IR 05000312/1986030
| ML20210R227 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 09/18/1986 |
| From: | Miller L, Myers C, Perez G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20210R212 | List: |
| References | |
| 50-312-86-30, NUDOCS 8610070187 | |
| Download: ML20210R227 (9) | |
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NUCLEARLREGULATORY COMMISSION
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Report No:
50-312/86-30 Docket No.' 50-312
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License No. DPP.-54 Licensee:
Sacramento Municipal Utility District P. O. Box 15830-Sacramento, California 95813 Facility Name:
Rancho Seco Unit 1 Inspection at:
Herald, California (Rancho Seco Site)
Inspection conducted:
Ju 14 t rough August 22, 1986 Inspectors:
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(/h u 2-/ 7-II#
C. J.
s, Acting Senior Resident Inspector Date Signed v1Lt2
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G. P. Pe esi spactor'
Date Signed
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- )YYb L. F.(fli11er, Chy, Reactor Projects-Section II Date Signed Summary:
Inspection between July 14 and August 22, 1986 (Report 50-312/86-30)
Areas Inspected: This routina inspection by the Resident Inspectors involved the areas of operational safety verification, plant procedures, surveillance observation, maintenance observation, and followup items.
During this inspection, Inspection Procedures 30702, 30703, 42700, 61726, 62703, 71707, 92701, 92702, 92703, 25575, 25580 and 93702 were used.
Results:
In these areas, two violations were identified; one violation concerned a failure to maintain inspection' records; a second violation involved inadequate maintenance instructions.
8610070107$h$12 PDR ADOCK PDR G
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DETAILS'
1.
Persons Contacted 4.= Ward,LAssistant General Manager
"G.. Coward,. Manager, Nuclear. Plant
J. McColligan, Assistant Manager, Nuclear Plant
<*D. Army, Nuclear Maintenance Manager
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B. Croley, Nuclear Technical. Manager D. Gillispie, Nuclear Engineering Department,' Manager,
S.-Redeker, Nuclear Operations Manager
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J. Shetler, Nuclear Scheduling Manager.
T. Tucker, Nuclear 0perations Superintendent M.-Price, Nuclear. Mechanical Maintenance Superintendent L. Fossom, I&C. Maintenance Superintendent
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R.' Colombo, Regulatory Compliance. Superintendent J. Field,LNuclear Technical Support Superintendent
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.S..Crunk, Incident Analysis Group Supervisor J. Jurkovich, Site Resident Engineer F. Kellie, Radiation. Protection Superintendent L. Schwieger, Quality Assurance Manager.
M. Hieronimos, Assistant'to the Operations Superintendent J. Jewett, Site'QA Supervisor
- C.'Stephenson, Regulatory' Compliance Engineer.
.B. Daniels, Supervisor, Electrical Engineering
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~J. Irwin, S_upervisor, I&C Maintenance
- M.E.Shanbhag, Deputy QEiSupervisor. ~
C. Linkhart, Electrical Maintenance Superintendent
- T. Khan. Principal; Mechanical; Engineer.
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$*J.'Reese, Health Physicist
- S.. Farkas,. Regulatory Compliaiice
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'Other. licensee-e'mployees contacted included' technicians, operators,
.-mechanics l, security /andofficepersonnel.
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- Attended.the Exit Meeting on, August 19,J1986.
2.
OperationalSafet[ Verification
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The inspectors reviewed control room operations which included access-control,' staffing, observat' ion of decay heat removal system alignment, and review of control room logs.
Discussions with the Shift Supervisors and operators indicated understanding by these personnel of the reasons-for annunciator indications, abnormal plant conditions ~and maintenance work in progress.
The inspectors also verified, by observation of valve and switch position indications, that emergency systems were properly aligned for the cold shutdown condition of the facility.
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Tours of the auxiliary building, turbine building, and reactor building, including exterior areas, were made to ascess equipment conditions and
. plant conditions.
Also the~ tours were made to assess the effectiveness of radiological controls and adherence to regulatory requirements..The
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inspectors also observed plant housekeeping and cleanliness looked for potential fire'and safety hazards, and observed security and safeguards
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practices.
No violations or deviations'were observed.
3.
Monthly Surveillance
. Technical Specification (TS) required surveillance tests sere observed and reviewed to ascertain that they were conducted in accordance with'
these requirements.
The following items were' considered during this' review:
Testing was in
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accordance with adequate procedures; test instrumentation was calibrated; limiting conditions for operation were met; removal and restoration of
.the affected components were accomplished; test results confirmed with-TS and procedure requirements and were reviewed by personnel other than the~
individual directing.the test; the reactor operator, technician or.
engineer performing.the test recorded the data and the data were in agreement with observations made by the inspector, and that any deficiencies identifie'd during the testing were properly reviewed'and resolved by appropriate management personnel.
While the licensee was performing the biannual overhaul inspection required by the Technical Specifications on the "A" diesel generator, the deadline for the "B" diesel generator'(DG) monthly surveillance test _came due.
As described in' Paragraph 6, the "B" train of the decay heat removal system had been declared inoperable at this time due to a small
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Because of this, the licensee performed an analysis of the
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potential safety impact that might occur if they ran the "B" DG surveillance test'while the "A" DG was out of' service.
The following was i
found:
Information Notice 84-69, described an occurrence' involving.
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loading a DG parallel to the grid in inclement weather and warned that L
this was not prudent.
Standard technical specifications do not require
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loading the second DG to verify o'perability when the first DG is o'ut of
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service.
The ^ licensee's interpretation of technical specification
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i 4.6.1.B was that it was not required to load or close the output breaker i.
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of the DG when one DG is out of service.
The licensee concluded that, E..*
for maximum reliability of the "B" DG with the "A" DG out of service, the
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"B" DG should not be loaded on'the grid during the monthly surveillance
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k test.
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.The licensee wrote and approved a modified surveillance procedure-
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intended to show operability of the DG without closing its output breaker.
On July _28, 1986 the above test was performed and
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satisfactorily completed.
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L The resident inspectors discussed the interpretation of Technical
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Specification 4.6.1.B with the licensee.
On July 29, 1986, in'a l
conference call with Region V, the licensee described their technical rationale for not loading the "B" DG to its bus during the monthly'
s surveillance test.
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Region V representative, Mr. Lew Miller, stated that it was the Region's understanding that the Technical Specification required the synchronization of the DG with its associated bus and that this would require output breaker closure during the surveillance test.
The licensee was reminded that if this was not, in their opinion, safe in this instance, they should seek emergency relief from the Technical Specification.
The licensee agreed that to continue to parallel the tested DG with the grid was safe, and conducted the regular monthly surveillance on the "B" DG to assure technical specification compliance.
In addition, the licensee plans to submit a proposed technical specification change to allow for not loading a diesel generator when the other diesel generator is out of service.
No violations or deviations were identified.
4.
Followup Items (0 pen) Open item 86-21-01 " Troubleshooting and corrective actions for the diesel generator panel light burnout incident".
On June 23, 1986, following a test of one bank of the station service batteries an attempt was made to transfer from the temporary battery charger to the normal charger. When the temporary battery charger was cut out, the normal charger tripped off the bus on over voltage, approximately 149 VDC. As a result, the bus was de-energized for a period of two to three minutes.
Several unsuccessful attempts were made to bring the normal charger back on line.
Finally, the temporary charger was brought on line and the bus was again energized.
A tour of the Emergency Diesel Generator (EDG) rooms following the event revealed three lights on both the "A" and "B" EDG control panels burned out.
Two hours prior to the event, Operations personnel had toured the EDG areas and found no lights to be burned out.
The concern was raised that there might be seme cross-connection between the "A" and "B" trains.
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The trains are required to be both electrically and physically independent.
The affected equipment was quarantined and engineering evaluations were
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initiated to ascertain if any cross-connection of trains existed.
The inspector reviewed the approved troubleshooting plan for the above event.
The plan included in detail, the description of the issue, the mmmary of information supporting the probable causes, a review of maintenance, surveillance testing and modification history, potential root causes, and an outline of troubleshooting plan.
One of the actions developed from the troubleshooting plan was to recreate the circumstance for the initial event while monitoring both diesel generators' electrical cabinets; this was Special Test Procedure, STP-960.
The results cf the STP-960 did not identify any apparent electrical links between the "A" and "B" trains.
The battery chargers acted in a manner-
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similar to the June 23 event with the normal charger tripping on overvoltage.
However, no lights burned out in the EDG control panels.
'The licensee was continuing the review of the June 23 event.
A licensee closure report was being developed at the end of this report period.
This item will remain open until a cause for the bus interaction is found, or bus interaction can be proven not to exist.
(0 pen Item 86-21-01.)
During the review of the licensee's Troubleshooting Action Plan program, it was evident that there was no administrative procedure that covered
'the development of a troubleshooting program for specific equipment events.
The program that was in place only dealt with troubleshooting from a transient, and therefore the licensee did not invoke the existing program for the diesel generator annunciator event.
The inspector discussed with the licensee the importance of a deliberate and thorough troubleshooting program to evaluate events that occur on a system or equipment related level. The licensee stated that they are developing a.
routine troubleshooting program, and that by restart this program will be in place.
This item will remain open until the licensee has their troubleshooting program in place.
(0 pen item 86-30-01.)
(CLOSED) Open item 86-18-09 " Proposed amendment to address current facility organization" The licensee had committed to submit a proposed technical specification (TS) ammendment to the NRC requesting a change in their TS to reflect the current organization for Rancho Seco.
This would be a revision of a submittal sent by the licensee in October, 1985.
The licensee submitted the revision, Proposed Amendment 138, Rev. 1 on August 12, 1986.
The inspector reviewed the submittal and found the appropriate changes to the TS were requested.
The inspector had no further questions.
This item is closed (86-18-09).
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5.
" Environmental Qualification of Limitorque Motor Valve Operator Wiring" The inspector reviewed the 1,icensee's activities in response to IN 86-03 to determine if unqualified wiring had been used in the electrical wiring of Limitorque valve operators.
The licer.see has incorporated inspection of internal wiring as part of their inspection / refurbishment program in response to IEB 85-03.
Initial ~results of the inspection of 30 sample Limitorque operators identified 21 operators having PVC insulated wiring which had been supplied by Limitorque.
The. qualification of PVC insulated wiring was not established by the Limitorque qualification test report.
Based on the initial results of the inspections, the licensee is currently expanding its inspection / refurbishment program to include all Limitorque operators in the plant to replace the PVC wiring with qualified wire prior to startup.
Furthermore, the licensee is researching the documentation on the existing PVC insulated wiring.
This item will be followed up in a future inspection.
(IN 86-03: OPEN).
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I No violations or deviations were observed.
6.
Event Followup
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A.
Decay Heat Removal System Leak On July 22, 1986, the licensee declared an Unusual Event on discovery of a leak in the "B" train of the decay heat removal (DHR)
system. At the time, the emergency diesel generator (EDG) for the
."A" train was out vf service undergoing biannual inspection.
Initially, the DHR pump casing was suspected as being the source of the leak, and the' licensee declared the "B" train to be inoperable.
Due to the. unidentified cause of the leak, the licensee concluded that both trains might be subject to the same degradation and declared an unusual, event.
After establishing contingency procedures > to cross connect the
'7" train EDG to supply the
"A" train and to establish an alternate means of decay heat removal using.a gravity drain of the borated water storage tank (BWST) _to the reactor vessel, and havi_ng obtained additional verification of
'the availability.of; backup hydroelectric power as an offsite power source, the.licensae secured from the_ Unusual Event on July 25, 1986,'and. initiated corrective actions to restore the
,. availability ~of the "A" DG and to replace the "B" DHR pump. The licensee subsequently determined that the source of the "B" train-leak was a small pinhole in the drain'line piping for the pump casing and not in the casing itself.
A temporary repair of the drain piping was made to stop the small leak.
The licensee plans to replace the drain' lines on both DHR pumps during a scheduled system outaoe in'0ctober.
e Based on radiographic examination of the extent of the drain line erosion on both DHR pumps, the licensee will continue to declare both trains of DHR to be technically inoperable until the piping is replaced in October.
Rancho Seco Technical Specifications require immediate corrective actions to restore two operable means of decay heat removal.
By separate letter to Region V, the licensee will submit an explanation of the current corrective actions to justify the interim functional status of the decay heat removal system.
This item will be followed up in a future inspection.
(Followup Item 86-30-04).
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Pipe Supports l
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On August 1, 1986, the licensee reported to the NRC via a 10 CFR 50.72 report that a wedge was found in a pipe support (Equipment Identification No. 10-26528-14) in the "B" train (line
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no. 26528-14"-CA) of the decay heat removal system which was not i
part of the design or support drawing.
The licensee's initial indication from the visual inspection of the support was that the wedge could prevent the movement of the support plate, which was designed for thermal expansion.
Therefore, the licensee declared the support inoperable and subsequently declared the decay heat train inoperable.
The licensee initiated a calculation to verify l
the' support's operability. The results of the calculation showed l
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that for a cold shutdown condition, the support would be operable and that for power operation the support would not be considered operable under design seismic conditions.
In additiun, the licensee walked down the pipe supports for both the "A" and "B" trains of decay heat; no other wedges were identified.
The following are the corrective actions taken by the licensee by the end of this report period:
reanalysis of the pipe support, issuance of a nonconforming report, issuance of a work request to rework the support, initiation of a root cause analysis of the occurrence, and initiation of a program to reverify the configuration of a sample of eighty pipe supports.
The inspector found these actions to be respon:i"e and appropriate.
The results of the licensee's corrective actions will be followed up in a future inspection.
This item is open.
(Followup Item 86-30-02)
No violations or deviations were identified.
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7.
Maintenance
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Maintenance activities for the systems and components listed below were-observed and reviewed to ascertain that theyswere conducted in accordance'
with approved procedures, regulatory guides, industry codes or standards, and the Technical Specifications.
The following items were considered during this review:
The limiting conditions for operation were met while components or systems were
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removed from service; approvals were obtained prior to initiating the work; activities were accomplished using approved-procedures and were inspected as applicable; functional testing orgcalibration 'was performed prior to returning components or systems to service; activities were accomplished by qualified personnel; radiological controls were implemented; and fire prevention controls were implemented.
A.
Followup on IE Bulletin 85-03:
Limitorque Motor Operated Valves The_ inspector reviewed the status of the ongoing licensee' program in response to Information Bulletin 85-03 regarding L%itorque inotor operated valves.
The licensee had completed the as-found data collection phase of their program for 30 selected valves in the auxiliary feedwater system (AFS) and the high pressure injection system (HPI).
Results of the initial inspection identified several common deficiencies:
- loose stem nut lock nut affecting repeatability of torque switch setting
- improper torque switch setting
- improper limit switch setting
- improper manual operation
- cracks in limit switch rotor
- limiter plate on torque bypass switch missing
- improper use of limit switch on 3-way valve
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Due to the variety and number of problems discovered in the initial sample of 30 valves, the licensee has expanded the scope of the inspection to incompass approximately 130 Limitorque operators in the plant.
In addition, the licensee has procured a motor operated valve analysis and test system (M0 VATS) to supplement its program to refurbish and adjust the Limitorque operators.
The inspector observed the maintenance personnel MOVATS training and found that use of the system appears to improve the licensee's ability to accurately adjust the torque switch settings and to diagnose overall equipment operability.
The licensee is proceeding with the operator refurbishment and data analysis phase of the IB 85-03 program.
This item will be followed up in a future inspection (IB 85-03: Open).
B.
Decay Heat Removal System Leak Repair The decay heat removal system leak described in Paragraph 6 appeared to have resulted due to erosion of the drain line pipe wall resulting from an unintended high velocity recirculation flow between the discharge and suction drain lines of the DHR pump.
This was a repeat of a similar leak on the same drain line in February,1986, as identified in LER 86-02.
The inspector questioned the use of a temporary repair in restoring the integrity of the drain line.
Specifically, the inspector was concerned that the use of a leak sealant as a pressure boundary would not meet the material requirements of the Rancho Seco original piping design (ASA B31.1) or the ASME Boiler and Pressure Vessel Code,Section III.
The licensee committed to address the inspector's concern.
This item is unresolved.
(Unresolved Item 86-30-03).
The inspector. reviewed the previous use of a leak sealant (Furmanite) repair of the DHR pump drain line in February, 1986, per l
NCR 5340.
The inspector found that the engineering review of the structural integrity of the existing drain line included evaluation of the eroded pipe wall and the additional weight of the clamp added to the line as part of the Furmanite repair.
In discussions with licensee representatives, the inspector determined that no record of the radiographs which were evaluated by engineering tad been retained and that the radiographs themselves had been recently thrown away.
The radiographs of the drain lines of both DHR pumps had been taken by maintenance for information only in troubleshooting the cause of the original leak.
However, the i
evaluation of the structural integrity performed by en0 neering used i
the same radiographs to quantitatively estimate the remaining wall thicknes.._
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The failure to maintain a record of the radiographic examination of the degraded condition of the DHR drain line is an apparent violation.
(Enforcement Item 86-30-05).
In addition, the inspector noted the following concerns:
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Since the radiographs were originally taken for information only, no procedural controls were established to define the quality requirements or acceptance criteria for " informational" radiographs.
For example, they did not have calibration standards on the film to compare densities of known and subject material.
Furthermore, a qualified inspector was not required to interpret the radiographic results.
Since the radiographs were used as inputs for the. engineering evaluation of the DHR pipe integrity, this failure to establish written procedures to control the quality of radiographic examinations is an apparent violation. (Enforcement Item 86-30-06).
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NCR 5340 did not appear to adequately address'any seismic calculations or avaluations performed by engineering in connection with the eroded pipe wall condition.
Licensee representatives explained how the eroded pipe wall condition had been evaluated along with the added weight of the temporary clamp used to seal the leak and found to be adequately supported.
This resolved the inspector's concern.
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Performance Indicators-The inspector compiled' data on various plant performance areas in response to an NRC initiative to trend indicators of the licensee's
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performance. 'This information was provided to NRC Headquarters for further review.
9.
Unresolved Items
An unresolved item is a matter about which more information is required in order to ascertain whether it is an acceptable item, an open item, a deviation or a violation.
An unresolved item was addressed in Paragraph
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10.
Exit Meeting The resident inspectors met with licensee representatives (noted in Paragraph 1) at various times.during the report period and formally on August 19, 1986. The scope and findings of the inspection activities described in this report were summarized at the meeting.
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