ML17158A175
| ML17158A175 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/08/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17158A174 | List: |
| References | |
| NUDOCS 9403160286 | |
| Download: ML17158A175 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO. NPF-14 AMENDMENT NO.
TO FACILITY OPERATING LICENSE NO.
NPF-22 PENNSYLVANIA POWER
& LIGHT COMPANY ALLEGHENY ELECTRIC COOPERATIVE INC.
SUS UEHANNA STEAM ELECTRIC STATION UNITS 1
AND 2 DOCKET NOS.
50-387 AND 388
1.0 INTRODUCTION
By letter dated October 8, 1993, the Pennsylvania Power and Light Company (PP&L or the licensee) submitted a request for changes to the Susquehanna Steam Electric Station, Units 1 and 2, Technical Specifications (TS).
The requested changes would revise the existing definition of CHANNEL CALIBRATION in TS 1.4 to allow in-place qualification methods to be used to verify resistance temperature detector or thermocouple sensor behavior.
- 2. 0 EVALUATION Section 1.0 of the TSs contains definitions of terms used throughout the document.
The definition of CHANNEL CALIBRATION in the present TSs is as follows:
1.4 A CHANNEL CALIBRATION shall be the adjustment, as necessary, of the channel output such that it responds with the necessary range and accuracy to known values of the parameter which the channel monitors.
The CHANNEL CALIBRATION shall encompass the entire channel including the sensor and, alarm and/or trip functions, and shall include the CHANNEL FUNCTIONAL TEST.
The CHANNEL CALIBRATION may be performed by any series of sequ'ential overlapping or total channel steps such that the entire channel is calibrated.
For the reasons discussed below, the licensee proposes to add the following sentence between the second and third sentences:
"Calibration of instrument channels with resistance temperature detector (RTD) or thermocouple sensors may consist of an in-place qualitative assessment of sensor behavior and normal calibration of the remaining adjustable devices in the channel."
9403160286 940308 PDR ADOCK 05000387 P
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Table 4.3.7.5;I of the TSs (Page 3/4 3-73) lists the accident monitoring instrumentation surveillance requirements.
The table specifies that the licensee perform a monthly channel check on the Suppression Chamber Water and Air Temperature instruments and a channel calibration on these instruments each refueling outage.
The temperature instruments are Resistance Temperature Detectors (RTDs).
The intent of the TS surveillance requirement to periodically calibrate RTDs that sense air and water temperatures is to ensure that the RTDs are sensing the actual temperatures.
The term "calibration", however, implies activities that are not possible on RTD or thermocouple sensors.
"Calibrations" typically require adjustments of devices to cause them to conform to a desired output.
In this sense, RTD and thermocouple sensors cannot be "calibrated" since there are no sensor adjustments that can be made.
The only means of calibrating the RTDs or thermocouples would be to physically remove them, which has the likely potential to damage them during removal.
A more appropriate activity to require on an RTD or thermocouple is to cross compare RTD or thermocouple output indications with sensors measuring the same temperature.
The in-place cross comparison of RTD or thermocouple sensor output indications with other sensors measuring the same temperature is one method that can be used to verify the consistency of indications in a group of sensors such as the suppression chamber RTDs.
The revised TS definition for CHANNEL CALIBRATION provides flexibility in choosing appropriate methods to verify the performance of RTDs or thermocouples.
The staff has previously expressed concern that the use of an average'RTD value as a reference for cross-comparison, instead of a calibrated reference, may lead to a net drift of the average temperature value indicated, should the installed RTDs drift systematically.
Studies have indicated that the installed RTD drift may be random.
Therefore, without a reference, the cross-comparison technique will not detect common-mode (systematic) drift and will provide information on the consistency and not the accuracy of the installed RTDs.
The staff is continuing to evaluate cross-comparison techniques on a
generic basis.
- However, based on operational experience, the proposed change to the definition of channel calibration meets the intent of the surveillance requirement and is acceptable.
- 3. 0 STATE CONSULTATION In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendments involve no
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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 Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (58 FR 59754).
Accordingly, the amendments meet 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 the amendments.
- 5. 0 CONCLUSION The Commission has 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
R. Clark Date:
March 8, 1994
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