

sts

mat

eria

ls in

eac

h S

FPP

idi

lld

td

–P

erio

dica

lly u

pdat

ed•

Issu

ed p

ublic

–Te

chni

cal L

ette

r Rep

ort:

ML1

1355

0241

–S

prea

dshe

et: M

L121

0905

00

11

Page 12: ineerin Overview of Spent Fuel Pool Neutron Absorbing

Surv

eilla

nce

Met

hodo

logi

es•

Bor

afle

x m

etho

dolo

gies

(pre

dict

ive

code

and

in-

situ

met

hod)

exam

ined

situ

met

hod)

exa

min

ed•

Rep

orts

pub

lishe

dTL

RB

flR

AC

KLI

FEd

BA

DG

ER

–TL

R o

n B

oraf

lex,

RA

CK

LIFE

, and

BA

DG

ER

m

etho

dolo

gies

: ML1

2216

A30

7TL

RB

AD

GE

Rt

lM

L122

54A

064

–TL

R o

n B

AD

GE

R to

ol: M

L122

54A

064

•B

AD

GE

R re

port

perta

ins

to a

ll ne

utro

n b

bii

lab

sorb

ing

mat

eria

ls

12