05000454/LER-2005-001
| Docket Number | |
| Event date: | 01-25-2005 |
|---|---|
| Report date: | 03-28-2005 |
| Initial Reporting | |
| 4542005001R00 - NRC Website | |
Background
Byron Nuclear Power Station is a two-unit site with a common Main Control Room (MCR), Auxiliary Building (AB), and Fuel Handling Building (FHB). The Heating, Ventilation, and Air Conditioning (HVAC) systems for these areas are also common to both units. The MCR HVAC system (VC) [VI] consists of two 100% redundant trains (i.e., OA and OB) as specified by Technical Specification (TS) 3.7.10, " Control Room Ventilation Filtration System and TS 3.7.11, "Control Room Ventilation Temperature Control System.
The AB HVAC system (VA) [VF] consists of three subsystems. These three subsystems consist of the AB accessible area, the AB non-accessible area, and the FHB [VG]. Only the HVAC for the VA non-accessible area and the FHB are specified in TS. The AB non-accessible area consists of three 50% trains (i.e., OA, OB, and OC) and the FHB area consists of two 100% trains (i.e., OA and OB.) TS 3.7.12, "Non-accessible Area Exhaust Filter Plenum Ventilation System," governs the VA non-accessible area and TS 3.7.13, " Fuel Handling Building Exhaust Filter Plenum Ventilation System" governs the FHB area.
Surveillance Requirements (SRs) for each of the above TS, require the filters in these systems to be tested in accordance with TS 5.5.11, " Ventilation Filter Testing Program".
At Byron Station, periodic activities, such as procedures used to satisfy a TS SR, are controlled by a Predefine Process. This process is coordinated by the Site Predefine Administrator in the Work Management Department.
B. Description of Event:
On January 13, 2005, a Nuclear Oversight assessment identified that 15 TS ventilation related surveillance procedures were electronically taken to a "finished" status in the computer tracking program (i.e., Passport) by the System Manager (a non-licensed employee). However, the completed surveillance procedures with the appropriate review signatures were not, in accordance with the Predefine Process, forwarded to the Site Predefine Administrator in a timely manner.
When the surveillance procedure is taken to "finished" status, it is credited as fulfilling the TS SR. However, the next scheduled due date for the surveillance procedure is not generated until it is taken to "completed" status by the Predefine Administrator. An investigation into this discrepancy led to the responsible individual admitting to electronically taking the surveillance procedure status to "finished" in Passport without actually performing the surveillance procedures.
All of the SRs that were satisfied by performing the surveillance procedures were now beyond their critical date (i.e., TS SR frequency plus a 25% grace period allowed by SR 3.0.2). The SRs were considered not performed within the specified frequency and TS SR 3.0.3 was entered. SR 3.0.3 allows a delay period to perform the SR before declaring the Limiting Condition for Operations (LCO) not met of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or up to the limit of the specified frequency, whichever is greater. In order to go beyond the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a risk evaluation is required and the risk impact managed.
A risk evaluation was conducted and approved by the Byron Station Plant Operations Review Committee. This evaluation concluded that the risk was acceptably low to perform the surveillance requirements beyond the 24-hour delay period but within the next five week period.
A root cause evaluation and extent of condition investigation was immediately initiated.
The extent of condition review discovered 12 additional TS ventilation related surveillance procedures that had been falsely taken to "finished" status in Passport by the same responsible individual. In addition, this review found 11 completed surveillance procedures with some of the required signatures suspected as being forged.
The same individual later admitted to forging these signatures. Of these 11 surveillance procedures, two were considered valid since independent results were obtained from the vendor test lab. The remaining nine surveillance procedures were previous or current executions of one of the previously discovered surveillance procedures falsely taken to "finished" status. These forged surveillance procedures were provided by the responsible individual to the site Predefine Administrator and consequently the surveillance procedure was electronically taken to the "completed" status, which in turn generated the next scheduled dates. Three of these additional surveillance procedures had already been re-performed based on a decision to re-perform all TS surveillance procedures that this particular individual had supposedly performed. All of the applicable SRs satisfied by these additional surveillance procedures had also exceeded their critical dates.
Nine of these 12 SRs were also considered not performed within the specified frequency and TS SR 3.0.3 was entered. The original risk evaluation was updated to include these additional missed surveillance requirements and concluded that the risk was acceptable to perform the surveillance requirements beyond the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> delay period during the next four week period.
The site-wide extent of condition review included 1262 randomly selected documents that could be verified through an independent means such as security door card readers.
This review did not find any other falsification issues with other site staff personnel. The 27 surveillance procedures involved and the falsified dates are listed in Table 1.
Twenty-five of 27 surveillance procedures were tied to TS 5.5.11. Item 4 of Table 1 satisfies TS SR 3.7.12.4 and item 6 satisfies TS SR 3.7.13.5.
All 27 surveillance procedures were re-performed between January 14, 2005 and February 24, 2005. Of these 27 surveillance procedures, six failed their acceptance criteria. These six are listed in Table 2.
Table 1 Scope of Missed Surveillance Requirements # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Procedure No.
(note 1) OBVSR 7.12.2-2 OBVSR 7.12.2-7 OBVSR 7.12.2-1 OBVSR 7.12.4-1 OBVSR 7.13.2-7 OBVSR 7.13.5-1 OBVSR 7.10.4-1 OBVSR 7.10.4-2 OBVSR 7.10.2-6 OBVSR 7.10.2-12 OBVSR 7.10.2-4 OBVSR 7.10.2-10 OBVSR 7.12.2-5 OBVSR 7.12.2-6 OBVSR 7.12.2-9 OBVSR 7.13.2-8 (All have a Frequency of 18 months) Title Unit 0 OA Non-Accessible Exhaust Filter Plenum Charcoal Adsorber Bank Operability Unit 0 "A" Non-Accessible Area Exhaust Filter Plenum Ventilation System Total Bypass Leakage Test Unit 0 OA Non-Accessible Exhaust Filter Plenum HEPA Filter Performance Test Unit 0 ECCS Equipment Rooms Differential Pressure Test Unit 0 OA Fuel Handling Building Exhaust Ventilation System Carbon Sample Analysis Unit 0 Fuel Handling Building Exhaust Filter Plenums Negative Pressure Test Unit 0 OA Control Room Ventilation System Flowrate and Pressurization Test Unit 0 OB Control Room Ventilation System Flowrate and Pressurization Test Unit 0 OB Control Room Make-Up Filter System Carbon Sample Analysis OB Control Room Recirculation Carbon Sample Analysis Unit 0 OB Control Room Make-Up Charcoal Adsorber Bank Operability Unit 0 "B" Control Room Recirculation Charcoal Adsorber Bank Operability Unit 0 OC Non-Accessible Exhaust Filter Plenum HEPA Filter Performance Test Unit 0 OC Non-Accessible Exhaust Filter Plenum Charcoal Adsorber Bank Operability Unit 0 OC Non-Accessible Exhaust Filter Plenum Ventilation System Total Bypass Leakage Test Unit 0 OB Fuel Handling Building Exhaust Ventilation System Carbon Sample Analysis Falsified Finished Date/s (*) Also Involved Forged Signature/s 10/7/02* 6/2/04 10/7/02* 6/2/04 10/9/02* 6/2/04 8/20/03* 10/20/03* 10/27/03* 11/19/03* 12/5/03 12/8/03* 12/8/03* 12/9/03 12/09/03 4/21/04 Note 3 4/21/04 Note 3 4/21/04 Note 3 5/5/04 Note 3 Last Known Valid SR Satisfaction Date 01/08/01 01/08/01 01/08/01 01/16/02 04/20/02 02/14/02 02/04/02 02/11/02 06/12/02 04/19/02 07/07/02 02/12/02 01/22/01 01/22/01 01/22/01 10/11/02 # Procedure No.
(note 1) OBVSR 7.13.2-3 17 Note 2 OBVSR 7.13.2-4 18 Note 2 OBVSR 7.13.2-6 19 Note 2 OBVSR 7.10.2-5 20 OBVSR 7.12.2-3 21 OBVSR 7.12.2-4 22 OBVSR 7.12.2-8 23 OBVSR 7.12.2-12 24 OBVSR 7.13.2-1 25 OBVSR 7.13.2-2 26 OBVSR 7.13.2-5 27 Table 1 (Continued) Scope of Missed Surveillance Requirements (All have a Frequency of 18 months) Title Unit 0 OB Fuel Handling Building Exhaust Ventilation System HEPA Filter Performance Test Unit 0 OB Fuel Handling Building Exhaust Ventilation System Charcoal Adsorber Bank Operability Unit 0 OA Fuel Handling Building Exhaust Filter Plenum "B" Train Total Bypass Leakage Test Unit 0 OA Control Room Make-up Filter System Carbon Sample Analysis Unit 0 OB Non-Accessible Exhaust Filter Plenum HEPA Filter Performance Test Unit 0 OB Non-Accessible Exhaust Filter Plenum Charcoal Adsorber Bank Operability Unit 0 "B" Non-Accessible Area Exhaust Filter Plenum Ventilation System Total Bypass Leakage Test Unit 0 OC Non-Accessible Exhaust Filter Plenum Carbon Sample Analysis Unit 0 OA Fuel Handling Building Exhaust Ventilation System HEPA Filter Performance Test Unit 0 OA Fuel Handling Building Exhaust Ventilation System Charcoal Adsorber Performance Test Unit 0 Fuel Handling Building Exhaust Filter Plenum "A" Train Total Bypass Leakage Test Falsified Finished Date/s (*) Also Involved Forged Signature/s 5/5/04 Note 3 5/5/04 Note 3 5/5/04 Note 3 6/21/04 Note 3 8/20/04 Note 3 8/20/04 Note 3 8/20/04 Note 3 9/8/04 Note 3 9/24/04 Note 3 9/24/04 Note 3 9/24/04 Note 3 Note 1 — OBVSR = Common to Units 1 and 2 (0), Byron (B), Engineering Department (V), Surveillance Requirement (SR).
Note 2 — SR 3.0.3 was not entered for these missed SRs since they had already been re performed prior to knowing they involved falsified records.
Note 3 — The previous execution of the surveillance procedure is suspect because it was performed by the system manager, however there is no direct indication of falsification.
Last Known Valid SR Satisfaction Date 06/11/01 06/11/01 06/11/01 11/25/02 07/01/01 07/01/01 07/01/01 07/13/01 05/21/01 05/21/01 05/21/01 Table 2 Surveillance Procedure Failures # Procedure Title Failed Date 1 OBVSR 7.13.2-8 Unit 0 OB Fuel Handling Building Exhaust Ventilation System Carbon Sample Analysis 1/25/05 2 OBVSR 7.12.2-12 Unit 0 OC Non-Accessible Exhaust Filter Plenum Carbon 1/27/05 Sample Analysis 3 OBVSR 7.10.4-1 Unit 0 OA Control Room Ventilation System Flowrate and Pressurization Test 2/19/05 4 OBVSR 7.10.4-2 Unit 0 OB Control Room Ventilation System Flowrate and Pressurization Test 2/23/05 5 OBVSR 7.10.2-4 Unit 0 OB Control Room Make- Up Charcoal Adsorber Bank Operability 2/24/05 6 OBVSR 7.10.2-10 Unit 0 OB Control Room Recirculation Charcoal Adsorber 02/24/05 Bank Operability OBVSR 7.13.2-8 is the carbon methyl iodide penetration test of the OB FHB charcoal adsorber train in the FHB Exhaust Ventilation System. The acceptance criterion is a penetration of 10% or less. The actual penetration was 13.2%. Since the FHB system was not currently in an applicable condition (i.e., moving irradiated fuel), the OB train was placed on the degraded equipment list. The OB charcoal adsorber bed was replaced on February 4, 2004 and the OB train subsequently removed from the degraded equipment list. The same test on the OA FHB train's charcoal bed was found acceptable on February 4, 2005.
OBVSR 7.12.2-12 is the carbon methyl iodide penetration test of the OC charcoal adsorber train of the AB non-accessible plenum. The acceptance criterion is a penetration of 4.5% or less. The actual penetration was 6.23%. The OC train was declared inoperable and TS 3.7.12, "Nonaccessible Area Exhaust Filter Plenum Ventilation System", Action Condition entered for one train inoperable. The OC charcoal adsorber bed was replaced and the OC train restored to an operable condition on January 30, 2005. The OA and OB trains surveillance procedures were performed by this individual, however the test vendor confirmed carbon results were actually received and analyzed as acceptable on July 16, 2003 and July 29, 2003 respectively. The SRs for these trains were considered acceptable and were still within their TS frequency.
OBVSR 7.10.4-1 is the OA train VC flowrate and pressurization test. The flowrate acceptance criterion for the make-up flow rate is between 5400 and 6600 cubic feet per minute (cfm). The actual measured flowrate was 7029 cfm. The OA train was declared inoperable and TS 3.7.10 "VC Filtration System", Action Condition was entered. The flowrate was readjusted to within limits and the OA train restored to an operable condition on February 20, 2005.
OBVSR 7.10.4-2 is the OB train VC flowrate and pressurization test. The flowrate acceptance criterion for the make-up flow rate is between 5400 and 6600 cubic feet per minute (cfm). The actual flowrate was 6884 cfm. The OB train was declared inoperable and TS 3.7.10 Action Condition entered. The flowrate was readjusted to within limits on February 24, 2005.
OBVSR 7.10.2-4 is the OB train VC Make-up Charcoal Adsorber Bank Operability test. In this test OVCO5FB filter failed the Halide bypass leakage test. The acceptance criterion is less than a bypass leakage of .05%. The actual measurement was .24%. The OB VC train was already inoperable due to the make-up flowrate failure. The leakage was readjusted to within limits and the OB train restored to an operable condition on February 27, 2005.
OBVSR 7.10.2-10 is the OB VC Recirculation Charcoal Adsorber Bank Operability Test.
In this test the OVCO2FB filter failed the Halide bypass leakage test. The acceptance criterion is less than a bypass leakage of 2.0%. The actual measurement was 3.99%.
The OB VC train was already inoperable due to the high make-up flowrate failure. The leakage was adjusted to within limits and the OB VC train restored to an operable condition on February 27, 2005.
These six TS surveillance requirement failures are considered an event or condition prohibited by TS and reportable to the NRC in accordance with 10 CFR 50.73, Licensee event report system", section (a)(2)(i)(b).
In addition, though the exact time the VC make-up flowrates exceeded the acceptance criteria is unknown, it is likely that the condition existed simultaneously on both trains for a time period longer than allowed by TS LCO 3.0.3. Consequently, this is also an event or condition prohibited by TS.
In addition, the two VC make-up flowrate failures are considered an event where a single cause or condition caused two independent trains to become inoperable in a single system. This is also reportable to the NRC in accordance with 10 CFR 50.73 (a)(2)(vii).
C. Cause of Event:
The cause of the 27 TS surveillances exceeding their TS specified frequency was the willful falsification of documentation by one non-licensed employee.
There are several causes that contributed to the failure to detect this inappropriate practice in a timely manner. The more significant of these causes include inadequate supervisory oversight of the responsible individual, inadequate management oversight of the Predefine Process, and inadequate use of the Corrective Action Program within the Work Management and Engineering departments.
The cause of both failed charcoal samples in the OB FHB and OC non-accessible train, was normal degradation of charcoal. Charcoal filters have a finite life and are expected to degrade over time due to oxidation and exposure to contaminants. The OB FHB charcoal filter was installed in 1997 and its last valid sample analysis was in October 2002. The OC non-accessible charcoal filter was installed in 1995 and its last valid sample analysis was in July 2001. In addition, the failure to perform valid sample and analysis between October 2002 and January 2005 for the OB FHB charcoal filter and between July 2001 and January 2005 for the OC non-accessible charcoal filter resulted in a missed opportunity for trending of the degradation and possible replacement prior to failure.
The cause of the higher than allowed VC system make-up flowrates was due to differences in the air flow profile between the installed flow elements and the pitot tube used as test equipment for the surveillance procedure. The installed flow measuring elements are installed less than the 7.5 duct diameters downstream from a major flow disturbance (i.e., duct elbow) which caused flow measurement distortions in the air profile. The pitot tube measurement for the surveillance procedure is measured at a different location from the installed flow elements and not within 7.5 duct diameters of a major flow disturbance. The approved setpoint for the flow controller is 6000 cfm. The OA train was found set at 6200 cfm, however when it was reset to 6000 cfm the flow still was outside acceptance criteria at 6806 cfm. The previous valid execution of the surveillance procedures, in February 2002, resulted in flows at 6432 cfm and 6438 cfm respectively for the OA and OB trains.
The installed instruments on each train were verified and all were still within calibration tolerances. A review of work activities on the system could not determine how the OA train was set at 6200 cfm or find any reason that may have caused an increase of air flow on either of the FHB trains. In addition, the failure to perform these surveillance procedures in late 2003, resulted in a missed opportunity for trending of the flow measurement and possible intervention before exceeding the acceptance criteria. The installed flow transmitter on each train was subsequently rescaled based on the pitot tube flow measurements. To ensure repeat successful performance, measurements will be taken three times within the next six months to ensure effectiveness of the corrective action.
The cause of the failure of the OB VC make-up charcoal adsorber bypass leakage test was determined to be the settling of the charcoal over time, allowing a leak to develop gradually. The OB charcoal trays were originally installed in 1988. In addition, failing to perform this surveillance in December 2003, resulted in a missed opportunity for trending of the degradation and possible intervention before exceeding the acceptance criteria.
The cause of the failure for the OB VC recirculation charcoal adsorber bank operability test was determined to be leakage past the closed bypass damper (i.e, OVC044Y). It is unknown why the bypass damper developed enough leakage to effect the Halide penetration test. No maintenance had been performed on the bypass damper since the last successful test. In addition, failing to perform this surveillance procedure in December, 2003, resulted in a missed opportunity for trending of the degradation and possible intervention before exceeding the acceptance criteria.
D. Safety Analysis
A risk evaluation was conducted using methods described in Engineering procedure ER AA-600-1045, "Risk Assessments of Missed or Deficient Surveillances." Both a bounding risk assessment and a refined assessment were performed. These assessments concluded that the risk impact of the missed surveillances was not significant and the surveillance frequencies could be extended to allow completion in a systematic manner.
In support of the SR 3.0.3 risk analysis, a conservative bounding analysis was completed of the applicable UFSAR chapter 15 accident analysis assuming no credit for AB filtration and a 50% efficiency on the FHB filters. The result of this analysis indicate that the offsite dose would be under 10 CFR Part 100 limits and the dose to the control room operators would be less than the limits specified in the UFSAR.
The impact of the three failed VC SR's involving both trains has been evaluated and given the actual VC system make-up flowrates, recirculation flowrate, inleakage flowrates and as-found filter efficiencies, the existing Main Control Room habitability analysis would bound these as-found conditions and there would be no adverse impact on the dose to control room operators.
E. Corrective Actions
The responsible individual's employment was terminated. All TS Ventilation surveillance procedures that were performed by this individual were reperformed unless the results could be independently verified by another means.
A review was conducted of 584 work documents completed by the individual during his tenure in the Byron Engineering Department. Several other non-TS falsifications of records were identified and appropriate actions taken to resolve.
Several actions were taken to improve supervisory oversight of system managers.
These include issuing clear expectations to Engineering supervisors for performing and documenting quality field observations. Additionally, Engineering supervisor's day-to day activities will be aligned to those expectations listed in the Conduct of Plant Engineering Manual. This should increase the amount of time allocated for supervisory oversight activities.
Management oversight of the Predefine Process has been improved. This will be accomplished by having all Predefine work activities at the "finished" status reviewed at the weekly Work Management Review meeting. In addition, an indicator or report on predefines at the "finished" status will be included in the agenda of the planning and status meeting attended daily by senior managers. This will provide additional senior management level oversight of the Predefine Process.
A self-assessment of the Corrective Action Program within the Work Management and Engineering Departments will be conducted. This assessment will focus on identification threshold, individual participation and type of issues generated.
The corrective actions for the surveillance failure are explained in the description section above.
F. Previous Occurrences
A review of Byron Station events since January 2003 found no similar events.
G. Component Failure Data:
Manufacturer� Nomenclature� Model N/A