ML20035H498
| ML20035H498 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 04/26/1993 |
| From: | Mcmeekin T DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20035H499 | List: |
| References | |
| NUDOCS 9305050159 | |
| Download: ML20035H498 (10) | |
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- l lice hesident T C Mevuus i
(TM)S754800 Duke Ibarr Company McGuire Nuclear Ceneratwn Department (TN)ST54809 ht s
f 12700lkgers ferry k%ad(MG01A)
Huntersed!c, NC:8978-8985 DUKEPOWER April 26, 1993 U. S. Nuclear Regulatory Commission Desk Document Control Attention:
20555 C.
Washington, D.
McGuire Nuclear Station, Units 1 and 2 50-369 and 50-370
Subject:
Catawba Nuclear Station, Units 1 and 2 Docket Nos.
Docket Nos. 50-413 and 50-414 Amendment Supplement to Technical SpecificationRelocation (COLR)
Core Operating Limits Report Dear Sir; 1993, Catawba and McGuire to amend their By a letter dated January 13, Nuclear Stations submitted an application The proposed respective Technical Specifications (TS). amendmen ific limits to By a letter dated March 12, ification regarding requested add'itional information and clar the COLR.
cur application.
h ent 1) our Accordingly, please find attached (attac m March 12, 1993 response to the questions provided by yourIn addition, atta rk-ups of TS 6.9.1.9 for McGuire and CatawbaThese changes are administ letter.
No Significant h
and do not affect the conclusions of t eHazards Cons respectively.
d d previously.
(704) 875-4002 if there any Please contact Paul Guill atquestions regarding this TS a est.
Very truly yours, fGh
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T. C. McMeekin 9305050159 930426ADOCK 05000369
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U. S. Nue?. ear Regulatory Commission i
April 2E, 1993 l
page 2 I
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Mr.
S. D.
Ebneter Regional Administrator, Region II
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U.
S. Nuclear Regulatory Commission
-l 101 Marietta Street, NW,LSuite 2900 1
Atlanta, Georgia 30323
{
Mr. P. K. Van Doorn Senior NRC Resident Inspector, McGuire-McGuire Nuclear Station 1
1 Mr. V. Nerses, Project Manager i
Office of Nuclear Reactor Regulation U. S.-Nuclear Regulatory Commission One White Flint North, Mail Stop 9H3 Washington, D.C.
20555-Mr. W.
T.
Orders Canior IIRC Resident Inspector, Catawba Catawba Nuclear Station j
o 1
Mr. R. E. Martin, Project Manager Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 1
One White Flint. North, Mail Stop 9H3 t
Washington, D.C.
20555 Mr. Dayne Brown, Chief 1
Division of Radiation Protection P. O. Box 27687 Raliegh, North Carolina-27611-7687 Mr. Heyward Shealy, Chief Bureau of Radiological Health Soitth Carolina Department of Health &
Environmental Control 2600 Bull Street Columbia, South Carolina 29201 I
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U.
S. Nuclear Regulatory Commission I
April 26, 1993 page 3 i
bec: with attachment R. O. Sharpe P.
F. Guill l
R. C. Futrell (CN0lRC)
L.
A.
Rudy (CN0lRC)
G.
B. Swindlehurst (EC08H)
M. E. Carroll (EC08H) l G. P. Horne (CNO3SE)
M.
T. Cash (MG01SE)
G. A. Copp (EC050)
R. H. Clark (EC08G)
L. T. Burba (EC050)[ file: MC801.01; CN801.01]
File: 801.01 l
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ATTACHMENT 1 DUKE POWER COMPANY MCWIRE NUCLEAR STATION l
CATAWBA NUCLEAR STATION SPONSE TO NRC REQUEST ICR ADDITIONAL INFORMATION I
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Request for AdditionalInformation Application to Transfer TS Values to COLR
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for Catawba and McGuire Stations j
i 1.
Q: Identify the repon pmviding the methodolgy for calculating the value of each of the parameters proposed to be Innsfened to the COLR. If the repon discusses the parameter implicitly, provide a reference for the definition of each parameter and a specific discussion of how the parameter values are determined. These parameters should include Tg, T, T T T.< T. K K K K K -
2 3 4 6
1 2 3 4 S
K f (AI). f (AI), the breakpoints and slopes for f(AI), B AST volume and concentration, RWST 6 1 2
volume and concentration, reactor water makeup pump flov' rate, and accurrlator boron concentration.
A: The methodology described below is how Duke Power Company cunently arrives at values for the OTAT and OPAT parameters. 'Ihis is one of many equally valid methods for determining these parameters. Once a new preliminary set of ovenemperature and overpower setpoint equation parameters is selected, they must be evaluated by reanalyzing the appropriate transient analyses with the new setpoint parameters. The transient analyses utilized to validate these new setpoints are perfonned using the NRC approved methodology documented in Duke Power Company topical repons DPC-NE-3002-A, "FSAR Chapter 15 System Transient Analysis M :thodology, DPC-NE-3001-A, "McGuire/ Catawba Nuclear Station Multidimensional Reactot Transients and Safety Analysis Physics Parameters Methodology" and DPC-NE-3000. "'Ihermal-Hydraulic Transient Analysis Methodology," approved by the NRC for McGuire/ Catawba use in November 1991.
Once the analysis is perfonned and the new setpoint constants demonstrate they are capable of protecting the plant during the appropriate transients, the new setpoint parameters may be used. In other words, there are many possible methods for selecting these setpoint parameters and regardless of the method used they are not considered valid parameters until they are proven capabic of protecting the plant under transient conditions with the NRC approved methodology described in the topicals above.
The OPAT parameter K is not being relocated to the COLR since it cunently is not calculated as 5
pan of the reload design methodology described below.
The purper,e of the OTAT trip function is to protect the reactor core against DNB and hot leg boiling for any combination of power, pressure and temperature during normal operation and transient conditions. The parameter values for K, K, K, K, K, and f (AI) breakpoints and i
2 3
4 6
3 slopes are calculated using as inputs the DNB core limit lines at different pressures, axial offset versus power limits, and various nominal opemting condition parameters. For steady state conditions and a reference power shape these inputs are used to calculate the ovenemperature and overpower AT selpoints based on the following constraints:
Thennal ovenempemture limits, which provide protection against DNB and hot leg boiling.
Pressurizer low pressure a"J high pressure safety limits, which limit the range of pressures over which the ovenemperature AT and overpower AT trips must function.
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De locus of conditions where the steam generator safety valves open, which places a limit on the primary side temperature based on the steam generator design pressure and the pdmary to secondary heat transfer capacity.
Dennal overpower limit, which pmtects against centerline fuel melt.
j Multiple K and K, pairs and contsponding K, K, and K s are calculated such that they meet the 3
2 3
6 above constraints. Using engineering judgment and plant operating experience a set of Ks is then chosen fmm these allowable sets. He chosen set is then evaluated in the tmnsient analysis using the methodology described in topical repons DPC-NE-3002-A, "FSAR Chapter 15 System Transient Analysis Methodology and DPC-NE-3000,"nermal-Hydraulic Transient Analysis Methodology," to detemiine whether the K parameter values are capable of protecting the plant during the appmpriate transients.
De thermal ovenemperature limits described above are calculated for zero axial imbalance.
j Ecrefore, once the setpoint constants are calculated, the f (AI) trip reset functior. for the OTAT i
i equation is determined using two axial offset versus power envelopes (typically 100% and 118%
power) supplied by nuclear design analyses. His function is determined as described in the technical justification using the methodel.7gy described in Chapter 4 of the NRC approved report DPC-NE-2011-P-A. A value ofimbalance, AI, and a point on the DNB line for a given pressure j
which is not bounded by the exit boiling line, steam generator safety valve line, or OPAT setpoint equation is selected. His point is compared with the OTAT setpoint and the amount the setpoint must be lowered,if at all, to beund this point is calculated. This process is repeated for this Al for the other non-bounded DNB points at this and other pressures. He largest reduction in the OTAT setpoint equation required to bound the imbalance corrected DNB points becomes the f (AI) g penalty for this panicular value of AI. His process is repeated for a range of Als that will envelope all the expected skewed axial power distributions. De f (AI) breakpoints and slopes are j
3 then selected in a manner such that they bound the calculated f (AI) penalties which were g
determined fmm the two axial offset envelopes.
Le purpose of the OPAT trip function is to pmvide protection against fuel center-line melt (CFM) during normal operation and Condition 11 transients. De AT trip setpoint for this trip function is typically set at 118%FP and is determined as described above. He trip reset ponion of this trip function, f (AI), is designed to lower the trip setpoint when measured imtniances exceed predetennined values. Since highly skewed power distributions lead to high kw/ft values, a f (AI)
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2 trip function can be developed to prevent CFM limits fmm being exceeded at large imbalances, or to increase the available margin to the CFM limit for highly skewed power distributions.
Current core designs do not challenge the CFM limits and therefore a f (AI) penalty is not required.
2 Ilowever, from an operational and design standpoint, it is desirable to eliminate from consideration pewer distributions with high imbalances. Derefore, a f (AI) trip reset function was established to 2
trip the reactor at high imbalances. De breakpoints and slopes of this function were arbitrarily chosen to limit the power distributions that need to be considered during the design of the reactor core and to increase the margin to the CFM limit and therefore reducing the probability of the CFM Technical Specification surveillance limits being violated.
l In the event that it would te be necessary to establish a f (AI) trip reset function because CFM 2
limits were being exceeded, one possible method of determining this tdp reset function would be to
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develop a kw/ft versus imbalance envelope based on the analysis of Condition 11 transients such l
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' that this envelope would conservatively bound expected transient peaks. His envelope would next be used to detemiine the f (AI) penalty as a function ofimbalance by comparing the CFM kw/ft 2
limit against the maximum expected peak for a given imbalance. he f (AI) trip reset function
_j 2
would then be developed such that the breakpoints and slopes bound the f (AI) penalties developed 2
from the kw/ft versus imbalance envelope which is generated in a manner similar to the f (AI) reset j
function described above.
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Ec dynamic tenus (T, T. T. T T. T )in the OTAT and OPAT setpoint equations compensate.
i 2 3 4 5 6 for inherent instrument delays and piping lags between the reactor core and the temperature j
sensors. lead-lag and rate-lag compensations are required for the following reasons.
To offset measured RTD instrumentation time delays.
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To ensure the protection system response time is within the limits required by the accident e
analyses.
l In addition, the dynamic terms are used as noise filters and to decrease the likelihood of an unnecessary reactor trip following a large load rejection.
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Models have been created to examine the effects of different sets of T values used in the lead-lag, lag, and rate lag functions of the overtemperature and overpower equations. Rese models are the same as those given in EPRI NP-1850-CCM-A,"RETRAN A Pmgram for Transient Thennal-Hydraulic Analysis of Csnplex Fluid Flow Systems." Using these models the T values q
are selected in a manner such th it the optimum response of the OTAT and OPAT setpoints to
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changes in plant vanables is obt tir.ed while satisfying the transient analyses acceptance critena.
t He acceptability of the chosen T values is detennined utilizing these same mathematical models, which are also contained in the transient analysis models described in DPC-NE-3000 "Rennal.
I Hydraulic Transient Analysis Methodology."
)
1 The B AST and RWST borated water volume limits are calculated using the bomn concentrations required to maintain shutdown margin for the fuel cycle, as detemiined by the methodology documented in DPC-NE-'2010-A, RCS volumes, and the minimum BAST and RWST bomn concentrations. De minimum BAST and RWSTconcentrations are assumed valuer used as input to these volume calculations. He methodology used consists of the solution of a simple differential equation c' scribing the boron mass balance during a feed and bleed operation. De calculations detennine the amount of borated water volume required to maintain shutdown margin when going fmm hot full power (HFP) conditons to hot zero power (HZP) conditions and then HZP to cold shutdown conditions. De resulting calculated B AST and RWST borated water volumes are the volumes required to maintain the shutdown margins required by TS 3.1.1.1 and 3.1.1.2. As mentioned in the technicaljustification for this change, a similar change was appmved for Oconec Units I,2, and 3. January 5,1993 under Amendments 197,197, and 194. De volume calculations for McGuire/ Catawba are identical to those for Oconce, except that pan of the coolant shrinkage makeup volume required in the Oconee calculation is neglected due to a pmgrammed j
themial contraction in the pressurizer level for McGuire/ Catawba when going from HFP to HZP.
As explained in the teclutical justification, the accumulators and RWST minimum bomn
" concentration limits ervute the reactor will remain subcritical during a Loss of Coolant Accident (LOCA). Le accumulators and RWST minimum bomn concentrations are input assumptions to l
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' the post LOCA subcriticality analysis which is described in Section 15.6.5.2 of the McGuire and i
i Catawba FSAR.
He reactor makeup water pump flowrates are input assumptions to the boron dilution arnlysis described in the NRC appmved methodology,".. rupplementary Information to Topical Report B AW-10173; Boron Dilution Analysis" dated May 15,1991 and the Catawba FSAR Section 15.4.6 given in the technical justification. Additionally, the boron dilution analysis described above has been approved in topical DPC-NE-3002-A, "FSAR Chapter 15 System Transient Analysis Methodology." The technicaljustification also explains how these flowrates are detennined.
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- 2. Q: he ovenempertture AT trip setpoint is understood to be defined by the equation in Note 1 of i
Table 2.2-1. The identification of K, a constant within that overall equation, as the 3
"ovenemperature AT reactor trip setpoint" would therefore seem to be inappropriate. Please expand on the definition and source of the K constant. Please comment similarly on the K4 1
constant.
l A: He use of the "ovenemperature AT reactor trip setpoint" and " overpower AT reactor trip setpoint" nomenclature for the Kgand K constants is not inconsistent with the actual definitions of K and l
4 1
K the reactor trip setpoint value at nominal, steady state conditions expressed as a fraction of 4
full power AT. De nomenclature was chosen to be a short description of the parameters function /use to pmvide consistency between the Technical Specifications and the COLRs. Rese descriptions are not intended to be the precise definition of the individual parameters. This l
consistent nomenclature will aid an individual refening to the Technical Specification for these l
values since the same nomenclature is used in both documents.
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- 3. Q: As an example of the concern expressed in 1. above, it is stated in the applications Technical l
Specification (pages C-66 and C-67) that the calculational methodology for about 20 parameters is described in Chapter 4 of the report DPC-NE-2011-P-A; however, this report does not explictly discuss the majority of these parameters.
Also, it would appear that a change to the reference to DPC-NE-2011 in TS 6.9.1.9 would be appropriate to reflect its applicability to TS 2.2 methodology. No changes to 6.9.1.9 were proposed in the January 13,1993, application.
A: See response to question 1 above. A change to the reference to DPC-NE-2011 in TS 6.9.1.9 would be appmpriate and will be marked up to include its applicability to TS 2.2.
4.
Q: He Technical Justification discusses several checks wherein thermal margin calculations are perfonned pursuant to DPC-NE-2011 and physics parameter calculations pursuant to DPC-NE-3001 are performed to ensure that previously existing analysis results remain valid. The discussion states thai. if the TS amendment tranferring these values to the COLR is approved and these checks fail but acceptable reanalysis can be perfomied,"..no Technical Specification change world be necessary." Ris is confusing since. if the parameter has been relocated to the COLR, a change to the TS is no longer necessary to change its value. Please clarify.
A: %e statement was meant to indicate that no Technical Specification change will be required after the values are relocated to the COLR. For example, currently the "K", "T" and f(At) values are located in the Technical Specifications. If the failure of one of the safety analysis physics Page 4 of 6
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l parameter checks requires a reanalysis with different "K", "T", and/or f(Al) values to obtain acceptable results, these new values would currently require a Technical Specification change submittal. Ilowever, if this Technical Specification change is approved and the values for "K", 'T" and f(AI) are relocated to the COLR, the values would be changed in the COLR and would not l
require a Technical Specification change submittal.
- 5. Q: Clarify whether the trpon DPC-NE-20M is intended as a methodology repon for the parameters to be relocated to the COLR. If so,it should also be included in a revised TS 6.9.1.9.
A: 1he topical repon DPC-NE-20M was not intended to be a methodology repon for the parameters being relocated to the COLR It was included to indicate where a discussion of the relationship between the AT reactor trip setpoints and the core safety limits could be found.
- 6. Q: Please clarify the applicability of the limits on minimum volume and boma concentration for the BAST and the RWST to providing an adequate shutdown margin.
A: The minimum borated water volumes and boron concentrations forthe BAST and the RWST are based on the calculations described in the response to question number 1. The volume limits consist of the calculated volumes required to maintain the shutdown margins as required by TS 3.1.1.1 and 3.1.1.2, plus unusable volumes,instmment uncenainties, and additional margin as shown in the cunent Catawba and p;oposed McGuire TS bases. Therefore, the minimum borated water volumes and boma concentrations will provide adequate shutdown margin at all times during a given fuel cycle.
7.
Q: One of the references cited in suppon of the reactor makeup pump flowrate limits has not yet been j
appmved by the NRC staff review processes. In the event cfits appmval, as pan of the subject amendment application, it should also be included in TS 6.9.1.9.
l A: An SER for topical trpon B AW-10173 P, Revision 2, dated Febmary 20.1991 was received by Duke Power Company on Febmary 25,1991. Section 3 of this SER gave 5 conditions for referencing this topical for future reload cycles with Mark-BW fuel. C(mdition 4 required that a bomn dilution analysis be provided in the first reload analysis repon. Responses to this and the four other conditions of the SER were provided in letters dated March 14,1991 and April 25, 1991. A letter dated May 15,1991, "... Supplementary Infonnation Relative to Topical R.epon BAW-10173; Boron Dilution Analysis," was provided to correct reactor coolant system volume assumptions for the bomn dilution analysis pmvided in the previous responses. The first reload to use Mark-BW fuel was Catawba 1 Cycle 6 and contained referen,:es to topical report BAW-10173 P. An SER for the Catawba 1 Cycle 6 reload, dated May 31,1991 was received by Duke Power Company on hme 5,1991. Therefore, the supplementary infonnation relative to the above topical report was approved by the NRC and Catawba 1 Cycle 6 was allowed to start up.
Subsequent to the above pmcess the boron dilution analysis was appmved in topical DPC-NE-3002-A,"FSAR Chapter 15 System Transient Analysis Methodology."
- 8. Q: The markup to the FSAR, enclosed with the application, pmposes to replace the term f(AQ) with ei31er f (A$) or f (AQ).110 wever, the definition of the term remains unchanged. Please comment 1
2 on the significance of the change in tenninology.
/,: The terms were changed in the FSAR to identify that there now exists two distinct functions of f(AQ), one applied to the OTAT setpoint and the second applied to the OPAT setpoint. The basic Page 5 of 6
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definition of the function has not changed, the addition of the subscripts serve to distinguish the i
similar functions which contain different parameters (slopes and breakpoints).
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