IR 05000410/1989014
| ML17056A288 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/31/1989 |
| From: | Blumberg N, Drysdale P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17056A287 | List: |
| References | |
| 50-410-89-14, GL-85-06, GL-85-6, NUDOCS 8909180019 | |
| Download: ML17056A288 (14) | |
Text
U.S.
NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-410/89-14 Docket No.
50-410 License No.
NPF
Licensee:
Nia ara Mohawk Power Cor oration 301 Plainfield Road S racuse New York 13212 Facility Name:
Nine Mile Point Unit 2 Inspection At:
Scriba New York Inspection Conducted:
Jul 17-21 1989 Inspectors:
f'. Drysda e, Reactor Engineer, OPS, OB, DRS, Region I Approved by:
N. Blumberg, hief, Operatio al Programs Section, Operations Branch, DRS, Region I 8/3c/8'f date
<<(<t date Ins ection Summar
Routine unannounced ins ection on Jul 17-21 1989 Ins ection Re ort No. 50-410/89-14 Areas Ins ected:
This inspection focused on the licensee's compliance with the
CFR 50.62 ATWS rule; the installation, testing, and operation of ATWS equipment analyzed in the Safety Evaluation Report (SER) for Nine Mile Point Unit 2; and the QA/QC controls over ATWS equipment during installation, testing, and operation.
Results:
The licensee is presently in compliance with the ATWS rule and has installed equipment dedicated to the mitigation of an ATWS event.
The ATWS systems inspected at Nine Mile Point Unit 2 reflect the descriptions and conclusions of the Updated Safety Analysis Report (USAR) and the SER.
The licensee's engineering, construction, QA/QC, testing and operational programs were found to be effective in assuring the operational readiness of ATWS systems, with the exception that no positive procedure controls were implemented to ensure that the redundant reactivity control system (RRCS)
automatic feedwater runback function is disabled only during RRCS surveillance testing.
Verification that the ATWS equipment complies with 10 CFR 50.62 completes the NRC review of the licensee's actions to implement the requirements of NRC Generic Letter 85-06 and Temporary Instruction TI 2500/20, Revision 1.
No violations or deviations were identified during this inspection.
TI 2500/20 is closed for Nine Mile Point Unit 2.
89091~0019 390907 PbR ADOCK 0 000410 O
Details 1.0 Persons Contacted R. Abbott, Station Superintendent, NMP-2 U. Buiva, Lead Electrical Engineer, NMPC Nuclear Engineering J. Burton, Supervisor Operations Surveillance, Nuclear QA Operations M. Dooley, Supervisor, Nuclear Regulatory Compliance G. Doyle, Lead QA Technician, Quality Engineering/Control J. Kinsley, I/C Supervisor, NMP-2
S. Moryl, Assistant Supervisor, Electrical Maintenance
V. Perry, QA Program Manager, NMP-2 A. Sassani, Lead Design Engineer, Site Project Engineering
D. Straka, Engineer, Nuclear Regulatory Compliance United States Nuclear Re viator Commission C. Anderson, Chief, Plant Systems Section, EB, DRS, Region I
R. Laura, Resident Inspector, NMP-2 V. McCree, Acting Project Manager, NMP-2, NRR R. Temps, Resident Inspector, NMP-1 Denotes individuals attending the exit meeting on July 21, 1989 The inspector also contacted other administrative and 'technical personnel during the inspection.
2.0 Nine Mile Point Unit 2 NMP-2 ATWS Rule Im lementation
CFR 50.62 Module 25020 2.1
~Back round In accordance with 10 CFR 50.62, paragraphs (c)(3), (c)(4),
and (C)(5), all boiling water reactors (BWRs) are required to install an ATWS mitigating system that is functionally and physically diverse from the reactor trip system (RTS).
This diversity must extend from the initial detector output to the final actuation device.
BWRs are required to have ATWS systems consisting of an alternate rod injection (ARI) system, a standby liquid control (SLC) system, and a
system capable of generating an automatic reactor recirculation pump trip (RPT) under conditions indicative of an ATWS event.
The ARI, SLC, and RPT systems are required to perform their functions reliably.
Although the ATWS system(s)
are not required to be "safety related" QA Category I, NRC Generic Letter 85-06 outlines QA/QC inspection guidelines which licensees have committed to impose on ATWS equipment, causing it to fall broadly within the scope of 10 CFR 50, Appendix B criteri Niagara Mohawk Power Corporation (NMPC) installed the redundant reactivity control system (RRCS)
and its subsystems ARI, auto SLC, and ATWS/RPT for the ATWS equipment at NMP-2.
This equipment was procured in accordance with "Alternate 3A" described in NUREG-0460,
"ATWS for Light Water Reactors'
"
A feedwater runback function was also included in the NUREG-0460 analysis and was installed with the RRCS at NMP-2; however, this feature is not required by
CFR 50.62.
The RRCS was included in the original design and construction of NMP-2 and was also part of the plant's design basis.
The entire RRCS design and all of the equipment (cabinets, panels, control devices, logic circuits, trip devices, sensors, etc.) were procured as a
complete package from the NMP-2 NSSS vendor (General Electric Company).
A safety evaluation of the licensee's submittals on compliance with the ATWS rule was completed by the NRC on March 24, 1988.
This safety evaluation report concluded that the NMP-2 ATWS system design is in compliance with the ATWS rule.
?n part, this conclusion is based upon the fact that the RRCS was designed, fabri-cated, installed, and tested as a safety related plant system exceed-ing the guidelines of Generic Letter 85-06 and meeting the design and quality criteria of 10 CFR 50, Appendices A and B.
This inspection reviewed the hardware installation and testing records to verify implementation of the ATWS system design criteria.
The documents reviewed during this inspection are listed in Attachment A.
2.2 S stem Oescri tion The RRCS consists of reactor pressure and water level sensors, logic circuits, power supplies, relay cabinets, and instrumentation which will activate ARI valves, automatically initiate SLC injection, and/or automatically initiate a recirculation pump trip (RPT)
upon sensing ATWS conditions in the core.
The RRCS at NMP-2 is inde-pendent from the reactor trip system and consists of two separate and independent instrument divisions.
Either division will initiate ATWS protective actions when both of the input channels (A and B) are tripped.
Each ATWS function can also be initiated from the control room by manually tripping both channels in either division.
The ARI logic causes the ARI valves in the scram air header to energize upon receipt of a trip signal from either high reactor pressure or low low reactor vessel water level.
This action causes complete control rod insertion to begin within 15 seconds.
High reactor pressure will also transfer high speed recirculation pumps to slow speed.
If reactor pressure remains high and reactor power in not reduced after 25 seconds, RRCS will then trip the recirculation pumps and initiate a feedwater runback.
Sustained high reactor pressure without a reduction in reactor power will cause the RRCS to automatically initiate SLC injection to the cor Low low reactor water level will also cause an immediate recirculation pump trip which reduces core flow, increases void content (negative reactivity insertion),
and reduces core thermal power.
After 98 seconds of sustained low low water level without a reduction of reactor power, the RRCS wi 11 automatically initiate SLC injection to the core.
NMPC installed a modification in the feedwater control circuits to manually disable receipt of the RRCS feedwater runback signal if desired.
This modification is non-safety related and consists of a manual two-position switch on the main control panel with a light indicator and an annunciator showing the runback bypassed condition.
This modification was installed to reduce the risk of experiencing a
severe reactor transient initiated by a spurious RRCS feedwater runback signal generated during RRCS surveillance testing at power.
2.3 Ins ection Review'for ATWS Rule Com liance IP 25020 The inspection to determine the licensee's compliance with the ATWS rule and to as"ess the operational adequacy and reliability of the ATWS equipme'nt was acccmplished by verifying that the installed systems perform as specified in the design documents.
The inspector reviewed selected design, installation, test, inspection, and operational records (see Attachment A) to verify the approved designs and programs are in place and are being properly maintained in accordance with NRC and licensee requirements within the scope of 10 CFR 50, Appendix B.
The inspection also included field verification of installed ATWS equipment to confirm that installation specifications and gA inspection requirements have been met.
This included a comparison of installation drawings and specifications with ATWS equipment located in the main control room, the relay room, and the reactor building.
The inspector also interviewed plant personnel responsible for maintaining, testing, and operating the ATWS equipment to evaluate their level of knowledge and training, and ensure that the system could perform its intended design function if necessary.
2.3.1 Desi n Verification The ATWS system design drawings and equipment installation were reviewed for diversity and separation from the reactor protection system (RPS),
incorporation of single failure design criteria, electrical class 1E, environmental qualification, and gA Category I qualificatio System diversity from the RPS was demonstrated by the fact that the analog trip units for the RRCS are designed and manufactured by General Electric Company and the RPS trip units are manufactured by Rosemont.
In addition, the RRCS activates the ARI valves through an "energize-to-function" action whereas RPS activates the ARI valves through a
"deenergize-to-function" action which causes the valves to open upon loss of RPS power.
Loss of RRCS power will not effect RPS.
The ATWS design has incorporated single failure criteria in that all ATWS/RRCS functions are capable of being fully activated within either system division.
A failure in one division will not affect the other division because of physical redundancy and separation of divisions and channels.
During the walkdown verification of ATWS instru-ment cabinets, it was noted that transmitter input cables for channels A&B to each division of RRCS did not fully meet separation criteria inside panels C22-POOl, C22-P002, 2CEC-736, and 2CEC-737.
The installation specifications recognized that the configuration or arrangement of electrical components inside panels and cabinets may prevent achieving the minimum separation required for channel cables, and that such conditions are acceptable.
A loose interpretation of this allowance may have been responsible for the original acceptance of these cable installations; however, the licensee agreed in this case that physical arrangement or configuration did not prevent separation from being accom-plished.
Four areas were involved, one in each divisional cabinet and one in each field termination cabinet.
During this inspection, NNPC wrote two work requests to move two bundles of instrument cabling inside each panel to provide the required I" minimum separation.
This work will be accomplished during the next scheduled monthly surveillance test when each division is taken off line.
At that time spurious alarms are less likely to occur from disturbance of instrument cable bundles during plant operations These instances appeared to the inspector to be isolated cases within the ATWS equipment, which otherwise was noted to provide full separation.
The inspector confirmed the system's testability at power by reviewing monthly surveillance tests on both divisions for the past six months and on the last two 18-month surveillance tests.
During the past two year period, two LERs have been generated from plant events which occurred during ATWS testing.
One LER (87-33) could not attribute any detectable cause to a plant trip during the monthly surveillance test, and one LER (88-66) identified a design deficiency in the ATWS instrument lines.
This result initiated plant modification PNZY88MX089 which will be
installed during the 1990 outage.
The inspector also noted that NMPC installed a feedwater runback signal inhibit function in the FW control circuits to allow blocking spurious runback signals from tripping the plant during RRCS testing.
However, the final Site Operations Review Committee (SORC)
and Safety Review and Audit Board (SRAB)
approved 50.59 safety evaluation for the FW runback modi-fication stipulated that positive procedure controls will be implemented to ensure that the runback inhibit function is used only during surveillance testing of RRCS.
The switch is a manual switch on the MCB with no physical restraint to preclude direct manipulation.
The FW opera-ting procedure did not contain a precautionary statement to prevent operation of the switch or any step to verify its position during startup, normal operation, shutdown, or emergency operation of the FW system.
The licensee agreed to revise the existing procedure and provide the necessary controls to satisfy the requirement of the 50.59 report.
This shall remain an unresolved item (50-410/89-14-01),
pending subsequent NRC review of administrative controls over the implementation of SORC, SRAB, and safety evalua-tion requirements, and licensee actions to revise the FW operating procedure.
The final SORC/SRAB-approved 50.59 evaluation also provided specific FSAR changes which amended those sections that describe the FW runback initiation from RRCS.
Those changes were withheld from the USAR because the input cutoff date was April 30, 1988, and the modification had not been accepted by operations until two weeks later.
Although the modification has been in use in the plant for over a year, it is not currently reflected in the USAR.
The inspector confirmed, through the NMPC Nuclear Licensing Department, that this modification is included in the next proposed revision to the USAR.
Licensing Document Change Notice (LDCN) No. U-222 was prepared on 1/23/88, and is currently awaiting approval by the Nuclear Licensing Manager.
The inspector reviewed the draft version of this document and concluded that the modification is adequately described for the next USAR revision due for issue by November 1989.
Conclusions After a review of NMPC's programs to procure, install, test, operate, and maintain the ATWS equipment at NMP-2, the inspector concludes that the licensee is in full compliance with the
CFR 50.62 ATWS rule.
This conclusion is based upon direct inspection, observation, and verification that the installed equipment meets the design endorsed by the NRC approved Safety Evaluation Report, and that the equipment satisfies the criteria required by design and installation
specifications.
In addition, the ATWS equipment was confirmed to perform its intended design functions as evidenced by the results of personal interviews, plant operational tests and surveillance procedures.
Also, it was confirmed that ATWS system performance does not compromise the safety functions of other plant protection systems.
The licensee's gA programs related to the ATWS equipment were verified to conform to
CFR 50, Appendix B criteria.
These programs in turn have been implemented to the extent necessary to ensure that ATWS systems have been and are currently maintained and operated as safety related gA Category I equipment.
3.0 Mana ement Meetin s
Module 30703 Licensee management was informed of the scope and purpose of this inspection at the entrance interview on July 17, 1989.
The findings of the inspection were discussed w'.th licensee representatives during the course of the inspection and were presented to the licensee's management at the July 21, 1989 exit interview (see paragraph 1 for attendees).
At no time during the inspection was written material provided to the licensee by the inspector.
The licensee did not indicate that proprietary information was involved within the scope of this inspectio 'C