ML20155E247
| ML20155E247 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 09/27/1988 |
| From: | Constable G, Ford E, William Jones NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20155E244 | List: |
| References | |
| 50-458-88-22, NUDOCS 8810120200 | |
| Download: ML20155E247 (9) | |
See also: IR 05000458/1988022
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A_PENDIX A
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U. S. NbCLEAR REGULATORY COMMISSION
REGION IV
NRC Inspection Report:
50-458/88-22
License NPF-47
Docket:
50-458
Licensee: Culf States Utilities Company (CSU)
P. O. Box 220
St. Francieville, Louisiana 70775
Facility Name:
River Bend Station (RBS)
Inspection Att River Bend Station, St. Francisville, Louisiana
Inspection Conducted: August 29 through September 15, 1988
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Inspectors:
,E. J. Foff, Senior Resident Inspector
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Project Section C, Division of Reactor Projects
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W. B. Jones, Resident Igsppctor
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Project Section C, Diddion of Reactor Projects
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Approved:
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. . ' . L G tabic, Chief. Project Section C
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Division of Reactor Projects
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Inspection Sumary
Inspection Conducted August 29 through September 15, 1988 (Report 50-458/88-22)
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Areas Inspected:
Special, unannounced 16;e ction of the fuel juilding
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ventilation charcoal filtration systen.
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Results: On August 29, 1988, GSU fod that the switches for heaters in both
trains of the fuel building (energency) ventilation system filters were not on
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as required to fully meet system operability requirements.
During an emergency, the heaters kaep the relative humidity of the incoming air
below 70 percent to maintain the efficiency of the charcoal filters.
It is not
clear how long the heaters were off.
Following automatic initiation of the
ventilation system on August 25 and 27, 1988, system line ups were performed
that should have ensured that the switches were in the proper position. Six
shift turnover control board checks and two line up checks prior to mode
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changes should also have identified the inoperable condition of the heaters.
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Corrective actions from a similar event in 1986 were not complete at the time
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of this event,
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Three potential violations (failure to maintain the fuel building ventilation
charcoal filtration system operable, failure to conduct adequate shift
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turnovers, and failure to implement timely ccrrective action) were identified.
An enforcement conference to discuss these potential violations will be held in
the Region IV office at a time and date to be announced.
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OETAILS
1.
Persons Contacted
- J. C, Deddens, Stnior Vice President, River Bend Nuclear Group
- L. A. England, Di;'ector, Nuclear Licensing
A. O. Fredieu, Supervisor, Operations
- P.
D., Graham, Assistant Plant Manager, Operations
J. R. Hamilton, Director, Design Engineering
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- L. G. Johnson, Site Representative, Cajun
- R. J. King, Supervisor, Nuclear Licensing
- V. J. Normand Supervisor. Administrative Services
- W. H. Odell, Manager, Administration
- T. F. Plunkett, Plant Manager
- M. F. Sankovich, Manager, Engineering
- K. E. Suhrke, Manager, Project Management
The NRC in:;pectors also interviewed additional licensee personnel during
the inspection period.
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- Denotes those persons that attended the exit interview conducted on
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September 22, 1988.
2.
Misaligned Fuel Building Charcoal Filtration System
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This area of inspection was conducted to review the l'censee identified
problem with the misaligned switches for the fuel building ventilation
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charcoal filtration heaters (1HVF*FLT2AH(BH)). The NRC resident inspector
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was notified on August 29, 1988, that the heater breakers for the
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Division I and II fuel building ventilation charcoal filtration system was
found in the off position. These breaker switches are located on Main
Control Board Panel 1H13*P863. Heater status light indication is provided
immediately above each of the heater breaker switches. However, placing
the breaker switch to "STOP" will not actuate a control room annunciator.
At the time of the discovery, the reactor was at 100 percent power. A
reactor startup from operational condition 3 was initiated at 12:00 a.m.
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(CDT)onAugust 28, 1988, with Operational Condition 1 achieved at
12:29 p.m. (CDT). The heaters were identified by the licensee to be
unavailable while preparing to perform a surveillance test on the fuel
building exhaust filter trains. The heaters were imediately returned to
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operable status. The licensee's management and the NRC resider.t irspector
were subsequently notified.
Condition Report 08-0679 has been initiated
to investigate the incident and effect corrective actions. As a result of
the licensee's investigation and response to questions by the resident
inspectors, the following information was obtained for the identified
condition.
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a.
Identification and Cause for the Misaligned Heaters
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The licensee identified the misaligned heaters at 7:50 p.m.
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(CDT)onAugust 29, 1988, during the performance of Surveillance
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Test Procedure STP-406 0201, "Fuel Building Exhaust Filter Train
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Monthly Operability."
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When the heater breaker switches were identified as being
improperly aligned, they were imediately returned to the
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correct position.
Licensee management and the NRC resident
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inspector were then promptly notified of this condition. The
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licensee initiated an investigation to detennine the reason the
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breakers were opened and what corrective actions should be
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taken. This investigation is being performed utilizing the
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condition report program and is being documented as Condition
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Report (CR) 88-0679.
The licensee is also preparing a licensee
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event report to be submitted to the NRC within 30 days of the
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event.
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Two automatic initiations of the fuel building exhaust charcoal
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filtration trains occurred during the four days prior to
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discovery of the heater breakers being misaligned. The first
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initiation occurred at 12:32 p.m. (CDT), on August 25, 1988,
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when the reactor protection system (RPS) Division I bus
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oeenergized during a reactor scram.
The loss of the Division !
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RPS bus initiated both trains of the fuel building exhaust
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charcoal filtration system. This system was subsequently
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restored to its normal lineup and an entry made in the control
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room log at 5:02 a.m. (CDT) on August 26, 1988, that a complete
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board walkdown was perfonned of the at-the-controls area to
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verify proper system lineup for plant conditions. The second
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automatic initiation of this system occurred at 2:51 a.m. (CDT),
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on August 27, 1988, when an instrumentation and control (!&C)
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technician lifted an incorrect lead on the fuel building exhaust
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radiation monitor, RMS*RE58, causing the fuel building
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ventilation system to align to the emergency filtration trains.
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An entry in the control room log at 3:32 a.m. (CDT) indicates
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that the fuel building ventilation system was restored to its
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normal lineup and that a second licensed operator verified the
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lineup to be correct.
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A final board walkdown was apparently completed between the
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hours of 6 a.m. and 6 p.m. on August 27, 1988, prior to the
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licensee entering Operational Condition 2.
A licensed operator
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and control operating foreran have stated that they verified the
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fuel building ventilatior
stem to be properly aligned during a
main control board walk + in preparacion for entering
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Operational Condition "'.
-ae performance of this main control
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board walkdown however * not documented in the control room log
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book or the General Operating Procedure GOP-0001, "Plant
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Startup", which provides the master startup checklist for entry
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into Operational Condition 2.
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The licensee has interviewed each of the operating crews who
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were on shift from the time the reactor scram occurred on
August 25, 1988, to the time the heater breakers were found open
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on August 29, 1988. Process computer data was also reviewed to
try to determine when the heaters were taken out of service. To
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date, the licensee's review of this event has been inconclusive
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in determining when the heater breakers were opened.
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Manually placing the heater breaker switches to "STOP" will not
generate a control room alarm other than the light status
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indication imediately above the breaker control switches. The
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other signal that will open the IHVF*FLT2AH(BH) breakers is an
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overcurrent trip however this trip will cause av annunciator in
the control room. The licensee has verified that the applicable
control room annunciators are operating properly.
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The licensee's routine operations shift turnovers failed to
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detect that the heater control breaker switches were in the off
position.
The licensee conducts shift turnovers twice daily at
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6:00 a.m. and then again at 6:00 p.m.
This provided for a total
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of six shift turnovers from the time the heater breakers were
last documented to have been properly aligned to the time tby
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were discovered in the open position. The licensee had in piace
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during this period, Operations Support Procedure OSP-0002,
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"Shift Relief and Turnover." This procedure requires that each
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licensed operator, prior to assuming licensed duties, review
plant evolutions, equipment status, significant limiting
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conditions for operations status, night orders, standing orders
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and complete a walkdown of the main control board.
The licensed
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operators who are required to perform these tasks are the shift
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supervisor, control operating foreman, at.the-controls operator
and unit operator.
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Potential Violation / Safety Significance
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River Bend Station Technical Specification 3.6.5.6 requires that
two independent fuel building ventilation charcoal filtration
subsystems be operable in Operational Conditions 1, 2 and 3.
The associated ACTION statement, 3.6.5.6.a. only provides for
one division of the fuel building ventilation charcoal
filtration subsystem being inoperable in OPERATIONAL
CONDITIONS 1, 2 and 3.
River Bend Station Technical Specification 3.0.3 requires, in
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part, that when a Limiting Condition for Operation is not met,
except as provided in the associated ACTION requirements, action
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shall be initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to place the unit in a
OPERATIONAL CONDITION in which the Specification does not apply
by placing it, as applicable, in:
(1) At least OPERATIONAL CONDITION 2 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />,
(2) At least OPERATIONAL CONDITION 3 within the following
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and
(3) At least OPERATIONAL CONDITION 4 within the subsequent
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
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In addition, River Bend Technical Specification 3.0.4 prohibits
entry into an OPERATIONAL CONDITION or other specified condition
unless the conditions for the Limiting Condition for Operation
are met without reliance on provisions contained in the ACTION
requirements.
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The charcoal filter heaters are designed to actuate when the
fuel building emergency ventilation system is operated in the
emergency mode,
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The emergency filtration mode of the fuel building ventilation
system is initiated by a loss of coolant accident signal,
detected high radiatiun in the fuel building exhaust duct or
manually,
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The charcoal filter subsystem is designed to remove 99 percent
of elemental iodine and 99 percent of the methyliodine provided
the filtered air is maintained at 70 percent or less relative
humidity (RH).
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The charcoal filter heaters actuate when the emergency fuel
building ventilation system actuates to maintain the (RH) at or
below 70 percent by heating the air entering the charcoal
filters,
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With the heater breaker switches open as identified oa
August 29, 1988, the heaters would not actuate as req red.
The licensee has taken RH readings in the fuel building and
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determined that the average RH readings are between 65 and
70 percent. An engineering analysis documented in
Memorandum ED-88-1023, dated September 9,1988, concludes that
there is no postulated accident which will result in higher
relative humidities in the fuel building,
The licensee has performed a bounding calculation for the fuel
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building radiction release with the charcoal filters functioning
at 97 and 0 percent efficiencies during a loss of coolant
accident. The subsequent exclusion area boundary 2-hour thyroid
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dose exposures were determined to add less than 1 REM and 6 REM,
respectively, to the release doses.
The resulting thyroid dose
exposures have been determir~d to be less than the 10 CFR 100 limit of 300 REM.
The failure to maintain the Division I and Il fuel building
ventilation charcoal filtration systems operable as required by River
Bend Station Technical Specification 3.6.5.6 was identified by the
rasident inspectors as a potential violation. This failure to
maintain both filter heaters operable also resulted in the licensee
not meeting the requirements of River Bend Station Technical Specifications 3.0.3 and 3.0.4.
A second potential violdtton
involving failure to perform adequate shift turnovers was also
identified. Six shift turnovers were conducted from the time the
fuel building charcoal filtration heaters were last documented to be
available to the time they were identified as being inoperable
because of the irrproper switch positions.
In accordance with
OSP-0002, "Shift Relief and Turnover," the shift supervisor, control
operating foreman, unit operator, and the at-the-controls operator
are each required to complete a board walkdown prior to assuming the
shift.
This resulted in at least 24 separate occasions where the
improper switch positions could have been identified by a licensed
reactor operator.
c.
Similar Occurrences
On July 1, 1986, the licensee identified in Condition Report
(CR) 86-0875, an event where the control building Division I filter
train heater failed to energize. A manual reset temperature switch
was found open, however, since there are no alams or indications
associated with the filter trains heater circuit, no annunciator
alarm was received when the temperature switch opened.
As part of the corrective actions for CR 86-0875, two modification
requests (MRs) were initiated to add alarms to the control building
and fuel building filter trains to annunciate when the heater's
control circuits deenergize. These MRs are identified as MR 86-1213
and MR 86-1214 for the control building and fuel building ventilation
filter trains respectively. The MRs suggest a solution to add a
relay to the control circuit that drops out when the heater circuit
is deenergized and gives an alarm in the main control room.
On April 9 and 23, 1988, MRs 86-1213 and 1214 were respectively
cancelled by memorandums. A reply to interoffice memorandum dated
May 16, 1988, concerning MRs 86-1213 and 1214, states that
cancellation of the subject MRs will not conflict with the final
disposition of CR 86-0875.
It should be noted that on June 16, 1988,
Quality Assurance Engineering returned the MR 86-1214 package to
Design Engineering because of the unsatisfactory response. The
response had indicated the cancellation of the MR would not affect
final disposition of CR 86-0875.
The failure to fully implement the
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corrective actions identified in CR 86-0875 appears to be a violation
of 10 CFR 50, Appendix B, and the licensee's QA program in that
timely corrective action to prevent future occurrence was not taken.
A review of licensee event reports did not reveal any other similar
occurrences as identified in this special inspection report.
d.
Licensee Review of Existing Program Controls / Planned Corrective Action
The licensee has reviewed the programatic controls and hardware
systems in place during the period the potential violations occurred.
As a result, additional programatic controls and hardware
modifications have been, or will be, implemented.
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The licensee has revised Operations Support Procedure OSP-0002,
"Shif t Relief and Turnover," Revision 4, to incorporate a unit
operator main control board walkdown checksheet.
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checksheet is completed by the unit operator prior to assuming
licensed duties. This checksheet is subsequently reviewed by
the shift supervisor as early in the shift as possible. This
procedure change was incorporated into OSP-002 utilizing
Temporary Change Notice TCN 88-0575.
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The licensee is also revising General Operating Procedure
G0P-0001, "Plant Startup," Revision 8 to provide a workable
startup checksheet that verifies the proper position of
safety-related controls and correct instrument indications for
startup from hot shutdown.
This checklist is being
developed from the existing station operating procedures
utilizing selected control board lineups and instrument
indications.
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Resurrecting Modification Requests (MR) 86-1213 and 1214 or
initiating new MRs to provide control room annunciator alarms if
the control building and fuel building ventilation charcoal
heater's control circuitry are not available is being reviewed,
The training department is reviewing exercises that can be
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incorporated into the simulator training classes to aid the
reactor operators in identifying abnormal c.ontrol board lineups.
The operations supervisor issued a memorandum on September 9,
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1988, to all operations personnel discussing the event,
corrective actions that are being taken and the requiremert for
all operators to perfonn thorough shif t turnovers and control
board walkdowns,
The resident inspector observed the Assistant Plant
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Manager-0perations meeting with one of the operating crews to
discuss the significance of the event and their responsibilities
for understanding plant conditions when they assume the shift.
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The licensee will document their investigation of this problem and
planned corrective actions in a licensee event report.
The resident
inspectors are rnonitoring the complation of licensee comitted
actions and observing selected shift turnovers.
3.
y t Interview
An exit interview was conducted with licensee representatives (identified
in paragraph 1).
During this interview, the RI reviewed the scope and
findings of the report.
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