IR 05000275/1989034
| ML16342B655 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/27/1990 |
| From: | Mendonca M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16341F616 | List: |
| References | |
| 50-275-89-34, 50-323-89-34, IEB-87-002, IEB-87-2, NUDOCS 9003260175 | |
| Download: ML16342B655 (30) | |
Text
U.
S.
NUCLEAR REGULATORY COMMISSION
REGION V
Report Nos:
50-275/89-34 and 50-323/89-34 Docket Nos:
50-275 and 50-323 License Nos:
Facility Name:
Inspection at:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 Diablo Canyon Units 1 and
Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:
December 10, 1989 through January 27, 1990 Inspectors:
K.
E. Johnston, Resident Inspector P.
P. Narbut, Senior Resident Inspector App,d Pp, en onca, ie
,
eac or roJec s
ect>on
~i~ ~i~o a
e igne Summary:
Ins ection from December
1989 throu h Januar
1990 Re ort Nos.
an A~Id:
Tb
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1
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1.1 1 p1 operat>ons, ma>ntenance and surveillance activities, follow-up of onsite events, open items, and licensee event reports (LERs),
as well as selected independent inspection activities.
Inspection Procedures 30703, 35702, 37700, 37702, 40500, 42700, 61726, 62703, 71707, 71710, 92702, 92720, 93702, 2515/104, and 2500/27 were used as guidance during this inspection.
Results of Ins ection:
One violation and no deviations were identified.
Summar of Violations and Deviations:
An apparent violation was identified (Section 3d) regarding the installation of scaffolding over the seismically sensitive Unit 2 vital batteries without appropriate engineering review.
Areas of Stren th
"Fitness for duty" training was observed to be comprehensive and presented in an interesting and engaging manner (Section 3c).
Engineering responded in a timely and conservative manner to address seismic concerns with the Unit 2 4160 Volt Vital Switchgear Cubicles (Section 4c).
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Areas of Weakness General Construction personnel failed to recognize potential seismic interactions when installing scaffolding above the Unit 2 vital batteries which demonstrated a weakness in GC's sensitivity to seismic issues (Section 3d).
An explosive concentration of hydrogen and oxygen was allowed to build up in the main generator stator cooling water head tank.
Although the condition had been recognized to exist for more than a week, no individual or group had taken primary responsibility to resolve the problem and ultimately NRC inspector involvement was required (Section 4d).
1.
Persons Contacted DETAILS J.
D.
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Townsend, Vice President and Plant Manager Miklush, Assistant Plant Manager, Operations Services Angus, Assistant Plant Manager, Technical Services Giffin, Assistant Plant Manager, Maintenance Services Crockett, Assistant Plant Manager, Support Services Barkhuff, Acting guality Control Manager Bennett, Maintenance Manager Taggert, Director guality Support Grebel, Regulatory Compliance Supervisor Phillips, Work Planning Manager Washington, Acting Instrumentation and Controls Manager Shoulders, Onsite Project Engineering Group Manager Leppke, Engineering Manager Fridley, Operations Manager Powers, Radiation Protection Manager Connell, Assistant Project Engineer 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 on February 3, 1990.
2.
0 erational Status of Diablo Can on Units 1 and
Unit 1 achieved criticality, following its third refueling outage, on the first day of the report period.
The Unit achieved full power on December 27, 1989, following physics testing and testing of the new digital feedwater control system.
Unit 2 remained at full power throughout the period.
During the period, an NRC team inspection was conducted to review the licensee's corrective action programs.
3.
0 erational Safet Verification 71707
'a ~
General During the inspection period,'he 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 Specifications (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)
Conduct of selected activities for compliance with the licensee's administrative controls and approved procedures.
(d)
Interiors of electrical and control panels.
(e)
Plant housekeeping and cleanliness.
(f)
Engineered safety feature equipment alignment and conditions.
(g)
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.
Radiolo ical Protection 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
~ radi ol ogi ca 1 condi tions and/or chall enges.
ALARA cons iderati on was found to be an integral part of each RMP (Radiation Mork Permit).
Ph sical Securit 71707, 2515/104 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.
The inspector also reviewed the licensee's fitness for duty training, in accordance with Temporary Instruction 2515/104.
The inspector observed that the licensee training assured employee understanding of the licensee's fitness for duty policies and procedures, of health and safety hazards associated with drug and alcohol abuse, of the testing requirements, of assistance programs and of the consequences from the failure to adhere to the policies.
Further the inspector verified supervisory and escort training which assured understanding of their responsibilities, and associated techniques and procedures.
The training was comprehensive and
presented in an interesting and engaging manner.
Information was collected and transmitted to NRC headquarters for their evaluation.
d.
Unreviewed Scaffoldin Erected in Unit 2 Vital Batter Rooms On a tour of the Unit 2 vital battery rooms on January 5, 1990, the inspector observed that tube and coupler scaffolding with wood planks had been erected over the South ends of the batteries.
The scaffolding had been erected on December 21, 1989, to support modifications to the Unit 2 plant process (P-250)
computer.
The inspector noted a number of concerns with the scaffolding:
o The proximity of the tube and coupler scaffolding to the exposed interconnecting battery conductor.
o The use of U bolts to secure the scaffolding to the battery seismic bracing.
o The "scaffoldinq erection request" form attached to the scaffold specified "protective wood boxes" and not the tube and coupler scaffolding that was installed.
o Mood planks were used which could be additional fuel from a fire protection stand point.
The inspector discussed the fourth concern with the onsite Fire Harshall.
He provided the following information which obviated the concern:
o The wood used was fire resistant.
o The fire protection analysis assumed 200 lbs of Class A type fuel used in a transient manner.
o A fire watch made walk-throughs of the area on a one hour frequency for the period the scaffolding was in place.
The inspector followed up the first three concerns with the Onsite Project Engineering Group (OPEG) to determine if they had performed any type of evaluation of this particular scaffolding and what was the appropriate procedure for erecting scaffolding in a seismically sensitive area.
OPEG determined that the scaffolding should have received an engineering review, had not received a review, and upon subsequent engineering walkdown, the scaffolding was found to be unacceptable.
On January 5, 1990, the scaffolding in Battery Room 2-1 was walked down by OPEG and removed.
A walkdown was not performed of the scaffolding in room 2-2 and 2-3 until January 8,
due to a miscommunication in OPEG.
Following that walkdown, the scaffolding in Battery Room 2-2 was removed and the scaffolding in Battery Room 2-3 was modified to remove the U bolts, add bracings, and secure the wood planks with tie-wrap to the scaffoldin The normal process for scaffolding review was discussed with the Onsite Project Engineer, the General Construction (GC) Civil lead engineer and Plant equality Control (gC).
A revision to Procedure PI-67, "Construction Work Package Development and Control Using Work Orders,"
dated January 2, 1990, included new steps which detailed the scaffold erection process.
In summary, when a work planner recognizes that a scaffold. needs to be erected to complete a construction job, he is to route a scaffold erection request to GC civil.
GC civil performs an initial review and man-hour estimate, following which the request is sent to plant operations for a walkdown and approval.
GC civil then performs a
review of the location for potential seismic interaction concerns and if a target is identified which could be impacted, a copy of the request is sent to OPEG for review and walkdown.
Although the procedure revision was not in place at the time of the battery, scaffold erection, the Onsite Project Engineer and the GC civil lead stated that the program was in place as described.
The process broke down when the GC scaffold evaluator determined that
'wood boxes" as described on the request, did not constitute scaffolding and did not represent a potential seismic concern.
The scaffold request did not get an operations department review nor an OPEG review before it was sent to the field.
In the field, the GC electrician and the GC scaffolding crew discussed the proposed wood boxes and determined that work would have to be performed above the box and boxes could not easily be fabricated to support the weight of the electrician.
They made the decision to erect tube and coupler scaffold, with the supervision of the electrician who was sensitive to the exposed battery conductor, and did not notify the GC scaffolding coordinator of their modification.
Licensee Administrative Procedure AP C10S1,
"SISIP Review of Housekeepinq Activities" defines the requirements and responsibilsties to assure potential adverse seismically induced system interactions (SISI) are not created.
Paragraph 4. 1 of the procedure states,
"Personnel who introduce 'non-design'r transient equipment into the plant shall assure that unrestrained items or materials, that are NOT staged for Maintenance, are positioned such that the unrestrained items or materials cannot impact or damage nearby SISIP targets."
Failure to implement this requirement is an apparent violation (Item 50-323/89-34-01).
The licensee performed an analysis of the potential impact the scaffolding could have had on the batteries during a design basis seismic event.
The analysis was based on as-built drawings and photographs of the scaffolding in the 2-3 battery room.
Two concerns were identified for analysis.
In the first, the legs of the scaffolding applied load to diagonal battery braces.
The analysis determined that loading to the braces would not exceed loading limits and the brace had adequate margin so that it would not buckle.
The second concern was the potential for the wooden
planks to interact with the battery lead cables and potentially pull the lead from the battery.
It was determined that the scaffolding would not move enough to cause this interaction.
Based on the analysis, the licensee determined that the scaffolding did not make the batteries inoperable.
In response to the finding, the licensee issued a non-conformance report (NCR).
The inspector will-follow-up the corrective actions in conjunction with the NCR and'the licensee's response to the notice of violation.
Stora e of Pressurized Gas Bottles The inspector noted that the methods of securing high pressure gas bottles had significantly deteriorated and that management walkdowns had failed to identify and resolve the gas bottle storage problems.
The bottles could represent significant missile hazards.
The inspector noted acetylene and oxygen bottles vertically stored on roll carts outside the control room, by steel framing installed for the new security complex.
No work was in progress, nor had there been for weeks.
No work was planned to be done for several months.
The inspector notified control room personnel who in turn notified construction personnel.
The inspector subsequently observed the bottles tied loosely to the steel structure in a still less than satisfactory manner.
Other tours showed areas where bottles were likewise tied loosely to what ever structure was handy.
For example, hydrogen bottles were observed on the 85 foot level of the Unit I penetration area which were secured by barrier tape, and many high pressure gas bottles were secured loosely by rope.
Licensee management was notified by the inspector, agreed that conditions had worsened significantly, and that the plant personnel were not sufficiently sensitive to procedure requirements to secure temporary bottles firmly and to remove them when the temporary job is complete.
Licensee management personnel then had many bottles removed and initiated the following actions:
Procedure changes were committed to be initiated to specify labeling the gas bottles with the name of the person and department responsible.
The Assistant Plant Manager for Maintenance Services was designated as the person with overall plant responsibility to resolve the longstanding gas bottle problem.
The plant purchased a large quantity of special purpose nylon straps which would be used to firmly secure temporary bottle At the exit interview the inspector discussed the long standing gas bottle problems and the ineffectiveness that the licensee had demonstrated in dealing with the problem.
The licensee appeared to be prepared to focus on and resolve the problem and committed to energetic actions to resolve the problem.
The proper storage of gas bottles will be followed up in a future inspection.
One violation and no deviations were identified.
4.
Onsite Event Follow-u 93702 a 0 Unit 1 Unex ected Main Feedwater Runback Followin Turbine Tri es in On December 14, 1989, with Unit 1 at 7X power, the main turbine was tripped as part of restart testing.
Due to wiring errors, the running main feedwater pump initiated a runback.
This eventually resulted in a steam generator high-high level signal (an ESF actuation)
which gives a turbine trip and a feedwater isolation.
Power was stabilized at 2X power.
Three wiring errors were made during the 1986 time frame, related to two design changes, which resulted in the main feedwater pump runback with a turbine trip and are characterized as follows:
o One wiring error was made during the implementation of a Design Change Notice (DCN).
Two leads which were to have landed on the same terminal were landed on separate terminals.
o A design error resulted in a relay being wired to perform a function opposite of what it was intended.
o Actual instructions to physically implement a field change were not issued, although drawings were changed to delete certain wiring.
The first two wiring errors were discovered and corrected in October 1989 as a result of another error.
This other error was similar to the second error discussed above, and was found on Unit 2 following the exciter failure and manual trip on October 26, 1989.
The licensee initiated a non-conformance report and submitted LER 1-89-15, dated January 16, 1990, on this issue.
The licensee determined that program improvements in the design change process taken since 1986 would preclude similar wiring errors from occurring.
This event was discussed with electrical and I8C maintenance as well as general construction personnel.
The inspector reviewed the licensee's actions and found them acceptable.
This review closed LER 1-89-1 Containment Ventilation Isolation Durin Routine Sam lin of Volume ontro an as ace On December 16, 1989, with Unit 2 at 100K power, a Containment Ventilation Isolation (CVI) was initiated due to the actuation of Plant Vent Radiation Monitor 2-RM-14B.
Prior to'the alarm, chemistry technicians were manually sampling the Volume Control Tank (VCT) gas space.
In accordance with procedures, the sample line purge was discharged to the plant vent through the sample room hood, setting off the alarm.
Sampling of the VCT gas space is normally done during startup when the noble gas source term is low.
However, the plant was at 100K power with activity levels close to full power equilibrium.
The calculated release was 1.49K of the technical specification limits.
The licensee issued LER 2-89-12 on January 16, 1990, discussing this event.
The event and LER were reviewed and will be discussed in greater detail in Inspection Report 50-275/90-03.
Unit 2 4KV Vital Bus G Seismic Concerns On December 29, 1989, the Onsite Project Engineering Group (OPEG)
identified that the seismic supports for certain Unit 2 4KV Vital Bus G cubicles did not match the configuration that was shake tested for seismic qualification.
The bus was declared inoperable on the evening of December 30, 1989, and modifications to return the bus to a seismically qualified configuration were completed on December 31, 1989.
In October of 1989, Nuclear Engineering and Construction Services (NECS; the licensee's corporate engineering)
performed walkdowns of the Unit 1 4KV breaker cubicles to get as-built drawings.
The drawings were then used to develop criteria for opening the doors to the breakers while maintaining seismic qualification of the bus.
In late December, while performing these reviews, NECS discovered that the as-built drawings did not correspond to the shake test configuration.
Of specific concern was how the cubicles were mounted to the base.
However, NECS determined that for the Unit 1 cubicles, the as-built configuration was equal to or more conservative than the shake tested configuration.
A review of the Unit 2 configuration was initiated on December 26, 1989.
It was determined that while the bus F and H cubicles were at least equivalent to the shake tested configuration, the bus G
configuration differed substantially.
NECS performed a hand calculation on December 29 that determined the cubicle was not seismically qualified.
NECS determined, however, that the hand calculation was conservative, the margin by which the cubicle would not meet seismic criteria as determined by the calculation was small, and therefore, a finite element calculation would find the as-found cubicle configuration to meet seismic criteria.
Based on this, NECS recommended that the cubicle did not need to be
considered inoperable.
This conclusion was later backed-up with the completed finite element calculation.
A design change was written on December 30 and implemented December 31 to ensure the cubicle configuration was at least as conservative as the shake tested configuration.
While the work was being done, the bus was declared inoperable by operations in a conservative response to NECS findings.
The inspector reviewed the above with the NECS project engineer.
The seismic review was carried out in a expeditious manner and conservative actions taken.
The inspector discussed the need to better document operability determinations which are based on
"Engineering Judgement" pending the completion of a more formal calculation.
The project engineer agreed to review their practices.
Ex losive Mixture Found in the Unit 1 Stator Coolin Water Head Tank over as Following the startup of Unit 1, conditions in the main generator stator cooling water (SCW) system resulted in air intrusion to the hydrogen cover gas of the SCW head tank.
The air intrusion created an explosive mixture of hydrogen and oxygen (concentrations of both elements greater than 4X).
This was discovered by the licensee during the week of December 24, 1989.
The licensee had determined that there was no ignition source in the tank and that corrective actions would include elimination of the oxygen inleakage.
Although some success was achieved in reducing the oxygen concentration, the efforts were only temporarily successful.
Explosive mixtures were identified during sampling on December 19, and 31, 1989, and January 2,
and 3, 1990.
The inspector read the December 29 concentration results in the shift foreman log on January 2 and discussed it with the assistant plant manager (APM) for operation services.
The APM stated that he was aware of the condition, that the concentration did not pose a
explosive condition, and the actions were underway to prevent recurrence.
The inspector followed up on the status of the SCW system on January 3.
o The chemistry manager confirmed that concentrations of hydrogen and oxygen each above 4X were considered explosive.
o The engineering manager noted that a system operation problem was the cause of the air inleakage.
He stated that the system engineer was involved in resolving the issue.
o The system engineer was under the impression that the air inleakage problem had been solved with the replacement of the hydrogen blanket with a nitrogen blanket.
This was accurate in that during the week of December
a nitrogen blanket was tried.
However, air continued to leak into the tank in
1 x
addition to hydrogen.
On December 29, concentrations of 23K hydrogen, 14K oxygen, and 63K nitrogen were found in the SCM head tank.
o The maintenance manager was unaware of current conditions, having just returned from vacation.
o The inspector talked to a shift technical advisor (STA) who others had said was involved in corrective actions.
The STA stated that only that day had he been given the lead at troubleshooting the leak and to his knowledge there had not been a problem "owner."
He described a logical methodology for detecting the leak based on work performed to correct leakage into the condensate system.
He also stated that he had just been told that the concentration of oxygen was above 4X and that the shift foreman was planning to vent the tank.
Based on a concern that there was not established responsibility of the SCW head tank problem and the new information that an explosive concentration had developed, the inspector and regional management asked the plant manager to assess the situation.
Subsequent to the discussion, the licensee did the following:
o A nitrogen blanket was reestablished.
o A four hour gas space sampling routine was initiated.
o Based on the results of the sample, the shift foreman would initiate a gas space purge and refill with nitrogen.
o The system engineer was made responsible for resolving the 1 eak.
The SCW system skid (pumps, filters, heat exchangers, and tank) is located on the 85 foot level of the turbine building and cools the generator stator at the 140 foot level.
There is no apparent ignition source in the tank where the explosive mixtures were contained.
The intent of the design was to have the discharge of SCM from the generator at a positive pressure.
This was confirmed by the system startup test and was the operating condition of Unit 2.
System performance of Unit 1 appeared to have changed such that as the SCM exited the generator, it was at a negative pressure with respect to atmosphere.
This resulted in inleakage at a number of SCW flandres on the return line at the 140 foot level.
The licensee s actions were to attempt to seal the flanges.
These efforts, although reducing the leakage, were not completely effective.
At the end of the inspection period, the licensee had not resolved the air leakage problem and was maintaining the compensatory measures.
The inspector discussed with plant management the perception derived from this event and others that while licensee organizations are usually adept at solving problems confined to one organization and
major problems that either could result in a plant event or did result in an event, they are not adept at addressing multidisclinary problems which do not threaten plant operations.
Management agreed that the issue of priority was one which needed to be further addressed.
e.
Ino erable Refuelin Cavit Orain The licensee identified a potential concern that a strainer in the refueling canal drain sump could clog and impound water in the refueling canal during an accident, reducing the inventory of water available for post-LOCA recirculation.
The licensee identified the potential for a clogged refueling canal drain strainer while performing a design change to ease their installation and removal.
The postulated source of debris was paint chips, of less than 3/16", entrained in the containment spray system through the containment recirculation sump.
The Unit 1 strainer (where the modification was completed prior to the problem identification) has a strainer with an opening of 5/32".
The Unit 2 strainer (with the original design)
has openings of 0.040".
If the strainer became clogged and the containment spray system was in operation, water would accumulate in the refueling canal to the level of the main reactor cavity floor at which level it would cascade into the reactor cavity sump.
The water entrapped in the canal was calculated by the licensee to be 7060 cubic feet.
The licensee evaluated the net loss of 7060 cubic feet of water on post-LOCA recirculation capability.
The two main considerations were adequate available net positive suction head (NPSH) to the residual heat removal (RHR) pumps and adequate flow area through the recirculation sump screens.
In both cases, the licensee's analysis found there was margin.
Based on this, the licensee determined that there were no operability concerns.
The licensee issued a non-conformance report (NCR) on this issue.
At the end of the inspection report, a technical review group had not met to conclude root cause and corrective actions to prevent recurrence.
The inspector will fol'low the licensee's review under routine NCR followup.
5.
Maintenance (62703 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.
Observation during this inspection period included work on relief valve blowdown settings.
The inspector had previously questioned licensee
(
~ 1
maintenance management on whether the blowdown setting for the letdown relief valve was proper.
This was questioned in response to an incident in 1989 when operators had to take special actions to get the relief valve to reseat.
Licensee maintenance personnel indicated that in response to the question they had examined a sample of relief valve blowdown settings in Unit j. during the outage and would sample others during the Unit 2 outage.
The licensee found some relief blowdown settings improper due to a lack of procedure clarity.
The inspector wi 11 followup this matter during the upcoming Unit 2 outage.
Other maintenance activities were examined as detailed in section 3d regarding scaffolding during modifications, 3e regarding pressurized gas cylinder storage controls for interrupted modifications, section 4a regarding feedwater system design modifications, section 4.c.
regarding 4kv cubicle modifications and section 4e regarding a refueling cavity drain modification.
No violations or deviations were identified.
6.
Sur vei 1 1 ance 61726 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.
Unit 1 Restart Ph sics Testin The inspector monitored the licensee's restart physics testings.
Shortly following startup, while at 35K power, the licensee noted that the incore flux map showed a quadrant tilt of 2.8X.
Hased on a position statement provided by the fuel vendor on core tilt, the licensee determined that operating at greater power was acceptable.
The position statement allowed the licensee to "zero-out" the incore flux tilt on the power range instruments, so that the quadrant power tilt ratio (gPTR) begins at zero, if margin existed in the heat flux hot channel factor F (Z).
According to the fuel vendor, incore tilts are common of IIew cores at low power.
At higher powers, F (Z) was found to be approximately 2X high.
According to Technical Specification 3.2.2.1, the licensee tightened its axial flux difference (AFO) requirements by two percent.
This also necessitated a seven day flux map to determine Fg(Z).
The high peaking factors were not unexpected since the licensee operated close to the end of their "burn-up window" which the new core physics analysis was based on.
New highly enriched elements surrounded by once used and comparatively burned out elements tend to bur n hotter.
The incore flux tilt is described by the vendor as not unusual but not predicted.
The combination of these two effects required added restriction in operation.
Technical Specification 3.2.2. 1 allowed the licensee to operate at full power with a measured Fg(Z) 2X greater than the limit established in the
specification if the licensee reduced the axial flux difference allowable operation band by an equivalent amount on both sides.
At the end of the inspection period the licensee was pursuing with the fuel vendor the cause of the 2X flux tilt.
The inspector will follow developments in this area.
No violations or deviations were identified.
7.
En ineerin Safet Feature Verification (71710 The inspector performed a walkdown of the Units j. and 2 containment spray systems in accordance with inspection module 71710.
No violations or deviations were identified.
8.
Tem orar Instruction 2500/27 Review of Corrective Actions Taken in es onse o
om sance u
e sn
-
as ener es sn This section concludes a review of the licensee's response to NRC compliance Bulletin 87-02 regarding fastener testing.
Two samples of bolts selected from the stock code which did not match the type specified by the stock code were reviewed.
'a ~
Sam le DC-938186 ASME SA 194 GR7 HH Nuts (Safet Related)
During the initial sample selection in December 1984 for testing,
nuts were selected from a Grade 7 stock code.
The inspector found one Grade 4 nut mixed in with the other Grade 7 nuts.
The licensee subsequently verified that the nut had the qualities of a grade
bo1 t.
In their follow-up review, the licensee determined that nuts from this stock code had been issued for use in the Unit 2 diesel generator 2-1 turbo charger exhaust flange.
The design drawing specified Grade 2H nuts and piping specifications allow Grade 7 nuts in lieu of Grade 2H.
Grade 4 nuts have the same tensile strength as Grade 7s but have a lower temperature range.
However, Grade 4 and Grade 7 have both a higher temperature range and tensile strength when compared to Grade 2H nuts.
The licensee determined that the use of Grade 4 bolts was acceptable in this application.
The licensee put the stock code on hold during their investigation that was tracked by a nonconformance report (NCR-DC0-88-(A-NOOl).
'he licensee found that of the bolts remaining in the stock code only 10 of 660 were Grade 4 bolts.
An audit of the supplier and sub-supplier was performed.
It was not determined how the Grade
bolts made it to the Grade 7 bolt bin.
Inspections by the supplier and the licensee were performed on a sampling basis.
A statistical analysis performed to determine the chances that a Grade 4 bolt would have been discovered by the sample found that the sample sizes were too small.
The sub-supplier claimed to perform a 100K inspection.
As a result of this finding, use of a sampling methodology was suspended until better criteria was identified.
The
~ v s
licensee's current procedures reflect sampling guidance provided in ANSI/ASQC Zl.4 - 1981.
The audit of the sub-supplier found their QA program to be acceptable.
The inspector found the licensee's actions for this stock code acceptable.
Sam le OC-193435 SAE Grade 5 Fasteners (Non-Safet Related)
The licensee found Grade 2 fasteners in a Grade 5 stock code bin.
The Grade 2 fasteners are of lower strength.
The cause of the problem was determined to be warehouse personnel error.
Hecause the stock code was non-safety related (NSR), the licensee's QA program for traceabi lity had not been applied for the installation of the bolts into the plant and therefore the use of the bolts is unknown.
With respect to NSR equipment, the licensee's current program would provide greatly improved traceability.
However, NSR bolts issued on one NSR job can still be used on others.
Following identification of this problem, warehouse personnel were trained on not accepting Grade 2 bolts in Grade 5 applications.
Given that these are NSR fasteners for which use cannot be determined, the inspector found the licensee's actions acceptable.
No violations or deviations were identified.
10.
Exit 30703)
On February 23, 1990 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 repor ~ Q