IR 05000528/1999004
| ML17313A942 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/19/1999 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML17313A941 | List: |
| References | |
| 50-528-99-04, 50-528-99-4, 50-529-99-04, 50-529-99-4, 50-530-99-04, 50-530-99-4, NUDOCS 9905260302 | |
| Download: ML17313A942 (9) | |
Text
EXECUTIVESUMMARY Palo Verde Nuclear Generating Station, Units 1, 2, and 3 NRC Inspection Report No. 50-528/99-04; 50-529/99-04; 50-530/99-04
~Oerations Misdiagnosis of plant conditions and unnecessarily hurried operator actions in response to a failure in the main turbine electrohydraulic control system caused a Unit 1 reactor trip on high pressurizer pressure.
Posttrip operator actions were good (Section 04.1).
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A violation of Technical Specification 4.5.2.d.3 was identified for the failure to perform the required surveillance test on the trisodium phosphate baskets.
This Severity Level IVviolation is being treated as a noncited violation per the guidance provided in Appendix C of the Enforcement Policy. This issue is in the licensee's corrective action program as Condition Report/Disposition Request 9-8-Q047 (Section 08.1).
Maintenance e.
Observable material condition of the three units was good.
During a posttrip walkdown of the Unit 1 containment, the licensee discovered a moderate amount of boron crystals on carbon steel components of Reactor Coolant Pump 2A. The licensee's actions to address the boron accumulation were good (Section M2.1).
The licensee failed to take actions to ensure that a deficient condition was appropriately corrected on all affected components.
As a result, the deficiency was not corrected for all turbine-driven auxiliary feedwater pumps in all units. This deficiency was identified again by an overspeed trip of the Unit 2 turbine-driven auxiliary feedwater pump. This is a violation of 10 CFR Part 50, Appendix B, Criterion III. This Severity Level IVviolation is being treated as a noncited violation consistent with Appendix C of the NRC Enforcement Policy. The licensee took prompt actions to assess transportability and
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correct the conditions. This issue is in the licensee's corrective action program as Condition Report/Disposition Request 2-9-0019 (Section M3.1).
The licensee failed to provide sufficient design basis information in the appropriate procedures.
As a result, missing and/or loose bolts were identified on the Units 1,2, and 3 emergency diesel generator air-start headers.
The torque value for the bolts was increased from 25 to 50 foot-pounds, and the bolts that required torqueing were not identified in the appropriate maintenance instructions. This is a violation of 10 CFR Part 50, Appendix B, Criterion III, for not implementing design basis information. This Severity Level IVviolation is being treated as a noncited violation consistent with Appendix C of the NRC Enforcement Policy. This issue is in the licensee's corrective action program as Condition Report/Disposition Request 3-9-0026.
During routine testing of a containment isolation valve for the hydrogen control system, the valve failed to function, as designed.
The failure was caused by the valve wiring being improperly installed following maintenance.
The condition was not detected by postmaintenance testing because the procedure, which specified the testing requirements for the valve actuators, was inadequate.
This is a violation of 10 CFR 99052b0302 990521.
PDR ADOCK 05000528
signal setpoint was reached, the operators continued the plant cooldown by using the atmospheric dump valves.
The operators successfully stabilized the plant in Mode 3 at normal operating pressure and temperature.
From review of personal statements taken from the shift crew and the control room alarm printout, the inspectors determined that the initial diagnosis was conducted in the first few seconds of the transient without observation of turbine load or control valve position. Although the operators looked for the RPCB, the decision to take the SBCS to emergency off was made just prior to receiving the RPCB alarm.
Lowering turbine load and control valve position was not observed by either the control room supervisor or the secondary operator prior to making the diagnosis.
These indications would have confirmed to the operators that the SBCS was functioning properly in response to closure of the control valves. The inspectors determined that operator response to the transient was conducted without the proper diagnosis, unnecessarily hurried, and inappropriate for plant conditions at the time. The licensee was further assessing operator performance through a formal human performance evaluation to determine how the event will be incorporated into operator training.
C.
Conclusions Misdiagnosis of plant conditions and unnecessarily hurried operator actions in response to a failure in the main turbine electrohydraulic control system caused a Unit 1 reactor trip on high pressurizer pressure.
Posttrip operator actions were good.
Miscellaneous Operations Issues (92901)
08.1 Closed Licensed Event Re ort LER 50-529/98-001:
Surveillance Test Deficiency Found During Quality Assurance Audit Leads to Technical Specification (TS) 3.0.3/4.0.3 Entry.
On March 1, 1998, Unit 2 control room personnel declared both trains of the emergency core cooling system inoperable due to exceeding the specified 18-month surveillance interval of TS Surveillance Requirement (SR) 4.5.2.d.3, "ph of Trisodium Phosphate,"
plus the maximum allowable extension of 25 percent.
The licensee entered limiting condition for operation TS 3.0.3 and invoked the provisions of TS SR 4.0.3 to allow up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to permit the completion of the missed surveillance.
The licensee satisfactorily completed TS SR 4.5.2.d.3 analysis within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and exited TS limiting condition for operation TS 3.0.3.
The failure to perform the SR within its required interval is a violation of TS 4.5.2.d.3.
This Severity Level IVviolation is being treated as a noncited violation, consistent with Appendix C of the NRC Enforcement Policy. This violation is in the licensee's corrective action program as condition report/disposition request (CRDR) 9-8-Q047 (50-529/9904-01).
C.
Conclusions The licensee failed to take actions to ensure that a deficient condition was appropriately corrected on all affected components.
As a result, the deficiency was not corrected for all turbine-driven auxiliary feedwater pumps in all units. This deficiency was identified again by an overspeed trip of the Unit 2 turbine-driven auxiliary feedwater pump. This is a violation of 10 CFR Part 50, Appendix B, Criterion III. This Severity Level IVviolation I
is being treated as a noncited violation consistent with Appendix C of the NRC Enforcement Policy. The licensee took prompt actions to assess transportability and correct the conditions. This issue is in the licensee's corrective action program as Condition Report/Disposition Request 2-9-0019.
M3.2 Emer enc Diesel Generator EDG Air-Start Manifold Bolts Not Pro erl Tor ued Units1 2 and3 Ins ection Sco e 62707 On February 18, 1999, during a routine surveillance, the licensee identified loose and missing bolts on the Unit 3 EDG A air-start manifold. The inspectors evaluated the circumstances surrounding the loose and missing bolts, conducted interviews with the system engineer, and reviewed documentation related to the event.
Observations and Findin s During performance of Surveillance Procedure 40ST-9DG01, "Diesel Generator A Test,"
Revision 6, an auxiliary operator noted that, of the two bolts holding the air-start manifold to Cylinder 9R, one was missing and the other bolt was loose.
The air-start manifold bolts on Cylinder 7R were also loose.
The licensee initiated CRDR 3-9-0026 to document the problem and to evaluate the transportability of the issue.
Licensee management did not consider the EDG to be inoperable, because the EDG started
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within its required time limits and the air-start header was still held in place by the other cylinders on the right side.
Licensee inspection of all EDGs (two in each of the three units) revealed that Unit 1 EDG A was also missing a bolt on Cylinder 3R. The licensee initiated WRs 955623, 955638, 955639, 955640, 955641, and 955642 to verify the torque on the air-start manifold bolts of all EDGs. All EDG manifold bolts required
. tightening approximately 1/4 turn to satisfy the current specification value of 50 ft-lbs.
CRDR 1-6-0030, dated February 20, 1996, described loose and missing bolts on the air-start manifold of several cylinders on Unit 1 EDG A and Unit 3 EDG B. An operability determination associated with this CRDR concluded that the EDGs remained operable with the loose or missing bolts, due to the rigidityof the manifold and the number of bolts that remained tight on the adjacent cylinders. The CRDR root cause determination identified a low torque value of 25 ft-Ibs as the primary reason for the bolts becoming loose.
In addition, the CRDR identified that, in order to remove the air-start manifold from one of the cylinder heads for maintenance, it was necessary to loosen the bolts on adjacent cylinders to allow removal of the manifold flange from the head being worked.
However, this portion of the task was not in the maintenance procedur the performance of design reviews. Contrary to these requirements, the licensee had not verified by design review or by another method, such as testing, the adequacy of conduit penetrating flooding barriers to resist water intrusion. This resulted in the potential for rendering the redundant trains of AFW unavailable following a design basis flooding event in the MSSS.
This Severity Level IVviolation of Criterion III is being treated as a noncited violation, consistent with Appendix C of the NRC Enforcement Policy. This violation is in the licensee's corrective action program as CRDR 1-60236 (50-528,-529,-530/9904-06).
Conclusions A violation of Criterion illwas identified for not specifying the correct type of seal fittings for conduits.
As a result, during flooding of a portion of the auxiliary building, water entered the conduits.
This affected the operability of safety-related equipment.
This Severity Level IVviolation is being treated as a noncited violation consistent with Appendix C of the enforcement policy. This issue is in the licensee's corrective action program as Condition Report/Disposition Request 1-60236.
IV. Plant Su ort R1 Radiological Protection and Chemistry Controls R1.1 General Comments on Radiolo ical Protection Controls Units 1 2 and 3 a.
Ins ection Sco e 71750 The inspectors monitored radiological protection activities during routine site tours.
b.
Observations and Findin s The inspectors observed radiation protection personnel, including supervisors, routinely touring the radiologically controlled areas.
Licensee personnel working in radiologically controlled areas exhibited good radiation work practices.
Contaminated areas and high radiation areas were properly posted.
Area surveys posted outside the room were current. The inspectors checked a sample of doors, required to be locked for the purpose of radiation protection, and all were in accordance with requirements.
Conclusions The radiological protection program was effectively implemented, in those areas reviewe 'I d
Arizona Public Service Company-4-MAY j 9 j909 E-Mail report to T. Ffye (TJF)
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