IR 05000275/1987034
| ML16341E420 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/20/1987 |
| From: | Johnston K, Narbut P, Padovan L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16341E419 | List: |
| References | |
| 50-275-87-34, 50-323-87-34, NUDOCS 8711090098 | |
| Download: ML16341E420 (22) | |
Text
U.
S.
NUCLEAR REGULATORY COMMISSION
REGION V
Report Nos:
50-275/87-34 and 50-323/87-34 Docket Nos:
50-275 and 50-323 License Nos:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 Facility Name:
Diablo Canyon Units 1 and
Inspection at:
Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:
August 16, 1987 through October 3, 1987 L.
M. Padovan, Resident Inspector
/O 2~
J'7 Date Signed K.
E. Johnston, Resident Inspector Date Signed P.
P. Narbut, Senior Resident nspector Approved by:
M.
M. Mendonca, Chief, Reactor Projects Section
Summary:
Date Signed C'u g.cp P7 Date Signed Ins ection from Au ust 16 throu h October
1987 Re ort Nos.
50-275/87-34
->>/
Areas Ins ected:
Routine inspections of plant operations, maintenance and surveillance activities; follow-up 'of on-site events and regional requests; open items; and licensee event reports (LERs),
as well as selected independent inspection activities.
Inspection Procedures 30702, 30703, 61726, 62703, 71707, 71710, 90712, 92700, 92701, 93702, and 94703 were applied during this inspection.
Results of Ins ection:
No violations or deviations were identified.
87il090098 87l02~
PDR ADOCK 05000276
DETAILS 1.
Persons Contacted
"J.
D. Townsend, Acting Plant Manager J.
A. Sexton, Assistant Plant Manager, Plant Superintendent
"W. B. McLane, Acting Assistant Plant Manager for Technical Services
- J.
M. Gisclon, Acting Assistant Plant Manager for Support Services C.
L. Eldr'idge, guality Control Manager
"D.
B. Miklush, Maintenance Manager
~S.
G. Banton, Engineering Manager D.
A. Taggert, Director guality Support W.
G. Crockett, Instrumentation and Control Maintenance Manager L.
F.
Womack, Operations Manager
- T. L. Grebel, Regulatory Compliance Supervisor S.
R. Fridley, Senior Operations Supervisor R.
S. Weinberg, News Service Representative
- M. W. Stephens, General Maintenance Foreman The inspectors interviewed several other licensee employees including shift foremen (SFM), reactor and auxiliary operators, maintenance personnel, plant technicians and engineers, quality assurance personnel and general construction/startup personnel.
Denotes those attending the exit interview.
2.
0 erational Safet Verification General During the inspection period, the inspectors observed and examined activities to verify the operational safety of the licensee's facility.
The observations and examinations of those activities were conducted on a daily, weekly or monthly basis.
On a daily basis, the inspectors observed control room activities to verify compliance with selected Limiting Conditions for Operations (LCOs) 'as prescribed in the facility Technical Specification's (TS).
Logs, instrumentation, recorder traces, and other operational records were examined to obtain information on plant conditions, and trends were reviewed for compliance with regulatory requirements.
Shift turnovers were observed on a sample basis to verify that all pertinent information of plant status was relayed.
During each week, the inspectors toured the accessible areas of the facility to observe the following:
(a)
General plant and equipment conditions.
(b)
Fire hazards and fire fighting equipment.
(c)
Radiation protection control (d)
Conduct of selected activities for compliance with the licensee's administrative controls and approved procedures.
(e)
Interiors of electrical and control panels.
(f)
Implementation of selected portions of the licensee's physical
'security plan.
(g)
Plant housekeeping and cleanliness.
(h)
Essential safety feature equipment alignment and.conditions.
(i)
Storage of pressurized gas bottles.
The inspectors talked with operators in the control room, and other plant personnel.
The discussions centered on pertinent topics of general plant conditions, procedures, security, training, and other aspects of the involved work activities.
b.
Summar of Plant Status Durin the Re ort Period This report covers the period between August 15 and October 3, 1987.
During the period both units stayed at 100K except for a couple days at 50K power for work on the feedwater system.
The following is a
chronology of significant issues and events during this report period:
August 24 An automatic initiation of the Unit 1 containment ventilation isolation system occurred when a licensed senior operator performed a source check on the wrong radiation monitor (see section 3a.).
August 25 Diesel Generator 1-3 started when maintenance personnel pulled the wrong fuse (see section 3b. ).
September ll The licensee repaired a leak in the Steam Generator 1-4 blowdown line inside containment after its isolation.
Steam Generator chemistry remained within specifications.
September
The emer gency pr eparedness drill was performed (see section 8).
No violations or deviations were identified.
3.
Onsite Event Follow-u a.
Inadvertent Initiation of the Containment Ventilation Isolation
~Setem On August 24, 1987, at 1:47 PM, with Unit 1 in Mode 1, an automatic initiation of the containment ventilation isolation system (CVIS)
occurred.
The sample line isolation valves for gaseous radiation monitors (RMs) ll and 12 closed, as designed.
All other CVIS valves
that received isolation signals were closed (as normal)
when the event occurred.
As required by 10 CFR 50.72, a 4-hour non-emergency event report was made to the NRC at 2:25 PM on August 24, 1987.
This event was caused by a licensed senior operator performing a
source check on an incorrect radiation monitor, prior to a liquid radwaste discharge.
The operator was performing pre-discharge checks on RM-18, the liquid radwaste effluent monitor, as required by Operating Procedure G-1:II, "Liquid Radwaste System - Processing and Discharge of Liquid Radwaste,"
prior to the planned discharge of floor drain receiver tank 0-2.
When the operator in the control room attempted to perform the source check on RM-18, he inadvertently initiated a source check on RN-14B, the plant vent radiogas monitor, whose control panel was located directly below the control panel for RN-18.
RM-14B exceeded its high trip setpoint while being source-checked, initiating the CVIS.
The CVIS was
'eset, and the RMll and RN12 sample line isolation valves were reopened.
Root cause of this event, as determined by the licensee, was lack of attention to detail by the operator performing the source check on RN-18.
The close proximity of the two radiation monitor panels in the control room was also a factor.
The inspector observed that labeling of the radiation monitors was satisfactory.
Labeling on the monitor racks had been previously improved, as a result of an identical CVIS initiation occurring on Unit 1 on May 25, 1987.
As corrective action, the operator was counseled concerning his improper RN panel manipulation.
Labeling on the radiation monitoring racks will be reviewed to determine if further improvements in identification can be developed.
The event was also reviewed with operators, emphasizing the importance of verification of the identity of equipment prior to actuating any functions associated with testing.
The licensee indicated an incident report will be issued on this event, and associated corrective actions will be reviewed with all operators.
Lessons learned from this event will be incorporated into the operator training program.
In addition, the Onsite Safety Review Group is to perform a Human Performance Evaluation System Report on this event to determine if additional corrective actions may be necessary to preclude recurrence.
Inadvertent Diesel-Generator Start On August 25, 1987, at 9:21 PN with Unit 1 in Mode 1, diesel generator (DG) 1-3 autostarted and loaded onto 4kv bus F.
The auto-sequenced loads did not load onto the bus.
Two attempts were made to transfer the bus back to its normal auxiliary power supply.
Both failed due to breaker "anti-pumping" design characteristics.
On August 26, 1987, 'at 4:35 AN, bus F was transferred back t'o auxiliary power, and diesel generator 1-3 was secured and returned
to normal standby mode.
A 4-hour non-emergency report to the NRC, required by 10 CFR 50.72, was made at ll:35 PM, August 25, 1987.
This event was caused by personnel error.
An unlicensed operator, in the process of returning a vital pump breaker to operability following generator preventive maintenance, inadvertently pulled a
"UA" fuse, simulating an undervoltage condition on bus F which started DG 1-3.
After the DG start, the auto-sequencing loads did not load onto the bus because of the initial conditions existing with the bus and the design of the internal "anti-pumping" relay associated with each 4kv breaker.
With the UA fuse pulled, the bus stripping relay was tripped, placing a continuous trip signal on all motor breakers on Bus F.
The sequencing timers were energized as normal during this event, and as soon as they timed out, a
simultaneous, continuous close signal was present on the Component Cooling Mater Pump, Auxiliary Salt Mater Pump, Auxility Feedwater Pump, Centrifugal Charging Pump, and Cont'ainment Fan Cooler Unit breakers on this bus.
By design, the "anti-pumping relay" (a device internal to each circuit breaker which prevents the breaker from continually cycling if trip and close signals are simultaneously present)
locked-up and prevented breaker operation until both the trip.and close signals were eliminated.
The attempts to transfer the bus back to auxiliary power were unsuccessful because of design characteristics of the automatic bus transfer system.
Auxiliary contacts on the breakers, inputting to the automatic transfer scheme were "racing" and causing the auxiliary feeder breaker to open.
The root cause of the inadvertent diesel generator start was personnel error.
Contributing to the event was the use of required protective gear and tight working conditions.
~In addition, the non-licensed operator was unaware that the "UA" fuse could affect other systems.
As corrective action, an incident report was issued on this event, and associated corrective actions.were reviewed by all operators.
Lessons learned from this event were incorporated into the initial non-licensed operator training program.
Operations and electt ical maintenance will investigate and implement additional actions, as necessary, to prevent inadvertent removal of fuses such as this on 4kv switchgear.
To eliminate the problem experienced while attempting to return bus F to auxiliary power, Operating Procedure OP J-6B has been revised to include cutting out the autotransfer feature when paralleling a
bus to auxiliary power when on a diesel generator.
A temporary test was successfully performed August 27, 1987, to verify proper operation of the diesel generator in an undervoltage condition.
In addition, the Onsite Safety Review Group is performing a
Human Performance Evaluation System Report on this
event to determine if additional corrective actions are necessary to preclude recurrence of this event.
No violations or deviations were identified.
4.
Maintenance The inspectors observed portions of, and reviewed records on, selected maintenance activities to assure compliance with approved procedures, technical specifications, and appropriate industry codes and standards.
Furthermore, the inspectors verified maintenance activities were performed by qualified personnel, in accordance with fire protection and housekeeping controls, and replacement parts were appropriately certified.
a ~
Unit 2 Containment S ra S stem CSS Pum 2-1 4kv Breaker Maintenance and Testin The inspector observed portions of CSS pump 2-1 4kv breaker preventive maintenance and testing.
The maintenance was performed in accordance with MP E-63. 1A, "Maintenance of 4kv Magna-Blast Circuit Breakers,"
during a scheduled CSS train preventive maintenance outage.
MP E-63. 1A includes general and detailed breaker inspections in addition to lubrication, high potential testing, meggering, and opening and closing speed testing.
The inspector observed high potential testing of the breaker air interrupter and the primary isolation.
The procedure specifies that 14kv be applied for one minute across the primary stabs for each phase with the breaker open to test air interrupter integrity and between one phase and ground with the breaker closed to test primary isolation integrity.
The electrician then m'easures current.
The inspector noted that the procedure did not include acceptance criteria for this test.
The inspector discussed this with the electrical engineer responsible for the test.
The engineer explained that a test failure would be signified when 14kv could not be applied for the full minute.
The engineer committed to include a
comment to this effect in a procedure revision.
The inspector discussed with the electricians problems they had noted during the performance of MP E-63. 1A.
These included problems with the breaker wheels and the condition of a stationary contact finger contact.
The inspector noted that the appropriate action requests and work packages had been issued to correct the problems'he inspector reviewed the procedure against the vendor manual and found no discrepancies.
The procedure is a vast improvement over the previous revision, in that, where the previous revision referred to the vendor manual, the current revision gives detailed instructions including tolerances, acceptance criteria, and illustrations.
b.
Unit 2 Containment S ra Pum 2-2 Overcurrent Rela Testin
The inspector observed portions of CSS pump 2-2 overcurrent relay preventive maintenance and testing.
The CSS pump 2-2 has three overcurrent relays, one for each phase, each of which has an instantaneous extreme high current trip and a time dependent overcurrent trip.
The electricians performed the test in accordance with Maintenance Procedure (MP)
E 50.4, "Routine Preventive Maintenance of Nondirectional Overcurrent Relay Type IAC and Similar."
The procedure requires that as-found and as-left data be taken of relays'nstantaneous, nominal, and time dependent trip points.
In addition the procedure requires burnishing of contacts and an inspection.
The as-found data for all three relays indicated the time dependent responses to be out of tolerance.
The electrician performing the test initiated an action request to evaluate the as-found data.
The engineer evaluating the action request determined that as-found trip times were not high enough to have affected the pump motor had an overcurrent condition existed.
Although the engineer identified a number of possible causes, he could not identify the specific cause.
No corrective actions were initiated since the problem had not been identified as chronic.
The engineer noted that if the problem recurs, further evaluation would be required.
The inspector walked down the clearance points for the CSS train outage and noted that proper controls were observed.
The inspector observed gC involvement in the taking of as-left data.
The appropriate procedure and work package was employed.
The inspector noted that extensive on-the-spot changes had been made to clarify and provide acceptance criteria.
The electricians expressed a
heightened sensitivity to procedural compliance and the need to revise procedures when problems arise.
C.
Other Maintenance Activities Observed The return to service portion of the preventative maintenance on DG 1-3 described in paragraph 3.b.
was examined in the maintenance area.
The inspectors examined other maintenance activities such as a containment spray pump oil change and a safety injection pump condition inspection.
No findings were made in these areas.
No violations or deviations were identified.
5.
Surveillance By direct observation and record review of selected surveillance testing, the inspectors assured compliance with TS requirements and plant procedures.
The inspectors verified that test equipment was calibrated, and acceptance criteria were met or appropriately dispositioned.
a.
Time Res onse Testin of Unit 1 Reactor Tri Breakers The inspector observed the performance of Surveillance Test Procedure (STP) I-33C, "Time Response Testing of Reactor Trip
0
Breakers,"
for Unit 1 trip breaker 52/RTB.
Plant technical specification 4.3. 1.2 requires that reactor trip breaker time response be tested every 18 months.
However, time response testing must also be performed after reactor trip breaker maintenance which is performed every 6 months.
The inspector observed that appropriate controls were established, including the use of a qualified procedure.
In addition, the technicians involved appeared to be knowledgeable of the system involved.
The inspector noted that a quality control inspector observed the performance of the testing.
The breaker met its time response acceptance criteria.
b.
Unit 2 S ent Fuel Pool Area Radiation Monitor The inspector observed the performance of a recalibration of the input to the P-250 computer from the spent fuel pool area radiation monitor, RE-58.
On high radiation in the spent fuel pool area, RE-58 trips a relay which provides control room annunciation and switches the fuel handling ventilation system to iodine removal mode.
In addition, RE-58 feeds a chart recorder and the P-250 computer.
Technical Specification Table 4.3-3 requires monthly functional testing and calibration every 18 months of RE-58.
The RM-58 input to the P-250 computer does not perform a safety function.
According to the related action request, the out of calibration input to the P-250 computer was identified in June 1986 during channel functional testing.
The technicians investigating the problem discovered that the wrong computer routine was used to interpret the RE-58 output.
This programing error has existed since the monitor was installed in April 1985.
This monitor and RE-59, the new fuel storage area monitor, were replacements for RE-5 and RE-9 which were not environmentally qualified.
Both monitors were designed to output to chart recorders and the P-250 computer as well as perform their technical specification function.
The input to the chart recorders did not match the output of the monitors and therefore have also been inoperable.
As a result, for Unit 2, from April 1985 to October 1987, no apparent capability existed for recordings to be made of activity from RE-58 and RE-59.
This item is unresolved (Open Item 50-323/87-34-01).
No violations or deviations were identified.
6.
Follow-u of Re ional Re uests
'a ~
Boron In ection Tank BIT Relief Valve On September 28, 1986 the Trojan Nuclear Plant shut down when a 226 cc/minute leak was discovered at the BIT relief valve.
The licensee had determined that amount of post-LOCA (Loss of Coolant Accident)
recirculation system leakage to be outside the design basis for their control room ventilation system.
The inspector therefore performed an examination to determine if Diablo Canyon had a similar post-LOCA recirculation system leakage concer At Diablo Canyon, FSAR chapter 15.5 postulates, for the purposes of determining offsite doses, a release based on normal recirculation loop leakage concurrent with the failure of the auxiliary building ventilation exhaust charcoal filter.
The recirculation loop includes the RHR system, safety injection system, high head injection system, and portions of the CSS aligned for post LOCA recirculation from the containment sump.
FSAR Table 6.3-9 lists the postulated normal leakage for these components.
The total postulated leakage is 1910 cc/hour.
The resulting dose to the control room was not calculated based on this number since the postulated
gpm RHR pump seal failure for 30 minutes without an auxiliary building ventilation failure, a condition also assumed in FSAR chapter 15.5, is the bounding condition.
The inspector requested the licensee to address the following questions:
o What is the basis for Table 6.3-9 and is the BIT relief valve considered as a leakage contributer?
o How.is the licensee complying with Table 6.3-9 and specifically how are they confirming that recirculation loop leakage is maintained below 1910 cc/hour?
o Why does the BIT relief valve discharge to the auxiliary building sump and 'not the pressurizer relief tank as implied by the FSAR chapter 6?
The licesnee did not have answers prior to the end of this report period; therefore, this item will be considered as an unresolved item (Open Item 50-323/87-34-02).
Following the close of this report period, the licensee discovered a
leak of approximately 30 cc/min. in the Unit 2 BIT relief valve.
This issue was actively being followed up at the close of the reporting period.
No violations or deviations were identified.
7.
En ineerin Safet Feature Verification Unit 2 Containment S ra S stem Walkdown The inspector performed a walkdown of the physically accessible portions of the Unit 2 containment spray system including electrical breakers and control room indication.
At the time of the walkdown one train was out of service for routine preventative maintenance on the associated pump and pump electrical breaker.
The train had been cleared appropriately.
No findings were identified.
No violations or deviations were identified.
8.
Radiolo ical Protection
e
'
The inspectors periodically observed radiological protection practices to determine whether the licensee's program was being implemented in conformance with facility policies and procedures and in compliance with regulatory requirements.
The inspectors verified that health physics supervisors and professionals conducted frequent plant tours to observe activities in progress and were generally aware of significant plant activities, particularly those related to radiological conditions and/or challenges.
ALARA consideration was found to be an integral part of each RWP (Radiation Work Permit).
No violations or deviations were identified..
9.
Inde endent Ins ection Emer enc Pre aredness Annual Exercise
The resident inspector participated in the licensees annual emergency preparedness exercise held on September 23, 1987.
The resident participated as a "player" and evaluator in the control room (simulator)
and the Technical Support Center (TSC).
The inspector attended the post exercise debriefings given by the simulator crew on September 23, the Federal Emergency Management Administration evaluation on September 25, and the NRC exit meeting with the licensee on September 25, 1987.
The results of the evaluation will be presented in inspection report 50-275/87-33.
No violations or deviations were identified.
Ph sical Securit Security activities were observed for conformance with regulatory requirements, implementation of the site security plan, and administrative procedures including vehicle and personnel access screening, personnel badging, site security force manning, compensatory measures, and protected and vital area integrity.
Exterior lighting was checked during backshift inspections.
No violations or deviations were identified.
Licensee Event Re ort Follow-u Status of LERs Based on an in-office review, the following LERs were closed out by the resident inspector:
Unit 1:
87-11, 87-12, 87-13, 87-14 Unit 2:
87-11, 87-12, 87-16, The LERs were reviewed for event description, root cause, corrective actions taken, generic applicability and timeliness of reporting.'o violations or deviations were identifie On October 2, 1987, an exit meeting was conducted with the licensee's representatives identified in paragraph 1.
The inspectors summarized the scope and findings of the inspection as described in this report.