IR 05000458/2018010
| ML18085B197 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 03/26/2018 |
| From: | Greg Werner NRC/RGN-IV/DRS/EB-2 |
| To: | Maguire W Entergy Operations |
| Werner G | |
| References | |
| BL-12-001 IR 2018010 | |
| Download: ML18085B197 (31) | |
Text
March 26, 2018 Mr. William F. Maguire, Site Vice President Entergy Operations, Inc.
River Bend Station 5485 US Highway 61N St. Francisville, LA 70775 SUBJECT: RIVER BEND STATION - NRC INSPECTION OF TEMPORARY INSTRUCTION 2515/194, INSPECTION OF THE LICENSEES IMPLEMENTATION OF INDUSTRY INITIATIVE ASSOCIATED WITH THE OPEN PHASE CONDITION DESIGN VULNERABILITIES IN ELECTRIC POWER SYSTEMS (NRC BULLETIN 2012-01) - INSPECTION REPORT 05000458/2018010
Dear Mr. Maguire:
On February 8, 2018, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at the River Bend Station. On February 8, 2018, the inspectors discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.
The NRC inspectors did not identify any findings or violations of more than minor significance.
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Gregory E. Werner, Chief Engineering Branch 2 Division of Reactor Safety Docket No. 50-458 License No. NPF-47 Enclosure:
Inspection Report 05000458/2018010 w/ Attachments: 1. Table 1 - Information Gathered for Temporary Instruction 2515/194 2. TI 2515/194 Inspection Documentation Request
U.S. NUCLEAR REGULATORY COMMISSION
Inspection Report
Docket Number: 05000458 License Number: NPF-47 Report Number: 05000458/2018010 Enterprise Identifier: 000512/05000458/I-2018-010-0019 Licensee: Entergy Operations, Inc.
Facility: River Bend Station Location: Saint Francisville, Louisiana Inspection Dates: February 5, 2018, to February 8, 2018 Inspectors: S. Graves, Team Lead, Senior Reactor Inspector, Region IV S. Makor, Reactor Inspector, Region IV Accompanying G. Matharu, Senior Electrical Engineer, NRR/DE/EEOB Personnel: K. Nguyen, Electrical Engineer, NRR/DE/EEOB J. Quichocho, Chief, NRR/DE/EEOB Approved By: G. Werner, Branch Chief, Engineering Branch 2 Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission continued monitoring licensees performance by conducting Temporary Instruction 2515/194, Inspection of the Licensees Implementation of Industry Initiative Associated with the Open Phase Condition Design Vulnerabilities in Electric Power Systems (NRC Bulletin 2012-01), at River Bend Station, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the Nuclear Regulatory Commissions program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations None.
Additional Tracking Items None.
INSPECTION SCOPE
This inspection was conducted using Temporary Instruction 2515/194 (ADAMS Accession No. ML17137A416), dated October 31, 2017. The inspectors reviewed the licensees implementation of Nuclear Energy Institute voluntary industry initiative in compliance with Commission guidance. The team discussed the licensees open phase condition system design and ongoing implementation plans with plant staff, Entergy Corporate staff and vendor staff.
The team reviewed licensee and vendor documentation, and performed system walkdowns to verify that the installed equipment was supported by the design documentation. The team verified that the licensee had completed the installation and testing of equipment (with the exception of the tripping functions), installed and tested alarming circuits both local and in the control room, and analyzed potential impacts associated with the design implementation on the current licensing basis.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL Temporary Instruction 2515/194 - Inspection of the Licensees Implementation of Industry Initiative Associated With the Open Phase Condition Design Vulnerabilities in Electric Power Systems (NRC BULLETIN 2012-01)
The objective of Temporary Instruction 2015/194 is to verify that licensees have appropriately implemented the Nuclear Energy Institute voluntary industry initiative including updating their licensing basis to reflect the need to protect against open phase conditions and to gather the information necessary for Office of Nuclear Reactor Regulation staff to determine whether the licensees have adequately addressed potential open phase conditions.
Temporary Instruction 2515/194-03.01 - Voluntary Industry Initiative (Part 1)
River Bend Station selected the open phase detection system designed and manufactured by PCS2000 Solutions, LLC, as the design vendor for the open phase condition system. At the end of this inspection the PCS2000 system was still in the monitoring mode of operation to facilitate continued data gathering of grid perturbations for evaluation of alarm and trip setpoints.
The open phase condition equipment was installed on the preferred station service transformers RTX-XSR1C and RTX-XSR1D which power the station vital busses. The licensee was scheduled to transition the PCS2000 system to full implementation (tripping functions enabled) in December 2018. The licensee was preparing the full implementation engineering changes and associated documents for this transition, however they were not available for review at the time of inspection.
Section 03.01 of the Temporary Instruction required the determination whether the licensee appropriately implemented the voluntary industry initiative, dated March 16, 2015 (ADAMS Accession No. ML15075A454), by verifying the following:
a. Detection Alarms and General Criteria 1. Either open phase conditions are detected and alarmed in the control room, or
- (a) The licensee has demonstrated that open phase conditions do not prevent the functioning of important-to-safety systems, structures, and components,
- (b) open phase condition detection will occur within a reasonably short period of time (e.g., 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />), and
- (c) the licensee has established appropriate documentation regarding open phase condition detection and correction.
2. Either detection circuits are sensitive enough to identify an open phase condition for
credited loading conditions (i.e., high and low loading), or if automatic detection may not be possible in very low or no loading conditions when offsite power transformers are in standby mode, automatic detection must happen as soon as loads are transferred to this standby source. Additionally, the licensee has established appropriate shiftily surveillance requirements to look for evidence of open phase conditions.
3. Open phase condition design/protective schemes minimize misoperation or spurious action in the range of voltage unbalance normally expected in the transmission system that could cause separation from an operable off-site power source.
Licensees have demonstrated that the actuation circuit design does not result in lower overall plant operation reliability.
4. New non-Class-1E circuits are not used to replace existing Class-1E circuits.
5. The updated safety analysis report has been updated to discuss the design features and analyses related to the effects of, and protection for, any open phase condition design vulnerability.
b. Protective Actions 1. If the licensee determines there is no single credible failure that could cause an open phase condition, then verify that the licensee has developed and issued a full engineering evaluation to document the basis for open phase condition as a non-credited event. The Bruce Power and Forsmark operating experience must be considered as part of this analysis.
2. With open phase condition occurrence and no accident condition signal present, either an open phase condition does not adversely affect the function of important-to-safety systems, structures, and components, or
- (a) technical specification limiting condition for operation are maintained or the technical specification actions are met without entry into Technical Specification Limiting Condition for Operation 3.0.3 (or equivalent),
- (b) important-to-safety equipment is not damaged by the open phase condition, and
- (c) shutdown safety is not compromised.
3. With open phase condition occurrence and an accident condition signal present, automatic detection and actuation will transfer loads required to mitigate postulated accidents to an alternate source and ensure that safety functions are preserved as required by the current licensing bases, or the licensee has shown that all design basis accident acceptance criteria are met with the open phase condition, given other plant design features. Accident assumptions must include licensing provisions associated with single failures. Typically, licensing bases will not permit consideration of the open phase condition as the single failure since this failure is in a non-safety system.
4. Periodic tests, calibrations, setpoint verifications, or inspections (as applicable)have been established for any new protective features. The surveillance requirements have been added to the plant Technical Specifications, if necessary to meet the provisions of 10 CFR 50.36.
Temporary Instruction 2515/194-03.02 - Information Gathering for Voluntary Industry Initiative Assessment (Part 2)
Section 03.02 of the Temporary Instruction required information gathering as part of the initial inspections to enable the Nuclear Reactor Regulation staff to determine whether the modifications implemented by the licensee of each unique open phase condition system design for the voluntary industry initiative adequately address potential open phase conditions. The information gathered for this section is tabulated in, Table 1 - Information Gathered for Temporary Instruction 2515/194, to this report.
INSPECTION RESULTS
Based on interviews and discussions with the licensee and the vendor, review of available design, testing, grid data trending results documentation, tour of the vendor facility, and walkdowns of installed equipment, the team had reasonable assurance the licensee appropriately implemented, with noted exceptions discussed below, the voluntary industry initiative.
Temporary Instruction 2515/194-03.01 - Voluntary Industry Initiative (Part 1)a. Detection Alarms and General Criteria
- (1) The team determined by walkdowns and observation that open phase conditions will be detected and alarmed in the control room.
- (2) The team determined that detection circuits were sensitive enough to identify an open phase condition for all credited loading conditions.
- (3) No Class-1E circuits were replaced with non-Class 1E circuits in the design.
b. Protective Actions Criteria
- (1) The team determined the licensee identified they were susceptible to an open phase condition and were implementing design changes to mitigate the effects.
- (2) The team determined that with an open phase condition present and no accident condition signal, the PCS2000 system would not adversely affect the function of important-to-safety systems, structures, and components.
No findings were identified, however the team identified the following exceptions to the Temporary Instruction criteria resulting from the incomplete design modifications:
c. Detection Alarms and General Criteria Exceptions
- (1) The licensees design was operating in the monitoring mode to gather data to ensure the open phase condition design and protective schemes would minimize misoperation, or spurious action in the range of voltage unbalance normally expected in the transmission system. Because actual demonstration of this criterion requires the system to be in operation with final trip setpoints established, the team was not able to fully verify this criterion. After discussions with licensee and vendor staff, and design document and test results reviews, the team had reasonable assurance that the actuation circuit design would not result in lower overall plant operation reliability.
The team did not identify any issues of concern.
- (2) The Updated Safety Analysis Report had not been updated at the conclusion of the onsite inspection. The team held discussions with the licensee concerning their interpretation of the guidance in the voluntary industry initiative related to adding open phase condition related entries to their licensing basis documents. The licensee entered this issue into their corrective action program as Condition Report CR-RBS-2018-00891 to determine if the Updated Safety Analysis Report would be updated prior to initiating the full design (trip functions enabled) or during the next normal final safety analysis report (FSAR) update cycle. The team did not identify any issues of concern.
d. Protective Actions Criteria Exceptions
- (1) The licensees open phase condition design solution used the existing load transfer scheme for safety-related accident loads; only a new tripping condition (open phase)had been added to the electrical faults which result in safety-related loads being transferred to the onsite emergency power system. Because actual demonstration of this criterion requires the system to be in full operation, the team was not able to fully verify this criterion. Through review of available design documents and discussions with plant engineering and vendor staff, the team had reasonable assurance that with an open phase condition present and an accident condition signal, the PCS2000 system automatic detection and actuation would transfer loads required to mitigate postulated accidents to an alternate source and ensure that safety functions are preserved, as required by the current licensing bases. The team did not identify any issues of concern.
- (2) The licensee had not finalized documentation for periodic tests, calibrations, setpoint verifications, or inspection procedures for open phase condition-related components at the time of this inspection. The licensee had initiated action requests to establish these activities. The team reviewed the action requests (AR283793 and AR283795)documents outlining the proposed periodic testing and periodicities for the newly installed equipment, reviewed historical system logs related to system performance, reviewed and discussed planned testing, calibration, and inspections. The team also held discussions on the licensees plans to include open phase condition-related components into the Maintenance Rule (10 CFR 50.65) program. The licensee entered this issue into their corrective action program as Condition Report CR-RBS-2018-00893. Existing plant equipment will continue to be maintained according to the licensees current preventative maintenance program. The licensee planned to use guidance in the North American Electric Reliability Councils Reliability Standard PRC-005 and vendor maintenance guidance to maintain the added switchyard relaying equipment for the PCS2000 design. The team did not identify any issues of concern.
EXIT MEETINGS AND DEBRIEFS
On February 8, 2018, the team presented the Temporary Instruction 2515/194 inspection results to Mr. W. Maguire, Site Vice President and other members of the licensee staff. The inspectors verified no proprietary information was retained or documented in this report.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision/
Procedure Date
TI 2515/194 Calculations G13.18.3.6-026 River Bend Open Phase with 0
Loss-of-Coolant Accident
Analysis
G13.18.3.6-025 River Bend Open Phase 1
Feasibility Analysis
G13.18.3.6*018 Electrical Transient Analysis 5
Program Database Input
Source Study
E-216 Normal Battery BYS-BAT01 B 1
(ECN 55751) Duty Cycle, Current Profile
and Size Verification
E-222-NJS- E-222-NJS-LDC1 QR, 480 1
LDC1 QR VAC Normal Load Center and
Motor Control Center Load
Tabulation including Cable
Verification
Drawings 0242.112-027- Outline - Type SL
20 Transformer, 230kV/4160V
242.112-027- RTX-XSR1C Power 0
25 Transformer Open Phase
Detection 3-Line AC
Schematic
242.112-027- RTX-XSR1D Power 0
26 Transformer Open Phase
Detection 3-Line AC
Schematic
242.112-027- RTX-XSR1C Power 0
034 Transformer OPD Sensor, and
CT Mounting Layout and
Details
242.112-027- RTX-XSR1D Power 0
035 Transformer OPD Sensor, and
CT Mounting Elevation and
Details
Inspection Type Designation Description or Title Revision/
Procedure Date
242.112-027- RTX-XSR1D Power 0
040 Transformer OPD Sensor, and
CT Mounting Layout and
Details
242.112-027- RTX-XSR1D Power 0
041 Transformer OPD Sensor, and
CT Mounting Elevation and
Details
EE-003ZQ RTX-XSR1D Power 0
Transformer Open Phase
Detection 3-Line AC
Schematic Asset Numbers
EE-030A Arrangement Transformer 10
Yard Unit 1
EE-030E Sections and Details 3
Transformer Yard 2A
EE-040A Conduit Plans and Details 4
Transformer Yard Area
EE-040B Conduit Plans and Details 2
Transformer Yard Area
ESK-08SPR18 Elementary Diagram 125VDC 6
Control Circuit Preferred
Station Service XFMR
Protection
ESK-08SPR19 Elementary Diagram 125VDC 7
Control Circuit Preferred
Station Service XFMR
Protection
EE-001AC Start-Up Electrical Distribution 56
Chart
ESK-08SPR04 Elementary Diagram 125VDC 23
Control Circuit Preferred
Station Service XFMR Backup
Protection
ESK-08SPR07 Elementary Diagram 125VDC 25
Control Circuit Preferred
Station Service XFMR Backup
Protection
Inspection Type Designation Description or Title Revision/
Procedure Date
ESK-08SPR15 Elementary Diagram 125VDC 27
Control Circuit Preferred
Station Service XFMR Backup
Protection
ESK-08SPR17 Elementary Diagram 125VDC 8
Control Circuit Preferred
Station Service XFMR Backup
Protection
EE-003ZS Wiring Diagram Open Phase 0
Detection Panel RTX-XSR1C
EE-003ZT Wiring Diagram RTX-XSR1D 0
Open Phase Detection Panel
242.112-027- Connection Diagram Power 0
048 Transformer System 1 and 2
Open Phase Detection
RTX-XSR1C
242.112-027- Connection Diagram 0
049 RTX-XSR1D Power
Transformer System 1 & 2
Open Phase Detection
ESK-11SPF01 Elementary Diagram Station 9
Protection Reserve Station
Service Line
ESK-11SPF02 Elementary Diagram Station 8
Protection Reserve Station
Service Line
ESK-08SPR20 Elementary Diagram 125VDC 7
Control Circuit Dual Channel
Transfer Trip ACB 06, 07, 11
ESK-08SPR21 Elementary Diagram 125VDC 7
Control Circuit Dual Channel
Transfer Trip ACB 15, 26, 27
Engineering EC 47357 Design Change to Detect 0
Changes Open Phase Condition on
Primary Side of RTX-XSR1C
and RTX-XSR1D (BYRON
EVENT) IER-L2-12-14,
Condition Report
2015
Inspection Type Designation Description or Title Revision/
Procedure Date
EC 47359 RTX-XSR1C, Design Change 0
to Detect Open Phase
Condition
EC 47360 RTX-XSR1D, Design Change 0
to Detect Open Phase
Condition
EC 56100 ECN to Revise PMTP of 0
47360
Engineering RBS-EE-17- RBS Open Phase Detection 0
Reports 00002 Monitoring Period Report
March 2015 - January 2016
RBS-EE-17- RBS Open Phase Detection 0
00003 Monitoring Period Report
January 2015 - July 2017
RBS-EE-18- RBS Open Phase Detection 00
00001 Monitoring Period Report July
2017 - January 2018
Miscellaneous RBG-47430 Letter from River Bend Station January 31,
Response to Request for 2014
Additional Information
Regarding Response to
Bulletin 2012-01, "Design
Vulnerability In Electric Power
System"
RBG-47299 90-Day Response to October 24,
Bulletin 2012-01, Design 2012
Vulnerability in Electric Power
System River Bend Station -
Unit 1
AR 283793 Preventive Maintenance October 16,
Change Request: 2017
RSS1 Open Phase Detection
System Protection Relays and
Current Transformers
RSS2 Open Phase Detection
System Protection Relays and
Current Transformers
Inspection Type Designation Description or Title Revision/
Procedure Date
Preventive Maintenance
AR 283795 October 16,
Change Request:
2017
RSS1 and RSS2 Open Phase
Detection System
Procedures AOP-0064 Degraded Grid 010
OSP-0028 Log Report - Normal 107
Switchgear, Control, and
Diesel Generator Buildings
OSP- Procedure Action Request
28R107CN-E Change Notice for Log Report
- Normal Switchgear, Control,
and Diesel Generator
Buildings
OSP-0031 Log Report - Outside Area 093
OSP-0031 Log Report - Outside Area 064
ARP-680-09 P680-09 Alarm Response 033
SOP-0055 Main and Station 040
Transformers (SYS #311)
Vendor P517-0109 PCS2000 Open Phase 0
Documents Detection System User
Manual
Work Orders 00365542 Install PCS2000 Relay on April 11, 2017
RTX-XSR1C for Open Phase
Detection
00365543 Install PCS2000 Relay on September 15,
RTX-XSR1D for Open Phase 2015
Detection
Corrective Action Documents (CR-RBS-)
2015-08755 2017-08510 2018-00893
2017-01281 2018-00360 2012-01000
2017-00493 2018-00396 2017-05750
2017-00501 2018-00495 2018-00892
2017-01217 2018-00857
2017-02356 2018-00859
2017-02770 2018-00894
2017-03493 2018-00891
Table 1 - Information Gathered for Temporary Instruction 2515/194
A Open Phase Condition Describe Observations/Comments
Detection and Alarm
Scheme
Are all credited offsite power Yes Updated Safety Analysis Report Section 8.1
sources specified in No states that River Bend Station is provided
Updated Safety Analysis power from the 230 kV bays of the Fancy Point
Report Chapters 8.1, 8.2, substation via two physically and electrically
and 8.3 and plant Technical independent lines. Each 230 kV line is
Specifications considered in terminated at a transformer yard. Transformer
the design of open phase yard 1 includes preferred station service
condition detection and transformer RTX-XSR1C and yard 2A includes
protection schemes? RTX-XSR1D. The Updated Safety Analysis
Report section also states that standby 4160 V
buses ENS-SWG1A and ENS-SWG1B are
connected to preferred station service
transformers RTX-XSR1C and RTX-XSR1D,
respectively. The transformers in both
transformer yards support the normal operation
and safe shutdown operation of River Bend
Station Drawings 0242.112-027-025 and
242.112-027-026 show the inputs of the new
open phase detection system being connected
to the high side of preferred station service
transformers RTX-XSR1C and 1D.
References:
Updated Safety Analysis Report Section 8.1
and 8.2
Drawings: 0242.112-027-025 and
242.112-027-026
Are open phase condition Yes The PCS2000 system overview and user
detection scheme(s) No manual states that the system is capable of
installed to monitor the detecting open phase conditions anywhere on
qualified offsite power paths the direct line between the source breaker and
to the engineered safety the power transformer while in standby mode
feature buses during all and drawing excitation current, lightly loaded or
modes of operation? fully loaded. This also includes the detection of
an open phase and grounded condition, a
double open phase and grounded condition,
and an open phase with line charging current
on the high side of a power transformer.
The system has two modes of monitoring the
power transformer for an open phase condition:
no load excitation current mode and transformer
load mode. Internal logic is used to measure
the power transformer high side current levels
and give alarming/tripping priority to either
mode based on the power transformer current
levels RTX-XSR1C and RTX-XSR1D provide
preferred source of power for the engineered
safety feature buses from Offsite sources. The
licensee stated that Engineering Calculation
G13.18.3.6*025 that performed the feasibility
analysis at River Bend Station considered
various open phase configurations for different
station loading scenarios. The audit team did
not review the feasibility studies.
What is the scope of open The scope of open phase condition scheme
phase conditions considered considered the high voltage side of the
by the licensee? transformers only. Open phase conditions on
Yes the low voltage side are not expected to occur.
Did the licensee exclude No The PCS system is capable of detecting open
certain open phase phase conditions anywhere on the direct line
conditions (e.g., high voltage between the source breaker and the power
or low voltage side of power transformer while in standby mode and drawing
transformers), operating and only excitation current, lightly loaded or fully
loading configurations in loaded. This includes the detection of an open
their analyses? If so, phase and grounded condition, a double open
identify the technical phase and grounded condition, and an open
justifications for any phase with line charging current on the high
exclusion. side of a power transformer. Preventive
maintenances on switchgears include
inspecting the bus for damaged components,
loose parts, corrosion, etc. Thermography tests
are performed on various safety-related
components that include motor control centers,
switchgears, transformers, and distribution
panels. Safety-Related breakers are inspected
and refurbished, motors are inspected and
baker tested on a periodic basis through the
preventive maintenance process. Apart from
various maintenance activities that ensure
expected operation, system engineering and
operations perform frequent walkdowns to
identify any system anomalies. Based on this,
the requirement for a separate system that
monitors for open phase condition on the plant
side is not required.
Are the detection schemes Yes The licensee indicated that Engineering
capable to identify open No Calculation G13.18.3.6*025 performed the
phase conditions under all feasibility analysis at River Bend Station and
operating electrical system considered various open phase configurations
configurations and plant for different station loading scenarios. Report
loading conditions? No. RBS-EE-17-00002, Revision 1 for RTX-
XSR1D open phase detection system provides
monitoring data between March 2015 and
January 2016. The report was revised to add
more detail on plant specific events.
Specifically, the report updated data for events
which includes timestamps, sequence
components, and calculations to estimate
horsepower for each motor start event and load
change event. A review of the revised report
RBS-EE-17-00001, shows the systems
response to motor starts at various estimated
loads, different load changes and transformer
energization. A review of the report indicates
that the detection schemes are capable of
identifying open phase conditions under all
operating electrical system configurations and
plant loading conditions.
If the licensee determined Yes The licensee has determined that open phase
that open phase condition No condition detection and alarm scheme is
detection and alarm scheme needed at its facility.
was not needed, did the
licensee provide adequate
calculational bases or test
data?
Are all open phase Yes The alarms from the open phase detection
conditions detected and No system are tied into common alarms for
alarmed in the main control transformer trouble and annunciated in a panel
room with the existing in the main control room. The alarms signify
relays? Preferred Station Service Transformer Trouble.
Are the detection and alarm Yes Relay contacts in each relay in the system
circuits independent of No provide trip/alarm signals which use circuits that
actuation (protection) are independent of each other.
circuits?
If the detection, alarm, and Yes There are no interfaces with Class 1E systems.
actuation circuits are No
non-Class 1E, was there
any interface with Class 1E
systems?
Did the manufacturer Yes The open phase detection system uses a
provide any information/data No combination of parameters to determine an
for the capability of installed open phase condition. These include specific
relays to detect conditions, differences between phase currents relating to
such as unbalanced voltage magnitudes and phase angles, as well as
and current, negative comparisons of current sequence components.
sequence current, A variety of initial input data is used for each
subharmonic current, or transformer: winding configuration, expected
other parameters used to and actual nominal excitation current, mega volt
detect open phase condition amp and voltage, inrush delay, and time delays
in the offsite power system? for trips. Monitoring data is used to update and
adjust input data and typical levels of
What are the analyses and unbalance. A high-level description of the open
criteria used by the licensee phase condition detection circuit requires the
to identify the power system following conditions: 1. The current(s) drops in
unbalance due to open the phase this is open, drops below a low
phase conditions; and percentage setpoint of the nominal current. This
loading and operating includes both fundamental and root mean
configurations considered square components. 2. The current in the intact
for all loading conditions phase(s) stays above a high percentage
which involve plant trip Yes setpoint of the nominal current. Certain
followed by bus transfer No restraint setpoints also need to be met such as
condition? the ratio of fundamental to root mean square
current, ratios of sequence components, and
If certain conditions cannot holding these conditions for the required
be detected, did the licensee Yes amount of time.
document the technical No River Bend Station performed calculations that
basis for its acceptability? evaluated various loading conditions in
conjunction with the transmission system model
for various open phase condition configurations.
Did the licensee perform
functional testing to validate Failure modes and effects analysis was
limitations specified by the performed and used as an input into
manufacturer of the relays? Engineering Change 47357 and testing
procedures for the engineering change to
ensure misoperation are minimized. Functional
testing including Factory Acceptance and Site
Acceptance testing were performed as part of
Engineering Change 47357 prior to
commissioning the system.
Do open phase condition Yes There are several restraints built into the
detection circuit design No detection logic to prevent spurious detections
features minimize spurious from normal transmission disturbances. These
detections due to voltage restraints with initial setpoints were created
perturbations observed from PCS Lab testing, and were updated and
during events which are expanded based on testing and data collected
normally expected in the from installed systems: Entergy engaged an
transmission system? external consulting company (Sargent & Lundy)
to develop test cases for the River Bend Station
Identify whether the licensee open phase condition detection scheme. The
considered alarm/trip test cases considered different types of
settings coordination with disturbances on the transmission system;
other electric power system monitoring data from the River Bend Station
relays including systems and from other sites open phase
transmission system detection systems include multiple transmission
protection features setup to faults and disturbances used to validate and
avoid false indications or tune restraint setpoints. Engineering
unnecessary alarms. Calculation G13.18.3.6*025 developed and
documented the power system model for the
station auxiliaries, and the transmission network
near River Bend Station for system analyses
using industry-approved software named
electro magnetic transient program. The
calculation provided inputs for testing a relaying
scheme that is able to reliably detect an open
phase event at the high voltage side of the
preferred station service transformers being fed
from offsite power circuits without false
actuation due to various disturbances (e.g.
transformer energization, motor starting, station
faults, transmission system disturbances etc.).
Alarm Circuits: As documented in Engineering
Change 47357, several fuses were installed to
provide adequate protection between the
PCS2000 cabinets and the transformer control
panels. Coordination plots of the fuses with the
upstream protective devices are attached with
Engineering Change 47357. The final alarm
actuation setpoints will be developed after
substantial monitoring periods.
Trip Circuits: Protective coordination of the trip
circuits with offsite and onsite protection system
will be evaluated as part of the future
engineering change that will be performed to
enable trip functionality.
Reference Documents:
RBS-EE-17-00002, RBS-EE-17-00003,
G13.18.3.6*025, and Engineering Change 47357
Identify how the alarm Alarms from the open phase detection system
features provided in the sent to the main control room are managed in
main control room including several ways. The monitoring period and data
setpoints are maintained, are used to adjust alarm setpoints, troubleshoot
calibrated, and controlled. issues that arise, and give operating experience
on alarms. The system has physical (test)
switches that can be used to block specific
alarms once they have been acknowledged,
such as a device problem or loss of power (this
allows the main control room alarm to be
cleared and prevents masking of other alarms).
The switches can also be used to prevent
spurious main control room alarms during
troubleshooting or when setpoints are updated
(in addition to procedures being developed).
The system cabinets are locked and the relays
are (non-default) password protected. Setpoint
control is also accomplished through
as-found/as-left relay settings comparison
procedures used in Entergy Transmission.
North American Electric Reliability Council
standards are utilized to perform preventive
maintenance and calibration of relays. The
relays and other digital components that are
part of the open phase detection system were
evaluated and are controlled by Entergy critical
digital asset procedures.
Does the open phase Yes The open phase detection system considers
condition detection scheme No both fundamental and root mean square
consider subharmonics in components of each phase current as well as
the supply power or offsite the ratio between fundamental and root mean
power system? square. The open phase detection system also
considers instantaneous current magnitudes
along with short- and long-term smoothed
(averaged) magnitudes. The monitoring period
will be used to establish the threshold for
background and transient subharmonics, and
adjust trip or actuation setpoints above the
threshold.
Are open phase condition Yes The Engineering Change required to install the
detection and alarm circuit No trip functionality is a work in progress. The
components scoped into the maintenance rule program applicability/inclusion
licensees maintenance rule will be evaluated in the ongoing engineering
program? change that enables the trip functionality. This
is consistent with the process and procedures
followed by Entergy. Condition Report
CR-RBS-2018-00893 was initiated to document
this question and ensure that the maintenance
rule applicability is evaluated through the
engineering change process.
The components added through the open
phase detection system are scoped into the
preventive maintenance program. These action
requests initiated preventive maintenances and
calibrations for the open phase components.
The actual preventive maintenance will be
processed through the regular work
management schedule. The licensee has
currently implemented a modification that
installed the open phase detection system in
the monitoring and alarm mode. The system
currently does not have the trip functionality
enabled.
B Open Phase Condition Yes/No Describe Observations/Comments
Protection Scheme
Record location of the Location:
sensing of the protection High voltage side of preferred power station
scheme (e.g., high voltage service transformers
or low voltage side of the
transformer, engineered
safety feature bus, etc.).
Record the classification of Classification: Non-Safety
the protection scheme,
safety or non-safety.
Did the licensee consider Yes There are no direct interfaces with safety-
the interface requirements No related systems
for non-safety with safety-
related circuits?
Record the type of the The protection scheme is digital. The open
protection scheme, digital or phase detection system utilizes microprocessor
non-digital. relays, computers, satellite synchronized
clocks, and annunciators. The components are
considered digital.
Are cyber security Yes The cyber security evaluation was performed as
requirements specified for No part of Engineering Change 47357. The
digital detection scheme? N/A components installed by this engineering
change are considered Critical Digital Assets.
The components installed by the engineering
change have software equipped which were
evaluated by the engineering change and
classified as Level B software.
Did the licensee consider Yes The engineering change evaluates the
any design features to No installation of the open phase system that has
prevent protective functional redundant circuits. To enhance reliability, the
failures for open phase two systems communicate by fiber optic
condition protection system? interface to exchange information. Separate
output contacts are provided in redundant
cabinets for the following functions: open
phase detection, ground overcurrent detection,
mode disagreements, and relay failure. The
open phase detection system installed on the
transformer follows a one out of two taken twice
logic. This ensures that a single failure of a
protective relay cannot affect the credited offsite
power source.
Identify the number of Two independent sets of current
channels provided per transformers/sensors are provided per offsite
offsite power source, and if power source. Each sensor provides input to its
there is independence own set of relays that sense current
between channels and imbalances. The relays are connected in such
sensors. a manner that the system requires a one out of
two taken twice logic.
What is the safety The power supply for the protection scheme is
classification of power non-safety related. This is consistent with the
supply for the protection safety classification of the preferred station
scheme? transformer and the open phase detection
systems.
Was a loss of power to the Yes
protection scheme No The impacts of loss of power supply to the
considered? protection scheme have been evaluated in the
failure modes and effects analysis performed as
part of Engineering Change 47357. The loss of
power supply is identified through a relay self-
test and a system alarm is provided that would
notify operations of a loss of power supply.
Moreover, the system relays and other
components are supplied by DC power that is
fed from a non-safety battery system. Upon
loss of charger, the battery is capable of
supplying loads for a 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> period as credited
in the system design. AC power is supplied to
the panels space heaters. Loss of AC power
supply is considered in the failure modes and
effects analysis.
Identify if the licensee The PCS2000 system installed at River Bend
considered the Station is built with coincidence logic to add
consequences of a failure or defense-in-depth and reduce spurious
malfunction of a channel. actuations. The open phase detection system
follows a one out of two taken twice logic. The
system has redundant panels that contain two
Schweitzer Engineering Laboratories (SEL)
451 relays each, which take inputs from
independent current sensors. To enhance
reliability, the two panels will communicate by
fiber optic interfaces to exchange information.
The SEL relays that sense open phase
conditions are digital microprocessor relays that
have self-monitoring capabilities. A relay failure
is detected through a relay self-test. A relay
self-test failure is identified by a system alarm.
In a one out of two taken twice logic, the failure
of one relay does not have the potential to
spuriously trip offsite power source. The
second relay in the panel and the two relays on
the redundant panel are relied upon to detect
The digital relays fail in as is configuration and
will not actuate a trip signal. It is unlikely that
two out of four relays will fail in an actuated
mode. Therefore, failure of a single channel
current sensor or the entire channel of an open
phase detection system, the coincidence logic
at River Bend Station (one out of two taken
twice) prevents spurious misoperation/spurious
trip of offsite power source.
Did the design consider the Yes The open phase detection is a non-safety
single failure criteria as No related system and may potentially fail during
outlined in the general postulated accidents or plant shutdown
design criteria (GDC) or the resulting from an external event. In the event of
principle design criteria an open phase condition in power source
specified in the Updated related with one safety division, coupled with a
Safety Analysis Report? single failure in the opposite (or redundant)
train, the safe shutdown capability may be
adversely impacted as both trains may not be
available to power the safety-related busses.
Since failures in non-safety systems are
considered to occur when evaluating
conformance to the single failure criterion
(safety systems), the open phase condition
scheme at River Bend Station does not conform
to the single failure criteria as outlined in the
GDC or the principle design criteria specified in
the River Bend Station Updated Safety Analysis
Report (i.e., for an open phase condition, a
non-Class 1E circuit should not preclude the
onsite electrical power system from being able
to perform its safety function given a single
failure of the onsite power system).
Did the licensee identify the Yes Based on the various loads and generating
industry standards and No stations around River Bend Station, the power
criteria to verify power flow from and to the Fancy Point switchyard
quality issues caused by does not see much noise. Additionally,
open phase conditions that Engineering Calculation G13.18.3.6*025
affect redundant engineered modelled the transmission system near River
safety feature buses? Bend Station on EMTP and ran various loading
scenarios for multiple open phase condition.
The monitoring period at River Bend Station will
also enable the site to monitor the offsite source
for general disturbances and noise. The
setpoints will be adjusted accordingly.
What industry standards The trip setpoints will be evaluated with the
were used to develop the associated industry standards in a future
acceptance criteria for open engineering change that will enable the trip
phase condition trip setpoint functionality. The licensee is proposing a trip
or analytical limit? setpoint of less than 5 seconds which will
ensure any heating effects from unbalanced
voltage conditions do not adversely impact plant
motors.
What are the analytical limits The actual setpoints for the actuation circuits
or criteria used for setpoints will be evaluated as part of the future
of the actuation/protection engineering change that will enable the trip
scheme to provide adequate functionality. The licensee is proposing a trip
protection for motors and setpoint of less than 5 seconds which will
sensitive equipment? ensure any heating effects from unbalanced
voltage conditions do not adversely impact plant
motors.
What are the design The PCS2000 system installed at River Bend
features provided to Station is built with coincidence logic to add
preclude spurious trips of defense-in-depth and reduce spurious
the offsite power source actuations. The open phase detection system
(e.g. coincidence logic)? follows a one out of two taken twice logic. The
system has redundant panels that contain two
SEL 451 relays each which take inputs from
independent current sensors. To enhance
reliability, the two panels will communicate by
fiber optic interfaces to exchange information.
The SEL relays that sense open phase
conditions are digital microprocessor relays that
have self-monitoring capabilities. A relay failure
is detected through a relay self-test. A relay
self-test failure is identified by a system alarm.
In a one out of two taken twice logic, the failure
of one relay does not have the potential to
spuriously trip offsite power source. The
second relay in the panel and the two relays on
the redundant panel are relied upon to detect
What analyses have been Engineering Calculation G13.18.3.6*026 was
performed by the licensee developed to determine the minimum amount of
which demonstrates that the time an open phase event on the high side of
open phase conditions do the preferred transformer, occurring
not adversely affect the simultaneously with a loss-of-coolant accident,
function(s) of could persist before damage to or tripping of,
important-to-safety medium voltage and low voltage auxiliary power
equipment required for safe system motors would result.
shutdown during anticipated
operational occurrences,
design basis events, and
accidents?
Further analysis including time delays
If an analyses was not associated with bus transfer schemes will be
performed, what justification evaluated by a future engineering change that
was provided? will be performed to enable the trip functions of
Yes the open phase detection system.
Are bus transfer schemes No
and associated time delays
considered?
Are open phase condition Yes The Engineering Change required to install the
protection/actuation circuit No trip functionality is a work in progress. The
components scoped, as maintenance rule program applicability/inclusion
appropriate, into the will be evaluated in the ongoing engineering
licensees maintenance rule change that enables the trip functionality. This
program? is consistent with the process and procedures
followed by Entergy. Condition Report
CR-RBS-2018-00893 was initiated to document
this question and ensure that the maintenance
rule applicability is evaluated through the
Engineering Change.
C Updated Safety Analysis No Describe Observations/Comments
Report Updates to Reflect
the Need to Protect Against
Open phase conditions: The open phase detection system is currently in
Using items 1 to 6 below as monitoring phase and a future engineering will
examples, identify whether be performed to actuate the trip functionality.
the licensee has updated All Updated Safety Analysis Report /Licensing
the Updated Safety Analysis basis changes will be evaluated by the future
Report (and supporting engineering change. Condition Report CR-RBS-
documents such as 2018-00891 was created to track Updated
calculations of record, Safety Analysis Report Changes.
design change
modifications, etc.) to
ensure plant-specific
licensing basis/requirements
include discussions of the
design features and
analyses related to the
effects of, and protection for,
design vulnerability:
The plant-specific analysis N/A
and documentation that
established the resolution of
design vulnerability,
including the failure mode
analysis performed.
Description of open phase
condition automatic
detection scheme, including
how offsite power system
detected from sensing to
alarm devices (loss of one
or two phases of the three
phases of the offsite power
circuit both with and without
a high-impedance ground
fault condition on the
high-voltage side of all
credited qualified offsite
power sources under all
loading and operating
configurations; and loss of
one or two phases of three
phases of switchyard
breakers that feed offsite
power circuits to
transformers without
ground).
Detection circuit design
features to minimize
spurious indications for an
operable offsite power
source in the range of
voltage perturbations, such
as switching surges,
transformer inrush currents,
load or generation
variations, and lightning
strikes, normally expected in
the transmission system.
Alarm features provided in
the main control room.
Discuss the engineered
safety feature bus alignment
during normal plant
operation and the operating
procedures in place to
address open phase
conditions. If the plant
auxiliaries are supplied from
the main generator and the
offsite power circuit to the
engineered safety feature
bus is configured as a
standby power source, then
should be alarmed in the
main control room for
operators to take corrective
action within a reasonable
time.
Describe the automatic
protection scheme provided
including applicable industry
standards used for
designing the scheme.
Design features to minimize
spurious actuations for an
operable offsite power
source in the range of
voltage perturbations, such
as switching surges,
transformer inrush currents,
load or generation
variations, and lightning
strikes, normally expected in
the transmission system
should be described.
Brief discussion of the
licensees analyses
performed for accident
condition concurrent open
phase conditions which
demonstrate that the
actuation scheme will
transfer engineered safety
feature loads required to
mitigate postulated
accidents to an alternate
source consistent with
accident analyses
assumptions to ensure that
safety functions are
preserved, as required by
the licensing bases.
D Technical specification Describe Observations/Comments
surveillance requirements
and limiting condition for The open phase detection system is currently in
operation for equipment monitoring phase and a future engineering will
used for open phase be performed to actuate the trip functionality.
condition mitigation All Updated Safety Analysis Report / licensing
basis changes will be evaluated by the future
engineering change. Condition Report CR-
RBS-2018-00891 was created to track Updated
Safety Analysis Report Changes. The final
design of the open phase detection scheme will
trip the offsite source emanating from the 230
kV switchyard (Fancy Point) upon detecting an
open phase condition independent of plant
operating mode (start up, normal operation, or
accident condition). The loss of one offsite
source will require entry into appropriate
technical specification related limiting condition
for operation. Technical specification related
surveillance requirements have not been
developed yet.
Are technical specifications Yes The open phase detection system is currently in
surveillance requirements No monitoring phase and a future engineering will
and limiting condition for be performed to actuate the trip functionality.
operation for equipment All Updated Safety Analysis Report /Licensing
used for the mitigation of basis changes will be evaluated by the future
open phase condition engineering change. Condition Report CR-
identified and implemented RBS-2018-00891 was created to track Updated
consistent with the Safety Analysis Report Changes
operability requirements
specified in the plant Yes
technical specifications? No
N/A - see above
If the licensee determined
that technical specifications
are unaffected because
being addressed by
licensee-controlled
programs, is the technical
justification adequate?
E Provide a brief summary of Engineering Change 47357 involved the installation of an
the open phase condition open phase detection system on the offsite power supply
plant modification performed to preferred station service transformers 1RTX-XSR1C
under and 1RTX-XSR1D. This system will be capable of
CFR 50.59. detecting open phase conditions - including an open-
phase and grounded condition, a double open-phase and
grounded condition, and an open phase with line charging
- anywhere between the Fancy Point substation 230 kV
buses and these transformers. The system will also be
capable of detecting open phase conditions while the
transformers are fully loaded, lightly loaded, or drawing
only excitation current. Upon detection of an open phase
condition, a control room alarm will be actuated.
The initial phase of the activity included data collection
and performance monitoring of the new system. The
open phase detection system will be modified under a
separate activity to trip preferred station service
transformers 1RTX-XSR1C or 1RTX-XSR1D - which will
result in an automatic start of the safety-related
emergency diesel generator to supply the engineered
safety feature buses.
The scope of Engineering Change 47357 involves the
installation of an open phase detection system on the
offsite power supply to preferred station service
transformers 1RTX-XSR1C and
1RTX-XSR1D, and includes:
- New bushing sensors and new neutral current
transformers will be installed on the high side of the
transformers
- New open phase detection cabinets and associated
structural components will be installed above the
transformer oil containment pits
- New cables to connect the new open phase detection
equipment to existing plant equipment will be
installed; AC power will be supplied from new
480/120V transformers located near the new
open phase detection cabinets, and fed from
NHS-MCC-18A and NHS-MCC-20A, while DC power
will be supplied from battery 1BYS-PNL03B via
1CES-PNL1G and 2CESPNL1F
- Upon detection of an open phase condition, the
existing transformer alarm circuit will be actuated
REFERENCE: River Bend Station Process Applicability
Determination Engineering Change 47357
TI 2515/194 Inspection Documentation Request
Please provide the following documentation (Items 1 - 6) to the lead inspector prior to the onsite
inspection date, preferably no later than January 22, 2018. Whenever practical, please provide
copies electronically (IMS/CERTREC is preferred). Please provide an index of the requested
documents which includes a brief description of the document and the numerical heading
associated with the request (i.e., where it can be found in the list of documents requested).
Sam Graves, Lead Inspector
RIV/DRS/EB2
1600 E. Lamar Blvd.
Arlington, TX 76011
817-200-1102
samuel.graves@nrc.gov
1. Copies of any calculations, analyses, and/or test reports performed to support the
implementation of your open phase condition (OPC) solution. If, in your implementation,
OPCs are not detected and alarmed in the control room please include documentation that:
a) demonstrates the OPC will not prevent functioning of important-to-safety SSCs; and b)
detection of an OPC will occur within a short period of time (e.g., 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />).
2. Copies of any modification packages, including 10 CFR 50.59 evaluations if performed,
used for or planned for the implementation of your OPC solution.
3. Copies of periodic maintenance, surveillance, setpoint calibration, and/or test procedures
implemented or planned, for your OPC solution.
4. Copies of your licensing basis changes to Updated Final Safety Analysis Report (UFSAR)
and/or Technical Specifications (TS), as applicable, which discuss the design features and
analyses related to the effects of, and protection for, any open phase condition design
vulnerability.
5. Copies of any procurement specifications and acceptance testing documents related to the
installation of your OPC solution.
6. Copies of any site training the team will need to accomplish to gain access to areas with, or
planned, major electrical equipment used in your OPC solution (i.e. switchyard).
Please provide the following documentation to the team when they arrive onsite. Whenever
practical, please provide copies electronically, except for drawings. Drawings should be
provided as paper copies of sufficient size (ANSI C or D) such that all details are legible.
7. A brief presentation describing your electric power system design and typical electrical
transmission and distribution system alignments; OPC design schemes installed to detect,
alarm and actuate; bus transfer schemes; and maintenance and surveillance requirements.
This presentation should be a general overview of your system. Please schedule the
overview shortly after the entrance meeting.
8. Plant layout and equipment drawings for areas that identify: (a) the physical plant locations
of major electrical equipment used in your open phase condition solution; (b) the locations of
detection and indication equipment used in the open phase condition sensing circuits.
9. If OPC actuation circuits are required, provide documentation that demonstrates continued
coordination with the other protective devices in both the offsite electrical system (within
River Bend Station area of responsibility) and the onsite electrical systems.
10. Access to locations in which open phase condition equipment is installed or planned (i.e.
switchyard, transformer yard, etc.)
11. Copies of documentation or testing that demonstrates your OPC solution minimizes spurious
actuation or misoperation in the range of voltage imbalance normally expected in the
transmission system that could cause undesired separation from an operable off-site power
source.
This document does not contain new or amended information collection requirements
subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). Existing
information collection requirements were approved by the Office of Management and
Budget, Control Number 31500011. The NRC may not conduct or sponsor, and a person
is not required to respond to, a request for information or an information collection
requirement unless the requesting document displays a currently valid Office of
Management and Budget control number.
This document will be made available for public inspection and copying at
http://www.nrc.gov/reading-rm/adams.html and at the NRC Public document Room in
accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for
Withholding.
SUNSI Review: ADAMS: Non-Publicly Available Non-Sensitive Keyword: NRC-002
By: STG Yes No Publicly Available Sensitive
OFFICE SRI: EB2 RI:EB2 C:EB2 C:PBC C:EB2
NAME SGraves SMakor GWerner JKozal GWerner
SIGNATURE /RA/ /RA/ /RA/ /RA/ /RA/
DATE 2/27/2018 2/27/2018 03/13/2018 03/26/2018 03/26/2018