ML20101K953
| ML20101K953 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/30/1992 |
| From: | Lyster M CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20101K954 | List: |
| References | |
| PY-CEI-NRR-1509, NUDOCS 9207060172 | |
| Download: ML20101K953 (6) | |
Text
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -
CENTERIOR ENERGY PERRY NUCLEAR POWER PLANT t
Addro s Michael D. Lyster 10 CE R ROA g
061 (2 m 2 m June 30, 1992 PY-CEI/NRR-1509 L U.S. Nuclear Regulatery Commission Docu'nent Cont rol Desk Vashington, D. C.
20555 Perry Nuclear Power Plant Docket No. 50-440 Technical Specification Change Request:
Relocation of the Simulated Thermal Power Time Constant to the COLR Gentlemen:
Attached is a request for amendment of Facility Operating License NPF-58 for the Perry Nuclear Power Plant (PNPP), Unit 1.
In accordance with the requirements of 10 CFR 50.91(b)(1), a copy of this request for amendment has been sent to the State of Ohio as indicated below.
This amendment requests revist to Technical Specification 3.3.1 " Reactor Protection System Instrumcatation" and Specification 6.9.1.9 " Core Operating Limits Report (COLR)" to transfer the specific value of the simulated thermal power time constant from the Technical Specifications to the COLR. The simulated thermal power time constant is an inherent characteristic of the fuel and can change cycle to cycle (as different fuel designs are utilized in the g
reactor), therefore it is appropriate to relocate this parameter to the COLR. provides the Summary, Description of Changes, and the significant llazards and Environmental Considerations. is a copy of the marked up Technical Specification pages. provides an example of how the cycle-specific information formerly within the Technical Specifications might be formatted when it is relocated to the Core Operating Limits Report.
If you have any questions, please feel free to call.
Sincerel,
et Michael D. Lyster MDL:RAL:ss Attachment cc:
NRC Project Manager NRC Resident Inspector Office
[8 NRC Region III State of Ohio f
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PY-CEI/NRR-1509 L Attachmsnt 1 Tage 1 of 5 Summary This proposed change revises the PNPP Unit 1 Technical Specifications to replace the specific value of the simulated thermal power time constant with a reference to the Core Operating Limits Report (COLR) for the current value.
Description of Change
)
Vith the advent of never Boiling Vater Reactor (BVR) fuel designs, one of the major changes is the increase in number of fuel rods per bundle, from the current 8x8 array designs to 9x9 or 10x10 arrays. Vith changes in array designs comes changes in parameters that are related to the array or fuel design; for example the number of fuel rods, length of the fuel rods, diameter of the fuel rods, time constant for heat transfer through the fuel pellets, number of water rods, and size of the water rods, etc.
Changes made in the advanced fuel designs offer advantages in thermal limit performance and fuel cycle economics.
In order for the never fuel designs to fit within the same locations in the reactor core as the older designs, the cross-sectional a must be the same as that for the existing fuel designs. This requires thas a fuel rod m
diameter (and hence the fuel pellet diameter) be decreased. A decrease in fuel pellet diameter causes a decrease in the thermal power time constant (a description of how the simulated thermal power time constant is used as part of a thermal power trip function is provided below).
Since the thermal power time constant is an inherent characteristic of the fuel and may change each cycle with the installation of new fuel designs, it is appropriate to relocate the simulated thermal power time constant to the Core Operating Limits Report.
This change is consistent with the guidance provided in Generic Letter 88-16,
" Removal of Cycle-Specific Parameter Limits from the Technical Specifications." Several BVRs have instituted this change already. While PNPP has not as yet committed to purchasing any new fuel designs where this parameter would need to be changed, some designs under consideration for the next cycle might require a change to this parameter. Therefore, it is prudent to request this amendment nov.
Description of the APRM Flow Biased Simulated Thermal Power-High Trip Function The Average Power Range Monitor (APRH) Flov Biased Simulated Thermal Pover-High function modifies the neutron flux signal to conservatively approximate the thermal power being transferred to the reactor coolant. As described within Section 15.1.1.2.2 of the PNPP Updated Safety Analysis Report (USAR), and approved by the NRC in the Perry Safety Evaluation Report (SER),
the flow biased thermal power monitor (TPM)-is the primary protection system trip in mitigating the consequences of a loss of feedvater heating (or any decrease in-core coolant temperature) event.
The SER Section 15.1 notes that the "TPM conservatively estimates thermal power by passing the APRM signal through a time constant."- This simulated thermal power time constant is dependent, in part, on the fuel pellet diameter. The fuel pellet diameter is reduced when the number of fuel rods is increased as is the case with the 9x9 or 10x10 fuel designs. As the fuel pellet diameter decreases, the thermal power time constant also decreases.
This is because it takes less time for the heat to reach the outer surface of
PY-CEI/NRR-1509 L Attachmsnt 1 Page 2 of 5 the fuel pellet as the radius decreases. The simulated, conservative, time constant for the 8x8 designs is 610.6 seconds (as compared to the actual time constant of seven to 10 seconds).
For the 9x9 and 10x10 designs the actual time constant is smaller, and hence the corresponding simulated thermal power time constant may also be smaller.
The smallest value of the simulated thermai power time constant for all the fuel types installed in the core for the cycle vill be listed in the COLR. Therefore, it is necessary to provide for changes in this parameter within the Technical Spacifications and it is appropriate to transfer this value to the COLR.
4 The APRH Flov Biased Simulated Thermal Pover-High trip level automatically varies as a function of recirculation drive flow but is clamped at an upper limit which is lover than the APRM Neutron Flux-High Setpoint. The APRM Flov Biased Simulated Thermal Pover-High function provides protection against transients where thermal power increases slowly (such as the Loss of Feedvater 2
Heating event) and protects the fuel cladding integrity by ensuring the Minimum Critical Power Ratio (MCPR) Safety Limit is not exceeded.
During these events, the thermal power increase does not significantly lag the neutron flux response and, because of a lower trip setpoint the APRH Flow Biased Simulated Thermal Pover-High function vill initiate a scram before the high neutron flux function.
For rapid neutron. flux increase events, the thermal power lags the neutron flux and the APRM Neutron Flux-High function vill provide a scram signal before the APRH Flow Biased Simulated Thermal Pover-High function setpoint is exceeded.
Proposed Changes Page 3/4 3-6 Table 3.3.1-2, " Reactor Protection System Response. Times",
Functional Unit 2.b: Average Power Range Monitor, Flow Biased i
Simulated Thermal Pover-High, Note **
Replace the specific value of the simulated thermal pc.er time constant, "610.6 seconds" with the words "specified in the COLR."
Page 3/4 3-8 Table 4.3.1.1-1, " Reactor Protection System Instrumentation Surveillance Requirements", Note (i)
Replace the specific value of the simulated thermal power time i
constant, "the 610.6 seconds" with the words "that the", and add at the end of the sentence the phrase, "is within the limits specified in the COLR."
Page 6-21 Technical Specification 6.9.1.9, " Core Operating Limits Report" Add a new item (4) before the second paragraph stating, "The Simulated Thermal Power Time Constant for Technical Specification 3.3.1."
~
PY-CEI/NRR-1509 L Page 3 of 5 Page B 2-7 Bases for Table 2.2.1-1, " Reactor Protection System Instrumentation Setpoints", Item 2.
Average Power Range l
Monitor.
Replace the specific value of the simulated thermal power time constant, "of 610.6 seconds" with the words "specified in the 3
CO LR. "
See Attachment 2 for a marked-up copy of the Technical Specification pages.
The format for how the simulated thermal power time constant value vill be presented is shown in the sample COLR pages provided in Attachment 3.
No Significant llazards Evaluation i
The standards used to arrive at a determination that a request for amendment involves no significant hazards considerations are included in the Commission's Regulations, 10 CFR 50.92, which states that the operation-of a facility in accordance with the proposed amendment vould not (1) involve a significant increase in the probability or consequences of an accident previously evaluated, (2) create the possibility of a new or different kind of accident from any acciden* previously evaluated, or (3) involve a significant reduction in a margin of safety.
The proposed amendment has been reviewed with respect to these three factors and it has been determined that the proposed changes do not involve a significant hazard consideration because:
1.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
There vill be no change in the operation of the facility as a result of this amendment. No safety-related equipment or function vill be altered.
The proposed amendment merely transfers the specific value of the cycle-specific simulated thermal power time constant from the Technical Specifications and references its inclusion in the Core Operating Limits Report section of the Plant Data Book. The simulated thermal power time constant specified in the COLR vill continue to be used for calibration of the APRM Flow Biased Simulated Thermal Power-High trip function within the Technical Specifications..NRC approved analytical methodology will-continue to be used as a basis for the generation of the simulated thermal power time constant that vill now be contained in the COLR.
The transfer of the specific value of the fuel and cycle-specific simulated thermal power time constant from the PNPP Technical Specifications has no influence or impact on the probability of any transient or accident occurrence. This value,'although not in Technical Specifications, vill still be utilized in operating the Perry Nuclear Power Plant. The proposed Technical Specification still requires exactly the same actions to be taken if this value is not met as are required by i
the current Technical Specification.
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'PY-CEI/NRR-1509 L Attachmtnt 1 Page 4 of 5 2.
The proposed change does not create the possibility of a new or dif ferent kind of accident from any accident previously evaluated.
As stated above, no safety-related equipment, safety functions, or plant operations vill be altered as a result of this amendment. The requested change does not create any new accident mode. The proposed change is in accordance with the guidance provided in Generic Letter 88-16 for requesting removal of the values of cycle-specific parameters from Technical Specifications. The establishment of the simulated thermal power time constant is in accordance with an NRC approved methodology and the incorporation of this value into the Core Operating Limits Report section of the Plant Data Book in accordance with the PNPP administrative control procedures ensures that proper steps have been taken to establish and maintain the value of this parameter.
Furthermore, the submittal of Core Operating Limits Report revisions to the Commission as required by Technical Specification 6.9.1.9 vill allow the Staff to continue to trend and review the values, j
As stated earlier, the removal of the cycle-specific values has no influence on, nor does it contribute in any way to, the probability or consequence-of an accident. The cycle-specific simulated thermal power time constt.c will continue to be calculated-using NRC approved methods.
The Technical Specification requirements regarding the simulated thermal power time constant are unchanged.
3.
The proposed change does not involve a significant reduction in a margin of safety.
The essential issue, relative to plant safety, is conformance with the appropriate value of the simulated thermal power time constant. Whether the value is located within the Technical Specifications or the COLR is immaterial. The thermal power time constant value is fuel design dependent and is determined in accordance with NRC approved methods.
The proposed amendment does not alter the requirement that the plant be operated in accordance with the value established for the simulated thermal power time. constant, nor alter the required remedial action that must be taken if this value is not met. The removal of this value from the PNPP Technical Specifications is coincident with its incorporation into the Core Operating Limits Report section of the Plant Data Book, 4
which is submitted to the Commission. The PNPP adelnistrative procedures control revisions of this value. Therefore, the proposed change is administrative in nature and does not impact the operation of the facility in a manner that involves a reduction in the margin of safety.
The margin of safety is not affected by the transfer of the simulated
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thermal power time constant from the Technical Specifications to the COLR. The margin of safety presently provided by the current Technical
)
Specifications remains unchanged. The proposed amendment still requires operation _vith the value obtained from NRC approved GE reload design methodologies (currently those described within GESTAR-II) and the actions to be taken if the value is not met remain unchanged.
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PY-CE1/liRR-1509 L Page 5 of 5 L
Environmental Consideration The proposed Technical Specification change request has been revieved against the criteria of 10 CFR 51.22 for environmental considerations.
As shovn above, the proposed change does not involve a significant hazards c>nsideration, nor increase the types and amounts of effluents that may be released offsite, nor significantly increase individual or cumulative occupational radiation e;posures.
Based on the foregoing, it has been concluded that the proposed Technical Specification change meets the criteria g
given in 10 CFR 51.22(c)(9) for a categorical exclusion from the requirement M
for an Environmental Impset Statement.
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i TABLE 3.3.1-2
- ~
i l
3 REAC7tR PROTECTION SYSTEM RESPONSE TIMES l
4 3
RESPON'?. TIME c5 FUNCTIONAL UNIT.
(Seconds)
-4
'1.
~
a.
Neutron Flux - High NA f
j.
b..
Inoperative NA 2.
Average Power Range Monitor *:
4 i
b.
Flow Biased Simulated Thermal Power - High
< 0.09**
~
a.
Neutron Flux - High, Setdown NA c.
Neutron Flux - High
< 0.09 4
d.
Inoperative RA i
t 3.
Reactor Vessel Steam Dome Pressure - High
( 0.35
[
w 4.
Reactor Vessel Water Level - Low, Level 3
< 1.05 1
D 5.
Reactor Vessel Water Level - High, level 8 31.05 w
6.
Main Steam Line. Isolation Valve - Closure
< 0.06 t
di 7.
Main Steam Line Radiation - High RA l
8.
Drywell Pressure - High NA
(
9.
Scram Discharge Volume Water I.evel - High NA j
- 11. Turbine Control' Valve Fast Closure, Valve Trip System
-< 0.06
[
- 10. Turbine Stop Valve - Closure t
I
< 0.07#
a -
011 Pressure - Low HA f
l 12.
Reactor Mode Switch Shutdown Position
- 13. Manual Scraa NA 7>7 i
n It Y ra r in l-
- Neutron detectors are exempt from response time testing.
Response time shall be measured from the de r output or-from the input of the first electronic component in the channel.
I H
i n
N t
- Not includi sulated thermal _ power time constant %. 0.0.....i. p edy,cA in th ColR h
I
- Measured from start of turbine control valve fast closure.
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=
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