RS-05-164, Response to NRC Request for Additional Information with Respect to Request for License Amendment Related to Application of Alternative Radiological Source Term
| ML053410195 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 11/28/2005 |
| From: | Bauer J Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2010-0209, RS-05-164 | |
| Download: ML053410195 (57) | |
Text
Exelon.
Exelon Generation 4300 Winfield Road Warrenville, IL 60555 www.exeloncorp.com Nuclear 10 CFR 50.90 RS-05-164 November 28, 2005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units I and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455
Subject:
Response to NRC Request for Additional Information With Respect to Request for License Amendment Related to Application of Alternative Radiological Source Term
References:
(1) Letter from K. R. Jury (Exelon Generation Company, LLC) to NRC, "Request for License Amendment Related to Application of Alternative Radiological Source Term," dated February 15, 2005 (2)
Letter from J. B. Hopkins (NRC) to C. M. Crane (Exelon Generation Company, LLC), "Braidwood Units 1 and 2, and Byron Units 1 and 2-Request for Additional Information," dated July 29, 2005 In Reference 1, Exelon Generation Company, LLC (EGC) requested an amendment to Appendix A Technical Specifications (TS), of Facility Operating License Nos. NPF-72, NPF-77, NPF-37, and NPF-66 for Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, respectively. The proposed amendment was requested to support application of an alternative source term methodology in accordance with 10 CFR 50.67, "Accident Source Term." In Reference 2, the NRC informed EGC that additional information was required to support the review of the amendment request. The NRC requested that the response be provided within 120 days from the date of Reference 2. Attachment 1 to this letter provides the EGC responses to the NRC request for information.
This proposed revision does not affect the supporting analysis for the original license amendment request as described in Reference 1. No other information submitted with Reference I is affected by this additional information. The No Significant Hazards Consideration and the Environmental Consideration provided in Attachment 1 of Reference 1 are not affected by this additional information.
November 28, 2005 U.S. Nuclear Regulatory Commission Page 2 EGC is providing the State of Illinois with a copy of this letter and its attachments to the designated State Official.
If you have any questions about this letter, please contact J. A. Bauer at (630) 657-2801.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 28' day of November 2005.
Respectfully,
/Josep A.Buer Manager - Licensing Attachments: : Response to NRC Request for Additional Information : Calculation ATD-0356, "Post LOCA Containment Sump pH," Revision 5 : Simplified Diagrams (For Information Only)
Attachment I BRAIDWOOD STATION UNITS 1 AND 2 Docket Nos. STN 50-456 and STN 50-457 License Nos. NPF-72 and NPF-77 and BYRON STATION UNITS 1 AND 2 Docket Nos. STN 50-454 and STN 50-455 License Nos. NPF-37 and NPF-66 Response to NRC Request for Additional Information
Attachment I Response to NRC Request for Additional Information A.
Iodine Leakage After a loss-of-coolant accident (LOCA), a significant portion of the inventory of core iodine is released to the containment and some of this iodine leaks to the outside. In the submittal, two release paths are identified: containment leakage and emergency core cooling systems (ECCS) leakage.
Containment Leakage Path (1)
The iodine from the damaged core is released to the containment as 95% cesium iodide (CsI) and 5% as iodine (12) and hydriodic acid (HI). CsI and HI are soluble in sump water but 12 is scarcely soluble. If the sump water is acidic some of the ionic iodine from Csl is converted to 12 and because of its low solubility it is released into containment atmosphere and some of it will leak to the outside. To prevent this from happening the pH of the sump water has to be maintained at the pH value of 2 7.
Describe your program for controlling sump pH to maintain it basic. The description should include: (a) chemicals used for sump pH control; (b) the procedure and corresponding calculations for determining the amount of chemicals needed for neutralizing the effect of acidic chemicals in the containment such as boric, hydrochloric or nitric acids.
Response
The Byron/Braidwood Updated Final Safety Analysis Report (UFSAR),
Section 6.1.3.3, "Loss-of-Coolant Accident," describes the process for controlling sump pH. In the event of a large-break Loss-of-Coolant Accident (LOCA), both safety injection (SI) and containment spray '(CS) will be initiated. The pH of the final sump solution is independent of the number of trains of ECCS and CS pumps in operation. The final sump pH is determined by the quantity of water and concentration of boron in the Refueling Water Storage Tank (RWST), the Reactor Coolant System (RCS), and the SI accumulators and the quantity of water and concentration of sodium hydroxide (NaOH) educted from the containment spray additive tank (CSAT). The pH of the spray solution is determined by the CS pump suction source and the quantity of NaOH educted from the CSAT. The systems function in the same manner regardless of whether one or two ECCSICS trains are in operation. The residual heat removal (RHR) pumps will be transferred to the recirculation mode when the RWST reaches the Lo-2 level setpoint. The charging and Si pumps are then manually aligned for the recirculation mode. The CS pumps will continue to operate with suction from the RWST until the RWST reaches the Lo-3 level setpoint. The operator will then manually align the CS pump suction from the RWST to the recirculation sump. NaOH addition will continue until the CSAT reaches the Lo-2 level regardless of CS pump suction source (i.e., RWST or recirculation sump) and the NaOH addition has continued for a minimum of two hours.
The minimum final sump pH following a LOCA for Byron and Braidwood is established by Calculation ATD-0356, "Post LOCA Containment Sump pH,"
Revision 5, provided as Attachment 2 to this submittal. Calculation ATD-0356 determines the minimum post-LOCA sump pH based on the NaOH quantity, the borated water quantity, and boron concentration in the sump. The calculation differs Page 1 of 9
Attachment I Response to NRC Request for Additional Information for Unit 1 and Unit 2 because Unit 1 is equipped with replacement steam generators and Unit 2 has its original steam generators.
The sump pH is calculated by determining the equilibrium quantities of the boron ionic species and sodium ionic species in the sump. These are calculated based on the amount of boric acid and sodium hydroxide added to the sump, the sump pH, the total water volume in the sump, and the temperature of the sump. Also, the equilibrium quantities of hydronium ion (H30) and hydroxyl ion (OH-) are determined based on the temperature-dependent ionic activity product constant of water and the sump pH. The equilibrium pH is determined when the sum of ionic charges of all species pertinent to the boron and water in the solution and the ionic charge of sodium reduces to zero, defined as when the difference is <1 E-7.
Calculation ATD-0356 establishes three equations to describe the concentrations of all ionic species. The equilibrium pH is obtained analytically by solving the three equations simultaneously, using the Math Solver in MathCAD 5.0. The pH is verified if the sum of all ionic species reduces to zero (i.e., when the difference is <1 E-7).
Calculation ATD-0356 determined that a minimum pH of 8.0 would be established by the addition of a minimum of 2500 gallons of 30 wt% NaOH from the CSAT.
Following the initial chemical addition and stabilization of pH, the sump pH would only be impacted by the nitric acid (HNO3) produced by irradiation of water and air and the hydrochloric acid (HCI) produced by irradiation of electrical cable insulation.
The plant-specific application of the guidelines for formation of HNO3 and HCI provided in NUREG/CR-5950, "Iodine Evolution and pH Control," (Reference 1) is discussed as follows:
The Executive Summary provided in Reference 1 indicates that during a LOCA, the most important acids in the containment will be HNO3 produced by irradiation of water and air and HCI produced by irradiation or heating of electrical cable insulation.
The most important bases in the containment will be cesium hydroxide, cesium borate, and pH additives, such as NaOH. Some aspects of the timing of pH change during an accident can be obtained from the fission product release into containment. Initially, the sump water pH becomes basic because of cesium entering the sump water pool as hydroxide, borate, or carbonate. Once the fission products enter the sump water pool, the radiation dose rate is established, and HNO3 begins to form and neutralize the basic solutes. A high concentration of fission products that contain basic solutes brings about a high initial pH but also a high radiation dose rate, which results in a relatively high production of HNO3. For a typical pressurized water reactor (PWR) plant, the maximum duration that a basic pH may be maintained in the absence of pH control additives is approximately 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />. This time can be further reduced if boric acid or HCI becomes prominent in the water pool.
Reference 1, Appendix B, provides the total HCI generation rate (g-mol/s) from gamma and beta radiolysis of Hypalon (i.e., electrical cable insulation) as follows:
R = RrH + RH Page 2 of 9 Response to NRC Request for Additional Information Where:
RH=1.32x1O1 5 x N
V and RH= 8.70x1016x EoxN V
Where:
Ey = total gamma energy release rate (Mev/s)
Ed = total beta energy release rate (Mev/s)
N = total mass of Hypalon cable insulation (Ibs)
V = containment free air volume (cc)
For the given mass of Hypalon and containment free air volume, the HCI generation rate is directly proportional to the post-LOCA gamma and beta radiation in the containment.
A review of post-LOCA pH analyses prepared for previously approved alternative source term (AST) license amendments for comparable PWR Stations, including the Seabrook Station, indicates that the reduction in the initial pH of the sump water due to acidic sources such as HNO3, HI, and HCI is considerably small because of pH control additives and the increased pH resulting from cesium entering the sump water providing a stronger base to neutralize the effect on the acidic sources produced during a LOCA. The Seabrook Station is comparable to the Braidwood and Byron Stations with respect to key parameters that directly impact the sump pH such as:
thermal power level (i.e., core activity, the primary source of radiation);
containment size (i.e., gamma air borne dose causing radiolysis of air for HNO3 and cable insulation (HCI)); and containment sump (i.e., gamma sump water dose causing radiolysis of water (HNO3)).
Seabrook performed the 30-day containment sump water pH analysis with and without acids produced from irradiation of water, air, and electric cable insulation.
The analysis concluded that the additional acids formed during a LOCA would reduce the initial pH by less than 0.1 pH units (i.e., Reference 2). The NRC staff independently determined that the production of HCI and HNO3 resulted in a change in pH of less than 0.1 after 30-days (i.e., Reference 3).
Because a sump water pH analysis has not been performed to establish the effect of the post-LOCA acidic sources on the initial sump pH of 8 at the Braidwood and Byron Stations, the following assessment is provided to establish the potential reduction of the sump water pH due to the effect of post-LOCA acids.
A comparison of the critical parameters used in determining the initial sump pH is provided in Table 1, "Comparison of Critical Parameters Determining Initial Sump Page 3 of 9
Attachment I Response to NRC Request for Additional Information Water pH," for Byron, Braidwood and Seabrook. N6te that the initial Braidwood and Byron sump water pH is 8, which is less than the Seabrook pH value of 8.6.
Table 1 Comparison of Critical Parameters Determining Initial Sump Water pH Description of Braidwood Braidwood Parameter Determining Seabrook Byron Byron Initial Sump Water pH Unit 1 Unit I Unit 2 Refueling Water Storage Tank olume Released (Maximum 428,000 457,904 457,904 Value) (gal)
Refueling Water Storage Tank Boron Concentration (Maximum 2900 2500 2500 Value) (ppm) pray Additive Tank Volume 52 Release (Minimum Value) (gal) 850 500 2500 Spray Additive Tank Sodium Hydroxide Concentration 19 30 30 (Minimum Value) (wt%)_
Reactor Coolant System Mass 492,200 620,800 562,457 Reactor Coolant System Boron Concentration (Maximum value) 4000 2300 2300 (ppm)
Accumulator Volume (Maximum alue) (gal in each of four 6596 7217 7217 accumulators)
Accumulator Boron Concentration (Maximum Value) 2900 2400 2400 (ppm)
Calculated Sump Water Initial 8.6 8.0 8.0
- Values taken from Reference 2 Since the post-LOCA gamma and beta radiations are very important for the irradiation of the sump water, containment air, and cable insulation that cause the acidic source, the parameters that determine the post-LOCA radiation are investigated and compared in Table 2, "Comparison of Design Parameters Determining Post-LOCA Radiation." The core thermal power levels of Seabrook, Braidwood and Byron are the same (i.e., 3,659 MWt). Therefore, the post-LOCA isotopic core inventories in Curie/MWt for these stations will be similar. The post-LOCA core activity release fractions are provided in the Regulatory Guide (RG) 1.183 (i.e., Reference 5), Table 2, "PWR Core Inventory Fraction Released Into Containment," which should be the same for these stations. The parameters that determine the post-LOCA gamma and beta doses that irradiate the containment air, sump water, and cable insulation, include:
the size of the containment and sump; Page 4 of 9
Attachment I Response to NRC Request for Additional Information the activity removal mechanisms (mainly of the containment spray and containmenVECCS leakage);
the spray removal coefficients for elemental iodine and particulates; and containment and ECCS leak rates.
The similarity in the major key parameters for these stations, for which small variations are considered insignificant, will produce approximately the same post-LOCA gamma and beta integrated dose in the containment air and sump water. This produces similar quantities of acidic sources, which tend to neutralize the initial sump water pH in the same manner as analyzed for the Seabrook Station. The relatively larger containment dilutes the source and the higher containment leakage rate removes the airborne activity faster at the Braidwood and Byron Stations. This results in a slight reduction in the gamma and beta irradiation of the containment air and cable insulation, and thereby produces a correspondingly slightly smaller amount of nitrogen ions and HCI. The smaller sump volume concentrates the source at the Braidwood and Byron Stations slightly increasing the gamma and beta irradiation of the sump water and thereby produces a correspondingly slightly larger amount of hydrogen ions which combines with the nitrogen ions generated by irradiation of the containment air to produce the HNO3.
Table 2 Comparison of Design Parameters Determining Post-LOCA Radiation Description of Braidwood Braidwood Parameters Determining Seabrook Byron Byron Post-LOCA Radiation Unit I Unit i Unit 2 Core Thermal Power Level (MWJ) 3659 3658 3658 Total Containment Volume (ft3) 2.704E+06 2.850E+06 2.850E+06 Sprayed Containment Volume (ft3) 2.309E+06 2.350E+06 2.350E+06 Un-sprayed Containment Volume 3.950E+05 5.OOOE+05 5.000E.05 Air Transfer Rate Between 2,0 3,0 3,0 Containment Regions (cfm)26,000 130,000 130,000 Containment Spray Removal Rates Before DF is Reached (1/hr)
Elemental Iodine 20 20 Particulate 5.75 6.0 6.0 Containment Leak Rate (%/day) 0-24 hrs0.15 0.2 0.2
>24 hrs 0.075 0.1 0.1 Containment Sump Volume (ft3) 69,159 58,506 58,506 ECCS Leak rate (gpm) 0.033 1.215 1.215
- Values taken from Reference 3 Using the similarity of the parameters contributing to the post-LOCA gamma and beta doses, the parameters for the acidic sources (including the quantity of Page 5 of 9
Attachment I Response to NRC Request for Additional Information uncovered cable insulation outside of conduit) are compared in Table 3, "Comparison of Critical Parameters for Post-LOCA Acidic Sources." The radiation exposure to covered cable insulation is reduced due to the shielding associated with the steel conduit. The resulting HCI will be confined inside the conduit thereby preventing its intrusion to the sump water due to the sealed conduit, conduit trays, and multi-layer arrangement.
Table 3 Comparison of Critical Parameters for Post-LOCA Acidic Sources Description of Braidwood Braidwood Parameters for Post-LOCA Seabrook Byron Byron Acidic Sources Unit I Unit I Unit 2 Mass of Uncovered Electrical Cable 50,000 11,359 11,359 Insulation (Ibm)______
Post-LOCA 30-Day Gamma and Beta Integrated Dose in Containment Sump 3.3E+07 3.3E+07 3.3E+07 Water (rads)
Post-LOCA 30-Day Gamma and Beta 7.1E+07 7.1E+07 71E+07 Integrated Dose in Containment Air (rads)
.1 0
- Values taken from Reference 2 Based on the similarity of the key parameters in Tables 1, 2, and 3 that control the sump pH, the conclusions of the Seabrook Station pH analysis and the NRC staff determination of sump pH, it is concluded that the 30-day post-LOCA containment sump water pH change due to the acidic source at the Braidwood and Byron Stations would be less than 0.1 pH units and that the final sump water pH would be approximately 7.9, which is considerably higher than the pH of 7 required by the RG 1.183 to eliminate any ionic 12 conversion of Csl.
ECCS Recirculation Leakaae Path:
(2)
Provide the basis for assuming the value of 276,000 cc/hr for the ECCS recirculation leakage rate used in the AST LOCA analysis. (NO ANSWER REQUIRED)
The NRC determined that question A.2 does not need to be answered because sufficient detail was provided in Reference 4.
(3)
In the ECCS leakage path leading to the Borated Water Storage Tank (BWST), the sump water will mix with the remaining borated water in the tank. Since the BWST water contains between 2300 and 2500 ppm of boron in the form of boric acid, the pH of the mixture of sump and BWST water will have lower pH (most probably well below 7). Lowering the pH of the sump water will cause the conversion of ionic iodine into the elemental form and its corresponding release to the reactor water storage tank (RWST) air space. This effect will increase the total release of radioactive iodine from engineering safety features and cause correspondingly higher radiation doses.
Page 6 of 9
Attachment I Response to NRC Request for Additional Information Was this effect included in the licensee's analysis? If it was included, provide its description and the analyses for determining its significance to the overall release of radioactivity in the ECCS recirculation leakage path.
Response
For the purposes of this response, the BWST is referred to as the RWST at Byron and Braidwood Stations. Sump leakage back to the RWST was not considered based on the design and operation of the ECCS. The ECCS is depicted in simplified diagrams ECCS-1, "ECCS System," and ECCS-2, "ECCS Ring," provided as to this submittal. During the injection phase of the LOCA, water is injected from the RWST into the RCS cold legs. When the RWST Lo-2 level is reached, Emergency Operating Procedure 1/2B(w)EP ES-1.3 is entered to align the ECCS for the recirculation mode of operation, i.e., suction is switched to the containment sump. The steps for aligning the ECCS for the recirculation mode are summarized below (refer to simplified Diagram ECCS-1):
- 1. The containment sump isolation valves, 1/2SI881 1A/B, automatically open on the RWST Lo-2 level signal.
- 3. The containment sump isolation valves, 1/2SI881 1A/B, are verified open.
- 4. The residual heat removal (RHR) pump suction isolation valves from the RWST (1/2SI8812A/B) are manually closed.
- 5. The centrifugal charging (CV) pump recirculation valves, 1/2CV8111/8114 and 1/2CV8110/8116, are isolated. It should be noted that the CV pump recirculation valves return to the pump suction and not the RWST.
- 6. The recirculation flow path to the RWST for the safety injection (SI) pumps is then isolated by closing 1/2SI8814, 1/2SI8920, and 1/2SI8813. At this time, the SI pumps suction is still aligned to the RWST. If RCS pressure is above the shutoff head of the SI pumps, the SI pumps will be shut down.
- 7. The discharge of the RHR trains is then split by closing 1/2RH8716A/B
- 8. The suction header for the CV and SI pumps is then cross-tied by opening 1/2SI8807A/B, and 1/2SI8924. The RWST is still the suction source to the CV and SI pumps.
- 9. The CV and SI pump suction is then aligned to the discharge of the RHR pumps by opening 1/2CV8804A and 1/2SI8804B. At this time, back flow into the RWST is prevented by check valve 1/2SI8926 (on SI pump suction side of 1/2SI8806) and check valve 1/2CV8546 (on CV pump suction side of 1/2CV1 12D and 1/2CV1 12E). The check valves are held closed by RHR pump discharge pressure.
- 10. The RWST is then isolated from the CV and SI pump suctions by closing 1/2CV112D, 1/2CV112E, and 1/2SI8806.
When the above steps are completed, the ECCS system is isolated from the RWST on both the suction side and the SI pump recirculation. The CS pumps are still running with suction aligned to the RWST. The realignment of the CS pumps to the containment sump is performed when the RWST reaches the Lo-3 level setpoint by performing the following steps (refer to simplified Diagram ECCS-2):
Page 7 of 9 Response to NRC Request for Additional Information
Note that in this lineup the CS pumps do not have a recirculation flow path back to the RWST. A portion of the CS pump discharge flow is directed through the CS pump eductor back to the pump suction in order to inject NaOH.
As described above, once the ECCS has been realigned for the recirculation mode of operation, potential leakage paths back to the RWST are isolated utilizing at least two valves in series, typically a check valve in combination with a motor operated valve (MOV). For a short period of time during realignment of the RHR pump suctions from the RWST to the containment sump, leakage back to the RWST is prevented by a single check valve (i.e., 1/2SI8958A/B) until the RHR pump suction isolation valves from the RWST (i.e., 1/2SI8812A/B) are closed. The ECCS valves are tested in accordance with the Inservice Testing (IST) Program required by Technical Specification 5.5.8, "Inservice Testing Program," to ensure meeting their specified engineered safety position. During testing, check valves 1/2SI8926 and 1/2CV8546, preventing back flow to the RWST, are verified closed utilizing one of the following methods: 1) ultrasonic testing, 2) acoustic testing, or 3) pressure testing. The IST of check valve 1/2SI8958A/B requires a pressure test be performed. The MOVs used to isolate flow paths back to the RWST are also stroke tested to the closed position in accordance with the IST Program. Additionally, MOVs are tested in accordance with the MOV Program used to satisfy the recommendations in Generic Letter (GL) 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance," dated June 28, 1989, and GL 96-05, uPeriodic Verification of Design Basis Capability of Safety-Related Power-Operated Valves,"
dated September 18, 1996.
Based on the discussion above, back leakage to the RWST is not considered in the analysis, consistent with the current analysis of record.
B.
Iodine Removal (4)
Provide the reason why natural deposition of elemental iodine was not considered in your analysis.
Response
RG 1.183, Appendix A, "Assumptions for Evaluating the Radiological Consequences of a LWR Loss-of-Coolant Accident," assumption 3.2 states: "Reduction in airborne radioactivity in the containment by natural deposition within the containment may be credited. Acceptable models for removal of iodine and aerosols are described in Chapter 6.5.2, 'Containment Spray as a Fission Product Cleanup System,' of the Standard Review Plan (SRP), NUREG-0800 (Ref. A-1) and in NUREG/CR-6189, 'A Simplified Model of Aerosol Removal by Natural Containment' (Ref A. 2). The latter model is incorporated into the analysis code RADTRAD (Ref. A-3). The prior practice of deterministically assuming that a 50% plateout of iodine is released from the fuel is no longer acceptable to the NRC staff as it is inconsistent with the characteristics of the revised source term."
Page 8 of 9
Attachment I Response to NRC Request for Additional Information Table B, "Conformance with Regulatory Guide 1.183 Appendix A (Loss-of-Coolant Accident)," of Attachment 7, "Regulatory Guide Conformance Tables," included in Reference 4 provided the following comment: "For BIB, the RADTRAD computer program, including the Powers Natural Deposition algorithm based on NUREG/CR-6189, is used for modeling aerosol deposition in Containment. No natural deposition is assumed for elemental or organic iodine. The lower bound (10%) level of deposition credit is used."
RG 1.183, Appendix A, assumption 3.2 does not require crediting natural deposition for elemental iodine. RG 1.183 states that natural deposition of airborne radioactivity may be credited. EGC did not choose to credit natural deposition of elemental iodine because elemental iodine only makes up approximately 4.85% of the total iodine released. Neglecting credit for deposition of elemental iodine results in a more conservative estimate of onsite and offsite dose consequences because more iodine is available to be released.
References (1)
NUREG/CR-5950, Iodine Evolution and pH Control," December 1992 (2)
Letter from M. E. Warner (FPL Energy Seabrook, LLC) to NRC, "Seabrook Station Response to Request for Additional Information Regarding License Amendment Request 03-02," dated May 24, 2004 (3)
Letter from V. Nerses (NRC) to M. E. Warner (FPL Energy Seabrook, LLC),
"Seabrook Station, Unit No. 1 - Issuance of Amendment Re: Alternative Source Term," dated February 24, 2005 (4)
Letter from K. R. Jury (Exelon Generation Company, LLC), to NRC, "Request for License Amendment Related to Application of alternative Source Term," dated February 15, 2005, (5)
Regulatory Guide (RG) 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Plants," dated July 2000 Page 9 of 9 Response to NRC Request for Additional Information BRAIDWOOD STATION UNITS 1 AND 2 Docket Nos. STN 50-456 and STN 50-457 License Nos. NPF-72 and NPF-77 and BYRON STATION UNITS 1 AND 2 Docket Nos. STN 50-454 and STN 50-455 License Nos. NPF-37 and NPF-66 Calculation ATD-0356, "Post LOCA Containment Sump pH," Revision 5
Exhibit D NEP-12-02 Revision S COMMONWEALTH EDISON COMPANY CALCULATION TABLE OF CONTENTS I PROJECT NO. 9135-198 CALCULATION NO. A__
D-0356 REV. NO.
S PAGE NO. 5 DESCRIPTION PAGE NO.
SUB-PAGE NO.
TITLE PAGE TI, 1 2-4 REVISION
SUMMARY
TABLE OF CONTENTS 1.0 PURPOSE/OBJECTIVE 6
2.0 METHODOLOGY AND ACCEPTANCE CRITERIA 6
3.0 ASSUMPTIONS 6-7 4.0 DESIGN INPUT 7-9
5.0 REFERENCES
1011 6.0 CALCULATIONS 11, 13-40 7.0
SUMMARY
AND CONCLUSIONS 12 ATTACHMENTS rLa APPENDIX Al-A5 I
1
Exhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO. 6 I I9135-198 1.0 PURPOSEIOBJECTIVE The purpose of this calculation is to determine the minimum final containment recirculation sump pH following a LOCA. The result of the calculation will be used to update the design basis for the Byron/Braidwood post LOCA containment sump pH for Units I and 2. The Unit I results address the impact of the replacement steam generator (RSG) project.
2.0 METHODOLOGY and ACCEPTANCE CRITERIA The minimum post LOCA containment recirculation sump pH is determined based on the sodium hydroxide (NaOH) quantity, the borated water quantity, and boron concentration in the sump for both Units I and 2. The calculation differs for each unit because Unit I is equipped with a new steam generator and Unit 2 has its original steam generator.
The sump pH will be calculated by determining the equilibrium quantities of the boron ionic species and sodium ionic species in the sump. These can be calculated based on the amount of boric acid, and sodium hydroxide added to the sump, the sump pH, the total water volume in the sump, and the temperature of the sump. Also, the equilibrium quantities of hydronium ion (H30) and hydroxyl ion (OH) can be determined based on the temperature-dependent ionic activity product constant of water and the sump pH. The equilibrium pH is determined when the sum of ionic charges of all species pertinent to the boron and water in the solution and the ionic charge of sodium reduces to zero (defined when the difference is c IE-7).
This calculation will establish three equations to describe the concentrations of all the ionic species. The equilibrium pH will be obtained analytically by solving the three equations simultaneously, using the Math Solver in MathCAD 5.0. The pH is verified if the sum of all ionic species reduces to zero (defined when the difference is < IE-7).
The purpose of this calculation is to determine the minimum containment recirculation sump pH. Technical Specification 3/4.6.2.2 Bases states that the post LOCA sump pH shall be 8.0 to 11.0. This will be used as the acceptance criteria for this calculation.
3.0 ASSUMPTIONS
- 1) The safety injection accumulator water temperature is assumed to be at 900F. This is a conservative estimate of the minimum temperature of this water and will result in a higher density of water (thus the mass of boron).
- 2) All RCS, RWST, CSAT, and SI accumulator volumes are conservatively assumed to reach the containment recirculation sump.
REVISION NO.: 5
Exhibit E NEP-12-02 Revision S COMMONWEALTH EDISON COMPANY CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO. 7 9135-198 3.0 ASSUMPTIONS. cont'd
- 3) The extended form of the Debye-Huckel equation is applicable to the range of ionic strength considered in this calculation.
- 4) The equation for the molal equilibrium quotient, Qu1, is based on ionic strength derived from molality. The ionic strength determined in this calculation is based on molarity. In dilute solutions, molality and molarity are approximately equal. Because this calculation deals with dilute solutions, molality and molarity are assumed to be equal.
- 5) The approximate ionic radii used in this calculation are those at 250C. The effect of temperature on the approximate ionic radii is assumed to be negligible.
- 6) All species and ions in solution are assumed to be in equilibrium; therefore, the results are based on steady state analysis.
- 7) Not used.
- 8) Not used.
- 9) The density of the solution in the containment recirculation sump (containing both borated water and NaOH) is assumed to be the density of pure water at the applicable sump temperature stated in Design Input 15. Increasing the solution from a specific gravity of 1.00 to 1.01 (conservative maximum based on level of boron and caustic in the sump) yielded a negligible difference in the sump pH.
4.0 DESIGN INPUTS
- 1) The density of water at atmospheric pressure and various temperatures used in the calculation for the areas noted is as follows (interpolated as necessary from Ref. 1, page 4-4):
Use Temperature.,F
- o. lb/ft3 Unitsl,2 containment recirculation sump 185 (Design Input 15) 60.45 SI accumulator 90 (Assumption 1) 62.12 RWST 35 (Design Input 5) 62.42 I REVISION NO.: 5 I
Exhibit E NEP-12-2 Revision 5 COMMONWEALTH EDISON COMPANY l CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO. 8
.1 9135-198 4.0 DESIGN INPUTS cont'd
- 2) The pressure, temperature, and density of water used in the RCS mass determination are shown below. The RCS nominal pressure and temperature conditions are used and the density is interpolated from Ref. 2, based on these conditions.
Pressure, psia Temperature. 0F
- p. b/t 3 Unit 1 2,235 (Ref. 3) 569.1 (Ref. 25) 45.58 Unit 2 2,235 (Ref. 3) 569.1 (Ref. 25) 45.58
- 3) The maximum boron concentration in the RWST is 2,500 ppm (Ref. 6 with clarification on fuel cycle being at or greater than 6 for both units at each station from Ref. 7).
- 4) The maximum RWST volume is 457,904 gal (Ref. 8). This is the full capacity of the RWST defined as 100% top of overflow pipe.
- 5) The RWST water temperature is at its Technical Specification minimum of 350F (Ref. 6).
This is conservative because the density of water (thus the mass of boron) is higher at lower temperatures.
- 6) The maximum boron concentration in the Si accumulators is 2,400 ppm (Ref. 9 with clarification on fuel cycle being at or greater than 6 for both units at each station from Ref. 7).
- 7) The maximum SI accumulator volume is 7,217 gal per each of the four SI accumulators (Ref. 10).
- 8) Per Ref. 11, a 30-36 wt% NaOH solution can be used in the CSAT. A 30 wt% NaOH solution is used in this calculation because it is conservative; resulting in a smaller mass of NaOH addition to the sump, and therefore, a lower sump pH.
- 9) The minimum NaOH solution addition from the CSAT is 2,500 gallons per Appendix A.
Appendix A calculates where the CSAT LO-2 level alarm must actuate to assure a minimum of 2500 gallons of NaOH is delivered to the containment spray system. Reference A.5.14 determines the CSAT LO-2 level setpoint necessary for alarm actuation at the level calculated in Appendix A.
- 11) The maximum RCS volume of Unit 2 is 12,340 ft3 (Ref. 26). The maximum volume is defined as hot, 0% tubes plugging and includes the steam generator pressurizer steam volume.
REVISION NO.: 5 l
Exhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO. 9 9135-198 4.0 DESIGN INPUTS cont'd
- 12) The maximum RCS volume of Unit 1 is 13,620 ft3 (Ref. 26). The maximum volume is defined as hot, 0% tubes plugging and includes the steam generator pressurizer steam volume.
- 13) The steam generator pressurizer volume for Units I and 2 Is 1,800 ft3 (Ref. 15). The steam generator pressurizer volume increases 1.6% from cold to hot conditions (Ref. 27). This yields a hot steam generator pressurizer volume of 1,828.8 ft3 (1.016 x 1,800 ft3).
- 14) The maximum steam generator pressurizer water volume for Units 1 and 2 is 1,656 ft3 (Ref. 16). The steam generator pressurizer water volume increases 1.6% from cold to hot conditions (Ref. 27). This yields a hot steam generator pressurizer water volume of 1,682.5 ft3 (1.016 x 1,656 ft3).
- 15) A range of containment recirculation sump temperatures from the data and curves in Ref.
27 was examined. The sump temperatures in Ref. 27 are maximum values, and lower temperatures are also possible post-LOCA. The total temperature range for the three scenarios in Ref. 27 over the time period required to drain the minimum CSAT volume were reviewed (approximately 165 - 2600F), down to a temperature of 1500F (to account for lower temperatures). (Note that the time period to drain the minimum CSAT tank volume ranges from: a) 2,500 gal, or the minimum CSAT volume + 120 gpm, or 2 eductors at maximum flow, =
21 min to b) 2,500 gal + 55 gpm, or I eductor at minimum flow, =45 min.) Through sample runs, it was determined that a temperature of approximately 185°F minimizes the sump pH.
Also, the sump pH throughout the temperature range of 150 - 2600F did not differ from the pH results at 1850F by more than +0.04. A sump temperature of 1850F was, therefore, selected.
- 16) The approximate effective ionic radii of H+ and OH-in aqueous solutions at 25*C are 9.0 and 3.5 respectively (Ref. 18, p. 8.4).
- 17) The Debye-Huckel constants for Units I and 2 at the containment recirculation sump temperature of 1850F (see Design Input 15) are A = 0.5842 and B = 0.3440 (Ref. 18).
- 18) The molecular weight of boron is 10.81 Ib/Ibmol (Ref. 19). The molecular weight of NaOH is 39.997 Ib/Ibmol (Ref. 19). The molecular weight of boric acid is 61.84 Ib/Ibmol (Ref. 19).
- 19) The temperature of the NaOH solution in the CSAT is 1 300F. This is the maximum temperature for the area that the CSAT is located in per the EQ design basis document (Ref.
20). This is conservative because the density of NaOH solution (thus the mass of NaOH) is lower at higher temperatures.
- 20) The density of the 30% NaOH solution at 1300F is 10.898 lb/gal (calculated / interpolated from Ref. 19 using 8.345 lb/gal per 1 gm/cm3 conversion factor).
I REVISION NO.: 5 I
Exhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO.
9135-198 10
5.0 REFERENCES
- 1) *Cameron Hydraulic Data%, C. C. Heald, Ingersoll Rand, Seventeenth Edition, 1988.
- 2) -Steam Tables", American Society of Mechanical Engineers, Sixth Edition, 1993.
- 3) Calculation 222-7720-A19, Revision 3.
- 4) Deleted.
- 5) Deleted.
- 6) Braidwood Technical Specification 314.5.5, Amendment No. 55 - Unit 2, 56 - Unit 1; Byron Technical Specification 3/4.5.5, Amendment No. 65.
- 7) "5 Year Nuclear Division Planned Outage Schedule", Revision 34, 9/26/96.
- 8) NDIT 960009, Revision 0, verified 10/23/96 in "Status Change for NDIT 960009" letter from H. Kim to R. Peterson (NDIT references calculation ATD-01 11 Revision 2).
- 9) Braidwood Technical Specification 3/4.5.1, Amendment No. 55 - Unit 2, 56 - Unit 1; Byron Technical Specification 3/4.5.1, Amendment No. 65.
- 10) Braidwood Technical Specification Bases 3/4.5.1, Amendment No. 25; Byron Technical Specification Bases 3/4.5.1, Amendment No. 38.
- 11) Braidwood Technical Specification 3/4.6.2.2, Amendment No. 4; Byron Technical Specification 3/4.6.2.2, Amendment No. 14.
- 12) NDIT 960181, Revision 0 (NDIT references "Safety Parameter Interaction List for ComEd Braidwood Cycle r dated 10/96).
- 13) Deleted.
- 14) Deleted.
- 15) NDIT 950028, Revision 1 (NDIT references USFAR Table 5.4-9 and Westinghouse calc note CN-TA-93-182 Rev. 0, p. 12).
- 16) Braidwood Technical Specification Bases 3/4.4.3, Amendment No. 33; Byron Technical Specification Bases 3/4.4.3, Amendment No. 44.
- 17) Deleted.
REVISION NO.: 5
Exhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY i
l CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO.
9135-198 11
5.0 REFERENCES
cont'd
- 18) "Lange's Handbook of Chemistry", J. A. Dean, McGraw-Hill Company, Fourteenth Edition, 1992.
- 19) "Perry's Chemical Engineering Handbook", Sixth Edition, McGraw-Hill Company.
- 20) EQ Design Basis Document PMED-P-BB-EQ-DBD-00.
- 21) "Basic for Instrument Scaling Methodology", TID-E/&C-21, Rev. 0, 1115193.
- 22) "Acidity Measurements in Elevated Temperatures. VI. Boric Acid Equilibria", R. E. Mesmer, C. F. Baes, Jr. and F. H. Sweeton, Inorganic Chemistry, Vol. 11, No. 3, 1972.
- 23) "Chemistry of Natural Waters", S. D. Faust and 0. M. Aly, Ann Arbor Science Publishers, Inc., 1981.
- 24) "Aquatic Chemistry", W. Stumm and J. J. Morgan, John Wiley & Sons, 1970.
- 25) NDIT 960119, Revision 3 (NDIT References NFS NDIT 960206, Revision 2 "Revised Braidwood Unit I Cycle 7 Reload Design Key Parameter Checklist").
- 27) NDIT 960159, Revision 5 (NDIT references WCAP-10326-A and Framatome calculation Containment LBLOCA Analysis-Long Term Cooling" document number 32-1266155-02 dated 1 1119197).
6.0 CALCULATIONS The detailed calculations for the minimum post-LOCA containment recirculation sump pH for Unit 2 (with its original steam generator) are shown first (pages 13-26). The detailed calculations for the minimum post-LOCA containment recirculation sump pH for Unit I (with its replacement steam generator) are shown second (pages 27-40).
The rest of this page is intentionally left blank.
REVISION NO.: 5
Exhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO.: ATD-0356 PROJECT NO.
PAGE NO.
9135-198 12 7.0
SUMMARY
AND CONCLUSIONS
- 1) Based on the minimum NaOH quantity and the maximum borated water quantity and boron concentration in the recirculation sump, the post LOCA minimum containment recirculation sump equilibrium pH for Unit 2 (with original steam generator) is 8.0.
- 2) Based on the minimum NaOH quantity and the maximum borated water quantity and boron concentration in the recirculation sump, the post LOCA minimum containment recirculation sump equilibrium pH for Unit I (with replacement steam generator) is 8.0.
The rest of this page is intentionally left blank I REVISION NO.: 5 I
COMMONWEALTH EDISON COMPANY EXHGIrrTE NEP-12-02 Revision 5 CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
13 6.0 CALCULATIONS - UNIT 2 V RCStot ;= 12340ft3 Maximum Total RCS volume (Design Input 11)
V PRE
= 1828.8.fl Steam generator pressurizer volume (Design Input 13)
V PRESwat := 1682.5-.f Maximum steam generator pressurizer water volume (Design Input 14)
T RCSavg = 569.1 Average RCS temperature, F (Design Input 2)
P PRES: 2235 Steam generator pressurizer pressure, psig (Design Input 2)
V P
- RESst=
V PRES-V PRESwat V PRESstm =`146.3 *ft3 Minimum pressurizer steam volume V RCSwat := V RCStot-V PRESstm V RCSwat = 1.21937' 10' *fi Maximum RCS borated water volume P RCSwat = 45.58-lb RCS water density at nominal pressure and temperature shown above (Design Input 2) ft aH =9.0 MwtgB:= 10-81 mole Mwt NOH: 39. 997 mole V MA :=457904. gal V accu:= 28868-gal P NaOH 10.898. lb gal VNaOH :=2500-gal Ionic radius of H. (Design Input 16)
Ionic radius of OH- (Design Input 16)
Molecular weight of boron, B (Design Input 16)
Molecular weight of sodium hydrowade, NaOH (Designinput 1e)
Maximum RWST borated water volume (Design Input 4)
Max. borated water quantity In accumulators, 4 x 7,217 gal each (Design Input 7)
NaOH soluion density at 1 30F and 30 wt % NaOH (Design Input 20)
Minimum NaOH soluton volume in spray additive tank (Design Inputs)
REVFISION NO. 5
EXHIBIT E NEP-12-02 Rcvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECr NO. 9135-198 PAGE NO.
14 6.0 CALCULATIONS - UNIT 2 cont'd 2500 B w :
RWST boron concentration (esgn Input 3) 110 B
2 30 RCS boron concentration (Design input 10)
B accu:=- 2Accumulator boron concentration (Design Input 6) pW185:=60.45-Ib Density of water @185 F (Desgn input 1) fe Ionic strength In sump solution rH activity coefficient of H* Ion YOH actvity coefficient of OH-Ion k W ionic activity product of water T :=358.15 K Sump temperature In Kelvin (or 185-F)
(Dasign Input 15)
A:=0.5842 B:=0.3440 Debye.-uckel Constants (oesign Input 17)
CBEB borated water charge balance error CBEN sodium charge balance error z
Ionic charge of species I 61.84 MwtH3BO3:=
Molecular weight of boric acid (esign npux 1i)
Calculate Si Accumulator borated water density at 90OF and a boron conc. of 2400 Pmp From Eq. D-1 0 of Reference 21, calculate the mass fraction of the boric acid solution (expressed as ppm wlo the 106 factor):
MwtH31303
ppm H3BO3accu =B cm, MwtB PpmH3BO3acc =0-01372951 REVISION NO. 5
EXHIrr E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
15 6.0 CALCULATIONS - UNIT 2 contd From Eq. D-1 1 of Reference 21, calculate the weight % of boric acid within the solution
%C baocu =PPMHB 3accu 100
%C baccu 1.37295097 From Eq. D-12 of Reference 21, calculate the weight density of the solution,p BAaccu P
=62.12. b Densityofwater@ 90 *F (oeslgnnputt)
W90 3
PBAacu :=pw90.[ I+ (0.0035.%Cbacu)
PBA CU62.418507 -lb ft Calculate borated water quantity in Accumulators, M accu based on accumulator volume of 28,868 gallons M acuV accu P BAaccu M accu =2.40878657* 105 *lb (Based on the conversion I.gal - 0. 1 3368056.ft3?
Calculate RCS borated water density at 569.1 °F and 2235 Dsia and a boron conc. of 2300 nDm MwtH 3BO3 PPm MBO3rcs: =B MBt ppmH3B03rcs =0-01315745
%C brcs M=Pm B03rcs. 100
%C brcs= 1.31574468 PBArcs :=PRCSwat [I+ (0.0035.%Cbcs)]
P BArcs 45.7899075.lb fl REViSION NO. 5
EXH[3Brr E NEP-12-02 Rvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
16 6.0 CALCULATIONS - UNIT 2 contd Calculate borated water quantity In RCS.
M rcs M
- =V RCSwat P BArcs Mrc= 5.58348313 10' *lb (Based on the conversion I gal 0.13368056 fi3)
Calculate RWST borated water density at 35OF and a boron conc. of 2500 Dpm PPmH3B03rwst =Bnrwst MWtB PPmH3BO3rwst '0.01430157 1eC brwst = P~PmH3BO3rwStf I0
%eC brwst = 1.43015726 Pw3s :=62.42 lb Density of water @ 35 OF pDeslnlnpu t) f3 PBArwst =PW35.[1 + (0.0035-%Cbrt)]
lb PBAwst =62.73244646.-
ft Calculate borated water auantitin RWST. M wst based on RWST volume of 4S7,904 gallons M :=s V rwsf P gArwst M,wst
= 3.84003259-106 *lb (Based on the conversion 1 gal = 0.13368056 *R3)
Calculate Boron mass. M., in RWST. Accumulators. RCS:
M B :=M rws B MA iM accu B accu+ B rcs. M r MB=1.146239146104 *-lb REVISION NO. 5
EXIBIT E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECr NO. 9135-198 PAGE NO.17 6.0 CALCULATIONS - UNIT 2 cont'd Calculate NaOH mass. M.,
in 30% solution (Design Input 8)
__ __--- -----
^ riaun-M NaOhiE=V NaOXP NaOH MNaOH :=M NaOHsi 0-3 MNaOHo=8.1735 103 lb Calculate net water mass inside containment, MH2 MpH0 =(M
+Mau + M rcs + M NaOHn) -M B-M NaOH M2 0 =4.64686867106 -lb Calculate water Volume. Vv inside containment (at 185'F per Deslon Inout 15):
M 1420 v
=-
Pwl85 Based on the conversion ( I.R =28.31684659.liter)
V w=2.17675215.16 *liter Calculate Molar concentration of boron. Moi8 and NaOH. Mo' N14OH MolB:=
MB VwMwtB Mo! B - 0.22095625 gin. mole liter Mo! NaOH -1 MNaOH V WMWtNaOH MO' NaOH =0.04258311 -gm mole liter REVISION NO. 5
EXHIBIT E NEP-12.02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
18 6.0 CALCULATIONS - UNIT 2 cont'd Set up three eguations to solve for equilibrium sump DH:
NOTE: For MathCAD purposes, the concentrations of various species are denoted as follows in all of the following equations:
[H3B0313 = H3B03
[B(OH)4 BOH4
[B2(0H)jJ - 120H7
[B3(OH)d-3 = B30H10 IB4(OH)141 = B40HI4 Hi>4
= H
[OR] = OH
[Na'j = Na Condition 1:
The sum of the molar concentration for all the boron ionic species should be equal to the molar concentration of boron, Mola, in the sump. This yields Equation I below.
MoIB a H3B03 + BOH 4 + 2-B20H 7 + 3-B30H l + 4-B40H 14 Eq. 1 Condition 2:
The borated water charge balance error, CBEB, represents the sum of the ionic charges of all species pertinent to boron and water in solution. The Ionic charge of HW is 1. The ionic charge of OH, B(OH)4, B2(OH)7-, and B3(OH)10-Is -1. The ionic charge of B4(OH) 14-Is -2. Ionic charge values are from Ref. 22. CBEB is then defined as follows:
CBEB =
H - OH-BOH 4 - B20H7 - B30H 10 B40H 14 The sodium charge balance error, CBEN, represents the ionic charge of sodium (defined as +1 per Ref. 18) and is defined as follows:
CBEN =
Na Electroneutrality requires that the sum of ciz1 (c Is molarity and z Is ionic charge) of all species and ions In solution equals 0, thus the sum of CBEB and CBEN equals 0. This yields Equation 2 below.
-Na = H-OH-BOH4 - B20H7 - B30H 10 B40H 14 Eq. 2 REVISION NO. 5 z
I I
EXHIlrr E NEP-12-02 Rcvision S COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECr NO. 9135-198 PAGE NO.
19 6.0 CALCULATIONS - UNIT 2 contd Condition 3: The Ionic strength, I, of solution Is calculated as follows:
I = O.5(C1z,2 + C2Z22 +.
+ c.. Z2)
(Ret. 18) where c is molarity and z is ionic charge. Utilizing the ionic charges defined in the Condition 2 section with the above equation yields Equation 3 below.
2-1 = Na+H+OH+BOH 4 +B2OH 7 +B30H1 O+ (B40H1 4)-4 Eq.3 All the variables in Eqs. 1, 2 and 3 will be defined in terms of pH, H3803 and 1.
Per Ref. 22, the boron Ionic species can be defined from equilibrium quotients as follows:
BOH4 Q II -H3B03-0H B20HH7 Q221-H3B032.OH 3
B30HO.
Q 3 1.B1303 -0H
- 40H1 4 =
Q 42-H3B034-OH Per Ref. 22, the molal equilibrium quotients, Q1,. Q21, Q3, and Q42 are defined as follows and canbereduced,given: T-358.15 K 157321 +28.6059+0.01207&T-13.225UqT) +(0.3250- 0.00033-T)-I- 0.0912.1!-
Q O[3.5446U4+(0206811)-I_0.0912.11.5 0(2761_ 1S.966+5i35.I3T))
Q21 :=lO Q 21 =4.288921-103 REVISION NO. 5
EXHHIT E NEP-12-02 Rcvision 5 CALCULATION NO. ATD-03!
COMMONWEALTH EDISON COMPANY 56 PROJECT NO. 9135-198 PAGE NO.
20 L.
VA 4
A Iff A"-,IVN
- U I
cw O.U LO.KLLLULMf I PJIma -
UJIS I I C onI a (33 1
.333950841oT Q 31 -1.15808569. 10
(
12820.0 134.56+4Z.5be(8)
Q 42: =1
_T Q 425.94241376-10 Per Ref. 23, the equilibrium quantities of the H and OH Ions are defined as follows:
YHiTyOH[OH1 ' k, and H[H8j =0,PH yielding:
H
-C OHH=
w TH HyF1ryoH Per Ref. 18, Individual activity coefficient, 11, may be estimated using the following equation of the Debye-Huckel theory:
A z,2j4ap5
-log r, yielding:
2.
1 j
A( 1)2.0.51
=
1 0
(
)+B-arO)
YOHme 10 f(I+B-aOrI5)
Per Ref. 24, the ionic activity product constant of water, kw, Is calculated as follows:
pkw = -log I 4470 99 - 6.0875 + 0.01706-T T
I
,?
REVISION NO. 5
EXWBrr E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULA11ON NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
21 6.0 CALCULATIONS - UNIT 2 cont'd yielding:
- (4470.99 6.0875 +0.01706 T) kW =10 TT Given: T -358.15 aHie 9 aoH-35 A - 0.5842 B - 0.344
.3(0.542)-
rH4 c I- ((I [+(0.3440.9.0.?.5],
1 (0.5s42)-?° 5 1o 1ttl+(0.3440) 3.s P° 5]I TOHc Ikw =3.11811884_ 1o z3 Substitute YH ' yOH and kw into the expressions for H and OH to obtain:
IO-pH H
a (0.S842).°S 1
1H 0 I t(O 3 4 40)-9.0I5JJ ]
OH -
HTHTyOH kw
-pHvK
_*7HrOH 1H e
kw PR t 13.11811884 13 I
(0.542).1° I
1 0-pH. I0It +(0J3440)-3.5--5))
Using the expressions and values developed for Q113Q21,Q3 19Q4 2, H and OH wIth Equations 1, 2 and 3, and given the following, all unknowns can be determined.
MO' B = 0.22095625 -=-n~
liter INa:=Mo! NaoH Mol NaOH =0.04258311 Im-mole liter Na '0.04258311 -ginmole liter Also for simplicity, define a vanable V for H3P0 3, Equations 1, 2, and 3 can be rewritten in terms of three variables (namely pH,I and V.
With three equations and three variables, the variables can be solved simultaneously.
The forms of the equations to be solved are shown on the next page. The Math Solver in MathCAD 5.0
- used to solve the equations.
REVISION NO. S
COMMONWEALTH EDISON COMPANY CALCULAON NO. ATD-0356 PROYECNO. 913F19S PAGE NO. 22 S.4 CALCULALIONS - UNRI 2 eonfd Guess values:
I 0.045200 V :0.1426000 pH S.05 Given Equelon 1 0.22095625=V i.
- 4.
- k5w, (O
(I)4.0Mt24'lv a
21)v2 V
kw _
1+(3Q3)
I
+ (4.Q42)4VI kw
'Olor
+ 3s0 5 lory"o [+'-')
Vlol 0 ltrp"Io Equalion 2
- 0.0425831 I a l;I 3
l k
It It
-Q 9
Q3_V
_Q2)II I
lo-'".o I afl}
1 1 o544+t2tI)-.l4I I0 t.o lo.,H.5'~)IJ Q 3 1
0V' 0 [I7 (2Q 1 J.) 3 ?))
Equallon 3 2-1=0.04238311+
=+
- l
+ll[~uz1.-"~
].V (Q21)'V'
+ 1 +(Q3l)-V 1+(4'Q42)-V4 o [ a tfi,
eik)] 1 i.{
.,N
- t.
t
] l lo[-eo+t2 W 4 I)4 M)]2 ' V I
-r l f ( Q 3 0.v 2
0 lo-lk.
to 1 ° H.101 21 0.04307249.
FmUL.V PH)1 0.14340439 8.05381635 REVISION NO. 5
EXIrTE NEP-12-02 Rcwuion S:
COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
23 6.0 CALCULATIONS UNIT 2 cont'd To verify the equilibrium sump pH; the pH, H3B03, and the ionic strength (1) that were calculated on the previous page are put into the following calculations. The pH is verified when three conditions are met:
- 1) the absolute difference between the concentration of boron used to develop the equations on the previous page and the concentration of boron resulting from the following calculations is < IE-7.
- 2) the sum of ionic charges of all species pertinent to boron and water in solution and the ionic charge of sodium reduces to zero (defined when the absolute difference is < I E-7).
- 3) the absolute difference between the ionic strength calculated on the previous page and the the Ionic strength resulting from the following calculations is c 1 E-7.
(a) Assume the solution ionic strength, I :0.04307249 The activitycoefficientof H,IH,is:
A11 j 7 H = 0.84369386 Theactivtcoefficientof'OH-, Y OH is:
H Ij A0 12p05
_ o (+BOH' Y OH - 0.799825 (b) Assume an equilibrium sump pH:
pH := 8.05381635 The ionic activity product constant of water, kN,, at 185 'F (358.15 Kelvin) is:
T =358.15 14470.99 6075 0 u.010 kw =10 k T
/
kw =3.11811884 10613 The equilbrium quantity of H* is:
H:= 102H YH H -1.04712556-107' REVISION NO. 5
EXHBrr E NEP-12-02 Rcvizion 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO. 24 6.0 CALCULATIONS - UNIT 2 cont'd The equilbrium quantity of OH-is:
k-w OH:-
H-tryOH OH 4.41279789 106 (c) Assume H3BO3 molality of 0.14340439:
H3B03: 0.14340439 The Molal equilibrium quotients of boric acid are:
Q1 7 1521 +28.6059+0.012071T-13.2251oL (T)+(0.3250-0.00033-T)-1-0.0912-15]
Q 11 3.57089321-10' (2756- _ 18.%6 + 3.935-loo(T)
Q 21:=I10\\ T Q 21 =4.28892-103 (3339.5 _ 9.084+1.497 108T))
Q 31 l
Q3 1 =.15808569-105
( 1222.0
- 10 2
T 134.36+42.105-.og(T))
Q 42: =10T Q 42 5.94241376-10 REVISION NO. 5
ExHIBI E NEP.12-02 R=Wis 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
25 6.0 CALCULATIONS - UNIT 2 contd The equilibrium quantifies of boric acid species are:
BOH 4 :=Q ll.H3B03.OH BOH 4 =0.02259713 2
B20H 7 :=Q 2 I-H3BO3.OH B20H7 -0.00389213 B30H 0 :=Q 3 1.H.3B03 3.-
1 B30H
=o 0.015071 B4H 14 =Q 4 2 -H3B03 H B40H1 4 =4.89373837 104 Concentration of boron, based on the above equilibrium quantities, is:
ConcB :3B303+BOH4 +2. B20H 7 +3 -B30HO+4 B40H1 4 Conc B 0.22095627 which is the same as MoIB =0.2 2 0 9 562 5 -gm'moke liter Conc B -.22095625 = 2' 108 (Condition I Is met)
Check Borated water charge balance error, CBEB, Is CBEB: = H-OH - BOH 4 - B20H 7 - B30H 10 B40H 1 4 CBEB = -0.04258313 Sodium charge balance error, CBEN, is MO! NaOHl CBEN: =
O (divide by unit to eliminate dimensions) mole gi.
liter CBEN =0.04258311 CBEB + CBEN =-1 101 (Condition 2 Is met)
REV1SION NO. S
EXHBrr E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
26 6.0 CALCULAllONS - UNIT 2 cont'd Na := CBEN Verify ionic strength of the solution:
Na+-H- 0H+ BOH4 +B20H 7
- B30H 10 (B4OH 14)2 lsol=2 I so, - 0.0430725 I=1*10 which Is the same as assumption (a)
(Condition 3 Is met)
I -0.04307249 Since conditions 1,2 and 3 are met, the equilibrium sump pH -8.05381635 The rest of this page is intentionally left blank.
REVISION NO. 5 i
I9
EXHIBIT E NEP-12-02 Rcvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
27 6.0 CALCULATIONS - UNIT i VRCStot:= 13620-f43 Maximum Total RCS volume (Design Input 12)
V PRES:- I828.8-fl3 Steam generator pressurizer volume (Design Input 13)
V PRESwat := 1682.541 Maximum steam generator pressurizer water volume (Design Input 14)
TRCSavg: 569.1 Average RCS temperature, F (Design Input 2)
P PRES :=2235 Steam generator pressurizer pressure, psig (Design Input2)
V PRESstm =V PRES -
PRESwat V PRESstm = 146.3.i3 Minimum pressurizer steam volume V RCSwat = V RCStot - V PRESstm V RCSwat = 1.34737104 fit3 Maimum RCS borated water volume PRCSwat :=45.58-3 fe aH:=9-0 8 OH :=3.5 MwtB:= 10.8 mole M 39.997 MWLNaOH=
mole__
V rwst := 457904. gal V accu := 28868.gal P NaOH = 10.898. lb gal V NamOH 2500. gal RCS water density at nominal pressure and temperature shown above (Design Input 2)
Ionic radius of H* (Design Input 16)
Ionic radius of OH- (Design Input 16)
Molecular weight of boron, B (Design Input 18)
Molecular weight of sodium hydroxide, NaOH (Design Input 16)
Maximum RWST borated water volume (Design Input 4)
Max. borated water quantty in accumulators, 4 x 7,217 gal each (Cesign Input 7)
NaOH solution density at 1 30F and 30 wt % NaOH Design Input 20)
Minimum NaOH solution volume in spray additive tank (Design Input S)
REVISION NO. 5
EXHIBIT E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
28 6.0 CALCULATIONS - UNIT I cont'd B
2wst:=
RWST boron concentration (Design Input 3) 1.10:
B cs := 23 RCS boron concentration (Design Input 10) 1.106 2400 B
2400 Accumulator boron concentration (Design inputS) 1.106 Pw185:=60.45 b Density of water @ 185 F (Design Input 1)
Ionic strength in sump solution TH activitycoefficientofH Ion 7 OH activity coefficient of OH-Ion ICv ionic activity product of water T :=358.15 K Sump temperature in KeMn (or 185F)
(Design Input 1S)
A:-0.5842 B :0.3440 Debye-Huckel Constants (Design Input 17)
CBEB borated water charge balance error CBEN sodium charge balance error z
Ionic charge of species I MWtH3B303
=
61.84 Molecularweight of boric acid (Design Input1 mole Calculate Si Accumulator borated water density at 900F and a boron cone. of 2400 Drom From Eq. D-1 0 of Reference 21, calculate the mass fraction of the boric acid solution <expressed as ppm who the 106 factor):
ppm HBO~acu
~ BsBcu ppm H3BO3accu = 0.01372951 REVISION NO. S
EXHIB1T E NEP-12-02 Rcvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
29 6.0 CALCULATIONS - UNIT 1 cont'd From Eq. D-1 of Reference 21, calculate the weight % of boric acid within the solution GAC baccu p:pWm H3B03accu 100
%C baccu 1.37295097 From Eq. D-12 of Reference 21, calculate the weight density of the solution,p BAaccu Pwo.=62.12 lb Density of water @ 90 *F (Design Inputi) fl P BAaccu = P w90[I + (0.0035 %C baccu)]
P BAaccu =62P 0
lb fl3 Calculate borated water cuantitv in Accumulators. M accu based on accumulator volume of 28,868 gallons M accu :=V accu l BAaccu M acu =2.40878657*10
- lb (Based on the conversion I gal a0. 13368056 -l3)
Calculate RCS borated water density at 569.1 OF and 2235 Psia and a boron conc. of 2300 nym B Mwt H3BO33 ppm HB03rcs B rcs MwtB ppm H
=3BO3r 0.01315745
%C brcs :-ppm H3B03rcs 100 e/.C brc 1.31574468 P BArcs :P RCSwat[I + (0.00351%C brcs)]
lb P ]3rc 45.78990075-REVISION NO. 5
ExHMrr E NEP-12-02 Revkion S COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0366 PROJECTNO. 9135-198 PAGE NO.
30 6.0 CALCULATIONS - UNIT I cont'd Calculate borated water ouantitv in RCS.
M Mrcs:=V RCSwatP BArcs
=6. 16959386k 1 lb (Based on the conversion I gal =0.13368056 i13)
Calculate RWST borated water density at 35F and a boron conc. of 2500 vpm PPmH3BO3wst M=
M nvst MwtB PPm H3BO3rwst -0.01430157
%C bwst: PPmH3BO3rwst I00
%C brwst 1.43015726 lb P w35 :=62.42-.--
Density of water @ 35 *F (DesIgn input 1) fl P BArwstPw35[I + (0.0035.%C brwst)]
BArwst 6 2 lb5 P BArwst 62.73244646.-
Calculate borated water quantitv In RWST. M wst based on RWST volume of 457,904 gallons M Mwt: V Vwsf P BAnvst M
= 3.84003259 106 -lb (Based on the conversion I gal =0.13368056 *fl )
Calculate Boron mass. M,. in RWST. Accumulators. RCS:
MB;=M st-Bwst M cu accu + 1 rsM rcs MB'I.15971968 I104 -lb REVASION NO. 5 I
EXCHITr E NEP-12-02 Rcvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO. 31 6.0 CALCULATIONS - UNIT I cont'd Calculate NaOH mass. MNao.
in 30% solution (Design Input 8)
M NaOHsln:= V NaOIHP NaOH MNaOH := MNaOHsn0.3 MNaOH'8.1735-103 lb Calculate net water mass inside containment. MH20 M H20 -N(M wst + M acu + M rcs + M NaOHsh)
M B-M NaOH MH20 4.70534493.106 *lb Calculate water Volume. V,,. Inside containment (at 185F cer DesiQn In"ut 15):
,MH20 w
- =
P w185 V w =2.20414443.106' liter Based on the conversion ( Ifl 3 =28.31684659 liter)
Calculate Molar concentration of boron. Molp. and NaOH. Mol NaO MB MOIB.=
M Mol B =0.22077659,gm mole liter M NaOH MolNaOH:
MM042NaQH Mol NaOH = 0.04205391 ginmole liter REVISION NO. 5
EXHIBT E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
32 6.0 CALCULATIONS - UNIT I cont'd Set up three equations to solve for equilibrium sump pH:
NOTE: For MathCAD purposes, the concentrations of various species are denoted as follows in all of the following equations:
[1H3
-1 3
B
= H3B03
[B(OH)j = BOH4
[B2(OH)j1 = B20H 7
[B3(OH) 0J = B30H1O IB4(OH)14
= B40H 14
[HiJ = H
[OH] = OH
[Na+] - Na Condition 1:
The sum of the molar concentration for all the boron ionic species should be equal to the molar concentration of boron, MoI 6, in the sump. This yields Equation 1 below.
Mole
= H3B03 + BOHI4 + 2.B20H 7 + 3*B30H o+ 4-B40H 14 Eq. 1 Condition 2:
The borated water charge balance error, CBEB, represents the sum of the Ionic charges of all species pertinent to boron and water In solution. The Ionic charge of Ha Is 1. The Ionic charge of OH, B(OH)4, B2(OH)r, and B3(OH)10-is -1. The Ionic charge of B4(OH)14-Is -2. Ionic charge values are from Ref. 22. CBEB is then defined as follows:
CBEB H-OH-BOH 4 - B20H7 - B30H iO-2-B40H 14 The sodium charge balance error, CBEN, represents the ionic charge of sodium (defined as +1 per Ref. 18) and is defined as follows:
CBEN -
Na Electroneutrality requires that the sum of ciz1 (c is molarity and z is ionic charge) of all species and Ions in solution equals 0, thus the sum of CBE8 and CBEN equals 0. This yields Equation 2 below.
-Na = H-OH-BOH 4 - B20H 7 - B30H 10 B40H 14 Eq.2 REVISION NO. 5
EXG1BfI E NEP-12-02 RevisionS5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECr NO. 9135-198 PAGE NO.
33 6.0 CALCULATIONS - UNIT i contd Condiffon3:
The onic strength, I, of solution is calculated as follows:
I = O.5(C1z12 + c2Z22 +.
+ CZ)
(Ref. 18) where c is molarity and z is ionic charge. Utilizing the ionic charges defined in the Condition 2 section with the above equation yields Equation 3 below.
2-1 = NA+H+ OH+BOH4 i-B20H7 + B30H 10 + (B4OH z4)
Eq. 3 All the variables in Eqs. 1, 2 and 3 will be defined in terms of pH, H3B03 and 1.
Per Ref. 22, the boron ionic species can be defined from equilibrium quotients as follows:
BOH4 =
Q 11-H3B03-OH 2
820H,-
7 Q21-H3B03.0H B30H10 a Q3I-H3BO3 3.OH B40H1 4
-Q 4 2-H3B034.0H 2 Per Ref. 22, the molal equilibrium quotients, 011, 0 21, Q31 and 042 are defined as follows and can be reduced, given: T =358.15 K
, 1573.21 +28.6059 +0.01207gT-13.2253.og( T) +(03250 - 0.00033.T)*1- 0.0912.115]
=
[3.544684+(0.206S11).- 0.0912.1 5 (2756-1_I.6+sfb)
Q21 -Io Q 21 =4.288921I103 REVISION NO. 5 f
EXHIBrr E NEP12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
34 6.0 CALCULATIONS - UNIT 1 cont'd (3339.5 _ t.094E 1.497ito( T)
Q31 Q 31 = 1.15808569-105 (M 20-
_ 134.56+4105.g(T))
Q4 2 :=10T Q4 2 5.94241376-10l Per Ref. 23, the equilibrium quantities of the H and OH ions are defined as follows:
yh[OHI[
I Z k, and
?H[1 = 10$PH yielding:
H OH.
YH H7 TH OH Per Ref. 18, Individual acty coefficient, 71. may be estimated using the following equation of the Debye-Huckel theory:
Az
-iog Ti
=
I + B a j-1° yielding:
PerlRef.
jQ[(B.S
)]
.( 1)]
Per Ref. 24, the Ionic activity product constant of water, k,, Is calculated as follows:
pk= 4-og 4470.99 - 6.0875 + 0.01706.T REVISION NO. 5
EXHMrr E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECr NO. 9135-198 PAGE NO.
35 6.0 CALCULATIONS - UNIT 1 cont'd yielding:
4470.99 6.0875+0.0170hT) kw:=10 r
Given: T=358.15 aH 9
aOH=3.5 A =0.5842 B =0.344 Ij (0.5S42)-?'5 10 t
+-(0.3440).9.01°]
(0.5H42)--S TOH 1° I(0.3440)-3.S.P-5].
kw 3.1a8n1t84-6 H13 Substitute IH fi rOH and kw into the expressions for H and OH to obtain :
Hlo-pH 7H j
_ ([.5942)-.°-*
1 10 [I+( 03440)-.-p
.OH-
-kw OH =
HTyf1.oH
=
kw lopH
-*HI OH kw IO-pH. OH 3.11811884 13 (0.5842)-10.5 10-PlB lo-1+(0.3440).3.5ol°45J Using the expressions and values developed for Q`11 Q2,Q3 11,Q4, H and OH with Equations 1, 2 and 3, and given the following, all unknowns can be deterrrmned.
Mol B - 0.22077659-gm-mole liter Na := Mol NaOH Mo0 NaOH =0.04205391 gmmole liter Na -0.04205391
.mmole liter Also for simplicity, define a variable V for H3803, Equations 1, 2, and 3 can be rewritten In terms of three variables (namely pH, I and V). With three equatons and three variables, the variables can be solved simultaneously.
The forms of the equations to be solved are shown on the next page. The Math Solver in MathCAD 5.0 s used to solve the equations.
REVISION NO. 5
MICY It C
CYC LL'I ot id it-idC.
b 4'
0
MBrr E
NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
37 6.0 CALCULATIONS - UNIT I cont'd To verify the equilibrium sump pH; the pH, H3B03, and the ionic strength (I) that were calculated on the previous page are put into the following calculations. The pH is verified when three conditions are met
- 1) the absolute difference between the concentration of boron used to develop the equations on the previous page and the concentration of boron resulting from the following calculations is < I E-7.
- 2) the sum of ionic charges of all species pertinent to boron and water In solution and the ionic charge of sodium reduces to zero (defined when the absolute difference is c 1 E-7).
- 3) the absolute difference between the ionic strength calculated on the previous page and the the ionic strength resulting from the following calculations is c 1 E-7.
(a) Assume the solution ionic strength, I:= 0.0425323 The activity coefficient of H+, IH
- is
( \\ 1 YH = 0.84424457 The activity coefficient of OH-,
O
[
A.12.10 j
5 s
7OH 10 H=
t y OH - 0.80072577 (b) Assume an equilibrium sump pH:
pH =8.0455942 The Ionic activity product constant of water, lk, at 185 OF (358.15 Kelvn) Is:
T =358.15 k
- =
(4470.6.0275+0.0170) kw =3.11811884-10 13 The equilbrium quantity of H* is:
_lo-pH H H H = 1.06644269-l >
REVISION NO. 5
EXHBIT E NEP-12.02 Raision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO. 38 6.0 CALCULATIONS - UNIT I cont'd The equilbrium quantity of OH-is:
k OH:-
W H-7 fry OH OH -4.32516875*10 5 (c) Assume H3BO3 molality of 0.14402951:
H3BO3 :=0.14402951 The Molal equilibrium quotients of boric acid are:
r l l21:=
10v29.60o9
+0.0t2DoT-13.225S lo@ T) +(0.3250 -0.00033-T).l- 0.0912.1'5 Q0.II12.11.5]
Q II '=3.57016044*I0 2 275611_ i.966+5.35-.T))
Q 21: =10 T
Q 2 1 e4.288921-1E0 QQ311 (1339.
(333
.084+ 1.497 htT)
Q 31 1.15808569-105 (12so.0- 134.56+42.10544o 8(T))
Q 42= 5.94241376-lo0 ru'lSION NO. 5
EXHWIT E NEP-12-02 Rcvision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECTNO. 9135-198 PAGE NO.
39 6.0 CALCULATIONS - UNIT 1 conrd The equilibrium quantities of boric acid species are:
BOH 4 :=Q 11-H3B03-OH BOH 4 =0.02224001 B20H7 :=Q 21 H3BO3.OH B20H7 =0.00384817 3
B30H10 := Q
- H3BO33-OH 31 B30H 10 =0.01496574 4
-2 B40H 14 :=Q 4 2-H3BO3'OH2 B40H 14 = 4.78382113 10 Concentration of boron, based on the above equilibrium quantities, Is:
COncB :=H3BO3+BOH 4 +2 B20H7 +3-1B330H 10+4-B40H 1 4 ConcB -0.22077661 which Is the same as MoIB =0.22077659 gm'mole M01 Bliter COneg- 0.22077659 = 2-10>
(Condition 1 Is met)
Check Borated water charge balance error, CBEB, Is CBEB:= H-OH - BOH 4 - B20H 7 - B30H 10 B40H 14 CBEB -- 0.04205392 Sodium charge balance error, CBEN, Is CBEN NaOH (divide by unit to eliminate dimensions) mole gtn.-
liter CBEN 0.04205391 CBEB + CBEN =-2 10>
(Condition 2 is met)
ASION NO. 5
Ex)mrr E NEP-12402 Revich 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-198 PAGE NO.
40 (Final) 6.0 CALCULATIONS - UNIT I contd Na :=CBEN Verify Ionic strength of the solution:
Na+H +OH +BOH 4 +B20H 7 +B30H 1 0 (B40H 1 4) 22 sol 2
I so, -0.04253231 1sl 1-=8'10-which is the same as assumption (a)
(Condition 3 is met)
I -0.0425323 Since conditions 1, 2 and 3 are met, the equilibrium sump pH - 8.0455942 The rest of this page is intentionally left blank.
fISION NO. 5 I
FROM!
SGRP F SiX Px
.i.2 e LS243324
!1!857 113*16 P.82 Exhibit K NEP-12-02 Revision S COMMONWEALTH EDISON COMPANY I CALCULATION NO.: ATD.0356 PROJECT NO. 9135-196 PAGE NO. Al l
Appendix A Byron/Braidwood Unit 1 and Unit 2 Determination of Minimum Delivered Volume of NaOH Prepared By/Date:
s 7Z.N A
/1177 Reviewea By/Date:
A Approvea By/Date: AL.
L-l9"
,80(1R BuIIlm~ ORIGINMtt REVISION NO.: 0* S i-:L/os/jqq-7 I
fQCM:
SGRP A!
824.4 It-4a-s t
r6 P.z3 Ethibit E NEP-t2-02 Revision 5 COMMONWEALTH EDISON COMPANY CALCULATION NO. ATD-0356 PROJECT NO. 9135-196 PAGE NO. A2 A.1 Purpose/Objective The purpose of this appendix is to determine the tzighest final Containment Spray Additive Tank (CSAT) level. cased on the lowest initial CSAT level, required to deliver a minimum of 2500 gallons of NaOH to the Containment Spray System. Past revisions of this calculation have demonstratea that delivering a minimum of 2500 gallons of NaOH (30 wt% at 130F) will satisfy recirculation sump minimum pH requirements. The highest final CSAT level required to supply 2500 gallons is used as tne System Safety Umit for calculating the CSAT LO-2 level alarm setpoint per Reference A.5.14. Therefore. minimum recircutation sunp pH will be calculated Dased on a minimum volume of 2500 gallons NaOH delivered to the Containment Spray System.
A.2 MethodologyiAcceptance Criteria The tank is a right circular cylinder with flanged and dishea heaas (Reference A5.3 and A.5.4).
This calculation is only concerned wlth the cylindrical portion at the tanK since the heads are outside the soan of the level measuring instruments. The volume of a nght circular cylinder is:
V=
/r 4 Ah 4
The highest final CSAT level is based upon the lowest initial CSAT level mirius the change in level correspor.ding to 2500 gallons. lntfial CSAT level is based on the lowest permissible fill level ot the tanK mintis (2)lLIC5021 instrument uncerlainty Minimum sump pH is calculated assuming 30% NaOH concentration at ! 30'lF (Cesign inputs 8 and 20). These assumptions result in the lowest allowable NaOH specific gravity and the lowest NaOH mass ava:lable to the Contairment Spray Sysiem. which Is tonservaNtve Level transmitter (2)tLT-CS021 scaling is based cn higher NaOH specific gravity (per Syronilraidwood EWC5 Equipmeno/Component Engineerng Oata). therefore. actual CSAT leve: would be higher than indicated level tased on these specific gravity conaitions. By assuming the lowest specific gravity NaOH solution. the total mass of NaOH delivered to the Contanrment Spray System Is conservative (lowest) regardless ot level measurement unceasinty assoc;atea with variation in NaOH specific gravity. Therefore. allowances forva.tiatlon in NaOt concernration ortemperature are not necessary in etermining (211U-CS021 levei indicator urcenanty Furthlermore. the CSAT LO-2 leveI alarm setpoint calculated in Reference A.5.14 accourcts forthe maximum potential change in NaGH specific gravity from calibrated conditions. Therefcre. level measurement uncertainty asoaateo with changes in NaOH specitic gravity is bounden for determination of recirculation sump minimum pH.
The results of this caicLlation are used as input forother calculations. There are no direct acceotance cnteria for the results of this calculation.
A.3 Assumptions A.3.1 Oeieted.
niIO r~v 0RI~4 A.3.3
.t is assumed that Ihe ooerator c-oses tneCS eductor a.ditive valves (2)ICSO1IA/B immediatlly after mne Spray Additive TanK LO-2 level alarm is received. and that spray REVISION NO.:.04-57 4
si3 I 4L/c>J /I1q
,:Ax I.G.:
S152:4Z32Z 11-19-9?
1111?
P.84 Eshibit E NEIP-12-02 Revision S COMMONWEALTH EDISON COMPANY CALCULATION NO.: AT0O0356 PROJECT NO. 9135-196 PAGE NO. A3 additive flow ceases immediately. This is conservative. since it will minimize tae amount of spray aaditive deliverea to the containmemt.
A.3.4 The volume displaced by the pipe wall of the rill line is assumed to be oeofigiblie. (Per Reference A.5.12, the area of metal ir. 4-Schedule 40 pipe is 3.174 in, which equals approximately 0.16 gal/ft of pipe.)
A.4 Design input A.4.
Tank Dimrenslons per Reference A.S.3 ane A.5*4:
Diameter:
8 ft Well Thickness:
0.41 in Distance Between Instrument Taps:
2 x (6vy,- 3-.)
Distance from Tap to Center Line:
66%/ - 3%'
Fill Pipe:
4 Schedule 40 A.4.2 The minimum fill level for the CSAT Is 78.13% per References A.5.13, A.5.9 and A.5.10.
A.4.3 Deleted.
AAA Deleted.
M0RQ~ l li lkst A.4.5 The maximum uncertainty (excluding changes in NaOH concentration) of (2)ILI-CSO21 is
+/- 5.0% per Reference A.5.1 1.
AS References A.5.1 Calculation SM-CS045A. Revision A. 'Containment Spray AdditIve Tank Level Switch (2)1LS-CS046A.' (Byron &Braidwood)
A.5.2 Calculation SM-CS0468. Revision A. 'Containment Spray Alaitive Tank Level Switch (2)1LS-CS046B.' (Byron & Braidwood)
A.5.3 vender Drawing NL-10753. Revisicn IS. T8 0.D. x 13'-4' High (Ten. To Tan.) Spray Additive Tank.0 (Byron)
A.S.4
'Venaor Drawing NL-10758. Revision 15. 8'- 0 O.D. x 13'-4" High (Tan. To Tan.) Spray Additive Tank.' (Brasdwooa)
A5.5 1 SwEP 1. Revision IA Loss of Reactor or Seconcary Ccolant unit. t 8raidwood)
A.5.6 2EwEP-1. Revision I A. "'Loss of Reactor or Seconcary Coolant Vnit 2.' (1raidwood)
A.5.7 IBEP-1. Revision 1. 'Loss ot Reactor or Secondary C30iant Unit i ( Myron)
A.5 8 28EP-1. Revision 1, 'Loss of Reactor or Secondary Coolant Unit 2.' fByron)
A.5.9 9WOP CS.8. Revision 4 'Filling the Containment SPray Aiddtive 'ank.' (raidwood)
A5.10 EOP CS-6. Revision B. 'Filling the Contatrnent Spray Additive Tank.' Myron)
REVISION NO.: 44-5
,t3m68
FROM I 343RP rAx NO.J e152Z45524 r~x
- 40.
eI5Z4~'
1-IS-91 1,111 PAS5 Eslhibit E NEP-1Z-02 Rnision COMMONWEALTH EDISON COMPANY CALCULATION IO.: ATO-0356 PROJECT NO. 9135-196 PAGE NO. A4 A.5.1t NDtT-B-ElXT-121e, 12118196. 'CSA7 Level Indicator Loop Inaccuracies.' (Byron &
eraidwood)
A.5.12 Crane Tecnnical Paper Number41 iO.FIoW ot Fluids Through Valves, fittings, and Pipe,'
1988.
A.5.13 Braiawood 1&2Technical Speofications, Amendment 76 and Byron 1&2TechnIcal Specifications. Amendment 83. Section ICO 3.6.2.2.
A.5.14 Calculation BRW-97-0274/BYR97-1t88 Revision 1, 'Containment SprayAdditive Tank Level Switch Lo-Lo Setpoint Analysis (Byron & Braldwood)
A.5.15 NDIT RSG-97-019. dated /20/97.
Subject:
Transmittal of design assumptions fortne S&L calculation revisions dealing with the CSAT level setpoints.
A.6 Calculations A.6.1 Minimum Initial CSAT Level Per References A.5.13, A.5.9. and A.5.10. the lowest CSAT fill level Is 78.6% per level Indicator (2)liU-CS021. (Note that the (2)ILT-CS021 upper and lower Instrlment taps are at the same elevation as the CSAT upper and lower tank taps per Refemence A.5.14 reference drawings). This tanx level converted to distance above the (2)ILT4SS21 and CSAT instrument lower tap is:
h a
K Le x Distance Between Taps 100 s O.788(2(661A^ - 3X)
= 792e.
Per Reference A.S.I1. the uncertainty ott2)1LI-CS021 is-equal to +/-5%. 8asea on the (2)ILT-CS021 instrument span of 149 5' (dlstance between instrument taps peroesign Input A.4 !). the associated level uncenainty is:
149.5k x 0.05
- 7.475' The minirnum initial CSAT level is equal to the total height above the 42)lLT-CS021 instnument and CSAT lower tap corresoonding to 78.40/c indicated level minus allowance for instrurnent uncertainty-hmwm~,Zt,,,,
h.4,-
Uncetaimnty flhIAI~fV t2 C 9.1691h I REVISION NO.:* 04 S
FROM:
-aX NO.2 5:443324 1 9 P!.06
[xhibit E NEP-12-02 Revision 5 COMMONWEALTH EDISON COMPANY ijii i
iI I
i CALCULATION NO.: ArD-0356 PROJECT NO. 9135,196 PAGE NO. AS I
I i
A.6.2 CSAT Final Level Requirea to Delver 2500 gallons N2O0I Basea on previous revisions of this caiculation. it is known that minimum sump pH requirernens are satisfied if a minimum of 2500 gallons of NaOH are supplied to the Containment Spray system. The 1lowing calculation determines the highest level
(
~,
above the CSAT lower tap to assure 2500 gallons cf NaOiH are supplied:
2500 gauons x (ft'e7.48 gal) c 334.225 ft" 4
7 n ft -2As0.11121 ge69 ft-h j
= 334.225 ft h
- 2.40 fA A.7 Summary and Conclusions The CSAT LO-2 level alarm must actuate at a maximum of 2.40 feet above the CSAT lower to assure a minimum volume of 2500 gallons NaOH is delivered to the Containment Spray System.
Reference A.5.14 determines the CSAT L0-2 level setpoint necessary for alarm actuation at or below 2.40 feet above the CSAT lower tap including allowances for (2%1 LS-CS04SA/B Instniment uncertaity, NaOH specific gravity uncertainty, and differences in tap elevation for the CSAT.
level transmitters (2)1 LT.CS02I.t and level transmitters (2)1LS.CS04BAJ.
Per References A.5.5 througn A.5.1, the CS eductor spray additive valves are closed wnen the CSAT LO-2 level is reached. Assuming tnat the operaor closes the vaives immediately and the system responds tnstantaneously (Assumption A.3.3). the final level In the CSAT will be at the LO-2 level. This is conservative since this resuwts in a smaller delivered NaOH volume.
In conclusion. calculation of sump minimum pH will be based on cellvenng a minimum of 2500 gallons of NaOH (30 wt% at 130). which is assured ey the CSAT LO.2 level setpoint per Reference A.5.14 occrnng at or telow 2.40 ft aDove the CSAT 'ower irnstrument tap.
MJR IAW'Y ORIGRIA1A
[FINAL)
REVISION NO.:.04 S I8/c)I P?
Response to NRC Request for Additional Information BRAIDWOOD STATION UNITS 1 AND 2 Docket Nos. STN 50-456 and STN 50-457 License Nos. NPF-72 and NPF-77 and BYRON STATION UNITS 1 AND 2 Docket Nos. STN 50-454 and STN 50-455 License Nos. NPF-37 and NPF-66 Simplified Diagrams (Provided for Information Only)
ECCS-1, ECCS System, Revision 6 ECCS-2, ECCS Ring, Revision 6
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- 2. SlSS40Ctibd l EZC$-2, ECCS JUINO MAR8, 2004. REV. 6 FOR TRAINNG USE ONLY