POND CONFERENCE THE COAL IN UP LESSONS CLOSING · WBF NPDES modified permit No. TN0005461 TVA Dam...
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CLOSING UP SHOP AT THE WATTS BAR FOSSIL PLANT LESSONS IN COAL ASH POND CLOSURE 2015 WORLD OF COAL ASH CONFERENCE Presenters: Jimmy Mullins (TVA) David Mason (CDM Smith) May 6, 2015
Transcript of POND CONFERENCE THE COAL IN UP LESSONS CLOSING · WBF NPDES modified permit No. TN0005461 TVA Dam...
CLOSING UP SH
OP AT
THE
WATTS BAR
FOSSIL
PLAN
T LESSONS IN COAL
ASH
POND CLOSU
RE20
15 W
ORLD OF CO
AL ASH
CONFERE
NCE
Presenters:
Jimmy Mullins (TVA)
David Mason
(CDM
Smith
)May 6, 2015
2015
Wo
rld
of
Co
al A
sh (
WO
CA
) C
on
fere
nce
in N
asvh
ille,
TN
- M
ay 5
-7, 2
015
htt
p:/
/ww
w.f
lyas
h.in
fo/
Presentatio
n Outline
•Introd
uctio
n and Ba
ckgrou
nd•
Regulatory Initiatives
•De
sign Process
•Co
nstructio
n/Im
plem
entatio
n•
Desig
n/Co
nstructio
n Ch
allenges
•Co
nclusio
ns and
Lessons Learned
Project B
ackgroun
d
•Watts Bar Fossil Plant near
Sprin
g City, TN
•Co
nstructed in th
e 19
40’s
•Ce
ased
pow
er produ
ction
in 198
2•
Closure of slag and
chem
ical pon
d areas in
2007
•Plant d
emolition
in 201
2
Regulatory Initiatives
•US EPA’s o
ngoing
effo
rts to assess
the managem
ent o
f coal com
bustion
resid
uals
–Po
or ra
ting du
e to lack of information
and po
tential threat for enviro
nmen
tal
damage
•Ash/Stilling Po
nd Area Outfall 00
2 falls und
er th
e WBF
NPD
ES m
odified
pe
rmit No. TN0005461
•TVA Da
m Safety Program fo
llows the
fede
ral dam
safety program
of the
Fede
ral Emergency Managem
ent
Agen
cy (FEM
A).
Prim
ary Objectives fo
r the
Ash Pon
d Closure Project
1.Re
place the existing
spillway;
2.Re
move all ash from
the
stilling po
nd;
3.Cap and close the existing
ash storage area; and
4.Ad
dress E
PA com
ments
related to th
e containm
ent
dike.
North Pon
d
South Po
nd
Dry Ash Area
Nuclear
Security
Barriers
Regulated
NPD
ES
Outfall
Existing
Riser
Structures
Security
Access
Road
Splitter
Dike
Existing Conditions & Site Features
Perim
eter
Containm
ent
Berm
Dewatering and Ash Re
moval Process
Metho
d to Verify
Ash Rem
oval
•Clearance of ash dow
n to so
il sub
base across a
pproximately on
e acre
of area
•Layout 40’ x 40’ grid
•Placem
ent o
f 1’ x 1’ tem
plate on
each flag
•Visual che
ck th
at no greater than
10% of the
area can be
con
sidered
ash
•Ph
oto do
cumentatio
n & GPS
De‐m
ucking
and
Ash Rem
oval Process (con
tinue
d)
Verification of Ash Rem
oval
Existing Co
rrugated
Metal, R
iser S
pillw
ays
Final Spillw
ay Design
Constructio
n of
Containm
ent B
erm fo
r Ash Storage
•Clear a
sh from
footprint o
f be
rm area
•Co
nstruct u
sing select fill in
8” lifts w
ith 95%
compaction
Constructio
n of th
e Ash Stack
•Cle
Constructio
n of th
e Ash Stack
Additio
nal Prep Prior to Line
r Dep
loym
ent
Und
ercut/Re
pair Ditch Subgrade
Kiln Dust A
pplication
Cap De
sign
SOD
Line
r Dep
loym
ent a
nd Cap
Con
struction
Line
r Dep
loym
ent
Protectiv
e Co
ver
Sod Placem
ent
Drainage Net
Desig
n/Co
nstructio
n Ch
allenges
•Co
ordinatio
n with
Watts Bar Nuclear
•On‐going, NPD
ES water quality mon
itorin
g requ
irements
•Archeo
logical &
sensitive habita
t areas
•Transm
ission lines and
structures
•Summer/W
inter P
ool
Accommod
ating Security Proced
ures Throu
ghou
t the Project
•Po
nd acts a
s a natural
vehicle barrier a
nd is
includ
ed in
the security
plan
for the
site
•Security patrols the
pe
rimeter every 30
minutes
•Im
peding
security was non
‐ne
gotia
ble
Construct N
ew Nuclear Barrie
r with
“King
Tuts”
Water Quality Treatm
ent D
uring De
watering Process
Addressin
g Sensitive Cultural and
Habita
t Areas
Bat h
abita
t
Major Transmission Line
s Throu
gh th
e Site
Transm
ission Line
Clearance/Avoidance
Test Pits to
Verify
Ash De
pth
Excavatio
n De
signe
d to M
eet S
tructural
Foun
datio
n Re
quire
men
ts
Dealing with
Varying
Sum
mer and
Winter P
ool
Elevations
•River/Lake is ope
rated at
vario
us levels based on
season
s•
Need to design a controlled
discharge to river a
nd prevent
erosion
•Limita
tions on fill w
ithin
Waters o
f the
State
Summer Poo
l: El 682
Winter P
ool: El 675
Spillway and
Ene
rgy Dissipation De
sign &
Constructio
n Co
nsiderations
•Re
quire
d a ph
ased
con
struction
sequ
ence dep
ending
on season
Riprap
Placemen
t via Barge
Final Site
Con
ditio
ns
Conclusio
ns and
Lessons Learned
•What C
an Go Wrong
Will Go Wrong
•Plan
Ahe
ad if a Fast Track Design is An
ticipated
•Perform Site
Investigations W
ell A
head
of D
esign Ph
ase
(cultural, environm
ental, etc)
•Interdisc
iplinary Co
ordinatio
n is Vital
•Ensure That You
Have Bu
y‐In On Im
portant D
ecision
s
Wrap‐up
& Que
stions
Wrap‐up
& Que
stions
