ML20127P737
| ML20127P737 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 05/07/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20127P734 | List: |
| References | |
| NUDOCS 8505240066 | |
| Download: ML20127P737 (6) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 89 TO FACILITY OPERATING LICENSE NO. DPR-59 POWER AUTHORITY OF THE STATE Of NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 1.0 Introduction By letter JPN-85-22 dated March 21, 1985, thelicensee(PowerAuthority C
of the-State of New York) proposed changes to the James A. FitzPatrick Technical Specifications associated with the installation of Analog Transmitter / Trip System (ATTS) components used to initiate reactor trip and actuate engineered safety feature systems. The ATTS modification consists of the replacement of existing flow, level, and pressure mechanical sensor switches, used to provide inputs to plant protection systems, with analog sensor / trip unit combinations which provide continual monitoring of critical parameters in addition to providing protection system inputs.
In addition, various leak detection system temperature elements will be replaced with nuclear-qualified Class IE Resistance Temperature Detectors (RTDs). The j
licensee provided additional information concerning the ATTS hardware i
changes by letter dated March 28, 1985.
The ATTS was developed by the General Electric Company (GE) to offset operating disadvantages r.egarding testing and setpoint drift associated with the mechanical sensor (differential pressure) switches. The licensee j
has stated that the purpose of the ATTS modification is to improve sensor accuracy and reliability, reduce the amount of time that the Reactor Protection System (RPS) logic must be in a half-scram condition (during testing), reduce instrument channel calibration frequency, and reduce personnel radiation exposure. The ATTS desi equipment in later-built BWRs (e.g., BWR-6s)gn is being supplied as original
, and is being backfitted on several earlier BWRs. The ATTS modification was reviewed and approved by the staff for Hatch Units 1 and 2.
GE provided a description of the ATTS design in Topical Report NED0-21617. The staff reviewed this report on a generic basis and concluded that the ATTS design was acceptable (Reference i
letter dated June 27,1978 from 0. Parr, NRC to G. Sherwood, GE). However, the staff identified plant-specific design information to be submitted by licensees implementing the ATTS design. This information pertains to interfaces between the ATTS and other systems, environmental qualification of ATTS components, and divisional separation of redundant ATTS hardware to be installed in the plant.
i Because of previous staff review efforts which have documented the overall acceptability of the GE ATTS design, the review of ATTS modifications at i
8505240066 850507 DR ADOCK 05000333 PDR
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. FitzPatrick was limited to plant-specific aspects of the ATTS installation, and the associated Technical Specification changes requested by the licensee.
2.0 Evaluation The licensee has stated that installetion of the FitzPatrick ATTS is in accordance with GE's Licensing Topical Report NED0-2167-A, " Analog Transmitter Trip Unit System for Engineered Safeguard Sensor Trip Inputs,"
dated December 1978. This report contains the staff's June 27, 1978 acceptance letter referenced above. The added ATTS hardware consists of Rosemount transmitters (models 1153GB, 1153DB, and 1153AB) located at instrument racks in the reactor building, RTDs used in area leak detection systems, instrument racks used to support the ATTS instruments (some existing ins.trument racks are being modified), and ATTS cabinets (located in the relay room in the administration buildin room) which house the solid state electronics (g, underneath the control trip units) used to process the analog signals. The instrument channel outputs from the ATTS cabinets
- j are routed to the existing RPS and emergency core cooling system (ECCS) logic cabinets in the control room. The ATTS modification does not involve any logic changes. The automatic and manual initiation functions and protective actions of essential systems remain unchanged.
Furthermore, all setpoint values for initiation of protective actions will remain unchanged.
The ATTS modification is limited to instrument channel components that provide inputs to the existing protection system logic.
The licensee has stated that existing components such as switches, racks, and accessories are being replaced by nuclear Class IE qualified equipment meeting more stringent codes and standards than the original equipment.
The ATTS transmitters, RTDs, instrument racks, and cabinets are environmentally and seismically qualified in accordance with IEEE Standards 323-1974 and 344-1975.
The licensee has stated that the installation of the ATTS at FitzPatrick satisfies the requirements of IEEE Standard 279-1971, and that.all ATTS wiring complies with the separation requirements of IEEE Standard 384-1981 and Regulatory Guide 1.75.
All new wiring from instrument racks in the reactor building to the ATTS cabinets in the relay room is routed in steel conduit. The output contacts from the ATTS cabinets are routed to the same points as they previously were. All previous safety analyses for individual instruments and interface equipment remain unchanged. The interface with the annunciator system is accomplished using relay coil-to-contact isolation between ATTS circuits and annunciator circuits.
-The ATTS instrument channels are powered from the same divisional /
essential distribution system as the corresponding equipment they_
replaced. The RPS portion of the ATTS is supplied (as is the remainder
'of the RPS) from the RPS buses. Redundant Class IE electrical protection assemblies (EPAs) are installed between each RPS bus and its power source
=.
r (motor-generatorset). This protects each RPS b'us against a sustained I
degraded voltage or frequency condition. Each EPA consists of a circuit breaker with a trip coil driven by logic circuitry that senses line
- voltage and _ frequency and trips the circuit breaker open on conditions of
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f overvoltage, undervoltage or underfrequency. The RPS itself is a fail-safe system (i.e., prctective action occurs on loss of power). Power for the.
ECCS portion of the ATTS is provided from Class IE inverters which are, i
in turn, powered from the 125 Vdc battery-backed ECCS buses. The Class IE batteries are'divisionalized and supplied by chargers that are powered from the emergency buses. The batteries are sized for two hours continuous duty without the chargers. Undervoltage/overvoltage to ECCS portions of the ATTS is prevented by protective design features of the inverters. The ATTS
. is designed to operate properly if inverte: input voltage is maintained between 100 and 140 Vdc. High and low input voltage detectors will automat.ically turn off the inverter if input voltage should stray outside of these limits. This in turn will activate power supply trouble alanns and trip unit trouble alarms to alert the operators. The staff concludes that the ATTS RPS and ECCS power supplies are acceptable.
Rosemount Instruction Manual 4247-1 dated July 1976 contains maximum transmitter lead length requirements to assure sufficient voltage out of 3
the trip unit to. drive the transmitter. The maximum allowable lead length for size 16 AWG copper wire used at FitzPatrick is 3,820 feet. The i
licensee has stated that the maximum cable length used in the FitzPatrick ATTS modification is 828 feet. The ATTS instrument channels are provided with high and low current gross failure alarms to detect short and open circuit conditions in the transmitter current loops. The high/ low gross failure setpoints will be set at values of 30 0.5 and 2.510.5 mA respectively. These setpoint values will provide adequate detection of short/open circuits.
GE Report NED0-21617-A outlines a stringent electromagnetic interfet ence (EMI) test made on the individual components of the ATTS on the basis of EMI' parameters which can be found ir. and around nuclear plants. Measures developed as a result of this test to minimize the effects of EMI will be implemented at FitzPatrick. In particular, shielded cables are used for all analog signals. These cables are routed in metal conduits.
Instrument racks and trip unit racks are grounded. Physical locations of instrument racks and trip units have been selected to minimize potential exposure to a connon source of EMI.
The staff has reviewed the Technical Specification changes proposed by the licensee to support implementation of the ATTS modifications. There are two major changes concerning instrument surveillance requirements. The first change involves added requirements to perfonn instrument channel checks for the ATTS channels. An instrument channel check is the qualitative assessment of channel behavior during operation by comparison of a group of instrument channel readouts / displays (in this case, trip unit panel meters) for a given monitored parameter. An instrument channel
4-readout that differs significantly from the readouts of the remaining instrument channels is indicative of a channel malfunction. The performance of a channel check provides a quick and easy method for detecting gross instrument failures in the non-conservative direction during the intervals between other more extensive tests (e.g., monthly channel functional tests) which would detect the failure. A gross failure in the conservative direction would typically be detected in the form of a channel trip (i.e., the setpoint value would be exceeded). The licensee will perform a channel check daily for all added ATTS instrument channels by comparing trip unit panel meters at the ATTS cabinets in the relay room.
These meters display the value of the measured parameter which can be scaled in units of the process variable. The meters monitor the normalized voltage at the output of the input buffer amplifiers (this voltage varies from 1 to 5 volts, for,a corresponding 4 to 20 mA signal from the transmitters). The capability to perform channel checks did not exist in the previous design because the mechanical differential pressure switches (sensors) were the non-indicating type. The daily channel check Technical Specification requirements proposed by the licensee provide an additional means of verifying instrument chanrel operability, and therefore, are acceptable.
The second major Technical Specification change proposed involves relaxation of the required channel calibration frequency for ATTS instrument channels. The calibration frequency for the mechanical sensor switches.specified in the existing Technical Specifications is once per three months. The proposed calibration frequency for ATTS instrument channels is once per operating cycle for sensors (transmitters), and once per six months for both master and slave trip units. The calibration frequency has been relaxed because the solid-state electronic ATTS components are highly reliable, more accurate, and have lower failure rates o
than the mechanical instruments being replaced. The proposed calibration frequencies are at least as conservative as the calibration frequencies specified for ATTS components in the BWR Standard Technical Specifications. The Standard Technical Specifications are recognized by the staff as an acceptable implementation of the applicable requirements.
The remaining Technical Specification changes proposed by the licensee involve the definition of channel functional tests for analog versus digital channels (i.e., injecting a simulated signal into the ATTS instrument channels versus exercising the sensor for mechanical instrument channels), or changes which are editorial in nature. These changes are also acceptable.
3.0 Sumary We have previously reviewed the use of the ATTS and found that, provided certain interface requirements were satisfied, the system is acceptable (letter of approval, dated June 27, 1978, is part of General Electric Topical Report NED0-21617-A dated December 1978).
Based on our review of a
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. the documentation submitted by the licensee, we conclude that the proposed modifications satisfy the constraints of our prior approval and also satisfy the requirements of the applicable General Design Criterion and Regulatory Guides as referenced in Sections 7.2 (Reactor Trip System) and 7.3 (Engineered Safety Features Systems) of the Standard Review Plan (NUREG-0800).
In addition, based on the data submitted, we concluded that:
1)
The replacement instrumentation has better reliability, accuracy, and response time than the existing instrumentation.
2)
The-separation criteria of the original plant design is unchanged.
Separation is provided by locating equipment on separate racks and panels'and by running cable in separated conduits. The power supply used for a given ATTS instrument channel is dependent on that channel,'s divisional assignment, and is the same as the supply used for the channel being replaced.
l 3)
No new single failure events have been created. Therefore, no single failure will result in any action not previously evaluated in the Final Safety Analysis Report (FSAR).
4)
All new equipment has been tested or analyzed to assure that the design basis environmental and seismic requirements are met.
5)
Means are provided to test the trip units periodically by injecting a signal into the transmitter current loop and observing trip unit response (trip setpoint and alarm functions). Operability of the analog loop is verified by periodic instrument checks.
6)
Proposed Technical Specification revisions permit the operation of the facility in a manner that is consistent with the licensing basis and accident analysis for FitzPatrick.
Therefore, we conclude that the modifications of the RPS and ECCS (including RCIC) as discussed above, and the associated Technical Specification revisions, are acceptable.
4.0 Environmental Consideration This amendment involves a change in the installation.or use of a facility component located within the restricted area and changes in surveillance
- requirements as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released-offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding' that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
. i Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
5.0 Conclusions
-We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal CQntributor:
R. Kendall Dated:
May 7, 1985 O
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