IR 05000373/1996018
| ML20134M565 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 02/13/1997 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20134M510 | List: |
| References | |
| 50-373-96-18, 50-374-96-18, NUDOCS 9702200293 | |
| Download: ML20134M565 (20) | |
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U.S. NUCLEAR REGULATORY COMMISSION
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REG!ON lil t
Docket Nos: 50-373, 50-374 License Nos: NPF-11, NPF-18 Report Nos: 50-373/96-18; 50-374/96-18 L
Licensee: Commonwealth Edison Company Facility: LaSalle County Station, Units 1 and 2
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Location: 2601 N. 21st Road Marseilles, IL 61341 '
Dates: October 26 - December 13,1996 Inspectors: M. Huber, Senior Resident inspector K. Ihnen, Resident inspector H. Simons, Resident inspector C. Mathews, Illinois Department of Nuclear Safety
Approved by: Marc Dapas, Chief, Projects Branch 2 Division of Reactor Projects l
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l 9702200293 970213 l PDR ADOCK 05000373 G PDR
EXECUTIVE SUMMARY !
LaSalle County Station, Units 1 and 2 l NRC Inspection Report 50-373/96-18; 50-374/96-18 I This inspection included aspects of licensee operations, maintenance, engineering, and plant support. The report covers a seven-week period of inspection activities by the resident staff.
The licensee's failure to ensure that the control room and auxiliary electric equipment room ventilation systems could perform their design function during accident conditions, j reflected a lack of understanding of the plant's design and licensing basis. In addition, I examples of the failure to identify and/or correct significant conditions adverse to quality continue to be identified. The examples identified during this report period are of particular )
concern because they represent potential common-mode failures of safety-related equipment in multiple systems.
Plant Ooerations
As a result of poor work planning and insufficient response to equipment concerns, i ventilation coils froze rendering the non-safety-related station heating systam and associated ventilation systems inoperable. (Section 01.2) )
- The inspectors identified that the surveillance procedure for the fast start test of the ;
emergency diesel generator did not contain acceptance criteria for the parameter of
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air receiver pressure drop measured during the surveillance test. Although the i licensee trends this parameter, the licensee does not have a formal mechanism in place, such as established test acceptance criteria, to ensure that a significant change in the measured value of this parameter, which is potentially indicative of starting air system degradation, is evaluated in a timely manner. (Section 02.1)
- The inspectors identified a violation involving the failure of an operator to have a surveillance test procedure at his assigned work location for periodic reference to confirm that all procedure steps have been performed and to document steps as required. (Section 03.1)
- The inspectors identified that licensed operator training lesson plans for the control room and auxiliary electric equipment room (AEER) ventilation systems were deficient in that they did not address operation of the recirculating charcoal filters in the event of a high radiation condition. (Section 04.1)
Maintenance
- Maintenance activities observed by the inspectors were conducted in accordance with work instructions, involved workers appeared knowledgeable of assigned work activities, and the involvement of operations and engineering department personnel was adequate for the work performed. (Sect;on M1.1)
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- The licensee's failure to implement timely corrective actions for an inoperable
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breaker event in April 1995 resulted in a similar event in October 1996 with two safety-related motor control center supply breakers. An apparent violation was identified for inadequate corrective actions for thi > . event. (Section M2.1)
- The licensee did not identify the presence of foreign meterialin the Unit 2 suppression pool, which could have potentially caused a common-mode failure of the emergency core cooling system, due to an inadequate inspection of the pool in March 1995. An apparent violation was identified for the failure to identify and correct this significant condition adverse to quality during previous inspections of the Unit 2 suppression pool. (Section M2.2)
Enaineerina
- The licensee did not conduct adequate testing to demonstrate that the control room and AEER ventilation systems would operate as specified in the Updated Final Safety Analysis Repon and Technical Specifications following a design basis accident. Three apparent violations were identified for this condition which existed since initial plant startup. The apparent violations pertain to inoperability of the AEER ventilation system, two examples of inadequate tests which resulted in missed opportunities to identify this problem earlier, and an inadequate surveillance test for ensuring operability of the control room ventilation system. (Section E2.1)
- An apparent violation was identified for the licensee's failure to take appropriate corrective action for degradation of safety-related single block module (SBM)
electrical control switches due to hydrocarbon exposure and excessive ag (Section E2.2)
Plant Sucoort
- Corrective actions implemented by the licensee to address previously identified performance problems with radiation worker practices appear to have been effective in the near-term. (Section R1.1)
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Report Details
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Sumrnarv of Plant Status Unit 1 was in a forced outage for the entire inspection period and Unit 2 remained shut ;
down for a refueling outage. On November 18,1996, the licensee decided to keep both 1 units shut down to address equipment and human performance problem I. Operations 01 Conduct of Operations 01.1 General Comments (71707)
The inspectors conducted frequent reviews of ongoing plant operations using l Inspection Procedure 71707. Walkdowns were performed in the main control room, emergency diesel generator rooms, auxiliary electrica! equipment rooms, safety- 1
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related pump rooms, the reactor building, the turbine building, and the radwaste facility. The inspectors also discussed the status of the plant with operating shift I personnel in the control roo .2 Potential Operation of Standbv Gas Treatment (SBGT) System Outside the Desian Basis Insoection Scoce (71707) l The inspectors reviewed the licensee's plans for shutting down the reactor building ;
ventilation system and operating the SBGT system to control reactor building differential pressure and ventilatio Observations and Findinas in 1996, the licensee modified the turbine building ventilation system by adding several chillers to the system. The modification was performed to address high building temperatures during the summer, as well as the inability to consistently maintain the turbine building at a negative pressure. As discussed in NRC Inspection Report 50-373/95009; 50-374/95009, the modification added the chillers to the existing station heating system. The station heating system is designed to conserve heat in the winter by preheating the ventilation air to the reactor building, turbine building, and radwaste building with recaptured heat from the drywel In preparation for installing the modification, the station hean .; system was drained. However, system heat exchangers were not tote!!y drained because portions of the heat exchangers were at lower elevations than the system drain The licensee became concerned over possible freezing of heat exchanger piping in mid-September with the onset of colder weather. However, the licensee did not-4-
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take any actions to address this concern, and as a result, several heat exchangers in
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the reactor building, turbine building, and radwaste building ventilation systems ruptured when water in the heat exchanger piping froze. The licensee proceeded to
, replace the heat exchangers to restore station heat and maintain plant temperatures.
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To prevent the intake of cold air and further freezing of the station heating system piping, the licensee shut down all ventilation systems and operated the SBGT system to maintain secondary containment at J negative pressure. Per Technical Specification requirements, the licensee intended to perform charcoal and high efficiency particulate air (HEPA) filter sampling of the SBGT system after 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of operation. Based on a review of the system's configuration and operating procedures and the results of discussions with the licensee, the inspectors were concerned that the licensee was operating the SBGT system outside its design l
. basis. The inspectors questioned if the licensee had evaluated system operating l l procedures to determine the effect of operating the SBGT system as the primary ventilation system and the long-term effects of continuous system operation on specific components such as charcoal and HEPA filters. Operation of the SBGT system as a compensatory measure for an inoperable station heating system and associated ventilation systems is considered an Unresolved item (50-373/96018-01; 50-374/96018-01) pending NRC review of the SBGT system's design basis and the results of the licensee's analysis of the long-term effects of continuous system operation, Conclusions As a result of poor work planning and insufficient response to equipment concerns, ventilation coiis froze which rendered the non-safety-related station heating system and associated reactor building, turbine building, and radwaste building ventilation systems inoperabl Operations Procedures and Documentation 02.1 Emeraency Diesel Generator (EDG) Surveillance Procedure Acceptance Criteria inspection Scope (61726)
The inspectors nbserved the licensee conduct LaSalle Operating Surveillance (LOS)
DG-M2, "1 A (2A) Diesel Generator Operability Test," and reviewed the surveillance test results. The inspectors also discussed their observations with the operations )
engineer, b. Observations and Findinos
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The inspectors observed tnat the pressure drop of the starting air receivers was one of the parameters measured and recorded by the licensee during the monthly EDG surveillance test conducted oer procedure LOS-DG M2, The inspectors noted,
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however, that the surveillance procedure did not contain acceptance criteria for air receiver pressure drop. The inspectors asked the operations engineer why the
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pressure drop data was recorded and the basis for not specifying acceptance criteria
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for this measured test parameter. The operations engineer did not know why data )
was obtained during the surveillance test for this particular parameter and questioned the diesel generator system engineer. The system engineer responded !
that the parameter was trended to evaluate degradation of the air start motor and starting air system. Based on discussion with the system engineer, the inspectors learned that the licensee may not evaluate the pressure drop data for up to three months after obtaining it during the monthly surveillance tes :
The inspectors also noted that operations personnel tasked with conducting the !
surveillance test identified some pmblems with the test procedure. The surveillance !
procedure contained instructions for both a slow speed start and a fast speed star Involved operators identified that procedure attachment E2, a data sheet for the !
local operator's use, was confusing with regard to which data pertained to fast '
versus slow speed start testin Conclusions The inspectors concluded that the licensee did not have a formal mechanism in j place, such as established test acceptance criteria, to ensure that a significant i change in the parameter of air receiver pressure drop is evaluated in a timely '
manner. An excessive drop of starting air receiver pressure during an EDG fast start I could be indicative of a degraded air start motor and/or starting air system, or other EDG problem. Although the licensee trends this parameter, test data may not be evaluated for up to three months and as a result, degradation of the EDG or the starting air system may not be evaluated for operability in a timely manne The inspectors reviewed pertinent licensing and design basis documentation, including Technical Specifications and the Updated Final Safety Analysis Report, and did not identify any specific requirements to test or trend emergency diesel generator air receiver pressure dro Operator Knowledge and Performance 03.1 Operator Conductina Surveillance Test Without the Surveillance Procedure at the Work Location Insoection Scone (71707)
The inspectors observed the licensee conduct LOS-DG-02, "1 A DG [ Diesel Generator) Auxiliaries," reviewed the surveillance test results, and verified that test acceptance criteria were appropriate. The inspectors also discussed their observations with the operators performing the surveillance test and the operations manager, l
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. Observations and Findinos
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While observing the licensee conduct a surveillance test per LOS-DG-02, the inspectors noted that the operator stationed at the EDG cooling water pump did not have a copy of the procedure. The procedure directs the operator to perform several actions at the local put. . operating station, such as valve manipulations, recording of instrument readings, and installing a temporary day tank sightglass. The inspectors further noted that procedure LOS-DG-02 is classified as a " Reference Use" procedure. Per LaSalle Administrative Procedure (LAP) 100-40, "Proce; o Use and Adherence Expectations," procedures classified as " Reference Use" are required to be available at the work location for periodic reference to confirm that all procedure steps have been performed and to document steps as require Conclusions The failure of the operator stationed at the EDG cooling water pump to have a copy of surveillance test procedure LOS-DG-02 available at his assigned work location, as required by LAP-100-40, is considered a violation of Technical Specification 6.2.A.a, as described in the attached Notice of Violation (50-373/96018-02).
04 Operator Training and Qualification 04.1 Licensed Operator Lesson Plans a. Inspection Scope (71707)
The inspectors reviewed the lesson plans for licensed operator training on the control room (CR) and the auxiliary electric equipment room (AEER) ventilation systems to determine if the lesson plans were consistent with design basis informatio Observations and Findinas Section 6.4.1 of NUREG 0519, " Safety Evaluation Report related to the operation of LaSalle County Station Units 1 and 2," stated that the licensee had committed to
"make provisions to manually initiate the control room heating, ventilating, and air conditioning supply air filters on receipt of a high radiation alarm from an outside air intake." These recirculating charcoal filters are designed for smoke and odor removal and are in addition to once-through charcoal filters which are part of the emergency filtration trains that automatically initiate upon detection of a high radiation condition in the outside air intakes. To meet the Safety Evaluation Report (SER) commitment, the licensee developed an alarm response procedure which required operators to place the CR and AEER charcoal filters in service under high radiation conditions.
l The inspectors identified that the lesson plans for licensed operator training on the l CR and AEER ventilation systems did not address operator actions described in the
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SER. The inspectors did not find any reference in the lesson plans to placing the
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recirculating charcoal filters in service in the event of a high radiation condition in the shared CR and AEER ventilation systems' intake plenum. The inspectors confirmed, through interviews with several licensed operators, th'at operators were not instructed to place the CR and AEER charcoal filters in service upon detection of high radiation at the air intake. These operators were not cognizant of the function I of the charcoal filters in the event of high radiation. The licensee initiated a lesson 1 plan review to determine appropriate corrective action for this identified training l discrepanc Conclusions i i
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Licensed operators were not cognizant of the function of the recirculating charcoal l filters and the required actions for these filters in the event of a high radiation !
condition. The inspectors attributed this to a deficiency in licensed operator training lesson plans for the CR and AEER ventilation systems which did not address operation of the recirculating charcoal filters in the event of a high radiation condition detected at the air intake. However, the associated alarm response procedure contained appropriate guidance on required operator actions with respect to the charcoal filters. Although the licensee did not conduct specific training on ;
required operator actions, the inspectors concluded that there was reasonable '
assurance that operators would take the appropriate actions in the event of a high !
radiation condition based on the premise that operators would follow the alarm l response procedur II. Maintenance M1 Conduct of Maintenance M 1.1 General Comments !
l Insoection Scope (62703)
Using Inspection Procedure 62703, the inspectors observed the following maintenance activities:
- Work Request (WR) 96-0093551, " Inspect / repair A RHR [ residual heat removal] service water pump discharge stop valve"
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- WR 960104145, " Replace seal cooler because its design pressure is too i low" ! Observations and Findinas Licensee personnel performed work in accordance with the work instructions. The i
! workers appeared knowledgeable of assigned work activities and the involvement of l i operations and engineering department personnel was adequate for the work !
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M2 Maintenance and Material Condition of Facilities and Equipment j
l M2.1 Inadeouate Corrective Action For Misalianed Breaker l- Insoection Scooe (62703)
! The licensee notified the NRC on October 30,1996, that Unit 1, Division 2,480 l Volt safety-related motor control centers (MCCs) 136X-1 and 136X-2 were
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inoperable. The inspectors reviewed the circumstances of the event, breaker maintenance histories and procedures, and corrective actions for a similar breaker f ailure in April 199 Observations and Findinas
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During a routine breaker inspection, a system engineer discovered misaligned mechanical trip mechanisms on supply breakers for MCCs 136X-1 and 136X- The licensee subsequently determined that the breakers were not fully inserted into their respective breaker cubicles preventing the mechanical trip interlocks for each breaker from completely disengaging. In this condition, vibration or jarring of the breaker could cause the trip interlock to actuate, preventing breaker closure or causing the breaker to trip open if it was already closed. With the supply breakers open, normal and emergency power would not be available to the MCCs and associated Division 2 loads, such as CR and AEER ventilation fans and the 1 A EDG
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room ventilation damper The licensee determined that MCCs 136X-1 and 136X-2 hed been inoperable since February 1996, when their supply breakers were returned to service following maintenance. The supply breaker for MCC 136X-1 was not properly racked into its breaker cubicle when it was returned to service. An additional one-half turn on the racking mechanism was required for the breaker to be fully racked into its cubicl The additional one-half turn would have alb H a required air gap (disengagement)
to exist between the mechanical trip interloc( tad a paddle on the trip shaft of the breaker. The mechanical trip interlock for the supply breaker to MCC 136X-2 could not be fully disengaged due to a breaker alignment problem which prevented the breaker from being fully racked into its cubicle. The licensee did not identify'this condition since no check of the mechanical trip interlocks was performed when the supply breakers were returned to service in February 1996. During the more recent breaker inspection, the licensee determined that mechanical adjustments to the breaker were required to fully rack the breaker into its cubicl The licensee identified that a similar failure occurred with the common emergency diesel generator cooling water (EDGCW) pump breaker on April 15,1995. The licensee determined that the racking mechanism, including the mechanical trip interlock, for this breaker was not properly adjusted when the breaker was inserted into its cubicle, in response to this event, the licensee inspected all 480 volt switchgear breakers. The licensee also planned to revise 480 volt AC switchgear
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electrical maintenance (EM) procedures to require inspection of the trip interlock mechanism before returning a breaker to service.
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Electrical maintenance personnel used LaSalle Electrical Surveillance (LES) procedure !
LES-GM-105, " Inspection of Low Voltage Air Circuit Breakers," to perform
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maintenance on breakers. This procedure did not contain guidance for inspecting '
the trip interlock before returning a breaker to service. The EM procedure was appropriately revised in February 1996, however, the 136X-1 and 136X-2 supply .
breakers were returned to service before the procedure revision was in effect. In i'
addition, EM personnel were not always present when breakers were racked into position by operators. The licensee did not revise operating procedures to provide for a check of the mechanical trip interlock ga The licensee's corrective actions for the inoperable condition of the MCC 136X-1 and 136X-2 supply breakers included an inspection of the 480 volt safety-related MCC breakers to ensure the mechanical trip interlock mechanisms were properly adjusted, revision of LaSalle Operations Procedure LOP-AP-20, "480 Volt Air Circuit Breaker Operation," additional equipment operator training, and repair of the MCC 136X-1 and 136X-2 supply breaker c. Conclusions I
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The licensee's corrective actions to prevent recurrence of the 1995 breaker misalignment problem with the EDGCW pump breaker were not adequate or timel l As a result, similar problems occurred with the MCC 136X-1 and 136X-2 supply l breakers. The condition of the MCC supply breakers was safety significant in that the breakers may have opened during a seismic event interrupting normal and emergency power to those safety-related loads supplied by the respective MCC The breaker alignment problems also reprosented a potential common-mode failure !
that could have simultaneously affected multiple safety-related systems. The failure l to implement adequate and timely corrective actions for the April 1995 common 1 EDGCW pump breaker failure is considered an example of an apparent violation of 10 CFR 50, Appendix B, Criterion XVI (50-373/96018-03a; 50-374/96018-03a).
M2.2 Inadeauate Corrective Action for Foreian Material in Sucoression Pool Scope (62703)
l As discussed in NRC Inspection Report 50-373/96013; 50-374/96013, the licensee identified considerable debris in the Unit 2 suppression pool during an inspection and cleaning of the pool in October 1996. During this inspection period, the m::pectors completed a review of the foreign material exclusion (FME) program and ;
the results of previous suppression pool inspections conducted by the license Observations and Findinos !
The inspectors observed the foreign material removed by divers during cleaning and ;
destudging of the Unit 2 suppression pool on October 12,1996. The licensee l concluded that the foreign material had been in the pool, under the bottom silt layer, since initial construction or one of the first few Unit 2 outages. The emergency core cooling system (ECCS) analysis in the Updated Final Safety Analysis Report-10-
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(UFSAR) assumes a limit of 50 percent for blockage or clogging of the ECCS
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suction strainer serface areas. The licensee determined that the amount of material in the suppression pool was sufficient to block grester than 50 percent of the ECCS suction strainers' surface area. This was based on the presumption that enough suppression pool turbulence would exist during a design basis accident to cause the material to migrate from the bottom of the pool to the ECCS suction strainer )
Blockage of the ECCS suction strainers could result in inadequate net positive suction head to the ECCS pump The licensee did not identify the foreign material during suppression pool cleanliness !
inspections conducted in refueling outages L2R03 and L2R06. The licensee most recently inspected the Unit 2 suppression pool on March 16,1995,in response to NRC Bulletin 93-02. During these inspections, the licensee focused on removing foreign material that was detectable without disturbing the bottom silt layer. The licensee did not consider removing the silt from the Unit 1 and Unit 2 suppression pools untillearning of an event at another plant involving strainer blockage due to the accumulation of silt and other foreign material. The licensee completed desludging the Unit 1 and Unit 2 suppression pools in the Spring of 1996 and in October 1996, respectively. The inspectors reviewed the licensee's FME program and determined that suitable controls had been implemented to prevent additional s debris from accumulating in the suppression pool l
- Conclusions The accumulation of foreign materialin the Unit 2 suppression pool was caused by the failure to implement an effective FME program during initial construction and the first few unit outages. The licensee did not identify the presence of foreign material ,
earlier due to inadequate inspections. The licensee had strengthened FME controls l before discovering the materialin the sitt layer of the Unit 2 suppression pool in !
October 1996. The foreign material could have potentially caused a common-mode failure of the ECCS. The failure to identify and correct this significant condition adverse to quality during previous inspections of the Unit 2 suppression pool, is considered an example of an apparent violation of 10 CFR 50, Appendix B, Criterion XVI (50-373/96018-03b; 50-374/96018-03b).
M8 Miscellaneous Maintenance issues (92700)
M8.1 (Closed) Licensee Event Report (LER) 373/94013-00: Reactor core isolation cooling (RCIC) system declared inoperable due to control system oscillations. The inspectors verified that the licensee had completed corrective actions described in the associated LER, including revision of LaSalle Instrument Surveillance LIS-RI-115/215. This item is considered close M8.2 (Closed) LER 50-373/374-96014: 480V safety-related switchgest breakers in j degraded condition due to untimely implementation of a previous corrective actio I This event is discussed in Section M2.1 of this report. The inspectors determined ( - 11 -
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that the licensee did not implernent adequate corrective action for a similar problem
identified in April 1995. This tiern is considered closed.
( M8.3 (Closed) Unresolved item 50-374/94013-04: Foreign material found in the Unit 2 i
suppression pool. This item is discussed in Section M2.2 of this report. The inspectors determined that the licensee did not identify and correct a significant condition adverse to quality, specifically, the presence of foreign materialin the l Unit 2 suppression pool, during previous suppression pool inspections. This item is i considered close Ill. Enoineerina E2 Engineering Support of Facilities and Equipment E Control Room (CR) and Auxiliarv Electric Eouloment Room (AEER) Ventilation Systems Outside Desian Basis
! Insoection Scope (37551. 92903)
l On October 30,1996, the licensee reported to the NRC that Unit 1 and Unit 2 had operated in an unanalyzed condition in that the AEER could not be maintained at a
, positive pressure as specified in the UFSAR. The licensee subsequently identified
! that control room ventilation system surveillance testing was not adequate to l ensure compliance with Technical Specification requirements. A system engineer
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identified these issues while reviewing plans for implementation of the improved Standard Technical Specifications (ISTS). The inspectors reviewed the design basis for the CR and AEER ventilation systems, reviewed operating procedures, performed system walkdowns, observed maintenance activities, and discussed system operation and design with operations and engineering department personnel. The inspectors also reviewed system test results and an AEER ventilation system modification, b. Observations and Findinas l
l The inspectors reviewed Problem Identification Form (PlF) 96-3060 pertaining to the failure to consider AEER t.abitability consequences from removal of the main steam isolation valve leakage control system (MSIVLCS). Removal of the MSIVLCS l affected postulated dose rates in the AEER following a design basis accident. The
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licensee had not evaluated the impact on AEER dose rates oefore removing the Unit 1 MSIVLCS from service in early 1996. The licensee had not removed the l
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MSIVLCS from Unit 2. The inspectors determined through a review of licensing documents that the NRC had previously approved removal of operability requirements for the MSIVLCS from the Technical Specifications for both Unit 1 and 2 on April 5,1996, with Amendments 97 and 112, respectively. While the licensee's supporting analysis for these amendments considered the effect of
- MSIVLCS removal on offsite and control room doses, an evaluation of the effects on j AEER habitability was not included.
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The licensee identified other issues relating to habitability of the AEER. Specifically, the licensee determined through testing in October 1996 that the AEER ventilation system could not maintain the AEER at a positive pressure of 1/8 inch water column (WC) as specified in Section 6.4 of the UFSAR. The licensee determined that with AEER pressure less than 1/8 inch WC the post-accMent dose to personne! in the AEER would have exceeded the limits in General Design Criteria (GDC) 1 j Consequently, the licensee concluded that the /.EER ventilation system was !
inoperable since it was unable to perform its int"nded safety function. Technical Specification 3.7.2 requires that two independent control room and AEER i'
emergency filtration trains be operable. The failure to maintain the AEER ventilation system operable since initial plant operation is considered an apparent violation of TS 3.7.2 (50-373/96018-04; 50-374/96018-04). At the end of the inspection period, the licensee was in the process of reviewing possible corrective actions to ensure AEER habitability requirements are met during postulated accident l condition The inspectors also reviewed PlF 96-3014 pertaining to the lack of testing to demonstrate that the AEER ventilation system could maintain the AEER at a pressure of 1/8 inch WC relative to surrounding areas. The inspectors identified i two missed opportunities for the licensee to identify and correct AEER ventilation !
deficiencies: ,
The AEER ventilation system pre-operational test, PT-VE-101, " Auxiliary Electric Room HVAC IHeating, Ventilation, and Air Conditioning]," specified acceptance criteria of 1/8 inch WC for differential pressure (DP) between the l AEER and surrounding areas. During the initial pre-operational test, a DP of !
1/8 inch WC could not be maintained. The licensee subsequently revised the test acceptance criteria for DP to 1/16 inch WC and conducted a second pre-operational test after making some system configuration changes. In June 1982, the licensee considered the results of the second test acceptable based on the revised acceptance criteria. The licensee did not evaluate the revision to the test acceptance criteria with respect to the ventilation system's design and licensing basis. The failure to incorporate appropriate acceptance criteria defined in applicable des lgn documents in the AEER pre-operational test is considered an example of an apparent violation of 10 CFR 50, Appendix B, Criterion XI (50-373/96018-05a; 50-374/96018-05a).
- The licensee modified the ventilation system supplying the computer room in 1982 and 1984. The 1982 portion of the modification added a separate computer room ventilation system, while the 1984 portion blanked off the former AEER ventilation supply to the computer room. The licensee did not conduct adequate post-modification testing. The test, conducted after both portions of the modification were complete, only verified that 100 cubic feet per minute of air flow could be routed around the computer room and did not
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address the ability of the AEER ventilation system to maintain the required
! design DP of 1/8 inch WC. The failure to incorporate appropriate acceptance criteria defined in applicable design documents in the AEER post-modification-13-l
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test is considered another example of an apparent violation of 10 CFR 50,
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Appendix B, Criterion XI (50-373/96018-05b; 50-374/96018-05b).
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.The licensee also identified on November 6,1996, a deficiency with surveillance testing of the CR ventilation system. LaSalle Technical Surveillance procedure LTS-40017, " Control Room HVAC lsolation Damper Surveillance Smoke and Radiation i- Detection,". Revision 5, did not verify the capability of the CR ventilation system to l maintain a positive pressure in the CR relative to d surrounding areas. The l_ surveillance test only evaluated the pressure of the CR relative to the Auxiliary Building and Turbine Building areas. adjacent to the CR. The test did not evaluate the pressure of the CR relative to areas adjacent to the top and bottom of the CR and adjacent areas in the secondary containment. No installed instruments existed in the areas above and below the CR, nor in secondary containment, that would 4 l allow measurement of the differential pressure between the CR and these area Technical Specification 4.7.2.d requires that each CR emergency filtration system l train be demonstrated operable at least once per 18 months by verifying that the {
emergency train automatically switches to the pressurization mode of operation on an actuation signal and maintains the CR at a positive pressure of 1/8 inch water gauge relative to adjacent areas. The failure to test the CR ventilation system since initial plant operation to ensure that the CR can be maintained at the specified positive pressure relative to d adjacent areas,is considered an apparent violation of I TS 4.7.2.d (50-373/96018-06; 50-374/96018-06). The licensee committed to i
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perform suitable as-found testing to determine if the control room ventilation system could operate within its design basi Conclusions Since initial plant startup, the licensee had not conducted adequate testing to demonstrate that the CR and AEER ventilation systems would operate as specified ,
in the UFSAR and TS following a design basis accident. The inspectors concluded ;
that the AEER ventilation system had been inoperable since initial plant startup since 1 it was not capable of performing its intended safety function of maintaining a positive pressure of 1/8 inch WC to ensure that dose rates to operators were within the limits prescribed by GDC 19 in the event of a design basis acciden E2.2 Jnadeouate Corrective Action for General Electric (GE) Control Switch Deoradation l Scooe (37551)
The licensee replaced the electrical control switch for the 1B reactor recirculation I pump on October 26,1996, due to problems encountered during downshift of the l recirculation pump speed. Based on the results of detailed walkdowns and analysis, the licensee expanded the scope of control switch replacemerit to include approximately 1150 switches that were determined to be safety-related and
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important to safety. The inspectors reviewed the results of the licensee's
investigation and associated documentation.
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b. Observations and Findinas
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l The licensee concluded that the contacts in the reactor recirculation pump switch were misaligned. The misalignment was caused by broken cam followers, which rotated when the switch was turned. The contacts were attached to the cam followers. The switch was one of numerous single block module (SBM) electrical control switches manufactured by GE that were used extensively throughout the plant. The licensee determined that exposure to hydrocarbons in the past could cause similar SBM switch degradation and failure. TI.e licensee determined, through further review of GE literature, that the 21-year qualified life of the switches may have been exceede The inspectors identified the following missed opportunities by the licensee to address SBM switch degradation:
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In 1979, GE personnel performed a walkdown of the LaSalle plant in I response to GE Service Information Letter (SIL) 155. The SIL pertained to ,
the use of Lexan, a clear plastic material, for the SBM switch cam follower i The Lexan material was subject to degradation related failures when exposed I to hydrocarbons. The use of Lexan cam followers was discontinued by GE ;
in 1976. During the LaSalle plant walkdown, GE personnel identified I approximately 106 switches that were exposed to hydrocarbons during the !
manufacturing process. General Electric personnel provided the results of their inspection to the licensee, however, the licensee did not replace the l affected switche l
- In 1990,in response to problems with the Division 3 switchgear for both )
LaSalle units, GE personnel inspected various electrical equipment. During
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these inspections, GE personnel identified installed SBM switches on the switchgear which had been included in the 1979 list of switches exposed to ,
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hydrocarbons during the manufacturing process. The licensee replaced these SBM switches, however, the licensee did not expand the replacement effort to Division 1 and 2 switchgear. The licensee also banned further use of I hydrocarbon-based contact cleane * In 1995, engineering personnel reviewed the SBM issue in response to industry information on SBM problems experienced by other licensees. This review included the SIL and the GE walkdown results. However, the licensee erroneously assumed that all defective SBM switches had been replaced when the issue was previously addressed in 1979 and 199 Based on this assumption, in conjunction with the observed switch failure rate to date at LaSalle, the licensee determined that a new SBM switch inspection was not warranted.
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. Conclusions
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Degraded SBM switches due to hydrocarbon exposure and excessive age represented a potential common-mode failure which could simultaneously affect multiple safety-related systems. The failure to take appropriate corrective action for safety-related SBM switch degradation concerns identified in 1979,1990,and
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1995 is considered an example of an apparent violation of 10 CFR 50, Appendix B,
, Criterion XVI (50-373/96018-03c; 50-374/96018-03c).
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E8 Miscellaneous Engineering lasues (92700)
l l E (Closed) LER 50-373/374-96017: Main control room found outside design basis
! due to inadequate TS surveillance procedure. This issue is discussed in Section E2.1. This item is considered close E8.2 (Closed) LER 50-373/374-96012: AEER did not meet GDC 19 habitability l requirements due to failure to understand the design and licensing basis. This issue is discussed in Section E2.1. This item is considered close E8.3 (Closed) Unresolved item 50-373/374-96013-07: NRC review of licensee dose calculations and AEER pressurization testing. The inspectors evaluated this issue during review of the CR and AEER ventilation issues discussed in Section E This item is considered close E8.4 (Ocen) LER 50-373/374-96018: Residual heat removal (RHR) pump seal coolers did not meet design pressure rating requirement The licensee identified that RHR system pump seal coolers did not meet design i
pressure requirements on the shell side of the coolers. The shell side of the coolers was supplied with service water at an operating pressure of 150 psig. However, the design pressure of the installed coolers is 75 psig. At the end of this inspection period, the licensee was in the process of replacing the existing seal coolers with a ones designed for 150 psig. The inspectors observed installation activities for some ;
of the coolers and did not identify any problems. The licensee also conducted a i review to determine if similar design problems existed with other coolers which l used service water for cooling of ECCS components. This LER will remain open ,
l pending NRC evaluation of the root cause for the design discrepanc '
l l IV. Plant SuDDort
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R1 Radiological Protection and Chemistry Controls R 1.1 Radworker Performance j inspection Scope (71750)
The inspectors observed the radiation worker practices of maintenance, engineering,
, and operations personnel in the radiological protected area. The inspectors also i
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discussed radiation control and as-low-as-reasonably-achievable (ALARA) control
practices with radiation protection technician l Observations and Findinos l Radiation protection technicians provided appropriate oversight of observed work activities, insuring that workers were cognizant of low dose areas at the work site The technicians also implemented appropriate controls for the removal of contaminated components from the work site )
l i Conclusions The inspectors did not identify any concerns with observed radiation worker ,
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performance. Corrective actions implemented by the licensee to address previously identified performance problems appear to have been effective in the near-ter I V Manaaement Meetinas ;
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X1 Exit Meeting Summary The inspectors presented the results of their inspections to licensee management listed below at an exit meeting on December 13,1996. The licensee acknowledged j the findings presented. The inspectors asked the licensee if any materials examined 1 during the inspection should be considered proprietary. No proprietary information was identifie i X3 Management Meeting Summary NRC and Commonwealth Edison management met at the NRC Region til offices on November 19,1996, to discuss the licensee's initiative to have an independent i safety assessment (ISA) of LaSalle County Station and Zion Station conducted by a >
contractor. At this meeting, the licensee described the purpose of each ISA, organization and staffing of the ISA team, the scope of each assessment, and the proposed schedule. The licensee stated that the ISA would consist of a comprehensive review of historical performance at each facility to determine why previous improvement initiatives had not been successful and to ensure the licensee was focusing resources on appropriate issue l l l
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l PARTIAL LIST OF PERSONS CONTACTED
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ComE_d
- W. Subalusky, Site Vice President j 'D. Ray, Station Manager l *L. Guthrie, Operations Manager
- A. Magnafici, Acting Maintenance Superintendent
- A. Javorik, System Engineering Supervisor
- D. Boone, Health Physics Supervisor
"R. Crawford, Work Control Superintendent
- P. Barnes, Regulatory Assurance Supervisor
- Present at exit meeting on December 13,199 INSPECTION PROCEDURES USED IP 37551 Onsite Engineering IP 40500 Effectiveness of Licensee Controls in Identifying, Resolving, and Preventing Problems IP 61726 Surveillance Observation IP 62703 Maintenance Observation IP 71707 Plant Operations IP 71750 Plant Support Activities IP 92700 Onsite Followup of Written Reports of Nonroutine Events at Power Reactor Facilities IP 92903 Followup-Engineering ITEMS OPENED, CLOSED, AND DISCUSSED Ooened 50-373/374-96013-01 URI Use of SBGT system to maintain reactor building pressure 50-373/96013-02 VIO Failure to have surveillance procedure at work location 50-373/374-96018-03a eel Inadequate corrective actions for misaligned breaker 50-373/374-96018-03b eel Inadequate corrective actions for suppression pool debris l 50-373/374-96018-03c eel Inadequate corrective actions for safety-related SBM
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switch degradation concerns 50-373/374-96018-04 eel Failure to maintain AEER ventilation system operable j 50-373/374-96018-05a eel Failure to incorporate appropriate acceptance criteria l into AEER ventilation pre-operational test 50-373/374-96018-05b eel Failure to incorporate appropriate acceptance criteria into AEER ventilation post-modification test 50-373/374-96018-06 eel Failure to test the CR ventilation system to ensure the specified positive pressure relative to all adjacent areas i-18-
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! Closed l *
l 50 373/374 96012 LER AEER found to not meet GDC 19 habitability I requirements due to failure to understand the design l and licensing basis ;
50-373/94013 LER RCIC declared inoperable dup to control system oscillations 50-373/374-96014 LER 480V safety-related switchgear breakers in degraded ;
condition due to untimely implementation of a previous ;
i corrective action ,
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50-373/374-96017 LER Main control room found outside design basis due to i inadequate TS surveillance procedure t 50-373/374 96013-07 URI NRC review of licensee dose calculations and AEER -
pressurization testing l
l 50-373/374-96013-04 URI Suppression pool FME
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LIST OF ACRONYMS USED
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AEER Auxiliary Electric Equipment Room l ALARA As-Low-As-Reasonably-Achievable l CR Control Room l
ECCS Emergency Core Cooling Systems l EDG Emergency Diesel Generator !
l EDGCW Emergency Diesel Generator Cooiing Water l EM Electrical Maintenance l FME Foreign Material Exclusion GDC General Design Criteria GE General Electric HEPA High Efficiency Particulate Air HVAC Heating, Ventilation, and Air Conditioning l IFl Inspection Followup Item ISTS Improved Standard Technical Specifications LER Licensee Event Report l LOS LaSalle Operating Surveillance MCC Motor Control Center MSIVLCS Main Steam isolation Valve Leakage Control System NRC Nuclear Regulatory Commission PIF Problem identification Form PDR NRC Public Document Room RCIC Reactor Core isolation Cooling System RHR Residual Heat Removal
! SER Safety Evaluation Report SBM Single Block Module SIL Service Information Letter TS Technical Specification UFSAR Updated Final Safety Analysis Report !
URI Unresolved item WC Water Column Water Gauge
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