ML17285B135
| ML17285B135 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/21/1990 |
| From: | WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | |
| Shared Package | |
| ML17285B132 | List: |
| References | |
| NUDOCS 9004030277 | |
| Download: ML17285B135 (3) | |
Text
NTROLLEI3 COPY IHSTRUMEH.ATIOH BASES 3/4.3.5 REACTOR CORE ISOLATION COOLING SYSTEM ACTUATIOH IHSTRUMENTATIOH The reactor core isolation cooling system actuation instrumentation is provided to initiate actions to assure adequate core cooling in the event of reactor isolation from its primary heat sink and the loss of feedwater flow to the reactor vessel without providing actuation of any of the emergency core cooling equipment.
Operation with a trip set less conservative than its Trip Setpoint but within its specified Allowable Value is acceptable on the basis that the difference between each Trip Setpoint and the Allowable Value is equal to or less than the drift allowance assumed for each trip in the safety analyses.
3/4.3.6 COHTROL ROD BLOCK IHSTRUMEHTATIOH The control rod block functions are provided consistent with the require-ments of Specifications 3/4.1.4, Control Rod Program Controls, 3/4.2, Power Distribution Limits and 3/4.3. 1 Reactor Protection System Instrumentation.
The trip logic is arranged so that a trip in any one of the inputs will result in a control rod block.
Operation with a trip set less conservative than its Trip Setpoint but within its specified Allowable Value is acceptable on the basis that the difference between each Trip Setpoint and the Allowable Value is equal to or less than the drift allowance assumed for each trip in the safety analyses.
3/4. 3. 7 MONITORING IHSTRUMEHTATION tidC 3/4 3
7 1 RADIATIOH MONITORING IHSTRUMEHTATIOH The OPERABILITY of the radiation monitoring instrumentation ensures that; (1) the radiation levels are continually measured in the areas served by the individual channels; (2) the alarm is initiated when the radiation level trip setpoint is exceeded; and (3) sufficient information is available on selected plant parameters to monitor and assess these variables following an accident.
This capability is consistent with 10 CFR Part 50, Appendix A, General Design Criteria 19, 41, 60, 61, 63, and 64.
The criticality monitor alarm setpoints were calculated using the criteria from 10 CFR 70.24.a.l that requires detecting a dose rate of 20 Rads per minute of combined neutron and gamma radiation at 2 meters.
The alarm setpoint was determined by calculational methods using the gamma to gamma plus neutron ratios from ANSI/AHS 8.3-1979, Criticality Accident Alarm System, Appendix B and assuming a critical mass was formed from a seismic event, with a volume of 6' 6' 6't a distance of 27. 7 feet from the two detectors.
The calculated dose rate using the methodology is 5.05 R/hr.
The allowable value for the alarm setpoint was, therefore, established at 5R/hr.
- 3. 4. 3. 7. 2 SEISMIC MONITORING IHSTRUMEHTATION The OPERABILITY of the seismic monitoring instrumentation ensures that sufficient capability is available to promptly determine the magnitude of a seismic event and evaluate the response of those features important to safety.
This capability is required to permit comparison of the measured response to that used in the design basis for the unit.
This instrumentation is consistent with the recommendations of Regulatory Guide 1. 12, "Instrumentation for Earthquakes,"
April 1974.
WASHINGTON NUCLEAR - UNIT 2 9004030277 90032i PDR ADDCK 05000397 P
B 3/4 3-4 Amendment Ho.
74
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INSERT TO BASES PARAGRAPH 3/4.3.6, CONTROL ROD BLOCK INSTRUMENTATION The test exception to the weekly Channel Functional Test of the SRM/IRM Detector Not Full In instrumentation noted in Table 4.3.6-1, Control Rod Block Instrumentation Requirements, is intended to avoid cable damage and radiation exposure during operational condition 5 periods when outage work is being done in the under core region.
Upon completion of all the work in this area, when access for maintenance or construction efforts is no longer required, the test will be completed per the prescribed frequency within seven days.