ML17250B289
| ML17250B289 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 06/22/1993 |
| From: | Eapen P, Gregg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17250B288 | List: |
| References | |
| 50-244-93-08, 50-244-93-8, NUDOCS 9307060058 | |
| Download: ML17250B289 (6) | |
See also: IR 05000244/1993008
Text
REPORT NO.
U.S. NUCLEARREGULATORY COMMISSION
REGION I
50-244/93-08
DOCKET NO.
50-244
LICENSE NO.
LICENSEE:
Rochester
Gas and Electric Corporation
1503 Lake Road
Ontario, New York 14519
FACILITYNAME: R. E. Ginna Nuclear Power Plant
INSPECTION AT: R. E. Ginna Nuclear Power Plant, Ontario, New York
and Rochester
Gas and Electric Corporation,
Rochester,
INSPECTION
CONDUCTED:
April 12-16, May 24-28, and June 14-18, 1993
INSPECTOR:
H.. Gregg, Sr. R
tor Engineer,
Systems Section, Engineering Branch, DRS
Date
APPROVED BY:
Dr. P. K. Eapen, Chief, Sy tems Section,
Engineering Branch, DRS
Date
Areas Inspected: Service water system valve failures and underground piping leak.
Results: The licensee's valve inspection and replacement were aggressive after identifying
two locked open manual valves that had failed in the closed position.
The two valves were
in the closed position for an undetermined time during operation and were not identified as
failed until the 1993 outage.
The untimely identification and corrective action of the failed
valves was identified as an apparent violation.
9307060058
930h28
ADQCN 05000244
DETAILS
1.0
Review of Service Water Problems
1.1
Background Review
Two recent SW valve failures were identified during the licensee's inspection of
March 28, 1993.
An unrelated underground SW piping leak observed in the screen house
basement wall was identified by the licensee on January 7, 1992.
The purpose of this
inspection was to assess
the licensee's actions in response to the two valve failures and the
underground SW piping leak.
The R. E. Ginna valve improvement program of inspection-refurbishment-replacement
during
the current 1993 outage included motor-operated
and manual valves in the service water
system (SWS).
The licensee's
SWS maintenance planning for the 1993 outage started in
1989, with con'tracted reviews.
Improvement plans were documented in the licensee's
correspondence
of May 22. and June 13, 1991, that pointed out the need for extensive
refurbishment, targeted a large number of service water valves, provided data on strategies
to
isolate the SWS, and detailed the planning needs of long lead obsolete valve replacements.
Additional considerations
such as extensive service water system reconfiguration and* fuel
offload to enable work to be performed on the system, refurbishment of safety system valves
assigned higher priorities, extensive installations of new recirculating fan cooler heat
exchangers
inside containment, and need to have on-hand replacements for obsolete valve
models that were ordered in 1991 were factors in the licensee's
reasons for delaying service
water (SW) valve repairs until the 1993 outage.
The licensee's
awareness
that the Crane model 101 gate valves and several other models of
SW gate valves were obsolete was factored into the licensee's planned phase V valve upgrade
program work to be performed in the 1993 outage.
A more current Crane model 47'h XU
gate valve required extensive evaluation in accordance with the Ginna commercial dedication
program and were the purchased
replacements.
1.2
Valve 4669 and 4738 Failures and Licensee's Actions
The inspector reviewed corrective action report (CAR) 2077 and related correspondence
that
documented
the licensee's-2993
outage inspection finding, of the valve failures.and subsequent
actions.
The inspector also observed in-process work, the material condition of many
removed valves, and the condition of in-place piping.
The CAR identified two locked open manual valves (4669 and 4738) that had stems separated
from their discs with the discs in closed position, and valve 4739 (identical in design and
function to valve 4738) with its stem marginally attached to the disc.
The material at the
disc T-slot was found entirely consumed by corrosion on valves 4669 and 4738 and almost
entirely consumed on valve 4739.
The valves were Crane model 101XU original installation
equipment and have been in service approximately 23 years.
The stem material was
410 stainless steel and the disc material was SA 105 carbon steel with weld deposited
410 stainless on the disc seating surfaces.
Valve 4669 in series with valve 4760 are 4" locked open valves in a cross connection
, between the A and B headers
and supply SW to the emergency diesel generators.
Valve
4738 in series with valve 4739 similarly are 3" locked open valves in a cross connection
between the A and B.headers
and supply SW to the safety injection pump thrust bearing
coolers.
The licensee's staff with high level management
direction was aggressive in expanding the
scope of the SW valve inspection-refurbishment-replacement
outage plan upon identification
of the stem separation problem.
The original scope of 20 valves was increased
to 31 and
included all Crane 101 SW valves except 4612, 4621, and 4705.
The expanded work scope
included replacement of 14 of 20 SWS Crane 101 valves and the refurbishment of three
others.
An upgraded Crane model 47'A that has a 410 stainless
steel disc was the
replacement valve.
The remaining Crane model 101 SW valves are to be replaced in the
1994 outage.
The NRC inspection report 50-244/93-06 also contains information relating to
the two failed SW valves.
1.3
Safety Concern Review of Failed Valves
The inspector reviewed the safety significance of the failed valves (4669 and 4738).
The
inspector determined from a review of the UFSAR and the SWS drawings that there are
individual flow paths to supply SW to the safety-related components
(diesel generators,
containment fan coolers, and pump coolers).
In addition, the 14" crosstie line with normally
open valves (4639 and 4756) enable the safety-related components to be supplied from either
SW loop.
However, the closing of valve 4739 for brief time periods up to 45 minutes during
monthly SW pump surveillance tests would have isolated flow to the safety injection pump
thrust bearing coolers.
The licensee had developed several documents relating to the. isolation of SW fiow to the
safety injection pump thrust bearing; one was an engineering letter of April,9, 1993, and
another was a recent telephone memorandum dated May 21, 1993, of a conversation with the
pump manufacturer.
These documents provided information on the safety injection pumps
capability with SW flow to thrust bearing coolers isolated ifsafety injection pump initiation
occurred.
CAR 2077 action item 26 assigned to fuHy document justification of SW isolation
to the safety injection pumps was completed with the issuance of a comprehensive
design
analysis report DA-ME-93-101, on June 14, 1993.
The licensee's analysis concluded that
during monthly SW performance testing with valves 4738 and 4739 in closed position,
complete loss of SW cooling to the safety injection pump thrust bearing did not affect
operability of the safety injection pumps.
The inspector reviewed the SW valve corrective maintenance history and determined there
were two prior instances of stem separations from discs due to severe disc corrosion.
These
occurrences
were valve 4675 in May 1990 and valve 4690 in April 1992.
Both valves were
the Crane model 101 type and were in the nonsafety-related
portion of the SWS.
No plant
incident reports were written because
the valves were nonsafety-related.
Based on interviews
with engineering and management personnel the inspector determined that although there was
no documentation that established why the safety-related valves were considered satisfactory
at that time, there was discussion concerning similar valves in the safety-related portions of
the SWS.
Acceptable and consistent SW pump performance tests, unchanged normal
operating parameters,
and the two loop SWS configuration capability to withstand a single
failure and not render SWS inoperable were some of the licensee's
reasons why the safety-
related valve repairs could be made in 1993.
The inspector also reviewed the current maintenance
requirements
and determined there were
no periodic preventive maintenance required inspections of SWS valve internals.
Motor-
operated valves require stroke testing on a quarterly or monthly basis and diagnostic testing
on a periodic basis.
Manual valves have no requirements for stroke testing.
Failure to promptly identify the failed condition of valves 4669 and 4738 is contrary to
10 CFR 50, Appendix B, Criterion XVI, requirements
to promptly identify and correct
nonconfoimance conditions and is an apparent violation (EI 50-244/93-08-01).
1.4
Observations of In-Process Work
The inspector observed
the removal of Crane model 101 valves 4013, 4027, 4028, and 4675.
Each of these valves had significant amounts of silt build-up in the valve inlets and in the
piping at the valve inlet. The valve internals and bodies had significant corrosion deposits
and the discs and body guides were badly corroded.
The stems were found to be undamaged
once the external corrosion product was removed from the stem T-slot area.
The exposed
piping viewed by the inspector had build-up of corrosion product type nodules of
approximately 1/8" to 3/8" on all internal surfaces; however, there did not appear to be any
wall thinning at the exposed pipe cuts.
The inspector observed a significant number of other
removed SW valves and internals and assessed
their material condition as poor.
The inspector noted that engineering had taken actions to improve silt removal by extending
flush times at the auxiliary feedwater pump valves, realigning the flush flow.path to the
turbine driven auxiliary feedwater pump valves, and submittal of an EWR to increase the
drain line size.
1.5
Service Water Leak in Screen House
The inspector reviewed the nonconformance report NCR 92-001 and subsequent
correspondence
relating to the licensee's identified underground SW leak in the screen house.
The interim use justification dated January
14, 1992, provided basis for continued
operability, hypothesized
on possible leak locations, and presented generalized
measures
to
identify significant leakage increases.
The NCR interim use expiration was June 30, 1993.
A request for the second interim use extension through June 30, 1994, was issued on
March 18, 1993.
The licensee's
basis for the second extension included the earlier
measures.
Additional reasons for the extension were to institute measures
to locate, quantify
and assess
the leak and to develop an adequate repair plan.
The licensee's EWR 5405 to
permit robotic viewing of the SW underground piping was also delayed until the 1994 outage
due to the higher priority containment recirculation fan cooler installations performed in the
'993
outage.
The licensee has installed an elapsed time counter on the screen house sump
pump and has determined the leak to the sump to be approximately
1 gpm.
Additionally,
auxiliary operators on their 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> tours log the elapsed time on the counter and are required
to notify management of any significant time change indicating increased leak rate.
1.6
Conclusions
The licensee's SW valve improvement program was aggressively expanded after the failures
of valves 4669 and 4738 were identified during 1993 outage.
However, the licensee was
unaware for some period of time that these two locked open valves had failed in closed
position and measures
to identify and correct defective SW valves was not timely considering
the two identical failures of Crane model 101 valves discovered in May 1990 and
April 1992.
2.0, Management Meetings
Licensee management
was informed of the scope and purpose of the inspection at the
beginning of the inspection.
The inspection was continued with an additional site visit on
May 24-28, 1993, to reconfirm licensee's actions on earlier valve failures and other service
water issues,
and on June 14-18, 1993, to review the licensee's design analysis that assessed
the safety injection pump operability.
The findings of the inspection were discussed with the
licensee management
at the April 16, 1993, May 28, 1993, and June 18; 1993, exit
meetings.
The licensee acknowledged the inspection findings.
Attendees at the exit meetings
are listed in Attachment 1.
,(
ATTACEBHFAT1
Persons Contacted
h
r
as
nd Electri
ti n
0
+S. Adams, Technical Manager
J. Bettle, Preventive Maintenance Engineer
+R. Bryan, Station Engineer
B: Carrick,'r. Mechanical Engineer
+~1. Cook, Technical Manager
- J. Fischer, Maintenance Planning and Scheduling Manager
+N. Goodenough,
Maintenance Corrective Action Analyst
G. Herrick, Maintenance Analyst
W. Harding, Modification Control Engineer
J. Janney, Project Manager, MOVATS
x+R. Jaquin, Licensing Engineer
+S. Lawlor, Associate Mechanical Engineer
- ¹ Leone, Quality Improvement Specialist
- R. Marchionda, Superintendent Support Services
+*R. Mc Mahon, Quality Control Engineer
x+T. Newberry, Sr. Mechanical Engineer
~R. Ploof, Technical Engineer
+*W. Rapin, Modification Support Engineer
+T. Schuler, Operations Manager
+*J. St. Martin, Corrective Action Coordinator
- J. Wayland, Reactor Engineer
x*P. Wilkens, Manager Nuclear Engineering Services
- J. Widay, Plant Manager, R. E. Ginna
~G. Wrobel, Manager, Nuclear Safety and Licensing
N iclear R
lat
mmi in
x"T. Moslak, Senior Resident Inspector
+E. Knutson, Resident Inspector
- denotes those present at the exit meeting on April 16, 1993.
+ denotes those present at the exit meeting on May 28, 1993.
x denotes those present at the exit meeting on June 18, 1993.