IR 05000443/2007006

IR 05000443-07-006, on 03/19/2007 - 04/26/2007, Seabrook Station, Unit 1, Component Design Bases Inspection

ML071590071
Person / Time
Site:	Seabrook
Issue date:	06/08/2007
From:	Doerflein L Engineering Region 1 Branch 2
To:	St.Pierre G Florida Power & Light Energy Seabrook
References
FOIA/PA-2010-0209 IR-07-006
Download: ML071590071 (41)

Text

une 8, 2007

SUBJECT:

SEABROOK STATION - NRC COMPONENT DESIGN BASIS INSPECTION REPORT 05000443/2007006

Dear Mr. St. Pierre:

On April 26, 2007, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at the Seabrook Nuclear Power Station. The enclosed inspection report documents the inspection results, which were discussed on April 26, 2007, with you 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.

In conducting the inspection, the team examined the adequacy of selected components and operator actions to mitigate postulated transients, initiating events, and design basis accidents.

The inspection also reviewed FPLs response to selected operating experience issues. The inspection involved field walkdowns, examination of selected procedures, calculations and records, and interviews with station personnel.

This report documents two findings of very low safety significance (Green), both of which involved violations of NRC requirements. However, because of the very low safety significance and because the issues have been entered into your corrective action program, the NRC is treating the issues as non-cited violations (NCVs), in accordance with Section VI.A.1 of the NRC's Enforcement Policy. If you contest any NCV in this report, you should provide a response with the basis for your denial, within 30 days of the date of this inspection report, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C.

20555-0001; with copies to the Regional Administrator, Region I; the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555-0001; and the NRC Resident Inspector at Seabrook.

Mr. Gene S In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its enclosures, 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 the 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/

Lawrence T. Doerflein, Chief Engineering Branch 2 Division of Reactor Safety Docket No. 50-443 License No: NPF-86 Enclosure: Inspection Report No. 05000443/2007006 w/Attachment: Supplemental Information

Mr. Gene S

SUMMARY OF FINDINGS

IR 05000443/2007006; 3/19/2007 - 4/26/2007; Seabrook Station, Unit 1; Component Design

Bases Inspection.

This inspection was conducted by a team of four NRC inspectors and two NRC contractors.

Two findings of very low risk significance (Green) were identified, both of which were considered to be non-cited violations (NCVs). The significance of most findings is indicated by their color (Green, White, Yellow, Red) using NRC Inspection Manual Chapter (IMC) 0609,

Significance Determination Process (SDP). Findings for which the SDP does not apply may be Green or be assigned a severity level after NRC management review. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 3, dated July 2000.

Cornerstone: Mitigating Systems

Green.

The team identified a finding of very low safety significance involving a non-cited violation of 10CFR50, Appendix B, Criteria III, Design Control.

Specifically, the instrument uncertainty calculation for the refueling water storage tank (RWST) level instruments took credit for instrument temperature compensation; however, the instruments were not temperature compensated.

Additional inaccuracies associated with the bulk temperature mismatch and air pressure differences resulted in a non-conservative RWST level error. In response, FPL implemented a compensatory action to maintain adequate margin to the Technical Specification (TS) limit until engineering modified the level measurement to include temperature compensation.

The finding is more than minor because it is associated with the design control attribute of the Mitigating Systems cornerstone objective of ensuring availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences. This finding was determined to be of very low significance, based on Phase 1 of the SDP, because it did not result in the loss of RWST operability. (Section 1R21.2.1.1)

Green.

The team identified a finding of very low safety significance involving a non-cited violation of 10 CFR 50, Appendix B, Criterion XI, Test Control. The team determined that FPL did not ensure that the turbine driven emergency feedwater pump (TDEFWP) steam admission valve, MS-V-395, inservice test (IST) procedures had acceptance criteria that incorporated the limits from applicable design documents. Specifically, the design basis stroke time of MS-V-395 was not correctly stated in the IST program so that the valve stroked faster than the design basis requirement, but was still considered operable per IST requirements. Following identification of the issue, FPL declared the TDEFWP inoperable, entered the applicable TS, restored the valve stroke time to within its design basis range, and entered the issue into the corrective action program (CAP) for resolution.

ii

The finding is more than minor, because it is associated with the procedural quality attribute of the Mitigating Systems cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. This finding was determined to be of very low significance, based on Phase 1 of the SDP, because it did not result in the loss of a safety function. (Section 1R21.2.1.2)

Licensee Identified Violations

None.

iii

REPORT DETAILS

REACTOR SAFETY

Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity

1R21 Component Design Bases Inspection (IP 71111.21)

.1 Inspection Sample Selection Process

The team selected risk significant components and operator actions for review using information contained in Seabrook Stations Probabilistic Risk Assessment (PRA) and the U. S. Nuclear Regulatory Commissionss (NRC) Standardized Plant Analysis Risk (SPAR) model. Additionally, the Seabrook Significance Determination Process (SDP)

Phase 2 Notebook, Revision 2, was referenced in the selection of potential components and actions for review. In general, this included components and operator actions that had a risk achievement worth (RAW) factor greater than 2.0 or a Risk Reduction Worth (RRW) factor greater than 1.005. The components selected were located within both safety related and non-safety related systems and included a variety of components, such as electrical buses, batteries, pumps, fans, diesel generators (DGs), heat exchangers (HXs), tanks, and valves. The components selected involved 12 different plant systems.

An initial list, consisting of over 50 components, was created based on the risk factors previously mentioned. A margin assessment was then performed to narrow this down to 17 components for a detailed design review. This design margin assessment considered original design issues, margin reductions due to modifications, or margin reductions identified as a result of material condition/equipment reliability issues. These included items such as failed performance test results, significant corrective action history, repeated maintenance, Maintenance Rule (MR) (a)(1) status, operability reviews for degraded conditions, NRC resident inspector input of problem equipment, system health reports and industry operating experience (OE). Consideration was also given to the uniqueness and complexity of the design and the available defense-in-depth margins. The team also selected 4 operator actions for detailed review based on risk significance, time dependency of the actions, and factors affecting the likelihood of human error.

The inspection effort included walk-downs of selected components, including a review of selected simulator scenarios. It also included interviews with operators, system engineers and design engineers, and reviews of associated design documents and calculations to assess the adequacy of the components to meet both design bases and risk informed beyond design basis functions. A summary of the reviews performed for each component, operator action, operating experience sample, and the specific inspection findings identified are discussed in the following sections of the report.

Documents reviewed for this inspection are listed in the attachment.

.2.1.1 Refueling Water Storage Tank (CBS-TK-8)

a. Inspection Scope

The team evaluated the refueling water storage tank (RWST) relative to the following attributes: calculation of water volume in the tank and comparison with licensing basis documentation, height of water needed to preclude the formation of a vortex in the tank, accuracy of water measurement instrumentation and loop uncertainty analysis, past corrective action regarding water chemistry, and corrective actions developed and implemented during the inspection regarding temperature compensation. The team also conducted a detailed walkdown to visually inspect the physical/material condition of the tank and support systems and to ensure adequate configuration control.

b. Findings

Introduction.

The team identified a Green non-cited violation (NCV) of 10 CFR 50, Appendix B, Criteria III, Design Control, associated with a non-conservative instrument uncertainty calculation for RWST level.

Description.

Seabrook Technical Specification (TS) 3.5.4 requires a minimum contained borated water volume of 477,000 gallons in the RWST to assure that 350,000 gallons of water is available for injection during an accident (Updated Final Safety Analysis Report (UFSAR) 6.3.2.8 and UFSAR Chapter 15 analysis). Operators rely on the RWST low level alarm (approach to TS alarm) and the Lo-Lo level alarm (at the TS limit) to maintain this required RWST inventory. Engineering established the alarm setpoints based on their Channel Statistical Accuracy evaluation that considered environmental conditions, system conditions and instrument error.

During the inspection, while responding to the teams request for the RWST level instrument loop analysis, engineering staff noted several deficiencies with the existing analysis. Specifically, the instrument uncertainty calculation took credit for instrument temperature compensation of the RWST level instruments as specified in the UFSAR; however, the instruments were not temperature compensated. Also, the calculation did not account for bulk temperature changes, increased water density due to borated water in the RWST, and several additional uncertainty terms in the analysis. On March 29, 2007, engineering initiated CR 07-04915 and performed a prompt operability assessment. Engineering determined that the RWST was operable but degraded.

Operations implemented a compensatory action (Standing Order 07-002) to maintain adequate margin to the TS limit until engineering modified the level measurement on April 19 to include temperature compensation.

The team also identified additional inaccuracies associated with the bulk temperature mismatch (between the RWST and the level instrument standpipe) and the impact of air pressure differences (the RWST and pressure indicator were located in different rooms and ventilated by separate non-safety ventilation fans). In accounting for all of the above inaccuracies, the RWST low level alarm (approach to TS limit warning) would not have adequately ensured that FPL maintained the design basis RWST inventory.

Based on a thorough review of historical values of actual RWST level and temperature, engineering determined that the RWST had remained operable. In the aggregate, the performance deficiency resulted in approximately 3 to 4 of non-conservative level error, leaving little or no margin to the TS level limit (over 1000 gallons of perceived margin was reduced to less than 300 gallons in some cases).

Analysis.

The performance deficiency associated with this finding was that Seabrook engineering failed to properly account for RWST level uncertainties which resulted in a non-conservative level error. The issue was reasonably within FPLs ability to foresee and correct prior to March 2007. The team determined that the issue was more than minor because it was similar to Example 3.j in NRC IMC 0612 Appendix E, Examples of Minor Issues. Specifically, an engineering calculation error resulted in a condition where there was a reasonable doubt as to the RWST operability. In addition, the finding was more than minor because it affected the design control attribute of the Mitigating Systems cornerstone objective of ensuring the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences. The team reviewed this finding using the Phase 1 SDP worksheet for Mitigating Systems and determined that the finding was of very low safety significance (Green), because it was a design deficiency confirmed not to result in loss of operability per Part 9900, Technical Guidance, Operability Determination Process for Operability and Functional Assessment.

Enforcement.

10 CFR 50 Appendix B, Criterion III, Design Control, requires, in part, that design control measures be established and implemented to assure that applicable regulatory requirements and the design basis for structures, systems, and components (SSCs) are correctly translated into specifications, drawings, procedures, and instructions. Contrary to the above, from initial plant operation until March 29, 2007, FPL did not ensure that the RWST level uncertainty analysis and resultant level alarm setpoints adequately maintained the design basis RWST inventory. Because this issue is of very low safety significance, and it was entered into the CAP (CR 07-04915), this violation is being treated as a NCV, consistent with Section VI.A.1 of the NRC Enforcement Policy. (NCV 05000443/2007006-01, Inadequate RWST Level Uncertainty Analysis)

.2.1.2 Steam Admission Valve to the Turbine Driven Emergency Feedwater Pump (MS-V-395)

a. Inspection Scope

The team inspected air-operated valve (AOV) MS-V-395 to verify its ability to meet the design basis requirements in response to transient and accident events, including admitting steam to the turbine driven emergency feedwater pump (TDEFWP). The team evaluated accumulator volume calculations to ensure that sufficient air would be provided to hold the valve closed for 31 seconds to prevent moisture to the TDEFWP under design basis conditions. The team verified that instrument setpoints were properly translated into system procedures and tests, and reviewed completed tests intended to demonstrate component operability. The team reviewed drawings, component calculations, and system calculations to verify that calculation inputs and assumptions were accurate and justified. The team reviewed the maintenance and functional history of the MS-V-395 valve by sampling corrective action reports, the system health report, operating procedures, and surveillance test (ST) procedures and results. The team reviewed the emergency feedwater (EFW) Design Basis Document (DBD) and Design Request 87-212, EFW Pump Steam Supply Time Delay, to determine the required stroke time for the MS-V-395 valve. The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the valve and its support systems and to ensure adequate configuration control.

b. Findings

Introduction:

The team identified a Green non-cited violation (NCV) of 10 CFR 50, Appendix B, Criterion XI, Test Control, associated with FPLs failure to correctly specify the minimum MS-V-395 stroke time acceptance limits to ensure that the systems design basis requirements could be met.

Description:

Teledyne Engineering Services performed a stroke time analysis for the TDEFWPs steam admission AOV (MS-V-395) after water hammer problems were discovered during system testing. The MS-V-395 valve was designed to stroke between 5-15 seconds. The basis for the valve's required minimum and maximum stroke time was part of a sequential timed opening after MS-V-393 and MS-V-394, to allow accumulated condensate to discharge and to allow the TDEFWP turbine governor to match a rapid steam demand, respectively.

The team determined that engineering tested MS-V-395 to meet the requirements of the ASME Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code)and TS 4.0.5. However, the team identified that the implementing procedure did not test the opening stroke time of MS-V-395 to meet the design bases requirements.

Specifically, the inservice test (IST) procedure established acceptance criteria allowing the MS-V-395 valve to stroke as early as 4 seconds, instead of the required 5 seconds.

The team reviewed recent MS-V-395 IST stroke times and determined that the B electrical train stroke time test did not meet the design basis stroke time of 5 seconds, and had been stroking between 4 and 5 seconds since June 2006. The team noted that operations satisfactorily completed the most recent TDEFWP test in February 2007, and determined that the faster opening time of the valve did not result in a loss of TDEFW system function.

Following identification of the MS-V-395 valve stroke time deficiency, FPL initiated CR 07-04990, declared the TDEFWP inoperable, entered the applicable TS (TS 3.7.1.2b), and restored the valve stroke time to within its design basis range on April 5, 2007. Engineering determined that inattention to detail caused the IST program document error on June 14, 1989.

Analysis:

The performance deficiency associated with this finding was that FPL did not establish an MS-V-395 valve stroke time test acceptance criteria that ensured that the valve would be capable of providing the required design basis stroke time during accident conditions. The issue was reasonably within FPLs ability to foresee and correct prior to April 2007. The team determined that the issue was more than minor because it was similar to Example 2.a in NRC IMC 0612 Appendix E, Examples of Minor Issues. Specifically, the B train MS-V-395 valve stroke time test records indicated that the TS IST limits were exceeded. In addition, this finding is associated with the procedural quality attribute of the Mitigating Systems cornerstone objective of ensuring the availability, reliability, and capability of the TDEFWP to respond to initiating events to prevent undesirable consequences. The team reviewed this finding using the Phase 1 SDP worksheet and determined the finding was of very low safety significance (Green),because it did not result in the loss of a safety function.

Enforcement:

10 CFR Part 50, Appendix B, Criterion XI, Test Control, states in part that a test program shall be established to assure that all testing required to demonstrate that SSCs will perform satisfactorily in service is identified and performed in accordance with written test procedures that incorporate the requirements and acceptance limits contained in applicable design documents. Contrary to the above, from June 14, 1989, to April 5, 2007, FPL did not include acceptance limits in the TDEFWP steam admission valve STs that were based on design basis requirements. Because this issue was of very low safety significance, and it was entered into FPL's CAP (CR 07-04990), this violation is being treated as an NCV, consistent with Section VI.A.1 of the NRC Enforcement Policy. (NCV 05000443/2007006-02, Non-Conservative TDEFWP Steam Admission Valve Stroke Time Test Acceptance Criteria)

.2.1.3 4kV Bus Degraded Voltage Relays

a. Inspection Scope

The 4.16kV bus degraded voltage relays function to ensure that adequate voltage levels are available to safety-related alternating current (AC) loads. In addition, the relay reset setpoint must be optimized to prevent a spurious loss-of-offsite power (LOOP). The team reviewed the degraded voltage relay setpoint and uncertainty calculations, calibration test acceptance criteria, relay calibration test results, and station voltage regulation studies (i.e., load drop calculations) to verify that the degraded voltage relays would function as designed during accident and transient conditions and satisfied TS requirements.

b. Findings

No findings of significance were identified.

.2.1.4 Service Water Cooling Tower Fan 2SW-FN-51B

a. Inspection Scope

The service water (SW) cooling tower is the safety-related ultimate heat sink for a postulated loss of SW intake structure event. The tower is a mechanical draft structure, which relies on forced air flow. Fan 2SW-FN-51B is located on the tower roof, has 12 foot fan blades, driven by a 250 horse power motor, and is directly exposed to the weather.

The team reviewed the cooling tower fan design basis, operating limits, engineering analysis, and ST results to verify that the fan would function as designed during accident and transient conditions and satisfied TS requirements. The review included fan motor ratings, load drop calculations, breaker settings and coordination, fan shaft torque ratings, and operating history as documented in ST results, condition reports (CRs), and system health reports. In addition, the team performed detailed walkdowns of the fan and interviewed personnel with fan blade de-icing experience, and reviewed winter cooling tower operating parameters to identify the likelihood of whether adverse winter weather could result in significant ice build-up on the fan blades. The team also walked down accessible portions of the cooling tower to assess material condition, and directly observed cooling tower operation on April 19, 2007.

b. Findings

No findings of significance were identified.

.2.1.5 1E 4kV to 480V Transformer EDE-X-5B

a. Inspection Scope

Transformer EDE-X-5B supplies power to engineered safety feature low voltage buses.

The team reviewed calculations, drawings, maintenance procedures, and vendor data to verify that EDE-X-5B was adequately designed and maintained. Specifically, the team reviewed load flow calculations to ensure that the voltage at the loads was supplied within the specified ratings. The team reviewed the design of protective relaying for this transformer to ensure that equipment was properly protected, and immune to spurious tripping under expected transient and steady state loading conditions. The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the accessible portions of the transformer and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.6 Primary Component Cooling Water Heat Exchanger Outlet Temperature Control Valve

1-CC-TV-2171-1

a. Inspection Scope

The team inspected air operated valve (AOV) 1-CC-TV-2171-1 to verify its ability to meet the design basis requirements in response to transient and accident events, including throttling for primary component cooling water (PCCW) temperature control.

The team evaluated nitrogen backup bottle volume calculations to ensure that sufficient nitrogen would be provided to throttle the valve as required under design basis conditions. The team verified that instrument setpoints were properly translated into system procedures and tests, and reviewed completed tests intended to demonstrate component operability. The team reviewed drawings, component calculations, and system calculations to verify that calculation inputs and assumptions were accurate and justified. The team reviewed the maintenance and functional history of the 1-CC-TV-2171-1 valve by sampling corrective action reports, the system health report, and operating and ST procedures. The team also conducted a detailed walkdown to visually inspect the physical/material condition of the valve and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.7 Residual Heat Removal Valve 1-RH-V-35 (Piggy-back Valve)

a. Inspection Scope

Valve 1-RH-V-35 is normally closed during plant operation and opened in certain loss-of-coolant accident (LOCA) scenarios as part of the swap-over from the injection phase to the recirculation phase. The team verified that FPLs analysis and testing of the valve supported this function. The team reviewed calculations to assure that engineering had adequately evaluated the potential for pressure locking and thermal binding. The team reviewed the valves motor operator capacity to assure that sufficient margin was available to open the valve during accident conditions. The team discussed valve performance and corrective actions with the valve engineer and systems engineer.

The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the valve and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.8 A Supplemental Emergency Power System Diesel Generator (1-SEPS-DG-2-A)

a. Inspection Scope

The team reviewed calculations and drawings to determine if the size of the A supplemental emergency power system (SEPS) DG was within equipment ratings. The team reviewed the adequacy and appropriateness of design assumptions and calculations related to the SEPS protection and relay coordination. The team reviewed design calculations to ensure fuel tank capacities were sufficient to meet required fuel oil consumption rates and to ensure vortexing would not occur in the fuel oil tanks. The team verified that tank capacity tests demonstrated the design basis required capacity.

The team verified that an appropriate fuel oil chemical control program was in place, such as moisture and impurity controls, to ensure that FPL adequately maintained fuel oil quality. The team performed a review of system normal operating and ST procedures to ensure that component operation and alignments were consistent with design and licensing bases assumptions. The team conducted several walkdowns of the SEPS DGs, observed a SEPS surveillance test, and reviewed additional ST results to assess system operation, configuration control, and material condition. The team reviewed calculations, system health reports, associated instrumentation and setpoints, and SEPS-related corrective action CRs to verify that FPL operated and maintained SEPS within its design basis. Finally, the team discussed the design, operation and maintenance of SEPS and related equipment with design and system engineers and plant operators.

b. Findings

No findings of significance were identified.

.2.1.9 Turbine Driven Emergency Feed Pump (FW-P-37)

a. Inspection Scope

The team reviewed the design of the TDEFWP. This review included the system flow calculations related to the pump operation under various transient and accident conditions and interactions between pumps under minimum flow conditions. The team reviewed the results of recent pump surveillance tests, ST acceptance criteria, corrective action CRs, system health reports, engineering evaluations, and responses to related industry operating experience (OE). The team also conducted several detailed walkdowns to assess the material condition of the pump and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.1 0 Start-up Feedwater Pump (1-FW-P-113)

a. Inspection Scope

The start-up feedwater (SUFW) pump is a non-safety related pump; however, it provides a back-up source of water for the EFW system. The team reviewed the SUFW vendor manual, test results, system drawings, and associated flow calculations to verify that the pump could provide the back-up function as designed. The team discussed system operating experience (suction header air intrusion, in particular) and corrective actions with design engineering. The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the pump and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.1 1 B Train Emergency Diesel Generator (1-DG-DG-1-B)

a. Inspection Scope

The team reviewed three sub-components of the B emergency diesel generator (EDG)to assess whether the EDG would function as required during normal and accident conditions. The three EDG systems inspected were the diesel fuel oil system, lube oil system, and starting air. The fuel oil system was reviewed to ensure a sufficient supply of fuel oil would be available and the system would function as designed; the lube oil system was reviewed to ensure the system would provide a continuous supply of oil to components of the EDG; and the starting air system was inspected to ensure the system would supply sufficient compressed air to initiate an engine start. The team reviewed calculations, hydraulic analyses, system health reports, associated instrumentation and setpoints, and corrective action CRs to verify that FPL operated the EDG within its design basis. The team reviewed ST results to verify levels and temperatures were within acceptable limits; and reviewed operating and test procedures to assess whether component operation and alignments were consistent with design and licensing basis assumptions. The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the EDG and its support systems and to ensure adequate configuration control. Finally, the team discussed the design, operation and maintenance of the EDG and related equipment with design and system engineers and plant operators.

b. Findings

No findings of significance were identified.

.2.1.1 2 B 125Vdc Battery (EDEB-1B)

a. Inspection Scope

The team reviewed the battery load and margin, charger sizing calculations, battery float and equalizing voltages, overall battery capacity, performance discharge test, short circuit calculation, and breaker interrupting ratings and electrical coordination to verify that the battery would function as designed during accident and transient conditions.

The team reviewed electrical schematics for selected 10 CFR Part 50 Appendix R circuits to ensure that coordination existed between the downstream and the upstream fuses. In addition, the team conducted several detailed walkdowns to visually inspect the physical/material condition of the battery and confirm that the battery room temperatures were within specified design temperature ranges. During the walkdowns, the team visually inspected the battery for signs of degradation such as excessive terminal corrosion and electrolyte leaks. The team also reviewed battery ST results to verify that battery condition and test acceptance criteria satisfied applicable TS requirements.

b. Findings

No findings of significance were identified.

.2.1.1 3 Service Water Secondary Isolation Valve (SW-V-5)

a. Inspection Scope

The SW isolation valves have a safety function to close on receipt of a tower actuation, safety injection (SI), or LOOP signal to isolate the SW supply to turbine building loads that are not necessary for safe shutdown. The team selected SW-V-5 as a representative sample of the two installed SW secondary isolation valves. The team reviewed valve design calculations, inservice test (IST) results, valve diagnostic testing procedures, engineering evaluations, system health reports, and disposition of CRs related to the valve. The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the valve and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.1 4 1E 480V Motor Control Center E621

a. Inspection Scope

The team reviewed calculations and drawings to determine if the size of 480V motor control center (MCC) E621 was within equipment ratings. The team reviewed the adequacy and appropriateness of design assumptions and calculations related to in-feed transformer protection and relay coordination. On a sampling basis, the team reviewed maintenance and test procedures, including acceptance criteria, to verify that MCC E621 was capable of supplying power necessary to ensure proper operation of connected equipment during normal and accident conditions.

b. Findings

No findings of significance were identified.

.2.1.1 5 Containment Sump Suction Motor-Operated Valve 1-CBS-V-14

a. Inspection Scope

The containment sump isolation valves have a safety function to open to start the recirculation phase during the recovery from a LOCA. The team selected 1-CBS-V-14 as a representative sample of the two installed containment sump isolation valves. The team reviewed valve design calculations, IST results, valve diagnostic testing procedures, engineering evaluations, and disposition of CRs related to the valve. The team performed walkdowns of the valve encapsulation, containment, sump debris interceptors, and the containment sump strainer to assess material condition and design control.

b. Findings

No findings of significance were identified.

.2.1.1 6 Primary Component Cooling Water Head Tank 1-CC-TK-19B

a. Inspection Scope

The team reviewed the B train PCCW head tank to assure that it would be capable of providing adequate suction pressure for the B PCCW pump given the postulated leak in the PCCW system. The team reviewed the head tank capacity analysis to determine if the tank had adequate volume to accommodate system thermal transients. The team reviewed Seabrook engineerings response to NRC Information Notice (IN) 98-25, associated operating procedures, and supporting drawings to assess the availability and qualification of the back-up supply of water for the head tank. The team discussed system operating experience and corrective actions with the PCCW system engineer.

The team also conducted several detailed walkdowns to visually inspect the physical/material condition of the tank and its support systems and to ensure adequate configuration control.

b. Findings

No findings of significance were identified.

.2.1.1 7 Train B Emergency Power Sequencer

a. Inspection Scope

The emergency power sequencer (EPS) has a safety function to provide appropriate contact outputs to the various safety-related loads to start them in a programmed time sequence. The team reviewed drawings, logic diagrams, maintenance and test procedures, and vendor manuals to verify that the EPS would function as designed during accident and transient conditions. The team reviewed the adequacy and appropriateness of design assumptions and calculations related to the load sequencer to assure proper operation.

b. Findings

No findings of significance were identified.

.2.2 Review of Low Margin Operator Actions (4 samples)

The team performed a margin assessment of expected operator actions, and selected a sample of operator actions for detailed review based upon risk significance, time dependency of the actions, and factors affecting the likelihood of human error. The operator actions were selected from PRA rankings of human action importance based on risk reduction worth (RRW) values and other PRA insights.

Considerations in the selection process included the following factors:

• Environmental conditions or restrictions for performing the actions;

• Personnel access to equipment;

• Plant procedures that address the actions;

• Need for additional personnel or equipment;

• Information available for diagnosing conditions and initiating actions;

• Ability of operator to recover from errors while performing task;

• Consequences of failure to complete action;

• Time to complete actions; and

• Task included in the Systematic Approach to Training (SAT) based training program and trained on.

The selected operator actions were generally characterized as having one or more of the following attributes:

• Low margin between the time required and time available to perform the actions;

• Reliability or redundancy of the components associated with the actions;

• Complexity of the actions; and

• Procedure or training challenges that increase the likelihood of an operator error.

.2.2.1 Operator Response to Loss of One Train of Primary Component Cooling Water

a. Inspection Scope

The team selected the manual operator actions for a loss of one train of PCCW.

Specifically, the actions reviewed were to reduce or isolate reactor letdown flow to the volume control tank and start a charging pump in the opposite equipment train, following a loss of one train of PCCW. These manual operator actions were identified in FPL's PRA as risk significant based on the risk importance of reactor coolant pump (RCP) seal integrity. FPL expected the operators to trip the two affected RCPs within ten minutes and control letdown and charging flows to maintain seal injection flow to all four RCPs.

The team selected this sample because these risk significant, time critical manual actions appeared to have low margin between the time required and the time available to perform the actions.

The team reviewed the mechanical, control, and instrumentation design for selected portions of PCCW, the chemical and volume control system, and the RCP seal cooling systems to assess component performance and design and operating limits during a loss of PCCW event. This review included operating assumptions, calculations, and system boundary conditions. The team evaluated the available process margins, based on fluid flow rates, temperatures, and heat transfer capacities; and performed limited independent calculations and analyses in several areas to verify the reasonableness of the design and operating values.

The team observed an operating crew respond to a loss of the A train of PCCW in the Seabrook simulator; interviewed licensed operators; and reviewed normal, abnormal, emergency operating procedures (EOPs), and alarm response procedures to evaluate the time margins to perform the manual actions. In addition, the team performed main control room walkdowns to independently identify operator task complexity. The team compared the available time, based on the identified equipment and operating limits, against the observed operator simulator performance and expected operator response based on nominal procedure usage demonstrated during licensed operator training.

The team evaluated those time margins to verify the reasonableness of FPL's operating and risk assumptions.

b. Findings

No findings of significance were identified.

.2.2.2 Operator Response to a Service Water Pump Failure to Restart in a LOOP Event

a. Inspection Scope

The team selected the manual operator action to start a SW pump during a LOOP scenario, following a failure of the previously running SW pump to restart. By design, during a LOOP event, each EDG will automatically start, re-energize the associated 4kV emergency bus, and sequentially start the safety loads on that electrical bus, including the associated SW pump for that equipment train. If the associated SW pump failed to automatically restart, then the operating EDG would trip due to high jacket water or lube oil temperature within a short time period. The team selected this sample because this risk significant, time critical manual action appeared to have low margin between the time required and the time available to perform the actions.

The team reviewed the control and instrumentation design, and hydraulic model for selected portions of the EDG and SW systems to assess component performance and design and operating limits during a loss of SW cooling event. This review included operating assumptions, calculations, and projected EDG cooling system performance and heat-up rates. The team evaluated the available process margins, based on fluid flow rates and cooling loop volumes, temperatures, and heat transfer capacities to verify the reasonableness of the design and operating values, and time margins. Seabrook engineering determined the time available to restart a SW pump was about 17 minutes.

The team observed an operating crew respond to a LOOP with a coincident failure to automatically restart a SW pump in the Seabrook simulator; interviewed licensed operators; and reviewed normal, abnormal, and EOPs to evaluate the time required to perform the manual actions. The team compared the available time against the time required to perform the manual actions to verify the reasonableness of FPL's operating and risk assumptions.

b. Findings

No findings of significance were identified.

.2.2.3 Energize Vital Buses from the Supplemental Emergency Power System during a Station

Blackout

a. Inspection Scope

The team selected the manual operator actions to energize emergency bus E5 or E6 from the SEPS during a Station Blackout (SBO) event. The actions reviewed included:

- Manual start attempt of the EDGs;

- Inhibit large loads from automatically starting;

- Isolate charging pumps before the Westinghouse time limit to prevent a RCP seal LOCA when charging is restored;

- Align SEPS to either Bus 5 or Bus 6;

- Manually sequence loads onto the vital bus; and

- Control bus loads to avoid over-loading the SEPS.

The team reviewed normal and emergency procedures and bases documents to evaluate the time required to perform the actions. The team reviewed FPL's SBO analysis, design basis documents (DBDs), and design calculations to evaluate the available operating limits and design margins. The team performed walkdowns of the SEPS diesels to identify operator task complexity and verify procedure adequacy. In addition, the team interviewed Seabrook operators to evaluate the time required to perform the manual actions. The team compared the available time against the time required to perform the manual actions to verify whether the implemented operator actions would be consistent with design, licensing, and PRA assumptions.

b. Findings

No findings of significance were identified.

.2.2.4 Transfer to Cold Leg Recirculation

a. Inspection Scope

The team selected the operator actions required to transfer the emergency core cooling system (ECCS) from the injection phase to the cold leg recirculation phase during a LOCA. By design, within three minutes of receipt of the RWST Lo-Lo level alarm, the containment sump isolation valves will automatically open and the operator must then take manual actions to shut the RWST suction valves placing the residual heat removal (RHR) system into cold leg recirculation. Failure to accomplish these actions could cause air ingestion by vortexing into all of the ECCS pump suctions, potentially damaging the pumps. The operator then has an additional five minutes after shutting the RWST suction valves to complete the transfer of suctions from the RWST to the containment sump for the remainder of the ECCS pumps. The team selected this sample because this risk significant, time critical operator action appeared to have low margin between the time required and the time available to perform the actions.

The team reviewed the RWST level detection system accuracy and tolerances, system design calculations pertaining to vortexing, design parameters for the associated motor operated valves (MOVs), and applicable Emergency Operating Procedures (EOPs).

The team evaluated the available margin based on fluid flow rates, instrument accuracies, operator and engineer interviews, and the vortexing calculation of record to verify the reasonableness of the design and operating values.

b. Findings

No findings of significance were identified.

.3 Review of Industry Operating Experience and Generic Issues (5 samples)

a. Inspection Scope

The team reviewed selected OE issues that had occurred at domestic and foreign nuclear facilities for applicability at Seabrook. The team performed an independent applicability review and selected issues with apparent applicability to Seabrook. The team performed a detailed review of the OE issues listed below to verify that FPL had appropriately assessed potential applicabililty to site equipment and implemented corrective actions as required.

• Operating Experience Smart Sample FY2007-02 NRC Operating Experience Smart Sample (OpESS) FY2007-02 is related to NRC IN 2005-30, Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design, and issues associated with conduit/hydrostatic seal issues. The team evaluated internal flood protection measures for the 4kV essential switchgear rooms, fuel oil transfer pump rooms, EFW pump room, and RHR equipment vaults. The team walked down the areas to assess operational readiness of various features in place to protect redundant safety-related components and vital electric power systems from internal flooding. These features included equipment drains, flood detection, flood barrier curbs, and wall penetration seals. The team conducted a detailed walkdown of the turbine, EFW, EDG, and primary auxiliary buildings with a design engineer to assess potential internal flood vulnerabilities. The team also reviewed engineering evaluations, alarm response procedures, preventive and corrective maintenance history, operator training, and corrective action CRs associated with flood protection equipment and measures. Finally, the team interviewed Seabrook personnel regarding their knowledge of indications, procedures and required actions during a postulated turbine building piping rupture.

• NRC Information Notice 2002-12: Submerged Safety-Related Electrical Cables The team reviewed the applicability and disposition of electrical cable degradation concerns described in NRC IN 2002-12, Submerged Safety-related Electrical Cables. The basis of IN 2002-12 was a concern that a potential common mode failure of underground cables could affect the operability of accident mitigation systems. The team reviewed the potential consequences of operating with submerged power cables. The team reviewed FPLs associated engineering evaluations, cable specifications, cabling monitoring and testing to ensure that permanent plant cables were appropriately qualified for submergence, as applicable. The team also reviewed potential adverse impact to the cable support structures due to water submergence.

• NRC Information Notice 2006-22: New Ultra-Low-Sulfur Diesel Fuel Oil Could Adversely Impact Diesel Engine Performance The team reviewed FPL's assessment of the potential impact on EDG operation with the use of the new ultra low sulfur fuel. The team reviewed fuel receipt forms, fuel oil sampling results, technical evaluations, and FPL's assessment of the potential impact on the EDGs. The team also reviewed a sample of corrective action CRs associated with EDG issues to verify that the problems identified in IN 06-22 had not occurred.

• Safety Injection System Gas Intrusion The team reviewed the applicability and disposition of various industry OE related to the potential for gas intrusion into Seabrooks SI system. The team reviewed Seabrook engineerings response to related industry OE, ECCS health reports, system venting and ultrasonic test (UT) procedures and practices, and established limits and controls. The team also discussed FPLs mitigation activities and trending with the system and non-destructive examination (NDE)engineers.

• NRC Information Notice 2006-29: Potential Common Cause Failure of Motor-Operated Valves as a result of Stem Nut Wear The team reviewed FPLs response to the OE presented in NRC IN 2006-29 regarding MOV stem nut wear. The team reviewed changes that FPL made in the MOV diagnostic procedures for MOVs to detect excessive stem nut wear.

The team also interviewed the MOV system engineer concerning the results and effectiveness of the modified diagnostic procedures.

b. Findings

No findings of significance were identified.

4OA2 Problem Identification and Resolution

a. Inspection Scope

The team reviewed a sample of problems that were identified by the licensee and entered into the corrective action program. The team reviewed these issues to verify an appropriate threshold for identifying issues and to evaluate the effectiveness of corrective actions related to design or qualification issues. In addition, condition reports (CRs) written on issues identified during the inspection were reviewed to verify adequate problem identification and incorporation of the problem into the corrective action system.

The specific corrective action documents that were sampled and reviewed by the team are listed in the attachment to this report.

b. Findings

No findings of significance were identified.

4OA6 Meetings, Including Exit

On April 26, 2007, the team presented the inspection results to Mr. G. St. Pierre and other members of Seabrook Station management. The team verified that no proprietary information is documented in the report.

ATTACHMENT

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee Personnel

R. Belanger Design Engineering

P. Brown MOV/AOV System Engineer

R. Cliche Manager, Design Engineering

S. Fournier Design Engineering

R. Jamison Design Engineering

J. Johnson EFW System Engineer

D. Kelly EOP Coordinator

A. Kodal PCCW System Engineer

R. McCormack SW System Engineer

D. McGonigle Design Engineering

M. OKeefe Regulatory Compliance Supervisor

R. Parry Supervisor, Component Group, Plant Engineering

L. Rau Supervisor, PRA Engineering

V. Robertson Regulatory Compliance

T. Schulz Design Engineering

G. Sessler SEPS System Engineer

G. St. Pierre Site Vice President

NRC Personnel

C. Cahill Senior Reactor Analyst

G. Dentel Senior Resident Inspector

S. Shaffer Resident Inspector

LIST OF ITEMS

OPENED, CLOSED AND DISCUSSED

Open and

Closed

05000443/2007006-01 NCV Inadequate RWST level uncertainty analysis. (Section 1R21.2.1.1)

05000443/2007006-02 NCV Non-conservative TDEFWP steam admission valve stroke time test acceptance criteria. (Section 1R21.2.1.2)