IR 05000390/2010003

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IR 05000390-10-003 on 04/01/2010 - 06/30/2010 for Watts Bar, Unit 1, Post-Maintenance Testing, Problem Identification and Resolution
ML102110476
Person / Time
Site: Watts Bar Tennessee Valley Authority icon.png
Issue date: 07/30/2010
From: Eugene Guthrie
Reactor Projects Region 2 Branch 6
To: Krich R
Tennessee Valley Authority
References
IR-10-003
Download: ML102110476 (26)
v • d • e


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION uly 30, 2010

SUBJECT:

WATTS BAR NUCLEAR PLANT - NRC INTEGRATED INSPECTION REPORT 05000390/2010003

Dear Mr. Krich:

On June 30, 2010, the United States Nuclear Regulatory Commission (NRC) completed an inspection at your Watts Bar Nuclear Plant, Unit 1. The enclosed integrated inspection report documents the inspection results which were discussed on July 9, 2010, with Mr. D. Grissette and other members of your staff.

The inspection examined activities conducted under your license as they relate to safety and compliance with the Commissions rules and regulations and with the conditions of your license.

The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel.

This report documents one NRC identified finding and one self-revealing finding of very low safety significance (Green). These findings were determined to involve violations of NRC requirements. Additionally, a licensee-identified violation, which was determined to be of very low safety significance is listed in this report. However, because of their very low safety significance and because they are entered into your corrective action program, the NRC is treating these findings as non-cited violations (NCVs) consistent with Section VI.A.1 of the NRC Enforcement Policy. If you contest any NCV in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the Nuclear Regulatory Commission, ATTN.: Document Control Desk, Washington DC 20555-0001; with copies to the Regional Administrator, Region II; the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-0001; and the NRC Resident Inspector at the Watts Bar facility.

TVA 2 In addition, if you disagree with the characterization of any finding in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the Regional Administrator, Region II, and the NRC Resident Inspector at Watts Bar.

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice, a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRCs document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Eugene F. Guthrie, Chief Reactor Projects Branch 6 Division of Reactor Projects Docket Nos.: 50-390 License No.: NPF-90

Enclosure:

NRC Inspection Report 05000390/2010003 w/Attachment: Supplemental Information

REGION II==

Docket No: 50-390 License No: NPF-90 Report No: 05000390/2010003 Licensee: Tennessee Valley Authority (TVA)

Facility: Watts Bar Nuclear Plant, Unit 1 Location: Spring City, TN 37381 Dates: April 1, 2010 - June 30, 2010 Inspectors: R. Monk, Senior Resident Inspector M. Pribish, Resident Inspector Approved by: Eugene F. Guthrie, Chief Reactor Projects Branch 6 Division of Reactor Projects Enclosure

SUMMARY OF FINDINGS

IR 05000390/2010-003; 04/01/2010 - 06/30/2010; Watts Bar, Unit 1; Post-Maintenance Testing,

Problem Identification and Resolution, Other.

The report covered a three-month period of routine inspection by resident inspectors. One NRC identified, one self-revealing Green findings, both of which are non-cited violations (NCVs), were identified. Additionally, one Green licensee identified violation is documented. The significance of an issue is indicated by its color (Green, White, Yellow, Red) using the Significance Determination Process in Inspection Manual Chapter 0609, Significance Determination Process (SDP). The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 4, dated December 2006.

NRC-Identified Findings and Self-Revealing Findings

Cornerstone: Mitigating Systems

Green.

A self-revealing, non-cited violation (NCV) of Technical Specifications (TS)5.7.1, Procedures, was identified for the licensees failure to adhere to OPDP-1,

Conduct of Operations, Section 5.1, Procedure Adherence, resulting in the 1B Emergency Diesel Generator being returned to service with 15 cylinder valves open.

The licensee entered this issue into the corrective action program as problem evaluation report (PER) 232018.

Failing to ensure that safety-related equipment was properly returned to service was a performance deficiency. The performance deficiency was determined to be more than minor, and therefore a finding, because it was associated with the human performance attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e.,

core damage). The finding was evaluated using the Significance Determination Process Phase I and was determined to be a finding of very low safety significance because the valve mispositioning was found and corrected in less than the TS allowable outage time. The cause of the finding was directly related to the cross-cutting area of the human performance, error prevention aspect of the work practices component, in that, the licensee failed to ensure that personnel did not proceed in the face of uncertainty when one of the cylinder valves was determined to be in the incorrect position H.4(a). (Section 4OA3)

Green.

The inspectors identified a NCV of TS 5.7.1, Procedures, for the licensee failing to develop and implement an adequate post-maintenance test procedure for valve 0-CKV-067-0502C, air release valve for C ERCW pump, resulting in the valve not being fully tested following rebuild per work order (WO) 07-820358-000. The licensee entered these issues into the corrective action program as PER 228680

The licensees failure to develop and implement an adequate post-maintenance test was determined to be a performance deficiency. The performance deficiency was determined to be more than minor, and therefore a finding, because it would have the potential to lead to a more significant safety concern if left uncorrected, in that, failing to ensure that adequate procedures are developed and implemented could allow risk-significant equipment to unknowingly be returned to service in a degraded condition. This finding was evaluated using the Significance Determination Process Phase 1 screening criteria and was determined to be of very low safety significance because the finding did not represent an actual loss of safety function of a single train of equipment for greater than its TS allowed outage time. The cause of the finding had a cross-cutting aspect in the area of human performance associated with the work control component. It was directly related to the licensee appropriately coordinating work activities by incorporating actions to address the impact of changes to the work scope on the plant H.3(b). Specifically, personnel failed to recognize the impact of changing the scope of the PMT. As a result, an inadequately tested valve was placed into service. (Section 1R19)

Licensee-Identified Violations

A violation of very low safety significance, which was identified by the licensee, has been reviewed by the inspectors. Corrective actions taken or planned by the licensee have been entered into the licensees corrective action program. This violation and the corrective actions are listed in Section 4OA7 of this report.

REPORT DETAILS

Summary of Plant Status

Unit 1 operated at or near 100 percent rated thermal power (RTP) until May 21, 2010, when the Unit 1 reactor automatically tripped due to a main turbine generator trip. The unit was restarted following troubleshooting and repair of the main turbine generator electro-hydraulic control circuitry and returned to full power operation on May 29, 2010. The unit operated at or near 100 percent RTP for the remainder of the inspection period.

REACTOR SAFETY

Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity

1R01 Adverse Weather Protection

Summer Readiness of Offsite and Alternate AC Power Systems

a. Inspection Scope

Inspectors verified plant features, interviewed control room personnel, and reviewed procedures for operation and continued availability of offsite and alternate AC power systems and determined they were appropriate. Inspectors reviewed the licensees procedures and interface agreements affecting these areas and the communications protocols between the northeast area dispatcher and the control room to verify that the appropriate information is exchanged when issues arise that could impact the offsite power system and the alternate AC power system. Also, the inspectors inspected the 161kV offsite switchyard for material condition and reviewed outstanding work orders (WOs) associated with the offsite power distribution system. Documents reviewed are listed in the attachment. This activity constituted one inspection sample.

b. Findings

No findings were identified.

1R04 Equipment Alignment

Partial System Walkdowns

a. Inspection Scope

The inspectors conducted three equipment alignment partial walkdowns, listed below, to evaluate the operability of selected redundant trains or backup systems with the other train or system inoperable or out of service. The inspectors reviewed the functional system descriptions, Updated Final Safety Analysis Report (UFSAR), system operating procedures, and technical specifications (TS) to determine correct system lineups for the current plant conditions. The inspectors performed walkdowns of the systems to verify that critical components were properly aligned and to identify any discrepancies which could affect operability of the redundant train or backup system.

  • A-train auxiliary air while B-train auxiliary air out of service for scheduled component outage

b. Findings

No findings were identified.

1R05 Fire Protection

.1 Fire Protection Tours

a. Inspection Scope

The inspectors conducted tours of the nine areas important to reactor safety, listed below, to verify the licensees implementation of fire protection requirements as described in the Fire Protection Program, Standard Programs and Processes (SPP)-

10.0, Control of Fire Protection Impairments, SPP-10.10, Control of Transient Combustibles, SPP-10.11, Control of Ignition Sources (Hot Work). The inspectors evaluated, as appropriate, conditions related to:

(1) licensee control of transient combustibles and ignition sources;
(2) the material condition, operational status, and operational lineup of fire protection systems, equipment, and features; and
(3) the fire barriers used to prevent fire damage or fire propagation.
  • B-train RHR pump room
  • B-train CS pump room
  • A-train centrifugal charging pump (CCP) room
  • B-train CCP room
  • A-train safety injection pump (SIP) room
  • B-train SIP room

b. Findings

No findings were identified.

.2 Annual Drill Observation

a. Inspection Scope

On April 9, 2009, the inspectors observed an announced fire drill performed inside 1C coolant charging pump room. The drill was observed to evaluate the readiness of the plant fire brigade to fight fires. The inspectors verified that the licensee staff identified deficiencies; openly discussed them in a self-critical manner at the drill debrief, and took appropriate corrective actions. Specific attributes evaluated were:

(1) specified number of individuals responding;
(2) proper wearing of turnout gear;
(3) self-contained breathing apparatus available and properly worn and used;
(4) control room personnel followed procedures for verification and initiation of response;
(5) fire brigade leader exhibited command and had a copy of the pre-fire plan;
(6) fire brigade leader maintained control starting at the dress-out area;
(7) fire brigade response timely and followed the appropriate access route;
(8) control/command set up near the location and communications were established;
(9) proper use and layout of fire hoses;
(10) fire area entered in a controlled manner;
(11) sufficient firefighting equipment brought to the scene;
(12) search for victims and propagation of the fire into other plant areas; (13)utilization of pre-planned strategies;
(14) adherence to the pre-planned drill scenario and drill objectives acceptance criteria were met; and
(15) firefighting equipment returned to a condition of readiness to respond to an actual fire. This activity constituted one inspection sample.

b. Findings

No findings were identified.

1R06 Flood Protection Measures

a. Inspection Scope

Inspectors directly observed four underground bunkers/manholes subject to flooding that contained cables whose failure could disable risk-significant equipment. Specific attributes evaluated were:

(1) the cables were not submerged in water;
(2) the cables and/or splices appeared intact and the material condition of cable support structures was acceptable; and
(3) dewatering devices (sump pump) operation and level alarm circuits were set appropriately to ensure that the cables would not be submerged or were in an environment for which they were qualified. This activity constituted one inspection sample. Below is a list of bunkers/manholes inspected.
  • 1E 6.9Kv manhole 27
  • 1E 6.9Kv manhole 23
  • 1E 6.9Kv manhole 5A
  • 1E 6.9Kv manhole 6B

b. Findings

No findings were identified.

1R11 Licensed Operator Requalification

a. Inspection Scope

On May 18, 2010, the inspectors observed the simulator evaluations for Operations Crew 5 per 3-OT-SRT-AOI-39-1, Load reduction/trip due to turbine vibration/ATWS. The plant conditions led to a Site Area Emergency level classification. Also observed was 3-OT-SRT-E2-5, MSLB in containment with loss of Containment Spray. The plant conditions led to a Notification of Unusual Event level classification. Performance indicator credit was taken by the licensee for this activity.

The inspectors specifically observed the simulator evaluations for the following attributes related to the operating crews performance:

  • Clarity and formality of communication
  • Ability to take timely action to safely control the unit
  • Prioritization, interpretation, and verification of alarms
  • Correct use and implementation of Abnormal Operating Instructions (AOIs) and Emergency Operating Instructions (EOIs)
  • Timely and appropriate emergency action level declarations per Emergency Plan Implementing Procedures (EPIP)
  • Control board operation and manipulation, including high-risk operator actions
  • Command and Control provided by the unit supervisor and shift manager The inspectors also attended the critique to assess the effectiveness of the licensee evaluators, and to verify that licensee-identified issues were comparable to issues identified by the inspector. This activity constituted one inspection sample.

b. Findings

No findings were identified.

1R12 Maintenance Effectiveness

a. Inspection Scope

The inspectors reviewed the two performance-based problems listed below. The focus of the reviews was to assess the effectiveness of maintenance efforts that apply to scoped structures, systems, or components (SSCs) and to verify that the licensee was following the requirements of TI-119, Maintenance Rule Performance Indicator Monitoring, Trending, and Reporting 10 CFR 50.65, and SPP-6.6, Maintenance Rule Performance Indicator Monitoring, Trending, and Reporting 10 CFR 50.65. Reviews focused, as appropriate, on:

(1) appropriate work practices;
(2) identification and resolution of common cause failures;
(3) scoping in accordance with 10 CFR 50.65; (4)characterization of reliability issues;
(5) charging unavailability time;
(6) trending key parameters;
(7) 10 CFR 50.65 (a)
(1) or (a)
(2) classification and reclassification; and (8)the appropriateness of performance criteria for SSCs classified as (a)(2) or goals and corrective actions for SSCs classified as (a)(1).

b. Findings

No findings were identified.

1R13 Maintenance Risk Assessments and Emergent Work Control

a. Inspection Scope

The inspectors evaluated, as appropriate, for the three work activities listed below:

(1) the effectiveness of the risk assessments performed before maintenance activities were conducted;
(2) the management of risk;
(3) that, upon identification of an unforeseen situation, necessary steps were taken to plan and control the resulting emergent work activities; and
(4) that maintenance risk assessments and emergent work problems were adequately identified and resolved. The inspectors verified that the licensee was complying with the requirements of 10 CFR 50.65 (a)(4); SPP-7.0, Work Control and Outage Management; SPP-7.1, Work Control Process; and TI-124, Equipment to Plant Risk Matrix. This inspection satisfied four inspection samples for Maintenance Risk Assessment and Emergent Work Control.
  • Risk associated with planned maintenance on the TDAFW pump and emergent work on the 2B-B 480v board room chiller
  • Risk associated with planned maintenance on the 1A EDG and planned work in the 161kv switchyard
  • Risk associated with movement of the B common station service transformer (CSST)tap changer into the 161kv switchyard

b. Findings

No findings were identified.

1R15 Operability Evaluations

a. Inspection Scope

The inspectors reviewed four operability evaluations affecting risk-significant mitigating systems, listed below, to assess, as appropriate:

(1) the technical adequacy of the evaluations;
(2) whether continued system operability was warranted;
(3) whether the compensatory measures, if involved, were in place, would work as intended, and were appropriately controlled;
(4) where continued operability was considered unjustified, the impact on TS Limiting Conditions for Operation (LCOs) and the risk significance in accordance with the significant determination process (SDP). The inspectors verified that the operability evaluations were performed in accordance with SPP-3.1, Corrective Action Program.
  • Problem Evaluation Report (PER) 217350, Bolt missing from ice condenser top deck blanket tape clip
  • PER 229333, EDG output breaker behavior during testing with concurrent fault on CSST (potentially inadequate surveillance)
  • PER 233633, Moisture in the TDAFW turbine oil system

b. Findings

No findings were identified.

1R18 Plant Modifications

a. Inspection Scope

The inspectors reviewed one temporary plant modification against the requirements of SPP-9.5, Temporary Alterations, and SPP-9.4, 10 CFR 50.59 Evaluation of Changes, Test, and Experiments, and verified that the modification did not affect system operability or availability as described by the TS and UFSAR. In addition, the inspectors determined whether:

(1) the installation of the temporary modification was in accordance with the work package;
(2) adequate configuration control was in place; (3)procedures and drawings were updated; and,
(4) post-installation tests verified operability of the affected systems.
  • 110846434, Improved cooling for TDAFW pump room by removal of general vent.

Balancing damper 1-BLD-31-3034

b. Findings

No findings were identified.

1R19 Post-Maintenance Testing

a. Inspection Scope

The inspectors reviewed four post-maintenance test procedures and/or test activities, (listed below) as appropriate, for selected risk-significant mitigating systems to assess whether:

(1) the effect of testing on the plant had been adequately addressed by control room and/or engineering personnel;
(2) testing was adequate for the maintenance performed;
(3) acceptance criteria were clear and adequately demonstrated operational readiness consistent with design and licensing basis documents;
(4) test instrumentation had current calibrations, range, and accuracy consistent with the application;
(5) tests were performed as written with applicable prerequisites satisfied;
(6) jumpers installed or leads lifted were properly controlled;
(7) test equipment was removed following testing; and
(8) equipment was returned to the status required to perform its safety function. The inspectors verified that these activities were performed in accordance with SPP-8.0, Testing Programs; SPP-6.3, Pre-/Post-Maintenance Testing; and SPP-7.1, Work Control Process.
  • WO 08-812356-001, 1B MDAFW pump pressure control valve I to P converter replacement
  • WO 09-815454-000, Inspection of auxiliary dryer B-train isolation valves

b. Findings

Introduction:

A Green, non-cited violation of Technical Specifications (TS) 5.7.1, Procedures, was identified by the inspectors for the licensee failing to develop and implement an adequate post maintenance test procedure for valve 0-CKV-067-0502C, resulting in the valve not being fully tested following rebuild per WO 07-820358-000

Description:

Following completion of work on 0-CKV-067-0502C, air release valve for C ERCW pump, inspectors reviewed the post maintenance test (PMT) activities for 0-CKV-067-0502C. The purpose of the PMT was to verify the American Society of Mechanical Engineers (ASME)Section XI, Inservice Test requirement, for proper valve operation in both the open and closed positions. The inspectors found that the original PMT listed on the WO to perform 0-SI-67-901-A, Essential Raw Cooling Water (ERCW) Pump A-A and ERCW Pump C-A Performance Test, was revised because the required equipment for this test was not installed. The inspectors reviewed the completed PMT paper work following the ERCW pump having been returned to service.

The inspectors went to the area of the ERCW pump check valve to observe how the revised PMT was accomplished. The revised PMT specified starting C ERCW pump, verify air was released and that the valve closed with no seat leakage. The inspectors discovered that the end of the pipe on the release line downstream of valve 0-CKV-067-0502C was not visible, leaving no way to visually verify seat leakage. Additionally, the valve disc had a hole drilled in it by design, providing a continuous leak path. The inspectors also noted that the revised PMT did not contain a requirement to verify that the valve properly opened when required.

After questioning the licensee about the adequacy of the revised PMT requirements, the licensee revised the PMT and re-performed the test using audible indications and determined the valve to operate satisfactory, meeting ASME Section XI, testing criteria to restore operability to the ERCW system.

Analysis:

The licensees failure to develop and implement an adequate post maintenance test was determined to be a performance deficiency. The inspectors determined that the performance deficiency was more than minor, and therefore a finding, because it would have the potential to lead to a more significant safety concern if left uncorrected, in that, failing to ensure that adequate procedures are developed and implemented could allow risk-significant equipment to unknowingly be returned to service in a degraded condition. This finding was evaluated using the significance determination phase 1 screening criteria and was determined to be of very low safety significance because the finding did not represent an actual loss of safety function of a single train of equipment for greater than its TS-allowed outage time. The cause of the finding had a cross-cutting aspect in the area of human performance associated with the work control component. It was directly related to the licensee appropriately coordinating work activities by incorporating actions to address the impact of changes to the work scope on the plant H.3(b). Specifically, personnel failed to recognize the impact of changing the scope of the PMT. As a result, an inadequately tested valve was returned into service.

Enforcement:

TS, 5.7.1, Procedures, states, in part, that procedures recommended in Regulatory Guide 1.33, specifically 8.f, Service Water Functional Tests, will be established and implemented. Contrary to the above, on April 30, 2010, the licensee failed to establish a revised post maintenance test procedure for the C ERCW pump air release valve that verified functional operation of the valve. Because this finding is of very low safety significance and was entered into the licensees corrective action program as PER 228680, this violation is being treated as an NCV, consistent with Section VI.A of the NRC Enforcement Policy: NCV 05000390/2010003-01, Failure to Assure that Adequate Test Requirements Were Developed and Implemented Following a Repair.

1R20 Refueling and Other Outage Activities

a. Inspection Scope

The licensee began a forced outage on May 21, 2010, when the Unit 1 reactor automatically tripped due to a main turbine generator trip. The inspectors observed maintenance activities, and startup activities to determine whether the licensee maintained defense in depth (DID) commensurate with the applicable TS. The inspectors monitored licensee controls over the outage activities listed below.

  • licensee configuration management, including daily outage reports, to evaluate did and compliance with the applicable Ts when taking equipment out of service
  • controls over the status and configuration of redundant safety systems to ensure risk was minimized
  • startup activities to verify that TS, license conditions, and other requirements, commitments, and administrative procedure prerequisites for mode changes were met prior to changing modes or plant conditions
  • reactor coolant system integrity was verified by reviewing reactor coolant system leakage calculations, and containment integrity was verified by reviewing the status of containment penetrations and containment isolation valves

b. Findings

No findings were identified.

1R22 Surveillance Testing

a. Inspection Scope

The inspectors witnessed seven surveillance tests and/or reviewed test data of selected risk-significant SSCs, listed below, to assess, as appropriate, whether the SSCs met the requirements of the TS; the UFSAR; SPP-8.0, Testing Programs; SPP-8.2, Surveillance Test Program; and SPP-9.1, ASME Section XI. The inspectors also determined whether the testing effectively demonstrated that the SSCs were operationally ready and capable of performing their intended safety functions.

In-Service Tests:

  • 0-SI-32-902-B, Auxiliary air compressor cooling water inlet valve full cycle exercising during normal operation - Train B Routine Surveillance Tests:
  • 1-SI-0-15, Rod position indication using incore, while the M-8 rod position indication was inoperable
  • WO 09-820646-000, 0-SI-31-56-A, Main control room pressure test A-train
  • WO 10-810577-000, 1-SI-30-26-A, Containment air return fan 1A-A quarterly operability test

b. Findings

No findings were identified.

OTHER ACTIVITIES

4OA1 Performance Indicator Verification

a. Inspection Scope

The inspectors sampled licensee submittals for the two PIs listed below. To verify the accuracy of the PI data reported during the periods listed, PI definitions and guidance contained in NEI 99-02, Regulatory Assessment Indicator Guideline, Revision 5, were used to verify the basis in reporting for each data element.

Mitigating Systems Cornerstone PI

b. Findings

No findings were identified.

4OA2 Identification & Resolution of Problems

.1 Review of Items Entered into the Corrective Action Program (CAP)

As required by Inspection Procedure 71152, Identification and Resolution of Problems, and in order to help identify repetitive equipment failures or specific human performance issues for follow-up, the inspectors performed a daily screening of items entered into the licensees CAP. This review was accomplished by reviewing daily PER summary reports and attending daily PER review meetings.

.2 Semi-Annual Review to Identify Trends

a. Inspection Scope

As required by IP 71152, Identification and Resolution of Problems, the inspectors performed a review of the licensees CAP and associated documents to identify trends that could indicate the existence of a more significant safety issue. The inspectors review was focused on human performance trends, licensee trending efforts, and repetitive equipment and corrective maintenance issues. The inspectors also considered the results of the daily inspector CAP item screening discussed in Section 4OA2.1. The inspectors review nominally considered the six-month period of January 2010 through June 2010, although some examples expanded beyond those dates when the scope of the trend warranted.

b. Observations No findings were identified. However, the inspectors identified a number of instances where the PER screening committees (PSC) review of incoming PERs failed to recognize conditions adverse to quality which required potential operability reviews, potential reportablity reviews, or the need to upgrade some PER classifications. Also, examples of degraded or non-conforming conditions of plant equipment related to the current licensing basis were not addressed by the PSC. Inspectors noted an increasing trend in the number of instances where questioning from the inspectors was necessary for the licensee to address these type of issues.

.3 Annual Sample: B-train Main Control Room Chiller Temperature Control Valve Failure

During Loss of Offsite Power Testing

a. Inspection Scope

The inspectors reviewed the apparent cause and the planned and completed corrective actions for PER 139875, B-train Main Control Room Chiller Temperature Control Valve Failure During Loss of Offsite Power Testing.

b. Findings

Introduction:

The inspectors identified an issue associated with the B-train Main Control Room Chiller temperature control valve. This issue is being characterized as an unresolved item (URI).

Description:

-Licensee procedure 0-SI-82-4, 18 Month Loss of Offsite Power with Safety Injection Test - Diesel Generator 1B-B, provides the detailed steps to verify the operability of Diesel Generator 1B-B and 6.9 kV Shutdown Board 1B-B load shed logic during loss of offsite power with and without safety injection (SI) actuation. 0-SI-82-4 also simulates a loss of offsite power and the subsequent recovery of shutdown board power from the 1B-B diesel generator.

One of the components affected during surveillance 0-SI-82-4 was the B-train main control room chiller. During the test, the chiller was initially in service with normal ERCW cooling flow supplied. When shutdown board voltage was lost during the test, the B-train main control room chiller stopped and B-train ERCW header flow ceased and ERCW pressure lowered to atmospheric pressure. The main control room chiller temperature control valve (TCV), 0-TCV-67-1053-B, was a hydraulically operated valve that used ERCW pressure for operation. Due to valve design, the TCV opened on the loss of ERCW pressure. When the shutdown board was re-energized from the diesel, the diesel load sequencer started the associated ERCW pumps and the main control room chiller.

During the performance of 0-SI-82-4 on March 10, 2008, the B-train MCR chiller tripped on low suction pressure. Subsequent licensee investigation revealed that the chillers TCV had failed in the open position. The licensee initiated a work order to repair the TCV and PER 139875 to document the chiller trip during testing. During TCV disassembly, the licensee discovered that the valves internal stem guide had become misaligned which prevented the valve from closing. No valve internal parts were found damaged in the valve body or actuator.

The corrective actions for PER 139875 included completion of the work order to rebuild the TCV and completion of the maintenance rule cause determination evaluation (CDE).

CDE 914 determined that the apparent cause of the shift of the TCVs valve stem guide was due to an ERCW header pressure surge which occurred when the ERCW pumps restarted after the simulated loss of offsite power during 0-SI-82-4. The CDE also determined that no actions to prevent recurrence were necessary since the testing on March 10, 2008, was considered to be a unique, isolated event that was caused by a peculiar ERCW transient which is unlikely to be repeated in future testing or any other anticipated plant condition.

During the performance of 0-SI-82-4 on October 9, 2009, the B-train MCR chillers TCV failed open. The licensee initiated a work order to repair the TCV and PER 204181 to document the chiller trip during testing. During TCV disassembly, the licensee discovered that the valves internals had shifted therefore preventing the valve from closing. No valve internal parts were found damaged in the valve body or actuator.

On December 23, 2009, the functional evaluation for PER 205438 determined that the B-train MCR chiller TCV was operable, but non-conforming, and that manual compensatory actions were required. The manual compensatory actions prescribed by the functional evaluation were implemented by revision to licensee procedure AOI-40, Station Blackout. The inspectors questioned the licensees compensatory action implementation and past operability of the MCR chillers. Pending additional information from the licensee regarding the past operability determinations and further review of the maintenance on the TCVs by the NRC, this issue will be identified as URI 05000296/2010003-01, B-train Main Control Room Chiller Temperature Control Valve Failure.

4OA3 Event Followup

Emergency Stop of 1B Emergency Diesel Generator Due to Human Error

a. Inspection Scope

Inspectors reviewed plant logs, procedures, corrective action documents, and personnel associated with an aborted start of 1B emergency diesel generator during the planned run of 0-SI-82-11B, Monthly Diesel Generator Start and Load Test DG 1B-B.

b. Findings

Introduction:

A Green, Self-Revealing, non-cited violation of Technical Specifications 5.7.1, Procedures, was identified for the licensees failure to adhere to OPDP-1, Conduct of Operations section 5.1, Procedure Adherence, resulting in the 1B Emergency Diesel Generator being returned to service with 15 cylinder valves open.

Description:

On May 31, 2010 operations personnel were preparing 1B-B emergency diesel generator (EDG) for surveillance 0-SI-82-11B, Monthly Diesel Generator Start and Load Test by performing steps of SOI-82.02, Diesel Generator (DG) 1B-B, section 8.2 Rolling DG to Check for Water in the Cylinders. This activity required the EDG to be removed from service and appropriate LCO statements to be entered. All 32 cylinder valves were opened 1 1/2 turns with a 5/8 inch wrench to allow manual jacking over of the EDG to verify that no water was present in the cylinders. The plugs were subsequently closed, independently verified, and documented in the procedure before returning the EDG to service in preparation for the surveillance run. The license previously modified these plugs to a dual purpose Kiene valve, which allowed the valve to perform both the petcock function and allow for the connection of external test equipment. As a result, the petcock function of the valve was accomplished by a reversed seated, rising stem device, where the stem was out when the valve was closed. The inspectors found that there was no Note or Caution in the procedure to alert the operator to the fact that the test plugs were reverse threaded.

The method by which the valves were closed and verified was for each auxiliary unit operators (AUO) to position one side of the EDG (16 cylinders), then each AUO went to the opposite side of the EDG to perform an independent verification. The two personnel, AUO #1 and AUO #2, involved had little and no previous experience with these valves, respectively. AUO #1 correctly positioned the west side of the EDG closed. AUO #2 initially positioned the first cylinder valve correctly on the east side of the EDG in the closed position. When the AUO closed the cylinder plug, the AUO noted that the visual indication did not match with what was expected for this operation, as the plugs were reverse threaded, the valve stem rose and exposed stem threads. Since the AUO was positioning the valve from mid position, the AUO became confused whether he performed the action correctly and positioned all of the cylinder plugs based on visual indication, which left all the valves in the open position. Once both parties had configured their valves, they changed side to perform the independent verification on the other operators work. A visual inspection of the threads was not required nor performed when the cylinder plugs were checked. The operator placed a wrench on the valves and attempted to operate them in the closed direction. The valves on the west side were verified closed. When AUO #1 performed the independent verification on the east side valves, the AUO placed a wrench on each valve and lightly tapped it with his palm to verify no motion. When the AUO got to cylinder #6, he noted movement indicating the valve was open and then closed the cylinder test valve. The open test valve was discussed between the two operators, but AUO #2 assumed he had missed #6 cylinder test valve on the initial positioning. The inspectors determined that neither operator questioned the need to recheck any of the other valves after one cylinder valve was found in the wrong position. Having been pre-job briefed on previous over torque damage to these valves, the AUOs avoided excess torque on these valves during the independent verification.

Following this evolution, the EDG was returned to service and started per the surveillance. Due to excessive noise and smoke, the AUOs shut down the EDG locally.

Initially, it was believed that the petcock packing had failed on two valves. Further investigation revealed that 15 valves were open.

Analysis:

Failing to ensure, by independent verification, that safety-related equipment was properly returned to service was a performance deficiency. The performance deficiency was more than minor, and therefore a finding, because it was associated with the human performance attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). The finding was evaluated using the Significance Determination Process Phase I and was determined to be a finding of very low safety significance because the mispositioning was found and corrected in less that the Technical Specification allowable outage time.

The cause of the finding was directly related to the cross-cutting area of human performance, error prevention aspect of the work practices component, in that, the licensee failed to ensure that personnel did not proceed in the face of uncertainty when one of the cylinder plugs was determined to be in the incorrect position. (H.4(a))

Enforcement:

Unit 1 TS 5.7.1, Procedures, requires, in part, that written procedures be established, implemented and maintained covering the following activities: a. The applicable procedures recommended in RG 1.33, Revision 2, Appendix A, February 1978. Regulatory Guide 1.33, states, in part, that safety related activities (that) should be covered by written procedures. Section 1.c, of RG 1.33, Revision 2, Appendix A, states Procedure Adherence as one of those procedures. Plant procedure OPDP 1, Conduct of Operations states, in part, that Plant equipment shall be operated in accordance with written approved procedures as discussed in SPP-2.2, Administration of Site Technical Procedures. SPP-2.2, Administration of Site Technical Procedures states, in part, that Procedure users (TVA and contractor employees) are responsible for: Following current approved procedures as written, or obtaining approval of necessary changes in accordance with this document before proceeding. SOI-82.02, Diesel Generator (DG) 1B-B, directs both the closure and the verification of closure of cylinder plugs on the 1B-B EDG. Contrary to the above, on May 31, 2010, the licensee failed to adequately implement SOI-82.02 in a manner which resulted in a non-licensed operator failing to ensure 15 cylinder valves were verified closed as required. Because this failure to implement procedures supporting TS 5.7.1 is of very low safety significance and the licensee entered this event in their CAP as PER 232018, this violation is being treated as an NCV, consistent with Section VI.A of the NRC Enforcement Policy: NCV 05000390/2010003-02, Lack of Procedure Implementation Results in 1B EDG being started with 15 Cylinder Plugs Open.

4OA5 Other Activities

.1 Quarterly Resident Inspector Observations of Security Personnel and Activities

a. Inspection Scope

During the inspection period, the inspectors conducted observations of security force personnel and activities to ensure that the activities were consistent with licensee security procedures and regulatory requirements relating to nuclear plant security.

These observations took place during both normal and off-normal plant working hours.

These quarterly resident inspector observations of security force personnel and activities did not constitute any additional inspection samples. Rather, they were considered an integral part of the inspectors normal plant status review and inspection activities.

b. Findings

No findings were identified.

4OA6 Meetings, including Exit

On July 9, 2010, the inspectors presented the inspection results to Mr. Don Grissette, Site Vice President, and other members of the licensee staff. The licensee acknowledged the issues presented. The inspectors confirmed that none of the potential report input discussed was considered proprietary.

4OA7 Licensee-Identified Violations

The following violation of very low safety significance (Green) was identified by the licensee and is a violation of NRC requirements which meet the criteria of the NRC Enforcement Policy, for being dispositioned as a non-cited violation.

Criterion V, Instructions, Procedures, and Drawings requires, in part, that instructions, procedures, or drawings shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplished.

Contrary to the above, on April 7, 2010, the licensee identified terminal screws in solid state protection system (SSPS) cabinets 2-R-48 and 2-R-51, which affected emergency diesel generators (EDGs) 2A-A and 2B-B, had been replaced with isolating plastic screws and washers. This occurred in January 2010 under Unit 2 WOs 09-954447-000 and 09-954448-000 which directed the installation of plastic screws and washers in 2-R-48 and 2-R-51. The result was that the Unit 2 diesel generators output breakers would not open if a Safety Injection (SI) signal on Unit 1 was initiated while in parallel with its associated shutdown board during EDG 2A-A and 2B-B testing conditions. Corrective actions are documented in PER 224586. This finding is of very low safety significance because the Unit 2 EDGs are lightly loaded during a Unit 1 Safety Injection and the condition only applies while the EDGs are operating in parallel with offsite power (e.g.

monthly surveillance procedures).

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee personnel

G. Boerschig, Plant Manager
M. Brandon, Director, Safety & Licensing (Interim)
S. Connors, Maintenance Manager
T. Detchemende, Emergency Preparedness Manager
D. Grissette, Site Vice President
W. Hooks, Radiation Protection Manager
B. Hunt, Operations Superintendent
G. Mauldin, Director, Engineering
M. McFadden, Operations Manager
R. Mende, Director, Safety and Licensing
C. Riedl, Licensing Manager (Interim)
T. Rose, Chemistry Manager
A. Scales, Work Control Manager
D. Voeller, Director, Project Management
J. Wilcox, Security Manager

ITEMS OPENED, CLOSED, AND DISCUSSED

Opened

05000390/2010003-03 URI B-train Main Control Room Chiller Temperature Control Valve Failure

Opened and Closed

05000390/2010003-01 NCV Failure to Assure that Adequate Test Requirements Were Developed and Implemented Following a Repair (Section 1R19)
05000390/2010003-02 NCV Lack of Procedure Implementation Results in 1B EDG being started with 15 Cylinder Plugs Open.

(Section 4OA3)

Closed

None

Discussed

None

LIST OF DOCUMENTS REVIEWED

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