ML20101G617
| ML20101G617 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 06/18/1992 |
| From: | Bevan R Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20101G620 | List: |
| References | |
| NUDOCS 9206260171 | |
| Download: ML20101G617 (2) | |
Text
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't.TMITI,NC C0!TDTTIONS FOR OPERATION St'RVE?IlANCE REOUTREWENTS 3.11.C.
Minfeum Critical Power Ratio 4.11.C.
Minimum Critical Power Ratio (MCPR)
.fMCPR )
During steady state power operation the MCPR for each MCPR shall be determined daily type of fuel at rated power during reactor power operation at ) 251 rated thermal power l
and flow shall not be lower and following any change in than the limiting value specified in the Core power level or disttibution that could cause operation on Operating Limits Report for the operating limit MCPR.
two recirculation loop operation.
If, at any time during steady state operation it is determined by normal surveillance that the limiting value for MCFR is being exceeded, action shall then be initiated within 15 minutes to restore operation to within the prescribed limits.
If the steady state MCPR is not returned to within the prescribed limits within two J
(2) hours, reduce reactor power to $ 25% of rated power within the next four (4) nours.
Surveillance and corresponding action shall continue until the prescrAbed limits are again being met.
I For one recirculation loop I
operation the MCPR limits arc 0.01 hi her than the S
comps:cble two-loop values.
Amendment No. 70, 94, 132, 142, 151 kR O
0 h
-212-e j
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3.11 Bases-(Cent'd' f
l C.
Minieur Critical Power Ratio (MCPR) i l
The required operating limit MCPRs at steady state operating conditions as specified ir. fpecification 3.11C are derived from the established fuel cladding integrity Saf ety Limit and an analysis of abnormal operational transients j
(References 2 and 11).
For any abnornal opt rating transient analysis l evaluation with the initial condition of the reactor being at the steady state operating limit it is req tired t. hat the resulting MCPR does not decrease below the Safety Limit MCPR at any time during the transient assuming instrument trip setting given in Specification 2.1.
To assure that the fuel cladding integrity Safety Limit is not exceeded during any anticipated abnormal operational transient, the more limiting transients have been analyzed to deteruine which result in the largest reduction in l
critical power ratio (CPR).
The models used in the transient analyses are diccussed in Reference 1.
Flow dependent and power-dependent MCPR limits (MCPRr and MCPR,) are used to define the required Operating Limit MCPR (OLCPR) such that the above Safety i
Limit MCPR requirement is cet for all power / flow conditions.
MCPRr provides the thereal cargin required to protect the fuel from transients resulting from i
inadvertent core flow increases.
MCPR, protects the fuel from the other liciting abnor=al operating transients, including localized events such as a rod withdrawal error, i
Direct scram on Turbine Stop Valve Closure or Turbine Control Valve fast closure provides the fastest response to an abnormal operating transient such
)
as load rejection, turbine trip, or feedwater controller failure. These direct scrans are bypassed at low power (Pey...), to reduce the frequency of scrans durin5 power ascension. For operation at or above P 3y,,, (30% of rated power),
the required OLMCPR is the larger of MCPRr or MCPR, at the existing core power / flow state; where MCPRr and MCPR, are determined in the Core Operating Limits Report by cultiplying the scram time dependent MCPR limit for rated power and flow MCPR(100) b'; the V, factor. Below 30% of rated power, when the
?
direct scra=s are bypassed, a slightly more severe transient response results.
To ce=pensate for the core severe transient response, two power dependent MCPR licits are established, one for high flow (>50% of rated) conditions _ and one for low flow ($50% of rated) conditions.
These limits are specified in the Core Operating Licits Report. Further information on the MCPR operating limits for off-rated conditions is presented in Reference 11.
Peferences for Bases 3.11 1.
"Cer.eral Electric Standard Application for Reactor Fuel," NEDE 240ll-P-A.
(The approved revision at the time the reload analyses are perforned.)
The apptoved revision number shall be identified in the Core Operating Limits Report.
2.
" Supplemental Reload Licensin5 Submittal for Cooper Nuclear Station," (applicable reload document).
3-8.
Deleted t
9.
Letter (with attachment), R. H. Buckholz (CE) to P. S. Check (NRC).
" Response to NRC Request for Information on ODYN Computer Model," September 5, 1980.
10.
" Cooper Nuclear Station Single-Loop Operation," NEDO 24258.
11.
" Extended Load Line Limit and ARTS Improvement Program Analysis for Cooper Nuclear Station Cycle 14," NEDC-31892P, Revision 1, May 1991.
-214a.
Amendment No. 62, 20, H,14,151
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