ML112220605
| ML112220605 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 12/17/2003 |
| From: | FirstEnergy Nuclear Operating Co |
| To: | NRC/RGN-III |
| References | |
| EA-03-197 | |
| Download: ML112220605 (27) | |
Text
. ( "
Desired Outcome
- Ensure a consistent understanding of the issue
- Present the causes and corrective actions
- Discuss further actions
- Present results from updated safety assessment
~
Background
- Emergency Service Water (ESW) Pump "A" coupling failed
- Enforcement discretion requested and granted (no net increase in risk)
- Repairs completed well within the discretionary period
.j
.~ 0)
-c
~
~
Q)
Q)
--c
~
-q:
C)
W c
N'+
0
~
+-'
C Q) ~
~ -.J.8 E ~
(J o -:
1-0
c.
Cl)
I Cl) "'C Cl) c:
-en w as
.c en 0) c 0..
- J C) 0 0 -a:c:
\J
--.....c.
CI) en
...- "C CO
~
0 Cl) lIo..
tn . N
-c: "'C
~
a:
C'"
Cl) 3:
Cl) lIo..
0 en N
~
- 0
>. 0 Cl) ...J
~
0 D..
c..
I
- 0) *
"C
> C 0) 0)
(J) ...
W co
.s:::.
(J)
C')
0'> -a:c C
--- -c..
- t:: ...
0) 0.. (J)
(J)
- l ......
o o 3:
o 0)
J...
o
-c 0)
(J)
~
o CD >
- 0) o CO
-0)
( J)
-J C')(J) tn - O......
c ......
-a
-c::
til
- l o
(.)
/
Root Cause Evaluated
- Evaluated the environment/application
- Conducted a detailed laboratory analysis
- Performed a detailed stress analysis *
- Fracture mechanics were evaluated
Root Cause Conclusion
- Stress corrosion cracking is the root cause
- Improper installation due to inadequate procedure
- Susceptible material
- Environment considered in design/operation
- Corrective actions address both installation and material
Extent of Condition Examined
- Safety and non-safety related pumps were included
- Similarities in configuration, couplings, and maintenance instructions were examined
- ESW Pump "8" - found to be identical
- ESW Pump "e" - similar
~ Q)
.~ 0 c
't.i ctS
~ c Q)
-q: +-'
-.- .CctS
~ -
Q)~
~ .
0
.Eo
.~
'I.j
~ 0 0 e
~
~o c+-'
0 Q)
Q) . :
- a U
~
~
en c
~
0
(
u
<< t
't.II
~
~
~ -i Q)
~
u Cb Cb Q) .~ ~
t e 0 ~
() CI) -Cb
~
~ ~
Q)
--en ~
c ~ m .~
Q) ~ 't.II .;:
..c Cb *5 ~
~ ~ ~
Q) c..
E 0
()
Corrective Actions ESWPumps
- Pump operability has been assured
- Further actions will be taken to assure continued reliability *
- ESW Pump "A" rebuild in 2004
- ESW Pump "8" inspect in 2004, rebuild in 2007
- ESW Pump "e" rebuild in 2004
Corrective Actions Procedures and Material
- Revision of procedures for ESW pumps
- Material upgrades for all ESW pumps *
- New requirements for heat treatment, hardness, and documentation
- 100% NDE of coupling sleeves e
Collective Significance Review Process
- Systematic evaluation of a collection of documented events or conditions
- Multidiscipline Review Team formed November 3, 200;3
- Scope includes four mitigating system equipment failures over last year
Collective Significance Review - Matrix Matrix used - Categories/Facts
- Problem category examples:
- Procedure guidance *
- Training
- Material deficiencies
- Design deficiencies
- Problem fact examples:
- Event type
- Organization
- Cause code FENOC 'I'C'i ::;,- 'i~'i-!,-:t:r :-'111 If) ClUplillCi f "if:I,)
..... 17
Collective Significance Review - Results Areas for Improvement Two collective issues identified during common cause evaluation
- Electrical/Mechanical maintenance instruction deficiencies
- Procedure "use" categories not pre-determined
Content of Procedures
Conclusion:
- Procedures were root or contributing causes
- Actions:
- 75 maintenance instructions will be systematically assessed
- Results of assessment will determine need for comprehensive procedure upgrade
- Interim - Safety related procedures will be reviewed as part of the work planning
Use of Procedures
Conclusion:
- Procedure use categories not assigned Actions:
- Interim - maintenance instructions will be "In Field Reference"
- "Use" category will be identified in
- maintenance instructions
Collective Significance Review - Summary Common causes are understood Comprehensive actions are being taken Systematic assessment will be used to adjust scope and timeliness
Summary - Cause and Corrective Actions Root and contributing causes are understood Corrective actions are comprehensive Extent of condition and extent of cause are being addressed
'1.1
~ 0)
~
c
~
(])
(])
~
c 0) c
~= N"P
+-'
C CD W
0
~
.....J.8
~ E ~
-!! o .=
1-0
~
Initial Safety Assessment Initial characterization of incremental core damage and large early release probabilities (ICCDP and ICLERP)
- ICCDP (including internal events) = 2.03E-6
- ICCDP (seismic, fire, and external flooding) = negligible
- ICLERP = 1.S6E-7
Safety Assessment Basis. for Initial Assesstnent
- Level 1 PSA model used
- Includes all failure modes
- Simplified assumptions due to model and computer capabilities (no time dependence between event failures)
- No consideration given to the time dimension relative to the ESW Pump "A" coupling failure Basis for Updated Assessl71ent
- The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> mission time was partitioned *
- Only the applicable scenarios based on this event were considered
- Human Reliability Analysis (HRA) was performed
Results of Updated Safety Assessment Updated characterization of incremental core damage and large early release probabilities (ICCDP and ICLERP)
- ICCDP (including internal events) = 8.5E-7 !
- ICCDP (seismic, fire, and external flooding) = 1.2E-7 I:
- ICLERP = <1.0E-7 (qualitatively)
~-=~~~--=--~~~~~-~":-;-~~~~~ ~~~-=--'-~~- '07-?=-~~~~~
Conclusion:
- ICCDP (including external events) = 9.7E-7
- ICLERP <1.0E-7 (qualitatively)
Low safety significance using a more detailed and accurate evaluation method
'1:1 I"":',;
l" 1/
[l
~
U r,
r J
- ' , L
(/) !.!'
CD f.' - '
- ~
(/)
~ \ t' I'~*
I.'
~
lJ OJ , , ,I' "
I'
'./;
U C \
.~
'j' c:::n 0 CD C ..- U
-0 ..- -a c lU
- l C CD (1) :....
'-- .!:l 0
- .... U ::l
- J ..- U ..
CIJ c ~
0 CD OJ 0 :....
C U ..- ..- ~ Q) c c 0 LU -a CD
..- Q) 0 U c >< > t:
CD ~
CO ~
~
CD CD Q)
CO ..- :....
0 CD Q. -a ;t .~
0
..c
-a
..0 OJ 0
- .... ;e~~~
S Q)
..c (J) c 0
..c (/)
CD ~.~
C 0 '
-a C
co c
E co
+-'
u OJ OJ :....
C
(]) -::l ta
~~
III
-- ..- .:::£ CO
+-'
CO, (/) ><
a>
CD
.:::t:. ~
~
+-' ~~
OJ
+-'
c (1)- CD a> +-' Q) Q) ~ ~
-a > > E )... CI) c... c
- J ct1
..c CO
..c -- Q. I-. ~
(..)
0 (1)
Q) s s s a> a>
S CD ::l 0- ~ --aa ~
'+
(\j Q)
~ if i;
(j) _\ \ \ \
~