ML20196E179
| ML20196E179 | |
| Person / Time | |
|---|---|
| Issue date: | 11/09/1988 |
| From: | NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | |
| Shared Package | |
| ML20196E137 | List: |
| References | |
| FOIA-99-50, TASK-AE, TASK-T811 AEOD-T811, NUDOCS 9812030058 | |
| Download: ML20196E179 (8) | |
Text
- . - - .
l .
AE0D TECHNICAL REVIEW REPORT UNITS: Ice Condenser Containment PWRs TR REPORT NO.: AE0D/T811 DOCKET NO.: Various DATE: Various
! LICENSEE: Various EVALUATOR / CONTACT: F. M. Manning NSSS/AE: Westinghouse /Various l
l
SUBJECT:
DEGRADATION OF ICE CONDENSER CONTAINMENT l FUNCTIONAL CAPABILITY
SUMMARY
There have been numerous incidents of ice condenser degradations or problems at plants having this type of containment. These degradations (refer to LERs shown in attached table 1) impact Tech. Spec. operational requirements. They have included excessive ice or frost buildup affecting the ability of ice I condenser bay doors to open, and ice buildup on lattice passageways with !
consequent expected reduction of steam flow through the ice bed given a LOCA (
or steam line break accident. This flow reduction would thereby affect the i containment pressure mitigation function. Another potential problem concerns j the reduction, by sublimation, of required ice quantity. There are eight i operating ice condenser plants as shown below, and they have exhibited different i susceptibilities to these problem over time.
Initial Number of LERs Plant Utility Criticality Reporting Problems Cook 1 Ind & Mich Elect 1/18/75 26 Cook 2 Ind & Mich Elect 3/10/78 15 Sequoyah 1 TVA 7/5/80 14 Sequoyah 2 TVA 11/5/81 7 McGuire 1 Duke Power Co 8/8/81 4 McGuire 2 Duke Power Co 5/8/83 0 Catawba 1 Duke Power Co 1/7/85 3 Catawba 2 Duke Power Co 5/8/86 1 Total 70 4
INTRODUCTION This study is limited to only a few specific types of ice condenser failures or degradations. Only those ice condenser system degradations or failures involving ice compartment door freezing or sticking, ice basket mass loss from sublimation, excessive passageway or lattice icing, or administrative failures leading to these types of problems are included. All other failures or failure modes of the rassure suppression function including circulating fans, contain-ment sprays, rue test or surveillance intervals, personnel errors concerning ice bay door com 4 tion, or loss or degradation of the glycol cooling systems are excluded. The study consider LERs, submitted by the 8 plants after their initial criticality, and which were in the LER file as of the search date of October 15, 1988.
9812030058 981130 PDR F0EA O'MEALIA99-50 PDR
' 99'/Z 03 0 0 S T
DISCUSSION The cause breakdown for the LERs of Table 1 gives some indication of the factors effecting ice condenser functionability-Degraded or Excessive Ice Nass Administrative Inoperable Flow Passage Loss by- Design / Testing /etc. '
Plant Ice Bay Doors Icing Sublimation Problems Cook 1 18 5 3 Cook 2 6 4 5 i Sequoyah 1 11 2 1 l
Sequoyah 2 4 2 1 )
McGuire 1 1 2 1 )
Catawba 1 3 l Catawba 2 1 Ice condenser failures or degradations are generally not immediately discernable insofar as ice condenser function is concerned. That is, these ice condenser failures or degradations of and by themselves do not generally initiate any kind of plant alarm. The ice condenser degradations are generally not an immediate :
problem, unless the degradations occurred or co-existed with a LOCA. However i operating events or accidents potentially requiring the containment / pressure mitigation function have in the past occurred at various nuclear plants and some have been estimated to have had relatively high core damage likelihood. If these same events had occurred in a failed or degraded ice condenser containment, the intended reduction or mitigation of radiologicai e4:asas could be impacted.
One of the problems which frequently occurred during the Nst 5 ynn + 7 operation of this type of containment concerned icing or s& kino d che ice compartment bay doors. This icing and sticking of ice condenser doors would require increased pressure for the doors to open given a LOCA - if they were operable at all. The door freezing or sticking problems were fairly repetitious at the Cook and Sequoyah plant units during their first five years of operation.
We understand that the D. C. Cook units are now checking for icing of the ice compartment doors on a daily basis. The other (and more current) types of problems pertain to all eight ice condenser plants and involve either deficient ice basket weight or excessive icing and ice buildup on the lattice structure.
The last problem types are administrative and primarily relate to design and testing.
One of the more serious events was the Sequoyah 2 event of 1/19/88 (LER 328/88-003) when manual chipping and scraping was followed by a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> defrost .
cycle but the plant still didn't meet Tech. Spec. requirements on maximum allowable ice buildup. While excess icing on steam passageways provides a lar heat sink, some concerns are that flow passageway icing may, given a LOCA, (a)ger allow preferential pathways for steam flow and possibly less effective steam quenching, and (b) cause a higher than intended containment back pressure due to restrictions of steam flow through the ice beds.
Several of the ice condenser related LERs reference analytical studies that had been undertaken by Westinghouse after the event and these studies indicated that the ability of the ice condenser to perform its function would not be
impaired even with up to approximately 15% to 20% of the weirs iced beyond specification. Also, there is some tradeoff between the ice required (or available) and the start time and flow rates of the containment spray to successfully perform the containment steam quenching / pressure reduction function to limit containment pressurization given a large LOCA or steam line break in containment.
The ice condenser problem categories are shown as a function of time in Figure 1.
It appears that ice condenser door problems (sticking, requiring too much prn-sure to open, etc) occurred mainly during the first five years or so of operation of the Cook and Sequoyah units. This might be expected since ths.
were the lead plants utilizing the ice condenser containment concept. This figure indicates that after an initial operating period, the majority of problems concerned loss by sublimation of ice condenser basket ice or excessive icing of weirs or lattices. Figure 1 indicates that the incidence rate for ice con-denser problems is lower now than in the past, and that all plants are now having problems with the ice condensers at roughly the same rate.
The requirements for reporting were changed by the new LER reporting rule which became effective January 1, 1984. Under this revised rule, some previously reportable events involving ice condenser containment degradations may not be reportable. The sharp break in Figure I for failures in 1984 and subsequent years are thought to be at least partially attributable to this new rule.
Furthermore, several of the more recent LERs are classified as voluntary, hence, the consistency of reporting may also have been reduced after 1984.
CONCLUSIONS The verification of some ice condenser functions are required by Technical Specifications to be made on a 9-month interval. Therefore, the ice condenser function may be degraded and remains undetected for a number of months.
Some of the more serious degradations were those involving ice condenser door freeze-ups, mainly due to leaking or dripping from air handler units. Even though the Figure 1 data indicates that the number of events involving containment functional degradations has decreased substantially, it isn't eartain what fraction of the reduction is due to changed reporting. Hence, it h felt the ice cendenser containment plants should keep alert to these operational events involving functional degradations, and AE0D will continue to follow the trending of these events.
S -
. U -
A C,
T O
. O R D D D D D D D D D D W D D D D D D W B
. )
e e r c -
u n -
l e i r a r f u d . c r . e d c o d d r . n t o -
o e e a s o i
n -
d e t e n t r s l a b u s -
f f u c e r r -
o j e g e i l r d e b v n t f -
s a o a n e i
s i a ( -
o n o i t e l e -
t o s d h .
t d l a h n p i t l d a o t & l n u a t u b a o i s h s d -
r y b a n o o l t e a r r i a p w r i t i e f u n D a e s o a o o e l
b d b
u i . t n a .
w o d s e d r e
e d t e n n d i
e d c -
r e p e e s e i c n d p t i
d w p l s n e l e
t r o o i . o -
a n i
g t o l a A t r
h n t i o t f s f 7 t l
a l c n i s s d e r r - e e p u i a e b k e o o 3 u t
e t e r r u u d s v o k
s n e c p d q s n a o s
. t a
d e o r I S e u d
n e t
i r e o b i b e t t s . .
t g
/ & d o u n / g e c r r n i
e r b n i d u s a e a o n n a l p a t b h o i
a o u g a u a n g l k
c n
s r i
s h n 0 d c o n o -
e d g a C o 2 d e i i i 0 -
d n n h 2 v l
e h n i e c .
i l o
f t l 2 b s t a i
s t 1 i . i a d 2 o r f u t l n
a v m e c l n 1 w o u g d n l n e e r e u a o f h n g a u a r u p m l f o n a i e s h - t s u h d e
l f -
y o f i h s b n t t e s c r r -
d e
o r e i c e c o b N p r D r s e i
o i l p x s e g s c I c a f u a d . p u i
a - n e s r q i e d i r d i . o e r e t s e h l
o n i i l n m f c e r r v w s u a i n c f
n d
o d
e g
o i p
p e v
g n o o
r g i t a n a
p -
R C m r
e c
i y
g i
t d i l a i
s k n f i
n b
y h
e h
a d
E f u a k s h u n g n a
. e I o b l s c a u n e d t t
h S
L T t
e . n d p n e d e
b y
t o c e
i m
p o
e s
s o
s s s d d o e f d n r r u r e y d e i s o n p u o d e t o
n t u o o d
e d
n i
a t f l
a c a f e
l b
a e d e
i a a w c t s u r s i d d n m s C o u o d e t - a x t e r n l n m a f l
o c d c e e e . e o c s i h i a x e
s u
t e
d n
t f
r e
z o
r s d
e i
i n t u l e
s s
l a o i f - t g f y h i t , _
d m v r e g o s s a e s e
R c b
- t c i o f r c k u u f k e l e e s e m n s g R o l d .
3 - y y o a s e y n b S t
a p p i e a a .
r b t s b u s x z b b s o
t u e T
e w y a u a o s -
r o h s d
e d
e u y d r b c a s r d e a _
d e e c e c p e d s u a
s u
e s u
d b d s d - e f
s i s t e
n e
c a c
d e
e a n e
t n
e e
e n
e e
s t
- h t
d n
u a n o w
n l z - c c
z h u z o
c x
d n
u a h u t u d o u c i a
l f
e i n o r t
- x e
- o r
s f
r e o c
c s h s d e f - t r r d f u t t f n s - n e r t e e _
r h u s u e e _
n e s
d n
s h r o h d z d
n r
o c t e
z n
e e
c o
o h u c s n
o n e
u n s
o s n u
o r
u o d o I h
u o r
z o
x e
d s t
d e
C d f o e z
n e
d n e f o f f t
e m
s f f
r s
k c
n e
s e
n o
n o z t z d s e o n d r e z t c o e r o e o s e c r f r l r r n
u r
o l
n s e z
e r
d n
o o
d o r e e c e c
e w d f
i n f o o f o
d o i e
, o r
e v
u o
d t
e f c n i c
I n d d d r c f o f k a d a i s u n r n s k e n c c i n l f r o u e u k r c w a r s r e d u o r o f o w o c o e o c o d e o l _
- e o f o f e o d l l
l e i
d o m f i
e n _
w d s l d d i d d d r v o o r r r e o e r e e r r i 1 l k o o o o e k t a v k o k t t o u t c o o w o t c a t r c o c a n o s c n e d d t d a e i u e d e d e e e p
d i d d g s d d i
d i
d p o
k k n k d e n k e r k e s l e c c o c e e m i d e c e m e c l n t e e e m t r n e t e t r s e u b o a d d e d r a e e l a d a e n d d i
a N t i d e e u
q e t e i d
t n
p o d u i d e i
d t
n d e
e h e l a
T d e t t r t n e i e e t e i n t c u D q m a a o a i m r h m a m e a s s I e r i i t i r 2 o c r i r 3 t t i i T r e d d d 2 e 9 f s e d e 9 d a v P t e e g e 9 t 1 t e t 1 e e I e n m m n e 1 n e g n m n c m g g R u i r r i r i f u n i r i f i r n n C q e e n e f o q i e o e i i S r o t t e t o o r r e t e e t r r E o w n n p n w 1 o u n n n 0 n n u u C T T I I O I 8 T 2 T D O I O 7 O I D D 9 9 9 9 ? 9 0 0 0 0 2 2 2 2 3 3 3 3 3 7 7 7 7 7 7 B B B B 8 B 8 8 8 8 8 8 B E/ / / / / / / / / / / / / / / / / / /
T 0 5 9 1 7 6 2 7 7 7 7 3 0 0 5 5 5 6 6 A 1 0 0 3 2 1 2 1 1 2 1 2 3 3 2 1 1 2 2 D4 E0
/ /
7 0
/
7 0
/
8 0
/
0
/
1
/
5
/
8
/
9
/
2
/
8
/
2
/
2 2
/ /
1 7
/
7
/ /
7
/
9 1 0 0 0 0 0 0 1 1 1 1 1 0 )1 0 0 0 0 0 8 4 6 5 6 0 0 1 4 B 2 9 0 1 2 7 8 3 9 2 3 3 4 5 6 1 2 2 2 7 0 1 0 0 6 6 7 9 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 9 9 9 9 9 9 0 0 0 0 2 2 2 3 3 3 3 3 3 7 7 7 7 7 7 B B B B B 8 8 8 8 B 8 B 8
/ / / / / / / / / / / / / / / / / / /
R5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 E. 3 1
1 1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
1 3
E M
A NI T
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 N k k k k k k k k k k k k k k k k k k k A o o o o o o o o o o o o o o o o o o o L o o o o o o o o o o o o o o o o o o o PC C C C C C C C C C C C C C C C C C C 1 2 3 4 5 6 7 8 9 0 ! 2 3 4 5 6 7 B 9 1 ! 1 1 1 1 1 1 I 1
/
120 Cook 1 .315/03-122 .12/12/83 Four intermediate deck doors found frozen shut .by ice accueelation free leaking drain lines on air bandlers'4-2A, 4- # , & 1-50 8 .
.21 i ook C 1 315/05 4 19 . 04/20/95 Ice condenser' ice basket weights los .u
.22 Coot 1- 315/05-067-0012/64/05 7 of 48 lower inlet doors failed opening torque test - analysis shows no probles even with 21 of 48 doors inop B 23 Cook 1 315/86 4 13 07/01/87 Ice buildup in ice condenser flow pas + ,es due to subliestion B 24- Cook 1 315/87-01340 07/01/87 7 of 24 bays had ice buildup greater than 3/8 inch in a total of 124 flow passages, & ice between wall n' baskets. iVoluntary LERI B '
]
25 Cook 1 315/88-002-00 03/26/88 4 of 24 bays had ice passageway icing in a total of twelve flow passagenys greater than 3/8 inch - Voluntary LER R 26 ' Cook 1 ' 315/98 4 07 09/08/08 Ice buildup in ice condenser flow passages due to sublication B -
27 Cook 2 316/78-057 08/22/78 Door seals taught on door frase rough spots - spots smoothed out & doors retested to TS force regets 9
-291 Coot 2 316/01-029 07/11/01 During routine tour, one ice condenser intermediate deck door found partially open - caused by ice buildup B 29 Cook 2 316101-038 07/29/01 latermediate deck deor'found froren shut. On 9/10/91 door.in same area also frozen shut. IFree broken drain line free air handlerl 5 -
. 30 Coek 2 316/02-025 03/26/82 during a scheduled surheillance; ice condenser basket weights less than required - U l
31 Cook 2 316/02-116. 12/14/82 During a scheduled surveillance test, einious weight of a sample of ice baskets less than required W 32~ Cook 2 316/B3-056 06/24/B3 Bering test on lower inlet doors, bay 3 door 3L exceeded eat torque lieit - Frase seals sticking to door due to glycol adherence D 33 Coot 2 316/93-059 06/29/93 During a scheduled test, einieue average weight of saeple baskets less than required W 34 Cook 2 316/B3-083 08/23/B3 during surveillance test, 5 of ice condenser lower inlet doors exceeded the man'imme opening force specification D s
35 Coot 2 316/83-105 !!/05/83Twoicecondenserintermediatedeckdoorsfoundinoperable.CausedbybracinginstalledaspartofdesignchangeobstructingdoorsD 36 Coot 2 316/84-004 03/20/84 Ice cendenser ice basket weights below specification W 37 Cook 2 316/95-013-01 07/26/95 AsegilpercentageofflowpassagesinicebaysonoutsidewallhadfrostbuildupinexcessofT.S.requireeents ,
B 38 Cook 2 316/96-011-01 03/19/B6 Ice inventory was below T.S. LCO N 39 Cook 2 316/87-002-00 03/05/97 2 of 24 bays had ice passagway icing buildup greater than 3/8 inch in 18 flow passages - Voluntary LER B-40 Cook 2 316/87-010-00 09/02/97 6 of 24 bays had ice passageway icing buildup greater than 3/8 inch in 46 flow passages between baskets and wall B 41 Cook 2 316/88-005-00 04/26/98 1 of 24 bays had ice passagway icing in 4 flow passages B i
,,. ., . , - - . . , .- -.,,,.--m . ,-. . _ - , . - , ~ , _, ..w.,
- i 42 Sequoyha !' 327/90-170 '10/16/90 fue latermediate deck doors discovered freren closed. Caused by failed heat tapes on air bandling unit drain line - B I
43 Sequoyah l' 327/90-203 12/16/90 Intereediate deck door found freren shut - caused by ANU-34 drain line flange leaking ,D 44 Segeoyah 1 327/90-205 12/29/B0 Two intermediate deck doors below ANU-3A froren shut - overflow free drip pan frere around doors. (Occurenced 12/29/B0 h 1/5/81) D t
45 Sequoyah 1 327/91-002 01/09/81 Two intermediate deck doors found froren closed - caused by water leaking free ANU-3A defrost line flange - loose flange bolts D- i 46 Sequeyah 1 327/81-000 01/16/01 Three intermediate deck doors under air handling units 6A, BA, & BB frozen closed. Due Heat 7 ape fuse f ailure & froren drain lines D !
47 Sequoyah 1 327/B1-015 02/16/B1 Ice Condenser basket bays I, IB, & 24 were found below limits for average basket weight. Caused by subliestion N 48 Sequoyha 1 327/B1-073 06/29/31 Ice condenser intermediate deck doors found frosted. Caused by noisture dripping free upper deck doors, due to damaged tape seals D 49 5egouyah 1 327/81-105 08/22/81 Intermediate deck door in bay 14 iced over caused by water free froren drain pan in air handling unit - Due to Heater eat failure B -
50 Sequoyah ! 327/82-065 05/28/92 Ice condenser intermediate deck door froren closed - caused by water free leaking air handling unit frozen condensate drain D f f
51 Sequoyah 1 327/B2-093 07/06/92 Intermediate deck doors 1 & 5 in hay 9 and door 1 in hay 10 failed lift test liced over). Failed heat tape allowed line rupture D j 52 Sequoyah 1 327/B3-049 03/24/83 Intermediate deck door found froren closed - caused by water dripping free condensate drain pan due to heater sat failure D f
53 Sequoyah 1 327/93-126 09/26/83 !ce discovered on intermediate deck doors - caused by hueidity entering ice condenser. Ice condenser insp frequency increased D l 54 Sequoyah 1 327/84-019 03/07/94 Analysis of ice condenser weights indicate one group-row average basket weight below design limit of 1,080 lb. W 55 .Sequoyah ! 327/97-047 07/17/B7 Potential for inadequate containeent cooling af ter non-LOCA event identified - caused by design error A
~
56 Sequoyah 2 328/82-001 01/03/B2 Intersediate deck door 98 frozen shut - cause by hueidity entering through top deck blanket vents, condensing on I-beae & dripping D t
57 Sequoyah 2 32B/B2-052 04/26/B2 Intermediate deck doors beneath air handling unit discovered frozen closed - caused by improper installation of unit drain pan D
[
t 58 Sequoyah 2 328/82-063-00 05/1B/82 Bay B ind excessive ice / frost in approximately 6 flow passages causing entry into LCO 3.6.5.1 B 59 Sequoyah 2 328/92-077 06/09/B2 One ijtermediate deck door in bay 19 discovered frozen closed - caused by broken solder joint in air handling unit D i i
60 Sequoyah 2 328/83-049 03/24/B3 Intermediate deck door in Bay 11 found frore, closed - caused by leaks in condensate drain lines of air handling units D- l 61 Sequoyah 2 328/93-107 09/05/93 Broup 1 row I average ice baket weight found below sin - caused by sublication of ice in crane wall area W 62 Sequoyah 2 328/98-003-01 01/19/88 Ice passage icing - did not exceed Westinghouse analysis which concluded 151 of flow passages blocked is acceptable B 63 McGuire 1 369/92-059-00 06/26/82 84 or 141 Row 9 Ice basket weights below required 1269 lbs due to subliestion (Add details of causes) W !
- __ . _ _ _ _ _ _ _ - - . - - _ _ - -- - _ - __-__ - ___ -=__ _ ___ _- _ _- _ _ _ _-_____ _ _ --___-__--____ - _ _
s.
64 kleiro 1 369/93-005-00 01/27/93 Nueerous accessible row 8 & 9 Ice basket weights in each of 24 bays had less than required 1269 lbs -W 65 k6 mire 1 369/83-000 09/09/83 During intermediate deck door & sanitoring sys inspection, two intermediate deck dov s discovered frozen shut D M R Guire 1 369/B5-029-00 10/01/95 Error in calculation of pressure reduction sargin IAdd details of error 3 A 67- Catawba 1 413/B5-002-00 12/31/94 Personnel error caused lower compartment doors to be blocked during sede 4 - TS violation A 68 Catawba 1 413/86-037 07/31/B6 Ice condenser inlet doors tuhnically inop since 03/10/96 - personnel error in acceptance criteria inter - Retest showed operable A 69 Catamba 1 413/96-051 01/06/96 Energency hatch between upper & lower contair.aent inop. Caused by personnel error A 70 Catawba 2 414/97-001 01/26/87 Two intermediate deck doors exceeded opening force regats on 11/18/86. Caused by personnel error. .D ;
i r
Root Cause Breakdown -
D = Ice Bay Door Icing / Binding W= Ice Basket Sublimation B = Lattice / Weir Iceupi I "
A = Administrative Type LERs W
- a. _ . - __ ___ _ _ . -. . . . _ _ _ . ___ ___ _m___.m_______.a.-u__-m __.______-__ __.__.-__.__- __ _-____ _ _ _ _---m____ _ _ _m___. _ _ _
8 COOK 1. Ice any poor icinstair %s ,
, _ re ice masket sublimation -
GR L*I**##*I' I'*"P ;
QTY 4 Administrative Type LERs o
Eii m m rsl 8 COOK 2 e
s ,
LER _
QTY 4 0
IN! A A r-"1 b A 8 SEQUOYAH 1 .
s -
LER M 4 -
on ,
2 -
r e <s n--a 8 - SEQUOYAH 2 6 -
LER QTY 4 ~
A 2 -
m i O
8 McGUIRE 1 i 6 -
i LER 4 -
QTY 2 -
r""1
- i. , n...
8 CATAWBA 1 -
8 -
LER l QTY 0
n 78 79 80 81 82 83 84 85 86 87 88 FIGURE 1 - GRAPH OF ICE CONDENSER LEP; (by Year of Occurence) t l
_ _ _ _ _ . . _ _ _ _ _ . _ . _ _ _