05000254/LER-2000-002-01, Re Inadequate Calibration of Post Accident Torus Temperature Monitors
| ML021340538 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/29/2002 |
| From: | Tulon T Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SVP-02-031 LER-00-002-01 | |
| Download: ML021340538 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2542000002R01 - NRC Website | |
text
ExelIo n.S Exelon Generation Company, LLC www.exeloncorp.com Nuclear Ouad Cities Nuclear Power Station 22710 206i Avenue North Cordova, IL 61242-9740 April 29, 2002 SVP-02-031 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Quad Cities Nuclear Power Station, Unit 1 and Unit 2 Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265
Subject:
Revision 01 of Licensee Event Report 254/00-002, "Inadequate Calibration of Post Accident Torus Temperature Monitors" Enclosed is Licensee Event Report (LER) 254/00-002, "Inadequate Calibration of Post Accident Torus Temperature Monitors," Revision 01, for Quad Cities Nuclear Power Station.
The root cause investigation for the event was completed subsequent to the submittal of the original LER. The LER has been revised to incorporate the pertinent root cause and corrective action information.
No actions are being committed to in this submittal. Any actions described in the submittal represent intended or planned actions by Exelon Generation Company (EGC), LLC. They are described for the NRC's information and are not regulatory commitments.
Should you have any questions concerning this report, please contact Mr. W. J. Beck at (309) 227-2800.
Respectfully, T
thy J. Tulon e Vice President Quad Cities Nuclear Power Station cc:
Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - Quad Cities Nuclear Power Station
Abstract
At 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> on October 4, 2000, with Unit 1 at 100% power and Unit 2 at 83%
power, it was determined that a full loop calibration was not being performed on the torus water temperature recorders (TR) 1(2)-1640-200A and 200B as required by Technical Specifications.
Technical Specification Table 4.2.F.1, "Accident Monitoring Instrumentation Surveillance Requirements," required that the torus water temperature post-accident monitors receive a channel calibration once every 18 months.
Although the recorders were being calibrated as required, the full loop instrument calibration was not being performed.
The root causes of this event were historical weaknesses in the modification process that resulted in a failure to specify periodic calibration of the instrument loop and inadequate tracking and maintenance of instrument loops identified to address Regulatory Guide (RG) 1.97 variables.
On October 5, 2000, the loops on Unit 1 and Unit 2 were calibrated and found to be within acceptable limits.
Also, daily channel checks are performed by Operations to compare the average temperature indicated on TR 1640-200A and 200B with torus temperature indicated by other instrumentation and confirm agreement within 109F.
Therefore, the safety significance of this event is minimal.
This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B).
I I
IU.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION Quad Cities Nuclear Power Station Unit 1 05000254 NUMBER NUMBER 2000 002 01 2 of 4 (if more space is required, use additional copies of NRC Form 366A)(17)
PLANT AND SYSTEM IDENTIFICATION
Boiling Water Reactor, 2511 Megawatts Thermal Rated Core Power Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
EVENT IDENTIFICATION Inadequate Calibration of Post Accident Torus Temperature Monitors A.
CONDITION PRIOR TO EVENT
Unit: 1 Event Date: October 4, 2000 Event Time: 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> Reactor Mode: 1 Mode Name: Power Operation Power Level: 100%
Unit: 2 Event Date: October 4, 2000 Event Time: 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> Reactor Mode: 1 Mode Name: Power Operation Power Level: 83%
Power Operation (1) - Mode switch in the RUN position with average reactor coolant temperature at any temperature.
B.
DESCRIPTION OF EVENT
At 1630 hours0.0189 days <br />0.453 hours <br />0.0027 weeks <br />6.20215e-4 months <br /> on October 4, 2000, with Unit 1 at 100% power and Unit 2 at 83% power, it was determined that a full loop calibration was not being performed on the torus water temperature recorders [TR] (TR) 1(2)-1640-200A and 200B as required by Technical Specifications (TS).
The TS in place at the time of the event, TS Table 4.2.F.1, "Accident Monitoring Instrumentation Surveillance Requirements," required that the torus water temperature post-accident monitors [IP] receive a channel calibration once every 18 months.
Although the recorders were being calibrated as required, no calibrations were being performed on the other instruments in the loop.
These instruments included signal conditioners, summers and temperature elements [TE1.
TS Table 4.2.F.1 has since been changed to TS Table 3.3.3.1-1, "Post Accident Monitoring Instrumentation," during the conversion to Improved Technical Specification (ITS).
In ITS, the Torus Water Temperature Surveillance Requirement 3.3.3.1.3 frequency is 24 months.
C.
CAUSE OF EVENT
The root causes of this event were historical weaknesses in the modification process that resulted in a failure to specify periodic calibration for the instrument loop and inadequate tracking and maintenance of instrument loops identified to address Regulatory Guide (RG) 1.97 variables.U.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME 1 DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REVISION Quad Cities Nuclear Power Station Unit 1 05000254 NUMBER NUMBER 2000 002 01 3 of 4 (If more space is required, use additional copies of NRC Form 366A)(17)
D.
SAFETY ANALYSIS
On October 5, 2000, the torus water temperature instrument loops on Unit 1 and Unit 2 were calibrated and found to be within acceptable limits.
The temperature transmitters provide eight temperature signals to the average temperature indication for each temperature recorder. The as-found conditions of all of the individual components were evaluated and the cumulative effect on the loop output was found to be within acceptable limits. This indicates that the average temperature indications on TR 1640-200A and 200B remained within tolerance since the last calibration performed during installation in 1991.
The as-found conditions of two of the Unit 2 temperature transmitters [TT] were outside acceptable limits.
The components were restored to the required tolerances.
The remaining transmitters and summers were within tolerance.
The as-found condition of the two transmitters did not prevent the loop calibration from being within acceptable limits.
In addition, the Daily Surveillances procedure requires daily channel checks to be performed by Operations that compare the average temperature indicated on TR 1640-200A and 200B with torus temperature indicated by other instrumentation and confirm agreement within 102F. A review of the history indicates that TR 1640-200A and 200B were not found to exceed this limit during that same period.
Therefore, the safety significance of this event is minimal.
E.
CORRECTIVE ACTIONS
Immediate Actions On October 5, 2000, the torus temperature loops were calibrated.
Corrective Actions to Prevent Recurrence The computer tracking of the calibrations for the torus water temperature instruments has been corrected to reflect the requirement to calibrate the instrument loop.
The instrument loops associated with all RG 1.97 variables have been verified to have appropriate tracking of calibration requirements.
Since the time frame of the modification to install the instruments in question, the modification process has been strengthened such that surveillance requirements are appropriately assigned and tracked. Therefore, no further corrective actions are necessary.
F.
PREVIOUS OCCURRENCES
A review of events involving historical calibration deficiencies over the last two years identified the following:
LER 254\\98-009 -
"Method Of Daily Temperature Verification Of Standby Liquid Control System Pump Suction Heat Tracing Operability Using Installed Temperature Switches Did Not Account for Calibration Tolerance Which Allowed Use of Temperature Switch Settings That Did Not Support The TS Requirement Resulting In Inability To EnsureU.S. NUCLEAR REGULATORY COMMISSION (7-2001)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6 PAGE (3)
YEAR SEQUENTIAL REVISION Quad Cities Nuclear Power Station Unit 1 05000254 NUMBER NUMBER 2000 002 01 4 of 4 (If more space is required, use additional copies of NRC Form 366A)(17)
Suction Line Temperature Was Above The Minimum Allowed Value."
The cause of this event was the failure to establish a process during implementation of the Technical Specification Upgrade program (TSUP) for ensuring appropriate evaluation or calculation conducted to support choice of instrumentation or methods to meet added TS requirements. One of the corrective actions for this event was:
- Maintenance Department will establish and implement the process to ensure that instrument setpoints and calibration information are appropriately reviewed, including any required supporting calculations, when new TS requirements are established or when a change in method of meeting existing TS requirements occurs.
This action was taken to ensure that appropriate reviews were conducted for changes of TS instruments outside of the modification process.
This action could have helped to identify the torus temperature post-accident monitor calibration issue, however the failure to establish the appropriate calibrations occurred prior to the action being taken.
LER 265\\98-001 -
"TS Surveillance for Source Range Monitors (SRM) Was Not Performed Within the Required Interval for Unit 1 and Unit 2 Due to Inadequate Identification of the TS Requirement in the Surveillance."
The root cause of this event was inadequate identification of the TS requirement in the original surveillance during implementation of the upgraded TS. One of the corrective actions for this event was:
- A TS compliance assessment was performed to verify adequate permanent processes are implemented, including the incorporation of TS data into the work control database.
The processes used to review and update the TS data in EWCS resulted in Operations raising questions in CR Q1998-01893 and CR Q1999-03774. Had those questions been addressed more comprehensively, the torus temperature post-accident monitor calibration issue may have been identified.
G.
COMPONENT FAILURE DATA
There were no component failures associated with this event.