ML20137S889
| ML20137S889 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 04/08/1997 |
| From: | Maine Yankee |
| To: | |
| Shared Package | |
| ML20137S885 | List: |
| References | |
| NUDOCS 9704150273 | |
| Download: ML20137S889 (2) | |
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Attachment B MN-97-53 Page1of2 t
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ATTACHMENT B i
Revised Basis l
Technical Specification 3.10.E.2 Basis Technical Specification Page 3.10-9 l
Proposed Change 194 Reactor Coolant Flow Rate Requirements I
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m thermocouples, the fixed incore detectors or in the movable incore detector traces.
The axial peaking factor can be determined from the fixed incore detectors, the movable incore detector traces or the excore detectors.
The requirement that the core power distribution be shown to be within the design I
limits after every refueling not only ensures that the reactor can be operated safely but will also provide reasonable verification that the core was properly loaded. The requirement for operability of incore instrumentation in the instance of an excore detector channel being out of service ensures that an unobserved quadrant power tilt will not occur.
The moderator temperature coefficient, coolant pressure, flow rate, and temperature specified are consistent with the values assumed ir the safety analysis.
The safety analysis assumes ranges in cold leg temperature corresponding to the allowable coolant conditions given in Figure 3.10-2. The actual values assumed in the safety analysis include an uncertainty on temperature measurements of +/-4 F conservatively applied to the allowable values.
The exception permits testing to determine decay heat removal capabilities of the Primary System while on natural circulation, prior to operation at higher power.
Operation with the turbine in IMPIN mode could result in a core power increase during a CEA drop transient above the initial pre-drop power level due to automatic opening of the throttle valves combined with moderator reactivity effects.
Thus, additional initial overpower margin is required to preclude violation of the SAFDLs. The modified symmetric offset LCO band provides this additional margin.
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The combination of reactor coolant flow rate and thermal power must be
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maintained within the regions of acceptable operation as shown in Figure 3.10-
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3 (Note: The upper and lower RCS flow boundaries of the restricted region
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acceptable operation apply for all power levels below the lower power value
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presented on the figure). This ensures that the combination of RCS flow rate
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and thermal power are within the ranges considered in the safety analyses, and
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that the calculated margins to the DNBR safety limit for the safety analysis
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are maintained.
If the combination of power and RCS flow fall within the
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unacceptable operation region of Figure 3.10-3 then power level shall be
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reduced to return to the acceptable operation regions in accordance with
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Technical Specification 3.0.A. In addition, the LCOs and trip setpoints shall
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be reduced within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of entering the restricted region by an amount
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greater than or equal to the following amount:
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%RTP = [150%)[1-(measured RCS Flow in kgpm)/360 kgpm)]
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Reducing power in accordance with Technical Specification 3.0. A and other
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limits within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the flow reduction allows sufficient time to
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accomplish these reductions without significantly increasing the probability
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or consequences of an accident previously evaluated.
Operation in the
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restricted region, combined with the reductions of the LCOs and trip
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setpoints, ensures that the calculated margins to the DNBR safety limit for
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the safety analysis are also maintained.
Reductions in the LCOs and trip
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setpoints are superimposed on any reductions required by Technical
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Specification 3.10.C.2.b.
3.10-9 Amendment No. R3. H 4