ML20206A361
| ML20206A361 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/19/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206A348 | List: |
| References | |
| NUDOCS 9904280140 | |
| Download: ML20206A361 (10) | |
Text
p Cte p
t UNITED STATES g
j NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 20666-0001
- l
\\
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS 108 AND 95 TO j
FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 STP NUCLEAR OPERATING COMPANY. ET AL.
DOCKET NOS. 50-498 AND 50-499 SOUTH TEXAS PROJECT. UNITS 1 AND 2
1.0 INTRODUCTION
By application dated August 6,1997 (Reference 1), as supplemented by letters dated September 4 and 18,1997 (References 2 and 7), December 9,1997 (Reference 10), and February 4,1999 (Reference 9), STP Nuclear Operating Company, et al. (the licensee),
requested changes to the South Texas Project (STP), Units 1 and 2, Technical Specifications (TSs). The proposed changes would revise TS Table 2.2-1,
- Reactor Trip System Instrumentation Trip Setpoints," TS 3/4.2.5,"DNB [ Departure from Nucleate Boiling)
Parameters," and associated Bases, to allow for the use of the cold leg elbow tap differential pressure (Ap) measurement as an alternate method for measuring reactor coolant system (RCS) flow rate.
The September 4 and 18,1997, December 9,1997, and February 4,1999, supplements provided clarifying information that did not change the scope of the original application and did not change the initial proposed no significant hazards consideration determination.
2.0 BACKGROUND
Limiting Conditions for Operation (LCO) 3.2.5 requires the RCS flow to be maintained greater than or equal to the specified limit value during Mode 1 operation. This LCO RCS minimum measured flow is an input value in the safety analyses of the design-basis transients using the Revised Thermal Design Procedure (RTDP) (Reference 3) to demonstrate that the DNB ratio (DNBR) limit is not violated for these events. Surveillance Requirements (SRs) 4.2.5.1 through 4.2.5.3, respectively, require that the RCS flow be verified within its limit at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the RCS flow rate indicators be subjected to a channel calibration at least once per 18 months, and the RCS total flow rate be determined by precision heat balance measurements at least once per 18 r,.rths.
In the precision heat balance measurement, calorimetric measurements are made on the steam generator secondary side with the feedwater flow rates measured by venturi meters. The RCS flow rate is calculated from the precision calorimetric measurement in conjunction with the enthalpy rise across the reactor vessel as indicated by the hot and cold leg resistance temperature detectors (RTDs). Each hot leg has three RTDs installed around a cross-section 9904290140 990419 PDR ADOCK 05000498 P
. to determine the bulk hot leg temperature. However, due to the use of low leakage core loading patterns that result in changes in the core radial power distribution, the phenomenon of increased hot leg temperature streaming has been observed in many plants. As a result of increased temperature streaming, the bulk hot leg temperature as measured by the three RTDs in each hot leg is erroneously high, resulting in a calculated RCS flow lower than the actual value. Therefore, the licensee proposes to use the cold leg elbow taps in place of the precision heat balance for the RCS flow measurements. The use of elbow taps RCS flow measurement has been approved by the NRC for the McGuire and Catawba nuclear stations (References 4 and 5).
The proposed TS changes would revise SR 4.2.5.3 to allow for the use of elbow tap Ap measurements as an alternate method for performing the 18-month RCS flow surveillance. No change is made on the RCS flow measurement uncertainty of 2.8 percent. TS Bases 3/4.2.5 is revised to reflect the use of the cold leg elbow tap Ap measurements, and to indicate that the flow measurement uncertainty of 2.8 percent assigned in the TS bounds the precision heat balance and the elbow tap Ap measurement methods.
The licensee also proposed to change the " Reactor Coolant Flow-Low" trip function in Table 2.2-1, " Reactor Trip System Instrumentation Trip Setpoints," from "Five Column" to "Two Column" specification by specifying as "N/A" for the three variables associated with instrumentation uncertainties, TA, Z, and S. Also, as a result of using the cold leg elbow taps as an alternative RCS total flow measurement, the " Allowable Value" for this trip function is revised from 90.5 percent to 91.4 percent of loop design flow.
3.0 EVALUATlON As part of the request for TS changes (Reference 1) to allow for the use of cold leg elbow tap Ap measurements in place of the precision heat balance measurements of the RCS flow, the licensee also provided a methodology of using the cold leg elbow taps for the RCS flow measurement in Attachment 5,"RCS Flow Measurement Using Elbow Tap Methodology Licensing Submittal"(Reference 6). The staff evaluation of the proposed TS changes, as discussed in the ensuing sections, includes the appropriateness of the cold leg elbow tap flow measurement, the procedure for converting the elbow tap Ap measurement to the RCS flow, the best estimate hydraulics calculation for RCS flow measurement confirmation, the flow measurement uncertainty evaluation, and the TS changes.
3.1 Elbow Tao Flow Measurement Aoolication j
3.1.1 Elbow Tao Flow Measurement Cold leg elbow tap flow meters are used by Westinghouse plants, including STP, Units 1 and 2, for verificatioi, of the RCS flow every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The purpose of the 12-hour elbow tap surveillance reading is to verify that the full power steady state flow has not decreased below its limit during the cycle. The principle of operation of an elbow meter is based on the centrifugal force of a fluid flowing through an elbow creating a Ap between the inner and outer radii of the elbow. The relationship between the volumetric flow rate through an elbow, Q, and Ap between the pressure taps at the outer and inner radii of the elbow can be expressed as O = C Ap".
The elbow meter coefficient C is a function of elbow bend and cross-section radii, and is affected by the location of pressure taps, upstream and downstream piping, and other factors.
3-The cold leg elbow tap - flow element is not calibrated in advance in a laboratory, but the measurement is typically normalized against the established RCS flow rate from the precision heat balance calorimetric flow measurement at the start of each fuel cycle. The cold leg elbow taps are typically used as an indication of relative changes in the RCS flow, rather than a measurement of absolute value of the RCS flow. The cold leg elbow tap Ap also provides a measure of the reduced RCS flow rate for the low-flow reactor trip.
The configuration of the STP, Units 1 and 2, cold leg elbow taps is described in the licensee's response to a staff request for additional information (Question number 12, Reference 7). The elbow taps are located in a plane 22.5 degrees around the first 90-degree elbow turn in each of the cold legs. Each elbow has three low pressure taps spaced 15 degrees apart on the inside pipe radius and one high pressure tap on the outside pipe radius used as a common tap. The pressure taps are connected to three differential pressure transmitters to obtain Ap data. As the elbow taps in the cold legs are fixed, the elbow meter coefficients in each elbow tap configuration should remain unchanged. The licensee also cited an ASME publication (Reference 8) stating that tests have demonstrated that elbow tap flow measurements have a high degree of repeatability, and are not affected by changes in the elbow surface roughness.
To confirm elbow tap flow measurement repeatability, Section 3.4.1 of Reference 6 provides the comparisons of the data between the RCS flow measurements using the elbow taps and ultrasonic leading edge flow meters (LEFM) from the Hydraulic Test Program at Prairie Island Unit 2. The Prairie Island Unit 2 Hydraulic Test Program was in place since 1973 and the test data covered 11 years of plant operation, during which a significant change in system hydraulics was made. The data show that the elbow tap measurements agree to within 0.3 percent of the LEFM flow measurements. The licensee also evaluated various processes or phenomena for possible effects on the elbow tap flow measurements. The evaluation includes the effects of fouling, erosion, upstream velocity distribution, steam generator tube plugging and replacement. The licensee concluded that (1) the condition for fouling process is not present in the cold leg elbow since there is no change in cross section to produce a velocity increase and ionization, (2) erosion of the stainless steel elbow surface is unlikely and the flow velocities are not large relative to the conditions that cause erosion, (3) the upstream velocity distribution, including the distribution in the elbow tap flow meter, remains constant so the elbow tap flow meter Ap versus flow relationship does not change, (4) the plenum velocity head approaching the outlet nozzle is cmall compared to the piping velocity head, and therefore, steam generator (SG) tube plugging does not affect elbow tap flow measurement repeatabilny, and (5) the configuration of the replaced SG is the same and the same difference in plenum and nozzle velocity heads will exist, therefore, SG replacement will have no impact on the elbow tap flow coefficient.
Although the elbow taps have not been calibrated and the flow coefficients have not been determined, the RCS flow measurements by the elbow taps have been normalized against the precision heat balance flow measurements. The staff concludes that as the elbow meter coefficients remain constant, the relative changes of flow rate through the cold leg elbows can be correlated with the relative changes in the elbow tap Ap.
3.1.2 Elbow Tao Flow Measurement Procedure Section 3.4.2 of Reference 6 describes the procedure for determining the RCS flow from eit;ow tap measurements. This procedure relies on the total baseline calorimetric flow (BCF), which is
. based on the calorimetric flow measurements from the previous cycles. With a repeatability of elbow tap Ap to accurately verify RCS flow, the future cycle flow will be determined from the baseline calorimetric flow multiplied by the elbow tap flow ratio (R). The elbow tap flow ratio, R, is defined as R = (K/B)", where B is the " baseline elbow tap total flow coefficient" defined as B = AP,x v., and K is the " future cycle elbow tap total flow coefficient" defined as K = AP, x v,.
The baseline and future cycle " flow coefficients" B and K, are calculated based on the average Ap from all elbow taps in the cold legs. For each individual elbow tap, the elbow meter coefficient C in the elbow meter equation would be constant, and the ratio of the volumetric flow rates through the elbow tap between two fuel cycles can be expressed in terms of the square root of the Ap ratio, which would be the same for the three elbow taps in the same cold leg, barring measurement uncertainties. In a question to the licensee (Question number 2b, Reference 9), the staff asked whether it would be appropriate to define the elbow tap flow ratio, R, based on the average of the square root of the Ap ratios from all elbow taps. In response to this question, the licensee provided comparisons of calculations of the elbow tap flow ratio R using the average of the square root of the Ap ratios and the method described in Section 3.4.2 using the average Ap, respectively, based on data from the STP, Units 1 and 2, indicated transmitter Ap values.for each cycle. The results show insignificant difference between the two calculations, with the method of Section 3.4.2 being more conservative. The staff, therefore, finds this method acceptable.
The licensee also indicated, in response to a staff question (Question number 2c, Reference 9),
that there is no need to include an additional allowance to the future cycle flow ratio R to account for the Ap ratio distribution among the elbow taps using an one-sided tolerance limit to provide a 95 percent probability at 95 percent confidence level. The overall approach in the elbow tap measurement procedure includes (1) a calculation of the future cycle flow ratio R based on the determination of the ratio (between the future and baseline cycles) of the average indicated ap values, (2) a separate comparison with the predicted system flow to account for the hydraulic effects such as steam generator tube plugging, and (3) a separate uncertainty calculation to account for the flow measurement uncertainties. The best-estimate flow confirmation and the flow measurement uncertainty calculation will be discussed Jr)
Sections 3.1.3 and 3.1.4, respectively, of this Safety Evaluation. Based on the above, the staff concludes that the method of Section 3.4.2 of Reference 6 is acceptable.
Section 3.6.3 of Reference 6 describes the evaluation of calorimetric flows. For conservatism, the BCF will be calculated based on the average flow of all cycles listed in Table 3.6-3, i.e.,
Cycles 1 through 7 for STP Unit 1 and Cycles 1 through 6 for STP Unit 2. The staff found these average values to be lower and more conservative than the baseline Cycle 1 calorimetric flow values for STP, Units 1 and 2, and are, therefore, acceptable.
3.1.3 Best-Estimate Flow Confirmation Section 3.4.2 of Reference 6 describes a procedure where the future total RCS flow determined from the elbow tap flow measurement is confirmed by a best-estimate hydraulics analysis. The best-estimate RCS flow calculation is based on the flow resistances of various components in the reactor coolant loops and the reactor coolant pump performance characteristics. Therefore, changes in the RCS flow rate can be evaluated based on system hydraulic changes in the plant, e.g., plugging and sleeving of SG U-tubes, reactor coolant pump wear, and changes in the fuel design.
4 With the best-estimate hydraulic analysis confirmation procedure, a comparison will be made between the measured elbow tap flow ratio (R) and an estimated flow ratio (R'), whicHits the ratio of the estimated future cycle RCS flow to the estimated initial baseline cycle flow based on the flow analysis of known RCS hydraulics changes, such as SG tube plugging or fuel design changes. If the measured elbow tap flow ratio R is greater than (1.004 x R'), R will be limited to (1.004 x R'), where the multiplier 1.004 applied to R' is a measure to provide an allowance of 0.4 percent for elbow tap flow measurement repeatability.
The repeatability value, which is used as an acceptance criterion for predicted versus measured RCS flow comparisons, was determined by a combination of the instrument uncertainties considered appropriate for two different cycle meast.ements of RCS flow at 100 percent rated thermal power by all of the cold leg elbow channels. A derivation of the repeatability value of 0.4 percent flow for STP, Units 1 and 2, was provided in response to staff requests for additional information (Question numbers 2 and 3, Reference 10). The repeatability allowance is implicitly included in the elbow tap flow measurement uncertainty calculations because all of the instrument uncertainties included in the repeatability derivation are common with those in the elbow tap flow measurement uncertainty calculations. The licensee states that since the elbow tap flow measurement uncertainty includes this repeatability allowance, the measured flow ratio R can be 0.4 percent higher than the estimated flow ratio R' and still define a consentative flow.
As described in Section 3.5 of Reference 6, the best-estimate RCS flow analysis employs an RCS flow calculational procedure developed by Westinghouse in 1974 using best-estimate values of the RCS component flow resistances and pump performance with no margins applied, so the resulting flow calculations define a true best-ectimate of the actual flow. In the analysis, the flow resistances of the RCS loops, which are comprised of the reactor vessel, reactor coolant piping, and SGs, are used in conjunction with the reactor coolant pump head-flow performance to define individual loop and total RCS flows. The component hydraulic design data and hydraulic coefficients are determined from analyses of test data. The flow resistance of the reactor vessel, consisting of the reactor core, vessel internals and vessel nozzle, is determined from the Ap measurements of a full size fuel assembly hydraulic test, and hydraulic model test data for each type of reactor vessel. The reactor coolant piping flow resistance combines the resistances of the hot leg, crossover leg and cold leg piping, and is based on analyses of the effects of upstream and downstream components on elbow hydraulic loss coefficients, using the results of industry hydraulic tests. The flow resistance of the SG is defined in five parts: inlet nozzle, tube inlet, tubes, tube outlet, and outlet nozzle. This hydraulic analysis procedure has been confirmed by numerous component flow resistance tests and analyses, including the overall flow resistance confirmed by the Prairie Island Unit 2 Hydraulics Test Program. The licensee states that uncertainties in the best-estimate hydraulics analysis, based on both plant and component test data, define a flow uncertairty of 2 percent flow, indicating that actual flow is expected to be within '2 percent of the calculated best-estimate flow. This hydraulics analysis procedure has been applied to estimate RCS flows at all Westinghouse plants, including STP, Units 1 and 2.
The STP, Units 1 and 2, plant-specific best-estimate flow analyses are described in Section 3.6.1 of Reference 6, and the analytical model, including the RCS hydraulic network diagram, and component flow resistance values, are provided in response to a staff request for additional information (Question number 1, Reference 10). The analyses determined the baseline Cycle 1 initial startup flows of both units based on the baseline hydraulic designs.
1 l
-s-Hydraulic changes during subsequent cycles, including pump impeller smoothing, SG plugging, and fuel design changes, are modeled to determine best-estimate flow rates of various cycles.
The licensee stated, in response to a staff question (Cuestion number 13, Reference 10), that the best-estimate flow ratio R'is used mainly as a check on the measured elbow tap flow, and applied only if the elbow tap flow ratio R exceeds R' by more than the conservatively defined repeatability allowance or 0.4 percent flow, if such a difference occurs, it could be due either to larger instrument channel calibration uncertainties than considered in the 0.4 percent allowance or to an underprediction of best-estimate flow. In this situation, although the elbow tap flow measurement is most likely still a valid flow measurement, the conservative approach used in the procedure is to apply the lowest best-estimate flow based on the best-estimate flow ratio, increased by the repeatability allowance. The staff finds that the best-estimate hydraulic analysis will be used only as a confirmation of the elbow tap flow measurement and will not change the TS surveillance requirement for a flow measurement, and is, therefore, acceptable.
3.1.4 Flow Measurement Uncertainties The RCS flow measurement uncertainties include the RCS flow calorimetric measurement uncertainties for the baseline cycle, and the plant process computer indication uncertainties for the current cycle RCS flow measurement using the cold leg elbow taps. Tables A-1, A 2, and
' A-3, respectively, in Appendix A of Reference 6 provides the values of the baseline calorimetric flow measurement instrumentation uncertainties, flow calorimetric sensitivities, and calorimetric flow measurement uncertainties. Tables A-4 and A-5, respectively, provide the cold leg elbow tap flow measurement uncertainties for the qualified digital processing system (ODPS) and process computer, and low-flow reactor trip uncertaintiec. The uncertainties for a calorimetric measurement or the elbow tap measurement consist of all components in the measurement channel, including noninstrument-related measurement errors such as temperature stratification of a fluid in a pipe, and instrument-related errors such as errors due to metering devices, calibration accuracies of sensors, process rack, and readout devices, drift, temperature, and pressure effects, etc. These uncertainty components are combined to derive a channel statistical allowance using the statistical combination technique consistent with the methodology recommended in NUREG/CR 3659 (Reference 11), which has been used in connection with the RTDP. In the statistical combination technique, those groups of components, which are statistically independent, are statistically combined, and those errors, which are not l
Independent, are combined arithmetically to form independent groups, which can then be statistically combined. As the elbow tap measurements were normalized with the calorimetric measurements of the baseline cycles, the overall RCS flow measurement uncertainty is a
]
statistical combination of the baseline cycle calorimetric measurement and elbow tap i
measurement uncertainties.
Table A-4 shows an overall RCS flow uncertainty of 2.6 percent for the ODPS/ process computer for the four-loop STP plants. Table A-5 shows the total allowance of 4 percent flow span for the low-flow reactor trip function, which is higher than the calculated channel statistical allowance. The licensee in response to a staff question (Question number 15, Reference 10),
provided the basis for the conclusion that the elbow tap measurement is a 95/95 probability / confidence value. The licensee asserted that the uncertainty input values relative to the reference accuracy, pressure and temperature effects, calibration accu acy for sensors and process racks, sensor and rack drift magnitudes, are 2o (standard deviation) or better. In addition, a conservative baseline RCS calorimetric measurement uncertainty, and the utilization
. of a conservative algorithm for the determination of instrument channel uncertainties and the inclusion of conservative assumptions for systematic and process effects have lead to the conclusion that the overall uncertainty for RCS flow utilizing the cold leg elbow tap methodology and used for the RTDP analyses is a 95/95 probabiiity/ confidence value. Based on the above, the staff agrees that the overall uncertainty is a 95/95 probability / confidence value.
With the proposed TS changes to allow for the use of cold leg elbow tap measurement in place of the precision heat balance measurement of the RCS flow at the beginning of each fuel cycle, larger drift of the sensors and process racks may arise due to the absence of current normalization of the elbow taps against the precision heat balance flow measurement. In I
response to a staff question (Question number 3, Reference 9), the licensee provided information indicating that sufficient allowances have been included in the uncertainty calculation shown in Tables A-4 and A-5. Based on a review of the information, the staff concludes that the RCS flow uncertainty value of 2.8 percent, which is specified in the TS LCO 3.2.5 and used for the RTDP safety analysis, and the total allowance of 4 percent for the low flow reactor trip setpoint are acceptable.
3.2 Technical Soecification Chanoes TS SR 4.2.5.3 requires that the RCS total flow rate be determined by precision heat balance measurements at least once per 18 months. The proposed TS changes would revise SR 4.2.5.3 to allow for the use of elbow tap Ap measurement as an attemate method for performing the 18-month RCS flow surveillance. The flow measurement uncertainty of 2.8 percent in the existing TS LCO 3.2.5 remains unchanged. In Attachment 6 to Reference 10, the licensee also provided changes to the Bases of TS 3/4.2.5, by stating that "The RCS flow measurement uncertainty of 2.8% bounds the precision heat balance and the elbow tap Ap measurement methods. The elbow tap Ap measurement uncertainty presumes that elbow tap Ap measurements are obtained from either QDPS or the plant process computer. Based on instrument uncertainty assumptions, RCS flow measurements using either the precision heat balance or the elbow tap Ap measurement methods are to be performed at greater than or equal to 90% RTP at the beginning of a new fuel cycle." The revised Bases also identifies the documents, i.e., References 1 and 7, where the elbow tap Ap RCS flow measurement methodology is described. Thue changes allow for the use of elbow tap flow measurement to replace the precision heat balancs measurements normally performed at the beginning of each operating cycle. In Appendix A to Reference 6, the licensee calculated the RCS measurement uncertainty, which combines the uncertainties associated with total RCS flow calorimetric measurement, and elbow tap Ap transmitters and indications via ODPS or the plant process computer, to be 2.6 percent, lower than the assigned 2.8 percent in the TSs. As discussed in Section 2.1 of this report, the staff has evaluated the elbow tap flow measurement methodology and procedure, and found them acceptable. Therefore, the proposed TS changes are acceptable.
TS Table 2.2-1, " Reactor Trip System Instrumentation Trip Setpoint,"is revised for Functional Unit 12. " Reactor Coolant Flow-Low." in the proposed TS change, the low-flow " Trip Setpoint" will remain unchanged at 91.8 percent of the loop design flow, and the " Allowable Value" will be changed from the current value of 90.5 percent to 91.4 percent of loop design flow to reflect th' increased uncertainties associated with the correlation of the elbow tap Ap measurement to a previous baseline calorimetric. Section 3.7.2 of Reference 6 indNA.tes that the low-flow reactor trip limit of 87 percent flow is assumed in the current safety analyses. Therefore, margins of
. more than 4 percent of total allowance for the instrument uncertainties have been maintained for the low-flow trip setpoint and the allowable value above the safety analysis assumption. The staff, therefore, concludes that both the trip setpoint and the allowable vales are acceptable.
In addition, the columns headed Total Allowance (TA), Z, and Sensor Error (S) are marked N/A, v'ith only the values for the columns " Trip Setpoint" and " Allowance Value" specifie,i The licensee stated in Section 3.7.2 (Reference 6) that this two-column approach is consistent with the NRC position for the Standard Technical Specifications, Westinghouse Plants (NUREG-1431), which no longer includes the TA, Z, and S columns. With a two-column approach, channel operability is based on the Allowable Value/ Trip Setpoint relationship at; determined by the plant setpoint methodology (including process rack allowances) and confirmed through plant surveillances. As a result, the reactor coolant flow values for Z and G will no longer be applied to Equation 2.2-1, Z+R+SsTA and are therefore marked N/A. With the values of TA, Z, and S deleted, the Action statement b.1 in LCO 2.2, Limiting Systems Settings, becomes invalid for Functional Unit 12, " Reactor Coolant Flow-Low." For Functional Unit 12, the channel must be declared inoperable when its setpoint is found less conservative than the allowable value or found inconsistent with the assumptions of the setpoint methodology. The two-column approach is conservative and is, therefore, acceptable to the staff.
4.0
SUMMARY
The staff has reviewed the proposed changes to TS SR 4.2.5.3 and associated Bases to allow for the use of the cold leg elbow tap flow measurement as an attemate method for performing the 18-month RCS flow surveillance, and the changes in Table 2.2-1 to use the "two column" approach for the " Reactor Coolant Flow-Low" trip channel. Based on its review of the technical bases regarding the cold leg elbow tap RCS flow measurement procedure and measurement uncertainty calculation provided in licensee's submittals, the staff finds these proposed changes-to be acceptable.
5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Texas State official was notified of the proposed issuance of the amendments. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement wlth respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (62 FR 43556, August 14,1997). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
o
.g.
7.0 CONCLUS1QN The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Y. Hall C. Doutt Date: April 19, 1999 1
l l
i 1
. REFERENCES 1.
Letter, T. H. Cloninger (HL&P) to US Nuclesr Regulatory Commission, " South Texas Project Units 1 & 2, Docket Nos. STN 50-498, STN 50-499, Proposed Amendment to Technical Specification Table 2.2-1 and 3/4.2.5 for Reactor Coolant System Flow Monitoring - Revised," August 6,1997, ST-HL-AE-5707.
2.
Letter, W. T. Cottle (HL&P) to US Nuclear Regulatory Commission, " South Texas Project Units 1 & 2, Docket Nos. STN 50-498, STN 50-499, Revision to Proposed
{
Amendment to Technical Specification 4.2.5.3 for Reactor Coolant System Flow Monitoring," September 4,1997, ST-HL-AE-5743.
3.
WCAP-11397-P-A, " Revised Thermal Design Procedure," Westinghouse Electric Corporation, April 1989.
\\
I 4.
Letter from Victor Nerses (USNRC) to T. C. McMeekin (Duke Power Company),
" Issuance of Amendments - McGuire Nuclear Station, Units 1 and 2, Reactor Coolant System (RCS) Flow Rate measurement (TAC Nos. M88659 and M88660)," January 12, 1995.
5.
Letter from R. E. Martin (USNRC) to D. L Rehn (Duke Power Company), " Issuance of Amendments - Catawba Nuclear Station, Units 1 and 2, Reactor Coolant System (RCS) 1 Flowrate measurement (TAC Nos. M88480 and M88658)," February 17,1995.
- 6. to Reference 1,"RCS Flow Measurement Using Elbow Tap Methodology Licensing Submittal," July 1997 (Proprietary).
7.
Letter, D. A. Leazar (HL&P) to US Nuclear Regulatory Commission, " South Texas Project Units 1 & 2, Docket Nos. STN 50-498, STN E0-499, Amended Response to Request for Additional Information on the Proposed Elbow Tap Technical Specification Change (Table 2.2-1 and Section 3/4.2.5)," September 18,1997, ST-HL.AE-5752.
8.
" Fluid Meters, Their Theory and Application," 6th Edition, Howard S. Bean, ASME, New York,1971.
9.
Letter, D. A. Leazar (HL&P) to US Nuclear Regulatory Commission, " South Texas Project Units 1 & 2, Docket Nos. STN 50-498, STN 50-499, Response to the July 20, 1998, Request for Additional Information on the Proposed License Amendment Regarding Reactor Coolant System Monitoring," February 4,1999, NOC-AE-000425.
10.
Letter, D. A. Leazar (HL&P) to US Nuclear Regulatory Commission, " South Texas Project Units 1 & 2, Docket Nos. STN 50-498, STN 50-499, Response to the October 21,1997, Request for Additional Information on the Proposed License Arnendment Regarding Reactor Coolant System Monitoring," December 9,1997, NOC-AE-000025.
)
11.
NUREG/CR-3659, PNL-4973, "A Mathematical Model for Assessing the Uncertainties of instrumentation Measurements for Power and Flow of PWR Reactors," February 1985.
i w
I