ML16148A655
| ML16148A655 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/24/1992 |
| From: | Belisle G, Binoy Desai, Harmon P, Poertner W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML16148A656 | List: |
| References | |
| 50-269-92-14, 50-270-92-14, 50-287-92-14, NUDOCS 9207270019 | |
| Download: ML16148A655 (4) | |
See also: IR 05000269/1992014
Text
UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTA STREET, N.W.
ATLANTA, GEORGIA 30323
Report Nos.:
50-269/92-14, 50-270/92-14 and 50-287/92-14
Licensee:
Duke Power Company
P. 0. Box 1007
Charlotte, NC 28201-1007
Docket Nos.:
50-269, 50-270, 50-287, 72-4
License Nos.:
DPR-38, DPR-47, DPR-55, SNM-2503
Facility Name:
Oconee Nuclear Station
Inspection Conduc ed: May 24 -
June 19, 1992
Inspectors:
E.
arE.
amon, enior
sident Inspector
Date Signed
B. B. Desai, Resi ent
pe tor
Date Signed
W. K. Poertner
eside
nspector
Date Signed
Approved by:
G. A. elisle, Se
on Chief
Date Signed
Division of Reactor Projects
SUMMARY
Scope:
This routine, resident inspection was conducted in the
area of plant operations..
Results:
One apparent violation was identified involving the
failure to maintain two emergency feedwater flow paths
operable as required by Technical Specification 3.4.1,
Emergency Feedwater System, prior to restarting Unit 1
after a reactor trip on May 8, 1992.
9207270019 920629
PDR ADOCK 05000269
Q
REPORT DETAILS
1.
Persons Contacted
Licensee Employees
- H. Barron, Station Manager
- S.
Benesole, Safety Review
- D. Coyle, Systems Engineering
- J. Davis,-Safety Assurance Manager
D. Deatherage, Operations Support Manager
- J. Hampton, Vice President, Oconee Site
- M. Patrick, Performance Engineer
- S.
Perry, Regulatory Compliance
G. Rothenberger, Work Control Superintendent
R. Sweigart, Operations Superintendent
Other licensee employees contacted included technicians,
operators, mechanics, security force members, and staff
engineers.
NRC Resident Inspectors:
- P.
Harmon
- W. Poertner
B. Desai
- Attended exit interview.
2.
Inoperable Emergency Feedwater Flowpath.
On May 24, 1992, a Unit 1 shutdown to cold shutdown was
commenced to repair reactor coolant pump seals on the 1A2
reactor coolant pump. During the maintenance outage the
licensee performed a stroke test surveillance on valves
1FDW-315 and 1FDW-316. These are the emergency feedwater
level control valves to steam generators 1A and 1B
respectively. These valves are air operated valves with a
nitrogen backup supply and open automatically to control
steam generator level on an emergency feedwater actuation
and are provided to maintain a water level of 30 inches or
approximately 4.6 percent in each steam generator.
When performance personnel tested valve 1FDW-315, the valve
did not open automatically when a low steam generator level
test signal was simulated in the valve control circuitry.
Subsequent to the surveillance test, the operators in the
control room had placed the valve in manual and successfully
opened and closed the valve from the control room. The
licensee initiated a work request to troubleshoot/repair
valve 1FDW-315.
2
The licensee determined that the solenoid valve that
deenergizes and allows the automatic level control signal to
control valve position had failed. This prevented the valve
from opening automatically. The solenoid valve was replaced
and the valve was retested and declared operable. These
solenoid valves have failed in the past and have resulted in
the failure of the EFW steam generator level control valves
to open automatically. The previous most recent failure
occurred on July 3, 1991, when Unit 3 tripped on a loss of
main feedwater and valve 3FDW-315 failed to open
automatically. The operator was required to take manual
control of the valve to maintain steam generator level in
the 3A steam generator. The maintenance outage was completed
and Unit 1 was returned to service on June 7, 1992.
During the May 1992 outage, the inspectors expressed concern
about the failure of valve 1FDW-315 to open automatically
and the operability of the valve prior to the Unit shutdown.
On June 9, 1992, the inspectors reviewed the post trip
review and Licensee Event Report (LER) 269/92-04 associated
with the Unit 1 trip from 14 percent power on May 8, 1992.
Unit 1 tripped due to an anticipatory trip signal on loss of
both main feedwater pumps. During the transient, both motor
driven emergency feedwater (MDEFW) pumps received a start
signal on low main feedwater pump discharge pressure and
started. The MDEFW pumps were secured by the operator
approximately 40 seconds after the trip based on the fact
that the lB main feedwater pump had not actually tripped.
The post trip review report and LER identified that the
emergency feedwater system operated properly during the
emergency feedwater initiation. During a review of the
transient monitor printouts, the inspectors identified that
EFW flow was initiated to the 1B steam generator-but flow to
the 1A steam generator was not indicated on the printout
even though steam generator level was below the automatic
level control setpoint of 30 inches.
The inspectors identified this item to the licensee on June
10, 1992, and requested that the licensee review the item to
determine if valve 1FDW-315 had operated properly during the
Unit 1 trip on May 8, 1992.
The inspectors were informed by
the licensee on June 11, 1992, that valve 1FDW-315 had not
operated properly during the EFW initiation on May 8, 1992,
and that the valve had been incapable of opening
automatically when the unit had been returned to service on
May 11, 1992.
The licensee stated that the valve would have
been capable of being opened manually by.the operators in
the control room and that manual operation of the valve had
been verified prior to returning the Unit to service.
3
During the event and subsequent event review, the licensee
had opportunities to identify that valve 1FDW-315 did not
operate properly. These opportunities were by the
operators, the post trip review, the transient analysis
report and the LER preparation.
Technical Specification 3.4.1, Emergency Feedwater System,
requires that two 100 percent emergency feedwater flowpaths
be operable prior to exceeding 250 degrees Fahrenheit. The
Technical Specification Bases defines a 100 percent flow
path as the flowpath to either steam generator including
associated valves and piping. Contrary to the above, Unit 1
was returned to operation from less than 250 degrees
Fahrenheit on May 11, 1992, and did not have two 100 percent
flow paths. Valve 1FDW-315, the 1A steam generator
emergency feedwater level control valve, was incapable of
opening automatically on an emergency feedwater actuation.
Valve 1FDW-315 remained inoperable until approximately May.
25, 1992, when the Unit was removed from operation for a
reactor coolant pump seal replacement outage. The failure
to meet the requirements of Technical Specification 3.4.1 is
identified as Apparent Violation 50-269/92-14-01: Unit 1
Restart With Inoperable Emergency Feedwater System.
3.
Exit Interview (30703)
The inspection scope and findings were summarized on
June 18, 1992, with those persons indicated in paragraph 1
above. The inspectors described the areas inspected and
discussed in detail the inspection findings. The licensee
did not identify as proprietary any of the material provided
to or reviewed by the inspectors during this inspection.
Item Number
Description/Reference Paragraph
Apparent Violation
Unit 1 Restart with Inoperable
269/92-14-01