IR 05000387/1999006
| ML17146B181 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 08/18/1999 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17146B180 | List: |
| References | |
| 50-387-99-06, 50-388-99-06, NUDOCS 9908240076 | |
| Download: ML17146B181 (21) | |
Text
U.S. NUCLEAR REGULATORYCOMMISSION
REGION I
Docket Nos:
License Nos:
50-387, 50-388 NPF-14, NPF-22 Report No.
50-387/99-06, 50-388/99-06 Licensee:
PP8L, Inc.
2 North Ninth Street Allentown, Pennsylvania 19101 Facility:
Susquehanna Steam Electric Station Location:
P.O. Box 35 Berwick, PA 18603-0035 Dates:
June 8, 1999 through July 19, 1999 Inspectors:
S. Hansell, Senior Resident Inspector J. Richmond, Resident Inspector A. Blarney, Resident Inspector G. Smith, Sr. Security Specialist P. Frechette, Security Specialist Approved by:
Curtis J. Cowgill, Chief Reactor Projects Branch 4 Division of Reactor Projects 9908240076 9908i8 DR ADOCK 05000387
EXECUTIVESUMMARY Susquehanna Steam Electric Station (SSES), Units 1 & 2 NRC Inspection Report 50-387/99-06, 50-388/99-06 This inspection included aspects of PP&L's operations, maintenance, engineering, and plant support at SSES.
The report covers a six week period of routine resident inspection activities and an announced inspection by regional physical security specialists.
~Oerattona A number of equipment problems occurred which challenged the plant staff and the availability of important plant systems.
Equipment problems caused two automatic plant shutdowns.
A stem/disk separation on the Unit 1 "C" outboard main steam isolation valve caused one shutdown and a failure on the Unit 2 "A"main transformer caused the second.
In addition, equipment problems caused two unplanned power reductions.
A tube leak on the Unit 1 "3A"feedwater heater caused one power reduction and a motor failure on the Unit 1 "C" circulating water pump caused the second.
(Section 02.1)
On July 1, 1999, PP8L did not notify the NRC within the required time period that the Unit 1 high pressure coolant injection system injected water into the reactor coolant system.
On July 3, PPBL did not notify the NRC within the required time period that a main steam isolation valve had degraded to the extent that the valve's leakage rate exceeded the Technical Specification requirements.
The failure to make these notifications within the required time period is a violation of 10 CFR 50.72. This Severity Level IVviolation is being treated as a Non-Cited Violation, consistent with Appendix C of the NRC Enforcement Policy. This violation is documented in PP&L's corrective action program as condition reports CR 187420 and CR 192457.
(Section 04.1)
Following the Unit 1 automatic reactor shutdown on July 1, 1999, operators unnecessarily delayed placing the second division of suppression pool cooling in service.
The operators placed the second division of suppression pool cooling in service approximately 40 minutes after the SSES emergency operating procedures directed suppression pool cooling to be maximized.
(Section 05.1)
PP8L's post trip event reviews following the Unit 1 automatic reactor shutdown on July 1, 1999, were weak in that the reviews did not identify the unnecessary delay in placing the second division of suppression pool cooling in service.
(Section 05.1)
Maintenance
~
A failed main transformer bushing resulted in the June 8, 1999, Unit 2 automatic reactor shutdown.
The PP8L root cause analysis team concluded that PP&L had failed to take correct action on a vendor's 1990 recall notice which identified a manufacturing defect.
which eventually led to this failure.
(Section M1.1)
Enrnineerinq On July 1, 1999, the Unit 1 "C" outboard main steam isolation valve (MSIV) stem separated from the valve poppet, resulting in an automatic reactor shutdown.
PP8L determined that the stop plate had not been properly installed in the valve poppet during valve maintenance performed in 1990. PP8L reviewed the maintenance history on all Unit 1 and Unit 2 MSIVs, inspected three additional Unit 1 MSIVs, and found no additional problems.
The inspectors concluded that PP8L had performed a thorough root cause analysis and a comprehensive extent of condition review. (Section E2.1)
S PP8L's physical security program testing and maintenance activities were conducted in a manner that protected public health and safety and met PPBL's commitments and NRC requirements.
(Section S1)
The SSES security force members adequately demonstrated that they had the required knowledge to effectively implement the duties and responsibilities associated with their position.
(Section S2)
TABLEOF CONTENTS I. Operations
02
08 Conduct of Operations
.
01.1 Unit Operations and Operator Activities Operational Status of Facilities and Equipment 02.1 Operational Safety System Alignment Operator Knowledge and Performance............................
04.1 Reportability Determinations..
05.1.
Control of Suppression Pool Water Temperature During Abnormal Plant Operation Miscellaneous Operations Issues..
08.1 Licensee Event Report (LER) Review
1
1
2
4 II. Maintenance..
M1 Conduct of Maintenance..............:.....................
M1.1 Surveillance and Pre-Planned Maintenance ActivityReview
.
...5
..5
III. Engineering..
E2 Engineering Support of Facilities and Equipment E2.1 Unit 1 "C" Outboard Main Steam Isolation Valve Failure.....
~.
..6
6 IV. Plant Support..
S1 Adequacy of Physical Security Program Testing and Maintenance.....
S2 Security and Safeguards Staff Knowledge and Performance.........
~
.7
8 V. Management Meetings X1 Exit Meeting Summary
.
...9
... 9 INSPECTION PROCEDURES USED
.
ITEMS OPENED, CLOSED, AND DISCUSSED LIST OF ACRONYMS USED
.. 10
. 11
Re ort Details Summa of Plant Status Susquehanna Steam Electric Station (SSES) Unit 1 was at 45% power at the beginning of the inspection period.
Power was increased to 100% on June 9, following repairs to balance of plant equipment.
On June 16, power was decreased to 75% to perform feedwater heater leak repairs and returned to 100% power on June 19. On July 1, the Unit 1 reactor automatically shutdown when an outboard main steam isolation valve failed closed.
On July 14, a reactor startup commenced; 100% power was reached on July 17. Unit 1 was operated between 92%
and 100% power from July 17 to July 19, due to a circulating water pump motor problem which limited main condenser vacuum.
Unit 1 was at 100% power at the end of the inspection period.
SSES Unit 2 was at 100% power at the beginning of the inspection period.
On June 8, the Unit 2 reactor automatically shutdown when the "A"main transformer failed. On June 15, a reactor startup commenced; 100% power was reached on June 19. On July 9, power was reduced to 85% for a control rod sequence exchange.
Unit 2 returned to 100% power on July 10 and remained at full power through the end of the inspection period.
Conduct of Operations
'1.1 Unit 0 erations and 0 erator Activities (71707)
Two automatic reactor shutdowns occurred during this inspection period.
Immediate operator response was good, with the exception of delayed event report (section 04.1)
and delayed operation of suppression pool cooling (section 05.1). The plant's safety equipment functioned as designed during both events.
The inspectors determined routine operator activities were performed conservatively.
Effective controls were implemented for safe plant operation.
In general, control room logs accurately reflected plant activities.
Operational Status of Facilities and Equipment 02.1 0 erational Safet S stem Ali nment (71707)
During routine plant tours, the proper alignment and operability of various safety systems, engineered safety features, and on-site power sources were verified. Partial walkdowns were performed for the residual heat removal (RHR) shutdown cooling flow path, security system power distribution, security sy'tem backup diesel generator, security system batteries, "E" emergency diesel generator, and standby liquid control system heat tracing.
No equipment problems were noted.
Topical headings such as 01, M8, etc., are used in accordance with the NRC standardized reactor inspection report outline. Individual reports are not expected to address all outline topic The inspector observed that a number of equipment problems occurred which challenged the plant staff and the availability of important plant systems.
Two equipment problems that resulted in automatic plant shutdowns were the stem/disk separation of the Unit 1 "C" outboard main steam isolation valve and failure of the Unit 2 "A"main transformer.
Two equipment problems that caused unplanned power reductions were a tube leak on the Unit 1 "3A"feedwater heater and a motor failure of the Unit 1 "C" circulating water pump.
Operator Knowledge and Performance
. 04.1 Re ortabilit Determinations Ins ection Sco e (71707,40500)
The inspectors reviewed PP8L's event reports for the failure of the Unit 1 "C" outboard main steam isolation valve (MSIV) and the associated event reporting requirements as specified in 10 CFR 50.72, "Immediate Notifications Requirements for Operating Nuclear Power Reactors."
Observations and Findin s On July 1, at 2:08 a.m., Unit 1 had an automatic reactor shutdown when an MSIVfailed closed.
The high pressure coolant injection (HPCI) system and the reactor core isolation cooling (RCIC) system started automatically and injected into the reactor coolant system.
The operations shift supervisor determined that a four hour notification was required for the automatic reactor shutdown in accordance with 10 CFR 50.72 (b)(2)(ii). During the preparation of the event report, the shift supervisor determined that a one hour report was also required, per 10 CFR 50.72 (b)(1)(iv) due to the HPCI injection. PP&L reported both events at 4:56 a.m. This exceeded the required one hour notification time specified in 10 CFR 50.72 (b)(1)(iv).
On or before Saturday July 3, with Unit 1 in cold shutdown, PP8 L determined that the leakage rate through the "C" outboard MSIVwas in excess of the required Technical Specification (TS) limit (SR 3.6.1.3.12).
PP8L determined that an event report, required by 10 CFR 50.72(b)(2)(i), would be delayed until all as-found MSIVleak rate testing had been completed.
On Tuesday, July 6, PP8L reported this event.
Station procedure NDAP-QA-0720, "Station Report Matrix and Reportability Guidelines,"
and NUREG 1022, Revision 1, "Event Reporting Guidelines 10 CFR 50.72 and 50.73,"
all require that this condition be reported within four hours of discovery. This condition was not reported within the required four hours.
Contrary to 10 CFR 50.72, PP8L did not report the HPCI injection or the degraded MSIV condition within the required time limit. This Severity Level IVviolation is being treated as a Non-Cited Violation, consistent with Appendix C of the NRC Enforcement Policy.
This violation is documented in PP8L's corrective action program as condition reports CR 187420 and CR 192457.
(NCV 50-387/99-06-01)
Conclusions On July 1, 1999, PP8L did not notify the NRC within the required time period that the Unit 1 high pressure coolant injection system injected water into the reactor coolant system.
On July 3, PP8 L did not notify the NRC within the required time period that a main steam isolation valve had degraded to the extent that the valve's leakage rate exceeded the Technical Specification requirements.
The failure to make these notifications within the required time period is a violation of 10 CFR 50.72. This Severity Level IVviolation is being treated as a Non-Cited Violation, consistent with Appendix C of the NRC Enforcement Policy. This violation is documented in PP8L's corrective action program as condition reports CR 187420 and CR 192457.
Operator Training and Qualification 05.1 Control of Su ression Pool Water Tem erature Durin Abnormal Plant 0 eration Ins ection Sco e (71707,40500)
The inspectors reviewed operator actions taken during the Unit 1 automatic reactor shutdown that occurred on July 1. The inspectors compared these actions to the actions specified in the station procedures, the Technical Specification and the Final Safety Analysis Report (FSAR).
b.
Observations and Findin s During the July 1, Unit 1 automatic reactor shutdown the main steam isolation valves closed.
As a result reactor decay heat was not transferred to the main condenser but instead was transferred to the suppression pool through operation of safety relief valves (SRVs), the high pressure coolant injection (HPCI) system and the reactor core isolation cooling (RCIC) system.
The operation of the SRVs, HPCI, and RCIC increased the suppression pool water temperature.
The plant control operators (PCOs) maintained the suppression pool water temperature within design limits. Nevertheless, the operators unnecessarily delayed placing the second division of suppression pool cooling in service.
The second division of suppression pool cooling was started approximately 40 minutes after the emergency operating procedures directed suppression pool cooling to be maximized. The inspectors concluded that the delay in starting the second division of suppression pool cooling resulted in a higher suppression pool water temperature.
The inspectors also noted that the delay in starting the second division of suppression pool cooling was not identified by either PP8L's Post-Trip Event Review or PP8L's Independent Safety Engineering Group (ISEG) review of this event.
PP&L prepared a condition report in their corrective action system to assess the delay in placing the second division of suppression pool cooling in service During the event, the operators monitored and controlled suppression pool temperature using different instruments than indicated in the Technical Specifications and FSA During this event the operators monitored suppression pool water temperature with the plant information computer system (PICSY). The Technical Specification Bases and the FSAR both indicate that the suppression pool temperature monitoring system (SPOTMOS) should be used to determine and control suppression pool water temperature during abnormal plant operation.
PP&L operator training module SY017 E-9, "Primary Containment Instrumentation," indicated that the PICSY indication for suppression pool water temperature was the "preferred" indication during normal and transient operations, including implementation of the EOPs.
PICSY indication was preferred since it was more representative of bulk suppression pool water temperature than SPOTMOS because PICSY calculated average suppression pool water temperature with more temperature sensors.
This issue was discussed with PP&L operations management and they agreed to address the differences.
c.
Conclusion Following the Unit 1 automatic reactor shutdown on July 1, 1999, operators unnecessarily delayed placing the second division of suppression pool cooling in service.
The operators placed the second division of suppression pool cooling in service approximately 40 minutes after the SSES emergency operating procedures directed suppression pool cooling to be maximized.
PP&L's post trip event reviews following the Unit 1 automatic reactor shutdown on July 1, 1999 were weak in that the reviews did not identify the unnecessary delay in placing the second division of suppression pool cooling in service.
INiscellaneous Operations Issues 08.1 Licensee Event Re ort LER Review (71707,92700)
Closed LER 50-387/97-020-01 Closed LER 50-387/98-014-01 Closed LER 50-388/98-008-01 Failure of Safety Relief Valve (SRV) Acoustic Monitor These events were previously discussed in'RC Inspection Report (IR) No. 50-387,388/97-09, NRC No. 50-387,388/98-06, and NRC IR No. 50-387,388/99-01.
PP&L corrective actions were previously determined to be acceptable.
These LER revisions updated the original submittals to provide a final root cause determination.
No violations of NRC requirements were identified. These LERs are close Closed LER 50-387/99-002-00 Failure to Maintain Environmental Qualification of SRV Acoustic Monitors This event was previously discussed in NRC Inspection Report No. 50-387,388/99-05 (section E1.1), and a violation of NRC requirements was cited (NCV 50-387,388/99-05-03). This LER was submitted after the NRC report was issued, and does not identify any additional issues or violations of NRC requirements.
This LER is closed.
II. Nlaintenance Conduct of Nlaintenance Surveillance and Pre-Planned Maintenance Activit Review ( 1726,62,
)
The inspectors observed and reviewed selected portions of pre-planned maintenance and surveillance activities, to determine whether the activities were conducted in accordance with NRC requirements and SSES procedures.
Observations and Findin s The inspectors observed portions of the following work activities and surveillances:
C90017 S91732 PCWO 187338 S84708 V99373 V91 371 SM-024-002 Thermolag Upgrade
"A"Standby Gas Treatment Damper Operator Rebuild HV-141F028C, "C" Outboard MSIV Inspection and Rework
"C" Emergency Diesel Generator Jacket Water Flush Unit 2 Bypass Valve Fast Acting Solenoid Valve Replacement Unit 2 Control Valve Fast Acting Solenoid Valve Replacement
"C" Emergency Diesel Generator (EDG) 2-year Inspection In addition, selected portions of procedures, drawings, and vendor technical manuals, associated with the maintenance and surveillance activities, were also reviewed and determined to be acceptable.
In general, maintenance personnel were knowledgeable of their assigned activities.
Unit 2 Main Transformer Failure On June 8, Unit 2 had an automatic reactor shutdown when the main generator tripped due to a load rejection. The load rejection was caused by actuation of a sudden pressure lockout relay on the "A"main transformer.
The transformer sudden pressure condition occurred when a neutral bushing on the transformer mechanically failed.
Although the main transformer is not a safety related component, its failure did initiate a plant transien The failed bushing had a manufacturing defect which the transformer vendor had identified to PP8L in 1990. The PP8L root cause analysis team concluded that PP8L had failed to take correct action on the vendor's recall notice. The root cause team also concluded that the present condition reporting program, which encompasses the Industry Events Review Program, would prevent a similar event from occurring today.
c.
Conclusions A failed main transformer bushing resulted in the June 8, 1999, Unit 2 automatic reactor shutdown.
The PP8L root cause analysis team concluded that PPBL had failed to take correct action on a vendor's 1990 recall notice which identified a manufacturing defect which eventually Ied to this failure.
III. En ineerin E2 Engineering Support of Facilities and Equipment E2.1 Unit 1 "C" Outboard Main Steam Isolation'Valve Failure f37 51,4 5GD)
The inspectors observed and reviewed PP8L's root cause analysis of the Unit 1 "C" outboard main steam Isolation valve (MSIV)failure.
b.
Observations and Findin s On July 1, 1999, the Unit 1 "C" outboard main steam isolation valve (MSIV)stem separated from the valve poppet (disc) and fast closed shutting off steam flow in the "C" main steam line. This resulted in an automatic reactor shutdown and automatic closure of all MSIVs.
When the "C" outboard MSIVwas disassembled, a visual inspection identified that the valve stem had separated from the poppet.
The stem is normally attached to poppet by a stop plate which is secured with 4 stud nuts and 4 studs that are torqued into the poppet; locking tabs installed under the stud nuts normally prevent the nuts from rotating offdue to vibration. On the "C" outboard MSIV, all 4 stop plate stud nuts and 1 stud had backed out and were laying loose in the bottom of the poppet; 3 locking tabs were badly worn and in pieces.
PP8L's root cause analysis determined that the stop plate had not been properly installed in the valve poppet during valve maintenance performed in 1990. The incorrect installation allowed one stud to back out of the poppet and the other 3 stud nuts to vibrate off, thus separating the stem and stop plate from the poppet.
PP&L concluded that this failure mechanism required several conditions to occur simultaneously.
The identified conditions included improper installation of the stop plate and valve poppet, low torque on the stop plate stud nuts and studs, and sufficient time to wear down the locking
tabs and allow the stud nuts to vibrate off. The inspectors concluded that PP8L performed a thorough root cause analysis.
During the PP8L review of the maintenance history on all Unit 1 and Unit 2 MSIVs, PP8L identified two additional IVISIVsthat were highly susceptible to this failure mechanism.
PP&L disassembled and inspected these two valves as well as a third MSIVwhich failed local leak rate testing.
Inspections of these three MSIVs did not find any improperly installed stop plates, relaxed stop plate stud nuts, or any other abnormal items.
In addition, PP8 L revised the MSIVmaintenance procedure to increase the stop plate stud torque value to prevent complete relaxation of the stud torque even ifa stop plate was not properly installed. The inspectors concluded that PP8L had performed a comprehensive extent of condition review.
Conclusion On July 1, 1999, the Unit 1 "C" outboard main steam isolation valve (MSIV) stem separated from the valve poppet, resulting in an automatic reactor shutdown.
PP8L determined that the stop plate had not been properly installed in the valve poppet during valve maintenance performed in 1990. PP8L reviewed the maintenance history on all Unit 1 and Unit 2 MSIVs, inspected three additional Unit 1 MSIVs, and found no additional problems.
The inspectors concluded that PP8L had performed a thorough root cause analysis and a comprehensive extent of condition review.
IV. Plant Su ort S1
.
Adequacy of Physical Security Program Testing and Maintenance a.
Ins ection Sco e (81042)
Determine whether PP8 L's program for testing and maintenance of security equipment conformed to the physical security plan, approved PP&L procedures, regulatory requirements and manufacturer's specifications.
The testing and maintenance program was inspected during the period of June 7-10, 1999. Areas inspected included: testing and maintenance records and procedures and compensatory measures.
b.
Observations and Findin s Testin Maintenance and Com ensato Measures.
The testing and maintenance records for security-related equipment for the previous six months indicated that PPBL was testing and maintaining systems and equipment as committed to in the physical security plan. The records indicated a good working relationship between electrical maintenance and security as evidenced by the minimal use of compensatory measure c.
Conclusions PP&L conducted its testing and maintenance activities in a manner that protected public health and safety, and this portion of the program, as implemented, met PP8L's commitments and NRC requirements.
S2 Security and Safeguards Staff Knowledge and Performance a.
Ins ection Sco e (81501)
b.
Area inspected was security staff requisite knowledge.
Observations and Findin s Securit Force Re uisite Knowled e. The inspector observed a number of security force members (SFMs) in the performance of their routine duties for alarm station operations and exterior patrol alarm response.
Based on SFM interviews, the inspector determined that the SFMs were knowledgeable of their responsibilities and duties and could effectively carry out their assignments.
In addition, the inspector observed from the alarm station, security force response to a transformer oil spill. The response was effective and well controlled. Communications were effective.
Res onse Ca abilities. The inspector determined based on a review of documentation of contingency response drills and critiques, that PP8L was appropriately exercising this portion of the program.
PP8L was using lessons learned from the drills to modify and refine the response plan to improve its effectiveness.
The planned changes to the response plan were complete prior to the Operational Safeguards Response Evaluation that was conducted on August 2-5, 1999.
On'June 8, 1999, a tactical response drillwas observed.
The drill pre-brief was well controlled and thorough, with a strong emphasis on personnel safety.
The drillwas conducted in a safe manner, and the response force demonstrated capabilities necessary to defend against the design basis threat. The post exercise critique was effective. Data collected at the critique was entered into a tracking system, which is used to insure incorporation of lessons learned into future exercises.
Conclusions The SSES security force members adequately demonstrated that they had the required knowledge to effectively implement the duties and responsibilities associated with their positio V. Mana ementIleetin s
X1 Exit Meeting Summary The inspectors presented the inspection results to members of PP8L management at the conclusion of the inspection period, on July 29, 1999.
PPBL acknowledged the findings presented.
The inspectors asked PP&L whether any materials examined during the inspection should be considered proprietary.
No proprietary information was identifie IP 37551 IP 40500 IP 61726 IP 62707 IP 71707 IP 71750 IP 81042 IP 81501 IP 92700
INSPECTION PROCEDURES USED Onsite Engineering Observations Effectiveness of Licensee Controls in Identifying, Resolving, and Preventing Problems Surveillance Observations Maintenance Observations Plant Operations Plant Support Activities Physical Security - Testing and Maintenance Physical Security - Personnel Training and Qualifications On Site Followup of Reports
~Qened None.
ITEMS OPENED, CLOSED, AND DISCUSSED
~d 50-387/99-06-01 NCV Reportability Determinations (section 04.1)
~Udeted None.
Closed 50-387/97-020-01 LER Failure of Safety Relief Valve Acoustic Monitor (section 08.1)
50-387/98-014-01 LER Failure of Safety Relief Valve Acoustic Monitor (section 08.1)
50-388/98-008-01 LER Failure of Safety Relief Valve Acoustic Monitor (section 08.1)
50-387/99-002-00 LER Failure to Maintain Environmental Qualification of SRV Acoustic Monitors (section 08.1)
LIST OF ACRONYMS USED CFR CR
LCO LER MSIV NCV NDAP NRC PCO PICSY PORC PP&L RCIC RHR SFM SPOTMOS SRV SSES TS Code of Federal Regulations Condition Report Emergency Diesel Generator Emergency Operating Procedure Final Safety Analysis Report High Pressure Coolant Injection Independent Safety Engineering Group
[NRC] Inspection Report Limiting Condition for Operation Licensee Event Report Main Steam Isolation Valve Non-Cited Violation Nuclear Department Administrative Procedure Nuclear Regulatory Commission Plant Control Operator Plant Information Computer System Plant Operations Review Committee Pennsylvania Power and Light Company Reactor Core Isolation Cooling Residual Heat Removal Security Force Member Suppression Pool Temperature Monitoring System Safety Relief Valve Susquehanna Steam Electric Station Technical Specification