ML20059D543

Proposed Tech Specs Re Borated Water Storage Tank

ML20059D543
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/08/1990
From:	ENTERGY OPERATIONS, INC.
To:
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ML20059D538	List: 1CAN089002, Revised Application for Amend to License DPR-51,increasing Reactor Power to Level of 100% & Borated Water Storage Tank Tech Spec Change ML20059D543
References
NUDOCS 9009070089
Download: ML20059D543 (73)

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{{#Wiki_filter:f. i l 4 LICENSE AMENDMENT REQUEST IN THE MATTER OF AMENDING LICENSE NO. DPR-51 ENTERGY OPERATIONS ARKANSAS NUCLEAR ONE, UNIT 1 DOCKET NO. 50-313 9009070009 900000 PDR ADOCK O 3 _J

( TABLE OF CONTENTS SECTION DESCRIPTION PAGE 3

1. 0 DESCRIPTION OF PROPOSED LICENSE AMENDMENT AND TECHNICAL SPECIFICATION CHANGE...........................

1 2,0 BACKGROUND............................................... 1 2.1 High Pressure Injection Line Break.................. 1 2.2 Low Pressure Injection Pump and Reactor Building Spray Pump Net Positive Suction Head....... 2 3.0 ' DISCUSSION - CORRECTIVE ACTION / MODIFICATION OVERVIEW..... 4 3.1 HPI Line Break...................................... 4 3.2 LPI and RBS Pump NPSH............................... 5 4.0 SAFETY ANALYSIS RESULTS.................................. 6 4.1 HPI Line Break...................................... 6-4.1.1 HPI Flow Requirements Review;.............. 7 4.1.2 HPI Flow Performance' Review............... 8 4.2 LPI and RBS Pump NPSH............................... 9 4.2.1 Pump NPSH................................. 10 4.2.2 Post LOCA RB Pressure and Temperature Profiles.................................. 10 4.2.3 Post LOCA Offsite. Dose.................... 11 4.2.4 Post LOCA RBS & RB Sump pH................ 11 4.2.5 Other Reassessed Areas'.................... 12 5.0 POST MODIFICATION TESTIhG................................ 12 5.1 HPI Line Break...................................... 12 5.2 LPI and RBS Pump NPSH............................... 14 6.0 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION.... 14 ATTACHMENTS PROPOSED LICENSE CHANGE PROPOSED TECHNICAL SPECIFICATION CHANGES ENGINEERING REPORT 86-1179795-01 ENGINEERING REPORT 89R-1006-02

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1. 0 DESCRIPTION OF PROPOSED LICENSE AMENDMENT AND TECHNICAL SPECIFICATION CHANGE The proposed amendment changes AN0-1 license condition 2.c(1) to increase the authorized steady-state reactor core power level to a maximum of 2568-1 megawatts thermal (100% full power) from the current restriction which is j

80% of full power (2054 megawatts thermal). Additionally, a change to the ANO-1 Technical Specifications involving an increase in Borated Water Storage Tank level and a change to the number of High Pressure Injection j motor operated valves referer.ced in the Technical Specifications are - attached. l 1 - 2. 0 BACKGROUND Two separate issues are involved with respect to the AN0-1 return to 100% full power, that of High Pressure Injection (HPI) line break (Section q 2.1), and that of Low Pressure Injection (LPI) pump and Reactor Building Spray (RBS) pump Net Positive Suction Head (Section 2.2). l l 2.1 HPI Line Break On January 20, 1989, AN0-1 experienced a reactor trip initiated by a generator lockout. Following the trip, plant, conditions required the operators to manually initiate additional HPI flow to the RCS, It' was later discovered that a check valve in the "B" HPI injection line had failed to reseat after HPI flow was terminated. This allowed. ~ reactor coolant to flow into the HPI line.resulting in the line being overheated. This event was described in Mr. T. G. Campbell's letter a to Mr. Jose A. Calvo dated-February 19, 1989 (ICAN028909) and LER 50-313/89-002-00 dated March 31, 1989'(ICAN038906). As a result of the January 1989 transient, ANO' undertook a~ thorough review of the HPI system. This review included a reevaluation of the qualification and ability of both.the individual components and the HPI system as a whole to-withstand all conditions that could result-from transients and steady state operations. During'this review, it i was discovered that a postulated break of an HPI injection line, just l upstream of the RCS cold leg connection and downstream of the first l check valve, could constitute a small break LOCA not previously enveloped by the approved 10CFR50.46 and Appendix K' analyses. AN0 j requested that Babcock & Wilcox (B&W), the nuclear steam supply W system vendor for ANO-1, evaluate the impact of this postulated break on current ECCS evaluations. B&W analyzed the break and concluded ) that the postulated break did not appear to be enveloped by I previously postulated breaks and that the ANO 1 HPI system might not be able to provide adequate core cooling (using conservative Appendix K assumptions) should the break occur at high power operation. This conditicn was promptly reported pursuant to 10CFR50.72 on March 18, 4 l 1989. B&W determined, based upon a comparative analysis of the ANO-1 system with the generic B&W analysis for a similar B&W plant,- that for power operation up to 74% of full power, the current ECCS response'using 1

t the HPI system would provide adequate core cooling in the event the postulated break were to occur. ~ That analysis was the basis for the March 23, 1989 (ICAN038914) License Amendment Request. Upon review of that submittal the NRC issued-Amendment No. 119 to the ANO-1 License (ICNA038905). This amendment limited maximum power to 50% due to the magnitude of the extrapolation from the generic B&W LOCA Evaluation Model analysis (an ANO-1 specific LOCA Evaluation Model -analysis had not been performed for the ANO-1 core). Subsequently an ANO-1 specific 10CFR50 Appendix K analysis of the postulated HPI.LOCA was performed to justify an increase in power operation until permanent modifications could be designed and installed to place the unit back-into conformance with the original small break LOCA assumptions-(1CAN058903). Upon review of that analysis, the NRC issued Amendment No. 120 to the ANO-1~ License (ICNA058904) to. permit operation up to 80%_of full power operation. A design change to the HPI system was developed for installation i during the ANO-1 December 1989 outage to permit _ operation of ANO-1 at -100% full power. Several options were considered prior to the selection-of cavitating venturis as the most viable. This selection was largely based on the passive nature of this design. The design consisted of the installation of. a cavitating venturi in each of the four HPI injection lines-and reconfiguration of the normal makeup line such that it would join the HPI injection line upstream of the cavitating venturi. This design and its basis are further discussed in our letter dated September 26, 1983 (1CAN098903)._ However, during post modification testing, an unexpected high level of vibration was experienced. Consequently, ANO removed the venturis, restored the system to its previous configuration, and continued to limit power to 80%. Additional and previcasly = considered options were reevaluated in order to develop an optimum design to allow 100% full power operation.

2. 2 LPI and RBS Pump Net Positive Suction Head l

In December 1989, while performing a Design Configuration Documentation-(DCO) Project system review of.the ANO-1 Decay Heat Removal.(OHR) system, several calculation errors and inconsistencies were identified which together incorrectly characterized the flow capabilities of the LPI pumps-and RBS pumps when the pumps would be aligned to take suction from the Reactor Building sump. .A description of this event was transmitted to you in our Licensee Event Report 50-313/89-044-00, dated January 15, 1990 (ICAN019008). Several design basis calculations are related to the post LOCA Reactor Building sump conditions and the operation of the LPI_ and RBS-pumps while taking suction from the Reactor Building sump. Conservatively assessed post LOCA operating conditions of the' LPI and RBS pumps, with existing Emergency 0perating Procedure (E0P) -guidance, could have resulted in cavitation of the LPI and RBS pumps and possible vortex formation in the Reactor. Building sump should a LOCA have occurred during power operation. l 2

Specifically-involved in the' assessment of this event were the calculations for.(1) posi LOCA, Reactor Building water level; (2) Net Positive Suction Head (NPSH)~available versus that required for LPI and RBS pumps; (3) post LOCA offsite dose; and (4) Reactor Building sump vortexing. Also involved was E0P guidance addressing Engineered . Safeguards (ES) system flows during Reactor Building sump recirculation. The Reactor Building water level calculation had an incorrect assumption of the available Borated Water Storage Tank (BWST). volume and incorrect accounting for water density. A reduction in available volume was also identified due to nonconservative assumptions with respect to the assumed water volume trapped in the RCS, reactor vessel cavity and incore instrument tube tunnel. Other minor errors contributed to a small reduction in water level. The NPSH calculations for the LPI and RBS pumps both contained a methodology error in accounting for Reactor Building pressure which overestimated the available NPSH for the pumps. Both calculations also~ assumed the incorrect level from the original Reactor Building water level calculation. The original vortexing calculation also contained the same erroneous level assumption. The E0P guidance for establishing proper ES system. flows during Reactor Building sump recirculation was not consistent with the original calculations. The E0P did provide guidance for throttling the LPI and RBS motor operated discharge valves within-indicated flow bands.

However, throttling at certain flow rates within the designated flow bands did' not assure adequate NPSH to prevent Reactor Building-sump vortexing and/or pump cavitation. With the E0P guidance existing at the time of the discovery of.this condition, and with the existing-calculational inconsistencies, there'was not absolute assurance that LPI and RBS pump cavitation and flow vortexing would not occur during operation from the Reactor. Building sump.

Immediate corrective actions were to establish E0P guidance to throttle the pump discharge valves when the pump suction is aligned to the Reactor Building sump, which would-limit LPI and.RBS pump flow to assure the NPSH requirements would be satisfied and assure that sump vortexing would not occur. Additionally, the incore tunnel access-hatch was modified to. assure water from this area would be diverted to the Reactor Building sump in a post LOCA condition. Several calculations were also revised to correct errors and' input assumptions. The results of the revised calculations and analysis evaluations were shown to support the revised E0P. guidance. Systematic reevaluations of the calculations related t'o post LOCA operations were also performed to ensure operational and design considerations were acceptable. The post LOCA Reactor Building pressure / temperature and. Maximum Hypothetical Accident (MHA) assessments were' performed based on the existing 80% power limitation on AN0-1 (License Amendment 120, dated May 16, 1989). Continued operation at 80% power was justified by virtue of the margin i available in the various analyses between 80% and 100% power. Commitments were made in the LER to reevaluate all of the ] calculations relatt post LOCA operation prior to the end of 1R9. l 3 l

3.0 DISCUSSION - CORRECilVE ACTION / MODIFICATION OVERVIEW _ i Permanent system modifications and changes have been developed in order to restore the capability of ANO-1 to operate at 100% full power, and analyses have been performed to demonstrate that these planned modifications and changes will' provide acceptable performance and adequad assm ince that all safety criteria are satisfied. These corrective actions are the result of several options which were considered to identify an optimum solution. As previously discussed, the areas requiring corrective action can be grouped into two major issues; the capability to provide adequate core cooling in the event of an HPI line break and the capability to' provide adequate LPI and RBS pump NPSH when aligned to take suction from the RB sump. _The corrective actions identified-to address these two issues are described below. 3.1 HPI Line Break-The HPI system provides borated cooling water to the RCS during accidents which result in an RCS depressurization. The injection flow provides additional inventory for core cooling and soluble boron for core reactivity control. Of_ the events that require the HPI system, a small break LOCA places the most stringent requirements on the HPI system, since the RCS may remain pressurized above the injection pressure of the core flood tanks and the LPI system. The classic limiting small break LOCA is a break in the bottom of the RCS cold leg pump discharge piping. A special type of small break LOCA is a break in the HPI line near the. RCS (i.e., between the RCS connection and the first~HPI line check valve). It is this specific type of LOCA that modifications have'been developed to address. At. present, the HPI system _has-two trains; each containing an injection pump,'two throttling isolation valves, two flow ~ indicators, and two injection lines. As shown on Figure 1 the injection line connects to the RCS cold legs at the reactor coolant pump discharge. Injection l lines A and D and injection lines B and C are connected downstream of l the isolation valves by crossover lines to allow injection through all four injection lines by either HPI pump. The valves and flow indicators on the injection lines are powered by the same train of safety grade power as the pump which supplies them. In the event of the loss of one train of safety grade power. l concurrent with an HPI line break, only one pump would be available L and all the flow would be supplied through two isolation valves. Since the crossover lines are located downstream of the isolation valves, each valve controls the flow through two cross-connected lines and the injection lines cannot be individually isolated or throttled. This inability to limit individual flow lines can result in inadequate flow to the core due to excessive flow out of the t.roken line. As shown in Figure 2, the planned modification (DCP 89-1012B)-will add four additional injection lines with throttling isolation valves and flow instrumentation similar to the existing lines. The existing injection line cross-connects will be removed since they are no longer needed with the capability of each pump to directly supply 4

flow through four injection lines to the RCS. After the modification is complete each injection pump will be capable' of suppling borated water through _ four lines with individual flow indication and throttling isolation valves powered from the same train of power as the pump. This will allow a broken line to be throttled independently-of the intact lines to provide adequate HPI flow, given any postulable single failure. E0P guidance will be incorporated to direct the operator to throttle the high flow injection line to within 20 gpm of the next highest flow injection line (if only one HPI train actuates). Detailed system modeling of the HPI system response to a spectrum of HPI line breaks and small break LOCAs has indicated that operator action will only be required for breaks approaching a full HPI line break. The new injection lines will connect to the existing 4" lines upstream of the flow elements (FE-1209, FE-1210, FE-1228,- and FE-1230) and wil1~ connect downstream to the existing 2h" lines at the location where the crossover-lines presently connect (the crossover lines will be removed). Each line will have high point vents and low point drains and there will be an additional drain line between the isolation valve and the check valve which'is located directly downstream to facilitate reversed flow testing. Since there will be twice as many flow meters as currently exist, the. flow through the new meters will be approximately one half of that currently and the new flow indication span will be one half of that currently. Chart recording will be added and the instrumentation will be upgraded to Reg. Guide l.97 Type A, Category I requirements to be fully safety grade, since these instruments will potentially be, used to ensure adequate _ core cooling. The ANO Reg. Guide 1.97 programs is_ described in letter ICAN068402. The manual globe valves located downstream of where the new lines t will connect will be pre-throttled and secured in place (stem welded) to provide a balanced system f. low. This pre-throttling will provide an optimum balance which will result in improved flow to the core I through the intact lines in the event of an HPI line break and a limiting single failure (i.e., failure of an emergency diesel generator). This pre-throttled flow will be confirmed by post l installation testing (as described in Section 5.0). New valves installed by this modification will'be tested consistent t with the'AN0 ASME Section XI program for similar valves. A revision to our current relief request dated October 20, 1989~(1CAN108809) to allow stroke testing for_new check valves to be changed-from a-quarterly to refueling frequency"and to allow position indication verification for motor o'perated valves to be performed on a refueling frequency rather than every two years is forthcoming. The pumps will be flow tested in accordance with our IST Program to monitor for degradat(on in accordance with ASME'Section XI, as at present. l' L 5 i

3.2 LPI and RBS Pump NPSH The ECCS provides borated cooling water to the RCS during accidents which produce a significant RCS depressurization. The RBS system provides borated cooling water spray to the RB during accidents which i produce a significant RB pressurization. The HPI, LPI, and core flooding systems are collectively designated as the ECCS, which for the entire spectrum of RCS break sizes terminates the core thermal transient, limits the amount of zirconium-water reaction, and assures that the core-integrity is maintained. The RBS system furnishes RB atmosphere cooling to reduce the RB pressure to near pre-accident-conditions. In addition, the RBS system promotes the removal of the fission products from the RB atmosphere to reduce the airborne fission product inventory available' for leakage. to the environment. The planned changes involve increasing the BWST water level Technical Specification limits (maximum and minimum) and revising the guidance in the E0P to throttle the RBS flow prior to pump suction alignment to the RB sump. Operator flexibility will be optimized by allowing the operator' to throttle RBS flow any time af ter the LOCA and prior to aligning the pump suction to the RB sump. RBS flow chart recording will be added and the instrumentation will be upgraded to-be fully safety grade to meet Reg. Guide 1.97 guidelines for Category 1 Type A variables, since these instruments will be used to ensure that adequate RBS pump NPSH is provided. A similar upgrade of the LPI flow indication is also planned due to various uses or planned uses of this indication in the E0P. All of these modifications are scheduled for completion prior to the end of the IR9 refueling l outage. Throttling RBS flow following a LOCA to provide adequate NPSH and avoid RB sump vortexing has the potential to change the analyzed offsite dose, RB pH and RB pressure-temperature profiles. These and other related analyses have been reassessed to assure acceptable performance at 100% power. A summary of these reassessments is provided in Section 4.2. 4.0 SAFETY ANALYSIS RESULTS The modifications and changes that are planned to allow ANO-1 to operate at 100%~ full power.have been analyzed to determine their acceptability with respect to the effect on safety. The capability of the HPI system te perform its required functions af ter the planned modifications are completed is summarized in Section 4.1. The capability of_the RBS and LPI systems to perform their required functions after the planned modifications are completed, is discussed in Section 4.2. 4.1 HPI Line Break The HPI system providas borated cooling water to the RCS during accidents which result in a significant primary system depressurization. The injection flow provides additioral inventory for core cooling and soluble boron for core reactivity control. The 1 events which require HPI flow, based on a review of t M AN0-1 Safety Analysis Report (SAR) and design basis calculations, sr a small break loss of coolant accident (including rod ejection), a steam line 6

'k break, and a steam generator tube rupture (SGTR). The.large break LOCA analysis does not credit HPI flow, since the primary system depressurizes immediately and allows LPI flow to provide adequate core cooling. No other SAR acci c nt analyses. credit the HPI system since they lead to primary system pressurizations or less significant primary system depressurizations. The HPI system flow requirements and the capability of the ANO-1 HPI system to meet these requirements following the planned modifications are presented below. A more detailed presentation of this information is provided in the attached Engineering Report .(86-1179795-01). 4.1.1 HPI Flow Requirements Review A review of the events which require HPI flow'has identified that the most stringent requirements are placed on the HPI system by a small break LOCA, since the RCS may remain pressurized above the injection pressure of the core flood tanks and the LPI system. As analyzed in the B&W small break LOCA ECCS Evaluation Model, BAW-10154A, July 1985, the HPI system is modeled to provide-flow based on a flow versus pressure table. This table contains the HPI flow rates which have been demonstrated to provide acceptable results for small break LOCA calculations. It should be noted that it is typical B&W practice to perform bounding (or " generic") analyses applicable to all of the B&W plants. Plant specific considerations are then made where they are warranted and justified. The classic small break LOCA is a break in the bottom of the RCS cold leg pump discharge piping. The generic HPI flow rates modeled for this event in the ECCS Evaluation Model are provided in tabular form'as "HPI flow into the RCS", verses "RCS pressure." A special type of small break LOCA is a break in the HPI line itself. The HPI flow rates modeled'for this accident are different from those modeled for the classic small break LOCA, since-the back pressures for the broken and intact lines vary greatly. The HPI flow rates modeled for the HPI line break ECCS analysis are also given in tabular. form. It should be noted that the flow rates modeled in the ECCS Evaluation Model analysis are the actual flow rates required into the RCS and not the total HPI pump flow. The modeled HPI flow also varies due to.the assumed flow balancing or flow isolation (via operator action) that was assumed in the ECCS Evaluation Model analysis. The analysis for a classic small break LOCA in the RCS cold leg pump discharge piping assumed flow belanciiig subsequent to l HPI actuation. The generic'B&W.HPI line break' analysis assumed isolation of the broken HPI line some time after HPI actuation. Although the actual credited operator 1 7

1 action may differ, the applicable flow rate requirements 4 must be satisfied. The HPI flow rates modeled in the generic ECCS Evaluation Model analysis prior to and subsequent to the assumed operator action provide a minimum requirement for the total flows' delivered to the core (as shown by the solid lines in Figures 3 through 6). Any HPI system design must be structured.to ensure that these flows, or at least the integrated equivalent of the modeled flows, are provided within.the time periods specified. While the modeled HPI. flow provides the minimum required flow,-it should be noted that the generic B&W analysis has shown that no core uncovering is expected to occur for both classic small break LOCAs and the specific case of an HPI line break. This provides considerable additional margin to the 10CFR50 : Appendix' K: requirements that peak clad temperature be maintained below 2200 F, 4.1.2 HPI Flow Performance Review The planned HPI system modification will involve pre-throttling the manual globe valves (MU-1231, MU-1232, MU-1233, MU-1234) downstream of where the injection lines of the two trains join. This pre-throttling will be established during post modification testing'to provide a single pump balanced flow within the bounds allowed by-the ECCS analysis. Pre-throttling the manual globe valves in the HPI lines will improve the HPI system response for an HPI line break, improved performance.will occur because the amount of HPI flow lost through the broken line is restricted by the pre-f.hrottle, diverting more flow to' the core through the intact lines.- However, pre-throttling the. manual globe _ valves in the HPI lines reduces the HPI system response for LOCAs other than the specific case of-an HPI line break. Reduced performance occurs because the increased system resistance results in'less-HPI flow into the RCS for any given RCS pressure.- Therefore, since these two types of breaks present competing demands on the HPI system resistance, the HPI system response must be considered for both types breaks to develop an optimum solution for all postulable LOCAs. l The planned HPI system design .been modeled in detail to assess the system response t < spectrum of'HPI'line breaks. The attached Engines.ng Report (86-1179795-01) i summarizes the results of a spectrum of HPI line breaks (including line pinch type breaks). The analysis shows that acceptable results may be analytically demonstrated without operator action. However, guidance will be included in the E0P to throttle.the highest flow - injection line to within'20 gpm of the next highest injection line flow (given only one HPI train actuates). As previously discussed,-this throttling of a single injection line MOV will be required only for breaks 8

i approaching a full HPI line break with a concurrent failure-of an emergency diesel generator. Other breaks will j inherently result in-injection line flows balanced to 1 within 20 gpm; therefore, operator burden is considered minimal. Figures 3 and 4 compare the minimum expected HPI flow performance to the HPI flow modeled in the ECCS analysis-for a RCS cold leg small break LOCA. Figure 3 presents the HPI flow modeled prior to any assumed operator action. For the planned HPI. system pre-throttle and E0P guidance,- no operator action will be required to adjust the HPI f1rw in the event of a classic small break LOCA. Therefore,.the minimum expected HPI flow is equivalent in Figures 3 and 4. Figures 5 and 6 compare the minimum expected HPI. performance to the HPI flow modeled in the ECCS analysis for a full HPI line break. . Figure 5 and 6 represents.the HPI flow modeled prior to and after the modeled operator action,_respectively. It should be noted that the operator actions to be required in the ANO-1 E0P for an HPI line break will be significantly less than that assumed in the ECCS analysis (i.e.,. throttling one injection line flow versus identifying and isolating the broken injection line).. It can be seen from Figures 3 through 6 that adequate margin exists between the minimum expected HPI l flow and the modeled ECCS analysis HPI flow. It should be noted that the conditions for the minimum l expected flow portrayed in Figures 3 through 6 represent bounding conditions. The actual margin between the expected and required HPI flow should be greater since Figures 3 through 6 boundingly account for such. things as pump degradation, post-modification testing pre-T.hrottle line-imbalance, allowed operator balance tolerance and potential-injection flow' instrument error. Following post-modification-testing, verifications will be performed to ensure that the HPI system will perform.within the bounds of the ECCS analysis (including pump degradation allowances consistent with ASME Section XI performance testing). 4.2 LPI and RBS Pump NPSH Due to the complex interrelationship between the various ECCS and'RBS~ l analyses, a change in one or more of the input conditions has the potential to require the revision of many related analyses. This proved to be true for the resolution of the subject pump NPSH inadequacies. -The major areas reconsidered include: LPI and RBS pump NPSH during post LOCA RB sump recirculation Post LOCA RB pressure and temperature profiles Post LOCA offsite dose Post LOCA RBS and RB sump pH l 9 i ~-

The reanalysis of these areas is summarized in detail-in an attached Engineering Report (89R-1006-02). -The major elements of these analyses and the results are summarized below: 4.2.1 Pump NPSH Additional NPSH margin was provided for the LPI and RBS pumps by providing additional water inventory in the RB sump in the event of a LOCA and by revising the E0P guidance to require the RBS flow to be throttled prior to aligning for RB sump recirculation. The additional RB sump inventory is to be provided by an increase in the BWST water level-Technical Specification limits, as identified in the attached change request. Throttling of the~RBS flow serves to both reduce the required NPSH and increase the available NPSH. The impact of reduced RBS ficw has been evaluated and shown to be acceptable.. The expected LPI and RBS flow conditions have been conservatively assessed with the'following NPSH results. ANO-1 LPI and RBS PUMP NPSH DURING RB SUMP RECIRCULATION' REQUIRED AVAILABLE NPSH(ft) Pump Train Flow (apm) NPSH(ft) NPSH(ft) MARGIN RBS A 1320 gpm 11.69 12.68 0.99 RBS C 1320 gpm 11.69 -12.09 0.40 LPI A* 3820 gpm 10.37 11.21 0.84 LPI B* 3820-gpm 10.37 11.21 0.84 A bounding assessment was made for both trains. NOTE: Considerable additional NPSH margin is available due to the RB pressure exceeding the RB-sump saturation pressure. However, in conformance with the conservative criteria of Regulatory Guide 1.1, no credit has been taken for this additional margin. 4.2.2 Post LOCA RB Pressure and Temperature Profiles Throttling of-RBS flow has been conservatively evaluated assuming reduced RBS flow from the initiation of the LOCA. The-impact on the peak.RB pressure and temperature, the RB -pressure and temperature profiles', the EQ temperature profile and the maximum RB sump water temperature have all been assessed and shown to be acceptable. ' Figures 7'and 8 present the RB pressure and temperature versus time for the new response to the DBA.,It should be.noted from Figure 7, that although the RB temperature briefly exceeds the EQ-temperature profile during the injection node, the overall integrated RB temperature profile is conservatively bounded by the EQ temperature profile. 10 l

Additional changes have occurred in the analysis other than the planned reduction in the RBS flow. In response to 4 staff questions, our letter ICAN049003, dated April 4,- 1990, previously identified some of these changes by noting that'the peak post-LOCA RB pressure and temperature had j increased slightly'due to changes in the RB net free

volume.

All of these changes are-described in the attached ~ Engineering Report (89R-1006-02) and.are the result of continuing efforts to maximize the calculational accuracy-of the post LOCA RB pressure and temperature analysis. ] 4.2.3 Post LOCA Offsite Oose The post LOCA and maximum hypothetical accident (MHA) offsite dose has been conservatively evaluated assuming ~ throttled RBS flow from the initiation of the' accident.- Using the iodine removal coefficients, maximum decontamination' factors and other data described-in the attached Engineering Report (89R-1006-02), the dose consequences of the LOCA and MHA events were calculated in a similar manner as the original analyses using the same source terms. Some differences in the evaluation from the original calculation occurred due to the use of the more recent Standard Review Plan which contains less restrictive methods for calculating iodine removal rates. These less restrictive methods are a result of the increased knowledge-(and subsequent lessening of conservatisms previously included to account.for uncertainties) of the. iodine / spray reactions obtained since the original design and licensing of ANO-1. The results, with the current SAR values in parentheses for comparison, are as follows: I

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Maximum Hypothetical ~ Accident--------------

Location Thyroid Whole Body Skin (Rem) (Rem)' (Rem) EZB (0-2hr) 148.1-(151)- 4.66 (8.8) 2.16 (3.7) l LPZ (0-30 days) 51.8~ (50) 1.54 (2.6)- 0.724-(1.3)

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LOCA w/ Gap 4 Release--------------------

Location Thyroid Whole Body Skin (Rem) (Rem) (Rem) EZB (0-2hr) 7.01 (7.02) 0.0165 (.013) 0.0158 (0.016) l LPZ (0-30 days) 2.66 (2.43) 0.0106'(.0082) 0.0135 (0.013) Therefore, it can be seen that the planned RBS throttling can be implemented with only minor changes in the calculated MHA and LOCA offsite dose. 11

4.2.4 Post LOCA RBS and RB Sump-pH. The post LOCA RBS and RB sump pH has been assessed using bounding assumptions for the possible variations in the BWST and NaOH tank levels and concentrations. These calculations resulted in a maximum sno minimum pH for the spray and sump water solutions of 10.4 and 8.F,, which is within the 8.5 to 10.5 range specified by SPP 6.b.2, Revision 1 and well above the 7.0 value specified by SRP 6.5.2, Revision'2. A conservatively bounding.value of 8.5 was used for the minimum spray and sump pH in the offsite. dose analysis. 4.2.5 Other Reassessed Areas Other areas of analysis were also reassessed to determine the impact of the planned changes. These additional areas include the RB sump vortexin0 analysis, the RB sump wateri level analysis,.the BWST seismic analysis and the E0P guidance. All of these-areas of analysis were shown to have acceptable results;for the planned changes, as described in greater detail in the; attached Engineer'ng Report (89E-1006-02). The planned E0P guidance will require the RBS flow to be throttled prior to realigning the RBS and LPI pump suction to the RB sump. The-operator will be given the discretion to throttle anytime prior to transferring to.-RB sump-suction. Applicable analyses have boundingly-assumed that the operator throttles the RBS flow immediately following a LOCA. The planned guidance minimizes the actions required 8 and maximizes the time available for the operator to-implement the actions required to provide adequate RBS and LPI pump NPSH when suction is aligned to the RB sump. 5.0 POST MODIFICATION TESTING 5.1 HPI Line Break-After the installation of the new injection lines is complete, the HPI system will be throttled to balance the injection line~ flows to that required as a result of the detailed system modeling used to determine the expected system response. This will be-accomplished by throttling manual globe valves MU-1231, MU-1232, MU-1233, and MU-1234. High accuracy differential pressure gauges will be-temporarily installed across the injection line ' flow orifices to measure flow through each line during.the test. It is expected that high accuracy test instruments with an accuracy of 11/2% can be obtained, minimizing the test error. To simulate'an RCS pressure of 600 psig, an orifice plate will be machined and. installed in the 4" HPI pump header for each train ~. By virtue of.the location of the orifice plate upstream of the point at which'the individual injection lines separate, the 600 psi pressure drop will. force the pump to operate at the same point on the pump curve as a 600 psig RCS i 12 m

backpressure without affecting the balance between the individual injection lines, thus simulating the actual conditions of 'a small break LOCA (cold leg break). The drop across the orifice plate will be verified to be'at least 600 psig. The detailed system modeling and the post modification test results will provide the required information to verify the predicted sy:, tem performance during a spectrum of HPI line break conditions, since the system has been shown to perform-acceptably by detailed system analysis using proven technology. Unlike the venturis, which were previously proposed to balance the system, all of the components and design features of the new HPI configuration are typical components whose behavior is well-understood. Therefore the primary function' of the post modification HPI flow testing (including pre-throttling) C 'be to demonstrate that the HPI system will perform consistent with that modeled and required for'a small break LOCA, Since throttling the system will, reduce the expected:HPI flow otherwise available in the event of a cold leg small break LOCA, it is planned-to test under the limiting conditions of a small break LOCA. During the testing, since the detailed HPI system flow calculations were. performed assuming an'HPI system balance using an HPI pump with nominal performance characteristics, the pumps will be tested to determine their performance with respect to the vendor pump curve. The system will then be balanced using that'HPI pump whose performance most closely matches the vendor curve. The system will be balanced by aligning the HPI pump in its typical ES configuration (one train of four injection valves) and adjusting the manual globe. valves to obtain a prescribed total system flow (including instrument' error and throttling tolerance), with no more than 27.5% of the flow through any one in,ection line. _ The other train will then be aligned to verify the flow-balance and total flow to the same criteria. The system will be verified using typical ES configurations, which are: the "A" pump-aligned to.the " red" train, the "B" pump aligned to the " red" train, the."B" pump aligned.to the. " green" train, and the "C" pump aligned to the " green" train. Suction will be provided from the discharge of..the LPI pumps in the " piggyback" mode with the HPI pump suction pressure adjusted to approximate the head from the BWST. Consistency of the system performance with the small break LOCA and HPI line break analysis flow requirements will be verified by comparison with minimum acceptance requirements defined by B&W for the post modification testing and by reanalysis of the expected flows (for an HPI line break) using the results from the post modification testing. As is standard procedural practice,- the planned modifications will be reviewed prior to DCP closecut for the inclusion of new components into the various surveillance programs at ANO. Among these requirements are motor operator testing and adjustment for the new M0Vs, baseline inspection of all of the new welds per Section XI, establishment of minimum pump performance requirements in accordance with the assumptions made in the. detailed system flow analysis which will be incorporated into the Section XI inservice testing of the HPI 13 1

f pumps, and reverse flow verification of the new check valves (for which the necessary vents and drain:.will be added by this modification). Although the injection valves are not required to be tested by a type "A" local leak rate test (LLRT), they will be included in integrated leak. rate testing (ILRT). Post modification testing of the HPI flow instrument loops and motor operated valve control loops will also be performed in accordance with standard AN0 procedures. This will include instrument loop functional verification, instrument calibration testing, instrument programming verification, control loop verification, electrical scheme testing, and power cable testing. Incorporation of the instruments into the Environmental Qualification.(EQ) program will ensure adequate documentation of the qualification of the equipment to perform its intended function. 5.2 LPI and RBS Pump NPSH Post modification testing of the LPI and RBS flow instrument loops will be performed in accordance with standard ANO procedures. Loop functional verification and instrument calibration J testing will be performed. Input to the Environmental Qualification (EQ) program will be provided as prescribed by ANO procedure, to ensure documentation of the qualification of the equipment to perform its required function. 6.0 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION Entergy Operations has performed an analysis of the proposed changesLin accordance with 10CFR50.91 (a)(1) regarding no significant' hazards consideration using.the criteria in 10CFR50.92(c)'as follows: l Criterion 1 - Does Not Involves a Significant Increase in the Probability or Consequences of an Accident Previously Evaluated. The proposed change does not involve a-signif.icant increase in the probability or consequences of an accident previously evaluated since previously. analyzed events remain essentially unaffected, as-r described previously in the discussion of the proposed changes. Increasing reactor power to 100% will not involve a significant increase in the probability or ' consequences of an' accident previously evaluated, as the proposed modification to the HPI system ensures adequate flow to provide for accident mitigation. The increase in BWST level along with operator action to throttle RBS valves =to a specified flow will nrovide adequate NPSI for RBS and LPI pumps thus l. not increasing the onsequences'or probability of.'an accident f previously evaluatea. Modifications to the HPI system pipi_ng have been designed to the same criteria as the currently-installed l components such that these changes to the facility design will not increase the probability or consequences of-an accident previously. evaluated. The reanalysis performed demonstrate that the ANO-1 HPI i (; 14 i +1.

configuration along with spec'fied operator actions provide adequatt core cooling in the event of I complete HPI line break at an operating power level of 100% in accordance with our Appendix K LOCA evaluation model. Criterion 2-DoesNotCreatethaFossibilityofaNeworDiperentKind of Accident from any Previously Evaluated, t ' A change in the reactor build 11g spray flow or the borated water storage tank inventory requirenents does not establish a new accident i precursor. The increase of reactor power ;o 10C% will not create the possibility of a'ned or different kind of iccident as the design changes and changes in operator actions unter accident conditions.are consistent with or bounded by the analyzel actions. Changes to the HPI system serve, to reestablish the. design basis and provide no new release paths and introduce no new fat'ure mechanisms. Therefore no new or different kind of accident is ireated by these changes.: Criterion 3 - Does Not Involve a Sig nificant Reduction in the Margin of Safety. The proposed changes do not intolve a significant reduction in a margin of safety since the anticisated system responses, as summarized in the discussion of tie proposed changeb are minor changes to the previously analyzed resul;s. conservative w Increasing reactor power to 100s will not siCnificantly reduce the margin of safety as-the proposui inodifications and-associated operator actions will mitigate the consequences of an accident as previously analyzed. operator action to throttle the;RES valves to a specified flow willIn provide adequate NPSH durin margin will be maintained. g RB st.mp recirculation such that adequate The reanalysis of the Appendix X LOCA Evalustion model has shown that the current margin to safety for l 100% power operation is preservud, therefore no significant reduction in the margin to. safe-t l has been demonstrated by analys y is incurred. An acceptable margin s such that the previous power. l restriction is no longer requira d. l L The Commission has provided guidance concerning the application of the \\ standards for determining whether a igiificant hazards censideration exists. The proposed change most clesely matches (iv): "A relief granted upon demonstration of acceptable operation i from an operating restriction thst was imposed because. acceptable operation was not yet demonstrated. This assumes that the operating restriction aid the criteria to be applied i to a request for relief have beni established in a prior review and that it is justified in a satisfactory way that the criteria have been met." 15 ,w, -w ,w,w - - ~, e. -r .,-en-- ,e. ,---,an, e,--

M 1-j 7 -f Tnerefore, based on th'e reasoning presented above and the previous - discussion of the amendment. request,' Entergy Operations -.has ' determined thatithe' requested change' does not involve.a significant' hazards cons ideration. -- ~ 9 I ? i ~h h

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i FIGURE 3 i HPI FLOW INTO RCS VS. RCS PRESSURE Comparison of RCS Cold Leg Small Break LOCA Required and Minimum Expected Flow i From BatW Document 32-1179793-00 450 - l ) 400 - i Expechd HPI flow

• l 350 -

^ E L ~ CL, a 2 ~~ i 300 - ~, ~ l ~ m ~ O E i 250 - O s F-s Z s j ~ 200 - N N .3 N., 's O 4 s f' a s Lt 150 - N g HPI clow assumed in i z ECCS model pnor to l 100 - me.Ad operator action Minimum expected HPI flow acx:ounting for pump 50 "g degradation and pre-throttle flow split imbalance i N~ L I a i l I I i I i 0 000 600 900 1200 1500 1800 2100 2400 RCS PRESSURE (psig) i

1 I i 1 i FIGURE 4 HPI FLOW INTO RCS VS. RCS PRESSURE Comparison of RCS Cold Leg Sean Break LOCA R%=*ued and Minimum Expected Flow l From BatW Document 32-1179793-00 i 450 - 400'- l' 4 E expected HPl flow * { } $ 350 - ~ ~ ~ -, ~ ,4, t en ~ i O 300 - '~ E i 4 h EO - HPl flow assumed in ECCS g model following modeled O 200 - Wor ach l J = sa. i I 150 - 100 - l

• Minimum expecteo HPI flow accounting for pump degradation and pre-theottle flow split imbalance s-1 0

i i i i i O 300 600 900 1200 1500 1800 2100 RCS PRESSURE (psig) 1 1 'l

i FIGURE 5 l HPI FLOW INTO RCS VS. RCS PRESSURE Comparison of HPI Line Break l 1 Required and Minimum Expected Flow f From B&W Document 32-1179793-00 450 - 400 - l ~ Mh* N s prior to operator action k 300 - 's s s ~ i f/) i O 250 - s EC I o 's Z_. 200 - t s l3: WI h h h i N O i' 150 - ECCS Model prior to. g modeled operator action N g I \\ 100 - i

• Minimum expected HPI flow accounting for pump i

50 - degradation and pre-throttle flow split imbalance 0 l 0 300 600 900 1200 1500 1600 2100 l RCS PRESSURE (psig) i i

d FIGURE 6 l HPT FLOW INTO RCS VS. RCS PRESSURE Comparison of HPI Line Break Required and Minimum Expected Flow From B&W Document 32-1179793-00 i 500 - Expected HPI flow

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balancing at 1200 psig to wettwn 35 gpm (15 gpm to bound potential instrument error) { i i l ^ 400 - i 5. ~_' ~ { S t _ ~ _ ""' ~ -. (o O 300 - ~ - i EE O ~ I i n / i 2 HPI flow assumed in 3: 230 - ECCS Model l O followeg modeled l if operator action it y L 100 -

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degradation and pre-thrMfe flow split imbalance. allowed operator thrMiing tolerance, and potential flowinstrument error. i k o s s s e s s e 0 200 400 600 800 1000 1200 1400 l l RCS PRESSURE (ps?; 4 1 j. ? I k 4 i i

Figure 7 Reactor Building Temperature Versus Time 300- ~ = = EO Profile = = = = = Old DBA 280- -y - - New DBA 1 l 260 - 1 1' 240-N_ O 220-t ] { " 200 - O b u p O 180-g - E 160-O s 140- ~ ( 120-100 .... mi...i .... iiii .. i n iiiii .... i ....y .....i .....y 10 -' 10 - 10 ~' 1 10 10 10 ' 10 ' 10 ' 10 ' 10 ' ime (sec)

Figure 8 Reactor Building Pressure Versus Time 60: Old DBA

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1 1 l 8 PROPOSED LICENSE CHANGE E l l l r

c. This license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter I: Part 20, Section 30.34.of Part 30, Section 40.41 of Part 40, Sections 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below: (1) Maximum Powr Level The licensee is authorized to operate the facility at steady state reactor core power levels not in excess of 2568 megawatts thermal. l (2) Technical _ Specifications The Technical Specifications cantained in Appendices A and B, as revised through Amendment No. 124 are hereby incorporated in the license. The licensee shall sperate the facility in accordance with the Technical Specifications. (3) The licensee may provide with and is required to complete the modifications identified in Paragraphs 3.1 through 3.19 of the NRC's Fire Protection Safety Evaluation (SE) on the facility dated August 22, 1978 and supplements thereto. These modifications shall be completed as specified in Table 3.1 of the Safety Evaluation Report or supplements thereto. In addition, the licensee may proceed with and is required to complete the modifications identified in Supplement 1 to the Fire Protection Safety Evaluation Report, and any future supplements. These modifications shall be completed by the dates identified in the supplement. (4) Obysical Protection The licensee shall fully implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 21817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The plans, which contain Safeguards Information protected under 10 CFR 73.21, are entitled: (a) " Arkansas Nuclear One Physical Security Plan," with revisions submitted through February 24, 1988; 5 1 F

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3.1.2.7 Prior to reaching fifteen effective full power years of operation, Figures 3.1.2-1, 3.1.2-2 and 3.1.2-3 shall be updated for the next service period in accordance with 10CFR50, Appendix G, Section V.B. The service period shall be of sufficient duration to permit the scheduled evaluation of a portion of the surveillance data scheduled in accordance with Specification 4.2.7. The highest predicted adjusted reference temperature of all the beltline region materials shall be used to determine the adjusted reference temperature at the end of the service period. The basis for this prediction shall be submitted for NRC staff review in accordance with Specification 3.1.2.8. The provisions of Specifications 3.0.3 and 3.0.4 are not applicable. 3.1.2.8 The updated proposed technical specifications referred to in 3.1.2.7 shall be submitted for NRC review at least 90 days prior to the end of the service period. Appropriate additional NRC review time shall be allowed for proposed technical specifications ubmitted in accordance with 10 CFR Part 50, Appendix G. Section V.C. 3.1.2.9 With the exception of ASME Section XI testing and when the core flood tank is depressurized, during a plant cooldown the core flood tank discharge valves shall be closed and the circuit breakers for the motor operators opened before depressurizing the reactor coolant system below 600 psig. 3.1.2.10 With the exception of ASME Section XI testing, fill and vent of the reactor coolant system, and to allow maintenance of the valves, when the reactor coolant temperature is less than 280 F the High Pressure Injection motor operated valves shall be closed with their opening control circuits for the motor operators disabled. 3.1.2.11 The plant shall not be operated in a water solid condition when the RCS pressure boundary is intact except as allowed by Emergency Operating Procedures and during System Hydrotest. Amendment No. 57, 83, 95 18a ARKANSAS - UNIT 1

e 3.3 EMERGENCY CORE COOLING, REACTOR BUILDING COOLING AND REACTOR BUILDING SPRAY SYSTEMS _ Applicability Applies to the emergency core cooling, reactor building cooling and reactor building spray systems. Objectivity To define the conditions necessary to assure immediate availability of the emergency core cooling, reactor building cooling and reactor building spray systems. Specificatiot 3.3.1 The following equipment shall be operable whenever containment integrity is established as required by Specification 3.6.1: (A) One reactor building spray pump and its associated spray nozzle

header, 1

(B) One reactor building cooling fan and its associated cooling uni t. (C) Two out of three service water pumps shall be operable, powered from independent essential buses, to provide redundant and independent fitw paths. (D) Two engineered safety feature actuated low pressure injection pumps shall be operable. (E) Both low pressure injection coolers and their cooling water supplies shall be operable. (F) Two BWST level instrument channels shall be operable. (G) The borated water storage tank shall contain a level of 40.2 1 1.8 f t. (387,4001 17,300 gallons) of water having a concentration of 2470 1 200 ppm boron at a temperature not less than 40F, The manual valve on the discharge line from the borated water storage tank shall be locked open. (H) The four reactor building emergency sump isolation valves to the LPI system shall be either manually or remotc-manually operable. l l l Amendment No. 26, 29, 121 36 i

r 370,100 gallons of borated water are supplied for emergency core cooling and l reactor building spray in the event of a loss-of-coolant accident. This amount fulfills requirements for emergency core cooling. Approximately 16,000 gallons of borated water are required to reach cold shutdown. The original nominal borated water storage tank capacity of 380,000 gallons is based on refueling volume requirements. Heaters maintiin the borated water supply at a temperature to prevent crystallization and local freezing of the boric acid. The boron concentration is set at a "alue that will maintain the core at least 1 percent Ak/k subtritical at 70 F without any control rods in the core. The concentration for 1% ak/k subcriticality is 1609 ppm boron in the core, while the minimum value specifiel in the bc rated water storage tank is 2270 ppm boron. Specification 3.3.2 assures that above 350 F two high pressure injection pumps are also available to provide injection water as the energy of the reactor c ulant system is increased. Specification 3.3.3 assures that above 80l' psig both core flooding tanks are operational. Since their design pressure is 600 1 25 psig, they are not brought into the operational state until 810 psig to prevent spurious injection of borated water. Both core flooding tanks are specified as a single core flood tank has insuf ficient inventory to reflood the core.(1) Specification 3.3.4 assures that prior to going critical the redundant reactor building cooling unit and spray are operatior.al. The spray system utilizes common suction lines with the low pressure injection i system. If a single traic of equipment is removed from either system, the other train must be assurec; to be operable in each system. When the reactor is critical, maintenance is allowed per Specification 3.3.5. Operability of the specified comtanents shall be based on the results of testing as required by Technical Specification 4.5. The maintenance period of up to 24 hours is acceptable if the operability of equipment redundant to that removed from service is demonstrated within 24 hours prior to removal. 1 Exceptions to Specification 3.3.6 permit continued operation for seven days if one of two BWST level instrument channels is operable or if either the pressure or level instrument channel in the CFT instrument channel is operable. In the event that the need for emergency core cooling shou'd occur, functioning of one train (one high pressure injection pump, one low prassure injection pump, and both core flooding tanks) will protect the core and in the event of a main coolant loop severance, limit the peak clad temperat.are to less than 2300 F and the metal-water reaction to that representing less than 1 percent of the clad. The service water system consists of two independent but interconnected, full capacity, 100% redundant systems, to ensure continuous heat removal.(4) One service water pump is required for normal operation. The normal operating requirements are grenter than the emergency requirements following a loss-of-coolant accident. i 39 l

~ l erv 4-u... L Engineering Report Data Sheet M A-I N -81 Uniti Aus-1 Categorys 2 f Report No.i f Report Title E* " ~ =* E System (s>i E I' ; L Pl. Wel f.R _5 l 1...m r..a Ecc 5 4 RB s Topic (s>i Ecc6; Pue ewe LTFT. PAi A LacA l klPsW Iminneme=< Plt Areai Bldg. Elev. Cogonent No(s).i PJ.4A4a Room Vatt - Coordinatesi PM Ma J MsteaCti TL' "' # ~ ~^ "

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l Cross References i Initiating Documents Resulting Document (s) Reference Docs. C R - l (. 5 t+ ti,t-loor.-ol DLP # 90 -Io 61 \\ Mn L-acte-oi l s ap 11F 18t817 % - os se-2z. i tit - coed c i i idia - eena -o s .E -Oles - 0 8 l' l H 68 - 6018 -14 o a - ase d - o1 <\\e. s u,4 - o 55 %W E2 - 18824d,5 e0 1 1a euse-oft 5 s7o-rees-et / se-mass to l r Supercedes Report (s)i sy, o n /v U:Wm #nm /1 as-vo Rvw'di - /'/' egg,,',J R.LJ-w rnr. /lEL /r as-9 Apy,d' A -- n M.e, /Ame h ar e. o w a.m.> a.*> Check if Additional Revisionsi Sml ARKANSAS NUCLEAR ONE [

i Engineering Report Data Sheet (Cont.) Report Np M A -Im t. - o 2 Uniti Akte -I Rev.Nor o Verification Methodi Design Reviewi X Alternate Calculationi Oualification Testingi f Pages Revised and/or Addedi h.4 si mfW.t.w ef +Le fat, O 4t b es Obe.uments 1 l= * *I l- Purpose of ReviNni l i Cross References Initiating Documents Resulting Document (s) Reference Docs, 930-iln o s i 44a misv-es < ht-cuas-on 4a elaw-oS 1 I t - esse - 09 t ie -po4+ - # + ~ p -- 1 1 a g cles-ci ~ 7 F t -otto + to k >l6 -ooIG os L m R Gho -L,) [ [H e - oo A - e t Supercedes Report (s>i MA / / Byi W/A / / Rvw'di YA / / Apv'di N/A / / l Chk'd =, u,

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FORM 6C20.003A RE Y. 0 f ENGINEERING REPORT FOR l ARKANSAS NUCLEAR ONE RUSSELLVILLE, ARKANSAS ',t. a ra n w. x ei,- l

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6 W R-N - u O I REPORT WWED REY. ARKANSAS NUCLEAR ONE ~

i s ENGINEERING REPORT 89R-1006-02 RESOLUTION OF DCD IDENTIFIED ECCS & RBS NPSH INADEQUACIES BY: YAlylAISEf vL JE Y HEAD hdM $1M TABLE OF CONTENTS SECTION DESCRIPTION PAGE I BACKGROUND AND PURPOSE 2 II CORRECTIVE ACTION OVERVIEW 3 A. LPI & RBS Pump Performance 5 B Post LOCA RB Water Level 8 C. Post LOCA RB Pressure and Temperature 9 D. Post LOCA Offsite Dose 14 E. Other Supporting enalysis and Reviews 17 III

SUMMARY

AND CONCLUSION 18 IV REFERENCES 18 ATTACHMENTS I I 1 89R-1006.

ENGINEERING REPORT 89R-1001-02 RESOLUTION OF DCD IDENTIFIED ECCS & RBS NPSH INADEQUACIES I. BACKGROUND AND PURPOSE In December 1989, while performing a Design Configuration Documentation (DCD) Project system review of the ANO-1 Decay Heat Removal (DHR) system, several calculation errors and inconsistencies were identified which together incorrectly characterized the flow capabilities of the Low Pressure Injection i (LPI) pumps and Reactor Building Spray (RBS) pumps when the pumps would be aligned to take suction from the reactor building sump. Conservatively assessed post LOCA operating conditions for the LPI and RBS pumps, with existing Emergency Operating Procedure (EOP) guidance could have resulted in cavitation of the LPI and RBS pumps and possible vortex formation in the RB sump should a LOCA have occurred during power operation. Specifically involved in this event were the calculations for post LOCA RB sump water level, Net Positive Suction Head (NPSH) available versus that required for the LPI and RBS pumps, and RB sump vortexing. Also involved was the E0P guidance addressing Engineered Safeguards (ES) System flows during RB sump recirculation. The RB sump water level calculation had an incorrect assumption regarding the available Borated Water Storage Tank (BWST) volume and incorrect accounting for water density. A reduction in available sump volume was also identified due to nonconservative assumptions with respect to the assumed value of water volume trapped in the keactor Coolant System (RCS), the reactor vessel cavity and the incore instrument tube tunnel. The NPSH calculations for the LPI and RBS pumps both contained a methodology error in accounting for reactor building pressure which overestimated the available NPSH for the pumps. Both calculations also assumed the incorrect sump level from the original sump level calculation. The original vortexing calculation also contained the tame incorrectly calculated sump level. The E0P guidance for establishing propar ES system flows during sump recirculation was not consistent with the cricinal calculations. The E0P did provide guidance for throttling the LPI and RBS motor operated discharge valves within indicated flow bands to prevent pump runout. However, throttling to certain flow rates within the designated flow bands to assure acceptable flows to prevent sump i vortexing and/or pump cavitation was not included. With the E0P guidance t existing at the time of the discovery of this condition, and with the existing calculational inconsistencies, there was not absolute assurance that LPI and RBS pump cavitation and sump flow vortexing would not occur during operation from the RB sump. Immediate corrective actions (as documented in reference 1 and 2) were to establish E0P guidance to throttle the pump discharge valves when the pump suction is aligned to the RB sump. This would limit LPI and RBS pump flow to assure the NPSH requirements would be satisfied and assure that sump vortexing would not occur. Additionally, the incore tunnel access hatch was modified to assure water from this area would be diverted to the sump in a post LOCA condition. Several calculations were also revised to correct errors and input assumptions. The results of the. revised calculations and analysis evaluations 2 89R-1006-02

l l have been shown to justify the revised E0P guidance. Reference 1 documents a systematic reevaluation of the calculations related to I post LOCA operations, performed to ensure operational and design considerations were acceptable. The post LOCA reactor building pressure / temperature and maximum hypothetical accident assessments were performed using the existing 80% power limitation on ANO-1. Continued operation at 80% power was justified using the margin in the accident analysis between 80% and 100% power. Commitments were made to reevaluate all of the calculations related to post LOCA operation prior to the end of refueling outage IR9. The purpose of this engineering report is to document the long-term corrective actions required to provide adequate ECCS and RBS NPSH when taking suction from the reactor building sump and justify a return to 100 percent power operation. II. CORRECTIVE ACTION OVERVIEW As evidenced by the subject of this report, the primary issue requiring resolution to allow ANO-1 to return to 100% power operation is the provision of adequate ECCS and RBS pump NPSH. There are several variables which directly affect the NPSH that can be changed without significant plant modifications. These variables, along with their respective advantages and disadvantages, include: RB sump water level increase advantages - directly increases available NPSH at any pump flow rate disadvantages - requires large volume to make small change; will impact calculated high level for EQ considerations RBS flow reduction advantages - increases available NPSH and reduces required NPSH - has great impact due to long pump suction lines and minimum NPSH margin disadvantage - impacts maximum hypothetical accident (MHA) dose calculation and RB pressure / temperature analysis; requires operator action LPI flow reduction advantnes - increases available NPSH and reduces required NPSH disadvantages - impacts RB pressure / temperature analysis; requires operator action Other possible changes include reducing the pump NPSH requirements by physical pump modifications and increasing the available NPSH by modifying the pump suction piping. Unfortunately these options are both costly and time consuming with potentially only minimal affects. Table 1 details many of the possible options considered to provide t. .tional pump NPSH. From these options, additional NPSH has been chosen to be provided primarily by throttling the RBS flow when the pump suction is aligned to the RB 3 89R-1006-02

~ sump. LPI flow is already limited by the existing injection line cavitating venturis. Additional NPSH is also to be provided by increasing the BWST Technical Specification low level limit. Therefore, the planned changes can be summarized by, RBS flow - limited to 1050 gpm to 1200 gpm during recirculation LPI flow - limited to less than 3820 gpm by cavitating venturis BWST level - increase high and low level limits to 40.20 1 1.8 feet. References 5 and 6 document the adequacy of the pump NPSH during RB sump recirculation for the LPI and RBS pumps, respectively. Table 2 summarizes the results from these analyses. From Table 2 it can be seen that the resulting LPI and RBS pump NPSH is adequate to provide acceptable performance when aligned to the RB sump following a postulated LOCA. Due to the complex interrelationship between the various ECCS and RBS analyses, a change in one of the input conditions has the potential to require the revision of many related analyses. This proved to be true for the subject NPSH inadequacies and the subsequent changes identified above to restore adequate LPI and RBS NPSH. The general areas requiring reconsideration were: LPI and RBS pump performance during post LOCA sump recirculation Post LOCA RB Water Level Post LOCA RB pressure and temperature profiles Post LOCA offsite dose Other supporting analyses and reviews The reconsideration of these areas was iterative in nature, due to Oc m1ysis interrelationships and the number of options explored. In general, the reassessment of the affected analyses was performed as follows: (1) Identify sources to increase the RB sump post-LOCA water level (i.e., increase minimum BWSi water level). (2) Determine the RB sump water level (minimum and maximum). 1 (3) Ensure adequate Environmental Qualification (EQ) submergence protection. (4) Assume LPI, HPI and RBS flows while ensuring acceptable operator response / burden (identify potential modifications if necessary - i.e., upgrade indication to be consistent with credited operator usage). (5) Determine LPI, HPI, & RBS sump recirculation NPSH (repeat items 1 to 4 as necessary to get acceptable results). 1 (6) Determine post-LOCA RBS and RB sump pH. (7) Determine post-LOCA offsite dose (repeat items 1 to 6 as necessary to get acceptable results). 4 4 89R-1006-02 I

(8) Determine post-LOCA RB pressure and temperature profile (repeat item 1 to 7 as necessary to get acceptable results). l (9) Review / revise related analyses and documentation to ensure consistency with items 1 to 8 (repeat items 1 to 8 as necessary to get consistency). The actions taken for each of these general areas is discussed below. Due to the complex interrelationship between the analyses involved, this discussion provides considerable detail for some of the areas of analysis. This. detail is s provided in an effort to avoid the calculational inconsistencies that led to this reevaluation of the LPI and RBS pump performance. A. LPI and RBS Pump Performance As previously discussed, adequate NPSH is to be provided primarily by throttling the RBS flow when the pump suction is aligned to the RB sump. Additional NPSH is to be provided by increasing the BWST Technical Specification low level limit. The proposed Technical Specification limits for low and high BWST water level are 40.20 feet 11.80 fact. This change has been assessed for its impact on all affected analyses, os summarized in this and other sections of this report. The recirculation mode LPI and RBS flov rates to be allowed in the E0P are given b.v. LPI flow - less than or equal to 3820 gpm RBS flow - 1050 gpm to 1200 ;;.. RBS Flow Considerations The required RBS throttling can be accomplished prior to switchover to RB l' sump suction and can remain in place during recirculation without causing an unacceptable impact on the spray pattern for iodine removal or the RB pressure-tempt "** for equipment qualification (see sections II.C and D for additional i., Throttling of the RBS flow to provide adequate NPSH requ 'mation). use of the RBS flow indication in the control room. The existing RBS fivw indication complies with the requirements for Category "2", Type "D" instruments as defined in NRC Regulatory Guide 1.97. The use of the RBS flow indication to assure adequate RBS pump NPSH via throttling requires the indication to be upgraded to a "Q" active status and to comply with the requirements for Reg. Guide 1.97 Category "1", Type."A" instruments. ANO Design Change Package (DCP) #90-1043 (reference 8) documents this RBS flow instrumentation upgrade. The DCP also documents a similar upgrade of the LPI flow indication due to its use in the E0P for the HPI and Emergency Feedwater (EFW) termination criteria and its proposed use to address a window of small break LOCAs that could result in combined high LPI and HPI flow. It should be noted that investigations were made into the potential to limit the RBS flow passively via orifice plates. Reference 20 documents orifice plate sizing analysis to limit the RBS flow to between 1000 ppm and 1200 gpm subsequent to a LOCA. Passive flow resistance is not currently being pursued in an effort to maximize operational flexibility (i.e., to maximize RBS flow during the initial injection and to provide flow control capability should degrading conditions develop). 5 89R-1006-02

h The RBS flow is actually subject to variations due to the allowed operator throttling tolerance (1125 gpm 175 gpm) and due to potential instrument l error (reference 7). The applicable variations have been considered to be independent and essentially random, although it could be easily argued that this is conservative and that the operator throttling tolerance is not completely random. The operator should tend toward the middle of the allowed tolerance band, correcting to this mid point if flow strays near the edge of the allowed band. However, it is also recognized that one could argue that the operator might delay until near the edge of the allowed band to correct to the midpoint. Per Reference 15, independent and random errors can be combined by means of the square root of the sum of the squares. Using this methodology, Reference 34 has assessed the potential RBS flow variations due to the combined effects of the allowed operator tolerance error and the instrument loop error. These potential RBS flow variations are 1014.83 gpm to 1308.78 gpm. Correspondingly, the minimum RBS flow effects have been conservatively assessed at 1000 gpm while maximum effects have been conservatively assessed at 1320 gpm, as shown in Table 2. i LPI Flow Considerations No manual action is required to assure the allowed LPI flow since it is the maximum expected due to the flow limiting cavitating venturis. Attachment I documents test results which indicate a maximum flow through a cavitatir.g venturi of 1910 gpm. Page 17 of reference 32 documents the expected flows for the limiting case of an LPI line break, demonstrating that the expected flow is bounded by the 1910 gpm test results. With two venturis per train, the maximum train flow is not expected to exceed 3820 gpm. Higher LPI pump flow could occur due to additional HPI " piggyback" flow if the HPI termination criteria (3100 gpm LPI flow for 20 minutes; for single train operation or 2650 gpm LPI flow for 20 minutes for two train operation) from the E0P (reference 4) is not met prior to establishing RB sump recirculation. Reference 3 conservatively assesses the expected LPI flow and the capability to meet the HPI termination criteria subsequent to a spectrum of small-break LOCAs. This assessment identifies a small " window" of breaks around approximately 0.03 to 0.05 ft2 for one train operation and around approximately 0.06 to 0.10 ft2 for two train operation that is potentially of concern. Breaks larger than this window, up to a complete 7.1 ft2 guillotine hot leg break, have adequate injection flow such that HPI will be secured prior to aligning for RB sump recirculation. Breaks smaller than this window physically restrict the combined HPI and LPI flow such that adequate LPI pump NPSH is assured. Since a potential small-break LOCA window of concern has been identified for which adequate ECCS NPSH may not be assured, specific consideration was taken for this condition and it has been concluded that this window can be adequately accommodated within the design basis. This conclusion is based upon the following considerations: 6 89R-1006-02

the low likelihood of the occurrence of the specific break " window" of concern the short duration of the high flows during the potential window of concern the expected presence of a RB pre sure in excess of the sump saturation pressure providing adequate NPSH the inclusion in the E0P of specific guidance to limit HPI flow during piggyback conditions with high LPI flow These considerations are discussed in greater detail below: l 1. As discussed previously, the window of concern is limited to only a small range of small-break LOCAs. In addition, the minimum water level calculation (reference 12) assumes a high elevation hot leg break that maintains the RCS full of water. Lower elevation RCS breaks would provide more RB sump inventory for LPI pump NPSH, further minimizing the small window of concern. 2. The window of concern occurs because the HPI and EFW termination criteria (>3100 gpm LPI flow for 20 minutes - one train or >2650 gpm - two trains) is not satisfied prior to establishing RB sump recirculation. During S.e conditions of concern, the LPI flew is well in excess of the required flow rate, however the 20 minute criteria is not yet satisfied. Once it is satisfied HPI flow can be terminated, eliminating the window of concern (i.e., LPI flow limited to 3820 gpm). Therefore the window of concern will exist for a duration not expected to exceed 20 or 30 minutes. Any postulable cavitation is expected to be of a magnitude such that operation for this short period would not lead to pump damage. Cavitation induced flow degradation is not a problem since this is an excess flow condition. 3. During post-LOCA recirculation the RB pressure exceeds the saturation pressure of the RB sump water, as shown in Table 3. NRC Safety Guide 1 (reference 14) states that no credit should'be'taken for this excess pressure to provide adequate ECCS and containment heat removal system NPSH. This position is maintained for the entire ANO-1 LOCA break spectrum, although only minimally for the identified small window of concern. Recognizing that 1 psi is equal to more than 2 foot of head, Table 3 shows that the expected RB pressure in excess of the sump saturation pressura provides considerable additional NPSH during post LOCA RB sump recircu1 Rion. 4. Specific E0P guidance is to be added to-throttle the HPI flow to approximately 100 gpm during high LPI flow piggyback conditions (LPI flow >3300 gpm). In addition a caution is expected to be added to the E0P to alert the operator to the possibility that under high LPI flow piggyback conditions, LPI pump NPSH margin may be minimal. This provision of minimal NPSH is based upon an extrapolation of references 5 and 6 to 3950 gpm (3800 gpm + 150 gpm) LPI and 1320 gpm A RBS flow conditions. At these conditions the "B" RBS pump is 7 89R-1006-02

l l estimated to be limiting with a not NPSH margin approaching 0.1 foot prior to accounting for the excess RB pressure. B. Post LOCA RB Water Level Since the BWST Technical Specification minimum water level limit will be increased to provide additional water for LPI and RBS-pump NPSH during sump recirculation, the impact of this additional water level was assessed for both the maximum and minimum post LOCA sump water level conditions. The reassessment also provided the opportunity to check the consistency of the new calculational assumptions with planned operating practice and phenomenological understanding. Previously identified discrepancies (reference 1) had resulted in a reduced minimum post LOCA sump water level. An increase in the minimum required BWST water level provided a means to restore some of this reduced sump water level. Reference 12 concludes that the new minimum post LOCA RB sump water level will be 4.51 feet above the 336'-6" RB floor level. A minimum injected water height of 32.3 feet was assumed for the BWST in this calculation. This height is conservatively 0.1 ft less than the minimum expected with the new Technical Specification limits, as calculated in reference 18. The maximum post LOCA sump water level (reference 13), which conservatively considers the maximum addition of potential water sources to the RB sump, was also reassessed to determine the impact of the incrused water addition from the BWST. Of principle concern in this analysis was the potential for submergence of equipment not environmentally qualified to be submerged. In the reassessment of the maximum post LOCA water level, additional increases in the potential water level were caused by the increase in the BWST level and by the use of more conservative assumptions for the water held-up in the RCS. The maximum water level, as determined in reference 13, following a large break LOCA is 9.18 feet above elevation 336'-6" and 8.88 feet for a small break LOCA (different flood levels result due to assumptions related to the expected blowdown phenomena, the corresponding RCS voiding and refill and the expected BWST drawdown). These increased maximum water levels have not resulted in the submergence of any additional EQ components not qualified for submergence. 1 Reference 30 suunarizes t1 EQ component review. It should be noted that during a large break LOCA that the potential exists for some of the Emergency Feedwater Initiation and Control (EFIC) steam generator (SG) water level transmitters to be slightly submerged. However, SG cooling during a large LOCA is physically impossible due to RCS voiding, so no required functions would be lost. As previously discussed, the EFW pumps should be secured prior to depleting the BWST (time of maximum sump level) so if the transmitters were to fail low if submerged, SG overfill would not occur. During a small break LOCA, when SG cooling is potentially possible, the EFIC SG 1evel transmitters are not submerged. In addition, the conservative accounting of potential water sources makes the calculated levels very unlikely. 8 89R-1006 9

C. Post LOCA RB Pressure and Temperature When evaluating changes to the post LOCA RB pressure and temperature profile.there are five major issues: 1) Peak RB Temperature 2) Peak RB Pressure 3) RB Pressure Profile 4) EQ Temperature Profile 5) Maximum RB Sump Temperature The effects of reducing the R3 spray flow and increasing the BWST volume on each of the above areas has been assessed and shown to be acceptable, as discussed below. Backaround - ANO-1 containment pressure and temperature analysis is performed by Bechtel using the COPATTA computer program, which is designed to analyze the effects of a LOCA on a reactor building. The original Design Basis Accident (DBA) Safety Analysis Report (SAR) analysis was revised in SAR Amendment No. 7 by calculation 88E-0098-02 Case 2 (reference 11). Presently, this is the current DBA analysis calculation. Several analyses have been performed since reference 11 was incorporated ir,to the SAR to assess the relative impacts of several minor discrepaN:ies on issues related to the original analyses. These are illustrated in Table 5. 1 The first of these re-analyses is calculation 88E-0098-10 (reference 17) which was performed to account for an error in containment net free volume. Additionally, the following changes were incorporated in this analysis: 1) Net free volume reduced 2) BWST temperature increased (the older value was not considered i bounding) 3) Hydrogen recombiner heat loads added (previously judged acceptable) 4) Instrument errors on the BWST level accounted for I This analysis was performed to support a Technical Specification revision to correct'the ANO-1 containment not free volume listed in section 5. However, this proposed change will be submitted later due to reasons discussed below. Several additional C0PATTA analyses were performed specifically to address the sump NPSH issue. Each is documented in calculation 88E-0098-14 (reference 10). These analyses incorporated the upgrades made in calculation 88E-0098-10 plus l 1) Accounted for the containment cooler performance data inaccuracies l 2) Larger BWST volume 302,574 gals Cases 1 and 2 312,210 gals Case 3 1 3) Reductions in R8 spray flow 9 89R-1006-02 l

i 4 Ca ws 1 and 2 use identical inputs except for the spray flow during injection. Case 1 used 1000 gpm spray flow throughout the transient and Case 2 used 1500 gpm during injection and 1000 gpm during recirculation. The new DBA analysis is Case 3, which is identical to Case 1 except Case 3 used a recirculation time based on a BWST volume of 312,210 gallons. This is the planned minimum credited 8WST injection volume. Additionally, Case 3 conservatively assumes 1000 gpm spray throughout the transient to 1 conservatively account for the planned operator action to throttle RB spray before recirculation. In reality spray flow will initially be higher. Each of the changes identified above are described below along with the effects they have on the COPATTA results. Table 5 gives a summary of all of the above changes. The results of these analyses are summarized in ] Table 6 with temperature and pressure profiles given in Figures 1, 2 and 3 3. Peak RB Pressure and Temperature - The peak RB pressure and temperature j occur within tne first minute following a large break LOCA (reference 11), i well before sump recirculation or pump throttling would occur. l Additionally, the RB analysis conservatively assumes that the RBS does not I start until after 300 seconds from the initiation of the LOCA, which is well after the peak pressure and temperature occurrence. Therefore, the peak RB pressure and temperature are not affected by throttling of ECCS or RBS pumps prior to R8 sump recirculation. Note, a small increase in peak pressure and temperature occurred during the DBA reanalysis (reference 10), but this increase is attributed to a smaller net free volume assumed in the analysis than that used previously. The smaller volume is the result of an error identified in the original calculation. When the value was used a slight increase in the peak pressure and temperature occurred. This change is the sole contributor to the increase in peak pressure and temperature which occurs at 20 seconds into the analysis. All other changes have no effect until after 300 seconds. The net free volume used in this analysis has been conservatively assumed to be 1.83x108 fta based on refertnce 31. Additional errors have since been identified in reference 31 which will return margin to the net free volume. Additional effort is presently being undertaken to restore as much additional margin as possible to the net free volume calculation. Preliminary estimates are that when completed. there will be no not changes to the RB peak pressure and temperature values. In any case, resolution of these minor issues does not affect the resolution of the NPSH issues described previously. RB Pressure Profile - The temperature and pressure profiles resulting from the reanalysis using throttled spray flow (reference 10) have been compared to the old profiles (reference 11) and included as figures 1 and 2. Figure 1 compares the temperature profiles from the old and'new DBA analysis. Additionally, the EQ profile is drawn on this figure to show that both temperature profiles are essentially bounded. Post 'OCA pressure profiles have been compared on Figure 2. 10 89R-1006-02

l t Previous analyses (reference 11) assumed recirculation mode flows of 3000 gpm for LPI and 1500 gpm for RBS. The effect of reduced RBS flow during recirculation has been analyzed to determine if the long term building i pressure and temperature response is impacted (Reference 10). The results of the analysis show that RB pressure and temperature are minimally affected. Sensiti/ity studies were performed that showed as long as l minimal flow (approximately 500 gpm) exists to maintain the RB atmosphere humidity, then the RB cooler performance is unaffected by RBS flow reductions and only minimal changes occur in the temperature profile. The LPI cooler. which is the major means of heat removal during recirculation, l 1s not aitected by RBS flow variations since it is cooling water directly l from the RB sump. It is partially for this reason that RBS flow has been throttled and LPI flow maximized in the planned E0P guidance. In a continuing effort to maximize the calculational accuracy, several input parameters to the DBA containment analysis have been changed besides j the RB spray flow and BWST volume. The following three parameters are the only changes which have had noticeable effects on the results. (Other I j l changes include increasing the BWST temperature from 85'F to 110'F and adding hydrogen recombiner heat loads.) 1) Smaller net free volume 2) Smt.11er decay heat 3) Reduced containment cooler performance l The smaller not free volume has the biggest effect on the peak pressure l and temperature as previously discussed. Additionally, the smaller net free volume leads to slightly higher temperatures and pressure across the i

profile, i

During a review of the DBA input parameters it was identified that the decay heat was multiplied by two safety factors. This conservative error was corrected, which resulted in a substantial decrease in the time to return the containment temperature below 140'F. Reference 17 evaluated the smaller containment volume and corrected decay heat. This evaluation produced a time to return to below 140'F of 6.4 days as opposed to 7.9 days in the original analysis (reference 11)~. As car, be seen in Figure 1, I this effect is still present, with a time to return to below 140'F of 5.2 i days for the new analysis. Containeer$t cooler performance data was also updated in the new DBA analysis. This data reflects corrections to the cooler performance data identif" by American Air Filter. Additionally, the new data was reduced by 5% tt, conservatively account for the accuracy of the computer model which determines the performance data. This potential inaccuracy was not accounted for in the past, but for conservatism it has been incorporated into the new DBA analysis. A slight increase in the containment temperature (approximately l'F) across the profile was noticed as a result of this change. The parameters identified above have accounted for most of the major changes that have occurred in the pressure and temperature profiles. I Figure 3 indicates the effects of a larger BWST volume (302,574 gais), 11 89R-1006-02 m m ,,._.,,._,._,,,._,.c,._- -,.,,.~% ,,,,mw.,

reduced containment cooler performance, and reduced RB spray flow only at recirculation (reference 10, case 2). F10ure 3 also indicates the effects of a larger BWST volume (302,574 gals), reduced containment cooler performance, and reduced RB spray flow at injection and recirculation (reference 10, case 1). As can be seen from these curves, the reduced RB spray flow and increased BWST volume have negligible effects on the temperature profile. Reducing RBS flow at the initiation of injection leads to slightly higher RB temperatures during injection; however, increasing the RB sump water volume and reducing the recirculation rmde RBS flow tend to reduce the RB temperature. E0 femoerature Profile - An evaluation of the new DBA temperature profile i ias been conducted (reference 9) to evaluate the changes to the curve. The new DBA profile crosses the EQ profile at several points for brief durations early in the transient, but as indicated in the evaluation, the redu:md temperatures for the long term cooldown (after 3700 seconds) substantially offsets these points. Therefore, it has been concluded that the bounding environmental qualification of equipment profile for the l ANO-1 DBA LOCA has not been impacted by the RB spray pump flow throttling (reference 9). It should also be noted that the ECCS flow rate 3 assumptions of 3500 gpm during injection and 3000 gpm during recirculation were cor.servatively left the same.' Trade-off studies have indicated that-a small increase in LPI flow post-injection results in substantial reductions in the time to return the containment temperature below 140'F. The new E0P guidance will allow the operators to throttle RBS flow any time prior to transferring to recirculation mode. Due to the actions required upon the initiation of a LOCA, it is expected that RBS flow throttling will not occur early in the injection mode. Wh6n the operators do throttle, guidance will be given to throttle RB5 flow to between 1050 and 1200 gpm. Since, spray flows in excess of 1700 gpm can be expected during most of the injection mode, this will offset the slight increase in temperature shown in Figure 1 during the injection mode. The new DBA, Case 3 of reference 10, assumes RBS flow of 1000 gpa during injection and recirculation. Additionally, the E0P guidance will not direct the operators to throttle LPI flow unless pump runout conditions exist, thus allowing flows up to approximately 3800 gpm. This additional LPI flow during recirculation will substantially reduce the time to return containment temperature below 140*F. The new DBA analysis has been chosen as Case 3 of reference 10, due to the conservative assumption of 1000 gpa RB spray flow at injection and a BWST level that is based on the proposed Technical Specification limit. As can be soon in Figure 1, this new DBA temperature profile crosses the EQ profile at several points within the first hour, then is bounded by the EQ profile for the rest of the transient. As indicated above, reference 9 has evaluated the inputs of this apparent discrepancy. If the above conservatises (i.e., greater spray flow at injection) were removed, one could see that representative assumptions would essentially maintain the temperature profile within the EQ profile. If 1500 gpm RB spray is i assumed at injection, which is a realistic assumption based on the proposed E0P guidance, (as was done in reference 10 case 2) the EQ profile is maintained. This can be seen in Figure 3. Therefore, even thcugh the ~ 12 89R-1006-02

i new DBA profile crosses the K profile it is obvious that representative assumptions would produce resu',ts that are within the EQ profile. l Maximum RBS Sump Temperature - The maximum sump temperature at the time of recirculation has increased from 250*F in reference 11 to 255'F in the new reference 10 analysis. This slight increase in temperature, even with the BWST increased volume, is considered a result of the following changes: 1) Smaller net free volume (~1*F) 2) Reduced R3 cooler performance curves (~3'F) 3) Increased BWST temperature (~1'F) 4) More conservative assumptions in the BWST volume and time to recirculation (minimal) The sump temperature at the time of recirculation is taken as the saturation temperature at the containment building pressure. Therefore, [ increating-the pressure by reducing the net free volume and cooler q! performance curves increr m the Jump temperature. The minimum credited BWST vo use that is modeled to be injected has i increased from 291,463 gallors assumed in reference 11_to 312,210 gallons, i It should be noted that the 2'1.,463 gallons did not properly account for_- ( instrument errors and was app oximately 11,000 gallons greater 'han it should have been (see reference 17). The difference between the above two volumes allowed for approximately 277 additional seconds of injection from the BWST. (312.210 --291.463) (60 sec/ min) = 277 seconds (1000 + 3500) This offset a 300 second error assumed in the original DBA analysis. In the original analysis 300 seconds was added to the BWST depletion time, which is the time at which COPATTA starts modeling the ECCS flow and Rt35 flow. However, the first 300 seconds of ECCS flow was not accounted for; leading to a longer assumed time to recirculation.- The increased BWST level has been offset by the above error. Hence the other changes to the 3 input parameters led to a 5'F increase in the-sump. temperature at recirculation. A review crf the ECCS and RBS sump suction piping qualification (reference

25) indicates that a sump water temperatut e of 255*F is acceptable and well within the piping stress allowables. The LPI piping that is used for decay heat removal operation from the RC3 hot leg is qualified for 280'F (reference 33) and is therefore not affected by sump temperatures less than 280'F. The HPI piping can'be aligned to the LPI cooler outlet during piggyback operation.

Reference 3 conservatively assessed the peak post LOCA LPI cooler outlet temperature to be 210'F-for a 2S0*F peak RB sump temperature. Reference 27 qualified the HPI piggyback piping fc: 240*F, providing 30'F of margin M*.een the potential ~ procers fluid toeperature and the piping qualification w perature. Therefore, the 5'F increase in the post LOCA RB sump temperature to M 5'F is bounded by previously analyzed margins. 13 89R-1006-02

l D. Post LOCA Offsite Dose While it is anticipated thet ~ full RBS. flow will be available throughout most of the injection phase, the dose consequences of reduced flow during l both the injection and recirculation phases were conservatively determined to provide bounding values. The impact of throttled or reduced RBS flow accompanied by an increase in the BWS1 water level is manifested 1) in reduced efficiency of the spray itself for cleansing the post-LOCA i containment atmosphere and 2) in sump and spray pH effects that could reduce the iodine retention capabilities of the spray solution. The following discussion summarizes the results of two engineering calculations, references 19 and 21, which evaluated these two issues.- Additional contributing factors and the overall results are also 4 womarized below. i f Reactor Buildina Spray Efficiency - The efficiency of spray in removing iodine from the RB atmosphere is dependent upon two factors direct 1) affected by the RBS system flow rates: droplet size and the volume of the RB actually sprayed. These two factors have been examined,-based uten data supplied by the spray nozzle vendor and first principle calcula'. ions, v to determine the effect of reducing spray flow to 1000 gpm from the original design flow of 1500 gpm. At the original design flow of 1500 gpm, the average pressure drop across the spray nozzles was 40 psig. Reducing flow to 1000 gpm reduces this presst're drop. to about 18 psig. Frw a correlation relating droplet size. I to differential pressure, it was determined that, when spray flow is reduced to 1000 gpm, the mass median droplet size is increased 31% from that obtained at the 1500 gpm flow rate used in the original design-calculations; i.e., 0.1163 cm vs. 0.08877 cm. An examination of Figure 6.2-22 of the ANO-2 SAR (provided as Attachment 2 for ease of reference) indicates that the original droplet mass median size of 0.08877 cm was 1 conservatively larger than the laboratory measurements for these spray nozzles so that the same level of conservatism could be expected to exic with the reduced flow rate droplet size. (ANO-1 and ANO-2 have identical spray nozzles.) The volume of the RB actually sprayed is dictated by equipment and spray nozzle placement and the diameter of the spray cone delivered from each nozzle. Since no rodifications were made to the original spray A.eader arrangement, the ofTect of reduced flow on the diameter of the spray cone from the nozzles was examined. A first principles calculatica of the spray cone diarater for a-flow rate of 1000 gpm was shown to closely agree with the vendor supplied data for the nozzles under those conditions. The same calculation also yielded a value for the terminal. velocity, and hence, the fall time of a mWian droplet. This data indicates that the reduction in spray flow rate causes only a small reduction in the spray cone diameter used in the original design. This reduction in diameter should easily be masked by air currents induced by the spray droplets 1 themselves during their fall through the upper RB atmosphere. These spray characteristics were then used to determine the iodine spray removal coefficients using the methodology in Standard Review Plan (SRP) 6.5.2. Revision 2 (December 1988). This SRP states that it may be adopted 14 89R-1006-02 y. O

g voluntarily and reflects the increased knowledge of iodine / spray reactions obtained since the original design and licensing of ANO-1. In some I instances this revision of the SRP removes unnecessary conservatisms as a result of this increased knowledge. The spray removal coefficients-calculated differ from the current SAR values due'to the difference in methods and the difference in spray characteristics resulting from the reduced flow. The not results, tabulated for comparison, indicate a slight increase in containment atmosphere cleanup of elemental iodine i species!but a significant improvement for particulate species. Organic j species of iodine are assumed, in both cases, to remain in the atmosphere 1 in spite of the spray. Removal Coefficient New Results Current SAR Values elemental (91%) 11.5/hr 10.0/hr, i . particulate (5%) 2.6/hr* 0.72/hr organic (4%) 0/hr 0/hr

• drops to a factor of 0.26/hr after the particulate aerosol mass has been reduced by a factor of 50.

Reactor Building Sump and Spray pH and Iodine Retention -'The RB sump and spray pH would be only slightly affected by the acidity of,the additional borated water added to the BWST. However, the reduced flow rates and-additional BWST driving head were expected to alter the NaOH tank drawdown rate causing a pH variation from the initial design. In order to quantify these effects, the entire reactor Duilding spray system was modeled to determine the expected NaOH drawdown rate (References 20'and 22). Using the original design conditions, this model "ompared well with the one used in the original design calculations, lending confidence in its~ results at the proposed new conditions. As in the original design calculations, this model was used to determine NaOH and borated water flow ratacinputs for pH calculations under a variety of limiting conditions including single failures and extremes of allowable BWST and NaOH tank levels and concentrations. Due to the iterative nature of the analyses cddressins the NPSH concerns, bounding cases were examined to determine th? expected range of pH values.- The bounding cases were based upon current Technical Specification allowable NaOH and boron concentrations and a rango of' tank levels. The tank levels used were: Tank Levels (ft) BWST NaOH 40.75 +1.75/-1.85 34.0 +1.87/-3.16 39.20 +1.80/-1.80 which encompass the planned Technical Specification levels for the BWST and the current Technical Specification levels of 34 +1.0/-0.8 feet for the NaOH tank. These bounding analyses resulted in worst case spray and sump pH values ranging between 8.50 and 10.92 when mixing of buffered and unbuffered spray droplets is assumed. These values are well within the allowable range provided by the SRP and provide assurance that the value of 8.5 assumed for the dose. calculations is bounding. 15 89R-1006-02

s The retention of iodine in the spray and sump solution is directly affected by the pH of the solution. The original design and licensing i specification required that pH of-the spray and sump remain between 8.5 and 11.0. Later research has indicated that iodine retention is still acceptacle witt a range of pH down to 7.0. This relaxed range, suggested by SRP 6.5.2 Rev. 2, was not credited in this analysis so that all values provided reflect a pH value of at least 8.5. The maximum decontamination factor, the ratio of original to final aerosol mass, was determined by the volume of water in the RB, the net ' free volume-in the RB containment, the inventory of iodine released and a lower bound pH of 8.5 for the water solution. Using this pH and volumes reflecting the increased BWST level, a partition factor of 1.0E+05.was. 3 calculated. This was conservatively reduced to 1.0E+04 and a maximum? decontamination factor (DF) of 300 was obtained. Since the new SRP does not allow credit for decontamination above a DF of 200,-a value of 200 was used. I RB Mixino and Leakage - Mixing between regions of containment was treated in the same manner as in the original design calculations, yielding a mixing rate of 1.988.8 cfm between the'unsprayed and sprayed regions.. This value is conservative since the new SRP allows a mixing rate of two unsprayed volumes per hour or approximately 6900 cfa. Containment leakage was assumed to be 0.2% per day for the first day and half that value thereafter. This leak rate was proportionately divided-l between the sprayed and unsprayed. regions of containment consistent with l the original design calculations and. half of the leakage was assumed to be filtered by the penetration room ventilation tystem with a filter efficiency of 90%. Dose Conversion Factors. X/O's, and Breathino Rates'- Dose conversion factors for the thyroid calculations-were the same as those used in the original design calculations. Whole body and skin dose calculations were-performed using the standard library of isotopic data generated by the Bechtel NE313 computer code and an improved method rather than that used in the original design calculations. Breathing rates wers conservatively selected from those provided'in Regulatory Guide 1.4, Revision 2 (June 1974) and the atmospheric dispersion factors (X/Q's) were consistent with those given in Table 14-49 of the ANO-1 SAR (provided by the NRC.in the. June 6, 1973 SER). It should be noted that the revised Regulatory Guide 1.4 breathing rates caused the exclusion zone boundary (EZB) dose to decrease and caused the low population zone (LPZ) dose to increa:,e. Dose Results - Using the iodine removal coefficients, maximum decontamination factors and other data' described above, the dose consequences of the LOCA and MHA events were calculated in the same manner as the original analyses using the same TID-14844 source terms. The results, with the original FSAR design values (in parentheses) for comparison are: 16 89R-1006-02 }

................ Maximum Hypothetical Accident----------------- Location Thyroid Whole Body Skin (Rem) (Rem) -(Rem) EZB (0-2hr) 148.1 (151) 4.66 (8.8) 2.16 (3.7) LPZ (0-30 days) 51.8 (50) 1.54 (2.6) 0.724 (1.3) .........................L0CA w/ Gap Release------------------- Location Thyroid Whole Body Skin (Rem) (Rem) (Rem) EZB.(0-2hr) 7.01 (7.02) O.0165-(.013) O.0158 (0.016)- LPZ (0-30 days) 2.66 (2.43) 0.0106 (,0082) 0.0135 (0.013) E. Other Supporting Analyses and Reviews i 1. BWST Seismic Analysis-The BWST Seismic qualification was consv sively reanalyzed for an additional 3.0 feet of water inventory V s proposed Technical i Specification water level limits allow up to-a-2.5 foot increase).- This reanalysis (reference 23) was done in accordance with ANSI /AWWA Standard D-100-84, considering variable wall thickness, sloshing frequency effects, as well as rigid motion. s The tank shell, roof, foundation and anchor bolts were conservatively evaluated to consider the 3.0 foot fluid height increase. Although the AWWA standard does not require that wind and earthquake loads be considered simultaneously, they were conservatively considered together and the stresses were still within the allowables. Therefore, the BWST is capable of supporting the additional head of 3.0 feet of water with no adverse.affects. l 2. Sump Vortexing' Analysis Vortex development in the RB sump can entrain air in the pumped recirculation fluid and impede the adequate performance-of the ECCS and RBS systems. Therefore the flows identified in Table 2 have been l-conservatively assessed to determine their acceptability with respect to RB sump vortexting. A considerable amount of research has been performed to evaluate and quantify the vortex phenomena (references 28 and 29). This data was used to determine if acceptable conditions will exist in the ANO-1 sump. ' Reference 24 evaluated'the data provided in. References 28 and 29 to determine applicability to~ANO-l' based upon geometrical considerations. Based upon the applicable data points in these references and the anticipated sump levels and suction flow rates, it has been determined that air entrain.unt due to vortex formation would not impede pump performance during post LOCA RB sump recirculation. l^ 17 89R-1006-02

3. E0P Guidance As mentioned previously, recommended changes to the E0P guidance were developed to provide consistency between the analysis assumptions and the expected operator response. The recommended changes are summarized briefly below: Throttle RBS to between 1050 gpm to 1200 gpm p.ior to transfer to RB sump suction, i If HPI pumps have not been secured and LPI flow exceeds 3300 gpe, throttle HPI flow to approximately 100 gpm until the criteria to terminate HPI flow.is satisfied. l Caution added tr

te.LPI and RBS NPSH may be only minimally avail,

.h LPI and HPI flow exist during-LPI-HPI'piggybac ,e In developing these changes, cortdination was st* Ith the HPI line break modification efforts (ref1rence 16) to avob onfli: ting or burdensome operator guidance. Input from other B#J plants was also taken to check the reasonablen,ss of the proposed actions. Table 4 summarizes the relevant E0P action associated with RB sunp alignment int the B&W piants. It should be'noted that the proposed E0P guidance actually results in a simplification of the actions required by the operator in the event of a LOCA.- III. SLM4ARY AND CONCLUSIONS Reference 1 documented short-term corrective actions _ required in response to DCD' identified inconsistencies in the documents that characterite the LPI and RBS pump performance when taking suction from the RB sump. This report summarizes the long-term corrective actions' required to resolve the DCD identified inconsistencies and allow 100% power cperation with adequate ECCS' and RBS performance. Throttling of RBS during RB sump recirculation, along with an increase in the BWST Technical Specification water level limits, has been shown to provide adequate LPI and RBS pump NPSH without unduly impacting the offsite dose, the RB pressure / temperature response, or any other affected analyses. IV. REFERENCES 1. ANO Engineering Report 89R-1006-01, Rev. 1, "ECCS Emergency Sump Recirculation - DCD Ideatified Inconsistencies", dated 1/22/90 2. ANO Condition Report 1-89-0634 3. ANO Calculation 89E-0018-01, Rev. 2, " Engineering F',aluation of ANO-1 Peak Containment Sump Temperatures for SBLOCAs", aated 3/20/89 m 4. ANO Procedure 1202.01, Rev. 19, " Emergency Operating Procedure", dated 12/18/89 18 89R-1006-02

N l 5. AN0 Calculation 89E-0010-26, Rev. 2, "LPI Pump NPSHA with 255'F Rx Sump, 1300 gpm RBS flow and 3820 gpm LPI pump flow" dated 07/11/90-6. ANO Calculation 90E-0046-01, Rev. 1, "ANO-1 RBS Pump NPSH", dated i 08/03/90 g 7. ANO Calculation 85EQ-0003-01, Rev. 3, "RBS Flow Indication Loop Error", dated 08/03/90 8. ANO OCP #90-1043,." Upgrade LPI and RBS Flow Indication loops to R.G.-1.97, Category 1 Type A Variables I d 9. AN0 Calculation 88E-0105-01, Rev. 3, " Effects of Rev'd LOCA Curves on EQ of EQT in the RB", dated 07/19/90 10. ANO Calculation 88E-0098-14, Rev. 1,'"ANO-1 DBA LOCA w/ Lower Spray Flow and Higher BWST Level" dated 07/17/90 11. ANO Calculation 88E-0098-02, Rev. 2, "ANO-1 DBA LOCA w/1600 gpm Service Water Flow @ 95'F, 98 F to Decay Heat Cooler + Additional Cases", dated 08/11/89 12. ANO Calculation 89E-0164-01, Rtv.1, " Post-Accident Water. Level in Containment," dated 05/31/90 l l 13. ANO Calculation 89E-0164-05, Rev. 2, "flaximum RB Sump Water Level-l post LOCA", dated 07/13/90 14. NRC Safety Guide 1 " Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal System Pumps," dated 12/1/70 I ' AP&L Design Guide 10G-001-0, " Instrument Loop Error Analysis and 15. Setpoiri Methodology Manual," dated 01/16/90, 16. ANO DCP #89-1012B, "HPI Line Break Modifications" 17. AN0 Calculation 88E-0098-10, Rev. O, "DBA LOCA w/1600 gpm Service Water Flow Q 95 F, smaller RCB, smaller BWST, Additional Area Input", dated 12/6/89 18. AN0 Calculation 830-1153-01, Rev. 2, " Error and Setpoint Analysis For BWST Level Instrumentation Loops", dated 07/16/90 19. ANO Calculation 89E-0164-06, Rev.' 0, " Spray Lambdas and LOCA. Radiation Doses with Reduced Spray Flow", dated 07/17/90 20. ANO Calculation 89E-0164-07, Rev. 0 " Containment Spray Orifice Sizing", dated 07/17/90 + 21. AND Calculation 89E-0164-08, Rev. 0", ANO-1 Maximum and Minimum Spray and Sump pH", dated 07/18/90 19 89R-1006-02

22. AN0 Calculation 89E-0164-09, Rev. O, "BWST/NaOH Tank Flow Analysis", dated 07/17/90

23. ANO Calculation 88E-0034-14, Rev.1, " Seismic Qualification of Equipment - T3 8WST Tank", dated 07/20/90 24.

ANO Calculation 89E-0163-01, Rev. 2, "ANO-1 Sump Vortex Calculation", f dated 08/03/90 25. ANO 1RF #3997, " Assessment of 255'F Sump Water on the Piping Analysis for Decay Heat Lines", dated 07/20/90 26. ANO Calculation 89E-0018-05, Rev.1, "8echtel COPATTA Analysis for Peak ANO-1 Containment Sump Temperature for a Spectrum of SBLOCAs", dated 03/08/89 27. AND Calculation 89E-0013-02, Rev.1, " Thermal Analysis of Makeup Pun:p-Suction", dated 03/14/90. 28. NUREG-0897, Rev.1 " Containment Emergency Sump Performance", October, 1985. 1 29. NUREG/CR-2758, "A Parametric Study of Con'tainment Emergency Sump Performance" 30. ANO Calculation 89E-0164-10, Rev. 0, "EQ Component Review of Submergence Conditions," dated 07/23/90 31. AN0 Calculation M3860-3, Rev.1, " Containment Volume Determination", dated 06/30/89 32. B&W Calculation 32-1102665-00, Rev. 0, "LPI' Flow Split For CF Line Break (NSS-8)", dated 5/27/79 33. AND Calculation 870-1098-02, Rev. 5, " Piping Analysis for Decay Heat Lines", dated 01/27/90

34. AN0 Calculation 90E-0058-01, Rev. 0, "ANO-1 RBS A0TE and Loop Error k&

Analysis," dated 08/03/90 L ~k [ 20 89R-1006-02

.g - ? l 89R-1006-02 .1 TABLE 1 OPTIONS TO PROVIDE ADEQUATE ECCS NPSH ~ i 1 l l l "I ESTIMATED OPTIONS NPSH BENEFIT l Increase RB Sump Water Level i Increase BWST Tech Spec Limit Small-Medium Drain Down'BWST'Before Opening Sump Valves (may require second alarm) Medium l Auto BWST to Sump Transfer Medium l Continue to Use NaOH Tank (may be filled with borated eater) Small-Medium tank again (filled with borated wates; Small-Medium Start using Na:S 03 Add Additional Tanks Small-Large 3 Cross-tie Ap9-1 BWST-.and AND-2 RW1. Medium-Large. i

l l'

Reduce RBS Flow j Provide revised E0P guidance to throttle RBS during sump-recirculation Medium-Large i ' Install flow limiting orifice plates-Medium-Large. i Install flow limiting cavitating venturis. Medium-Large Reduce Instrument Error to Increase Credited Accuracy Upgrade Instruments and/or Minimize Calculational Conservatisms BWST Level Very Small i NaOH Level Very Small i I Ma250 Level Very Small ? 2 3 RBS Flow Saall-Medium i LPI Flow Small l a I 89R-1006-02 1 ~

89R-1006-02 TABLE 1 (Cont'd) OPTIONS TO PROVIDE ADEQUATE ECCS NPSH NPSH BENEFIT OPTIONS Make Instrument Modifications Median Add Narrow Range Indications (and potentially flow meters) ir region of concern Small Replace Flow Transmitters to Increase Accuracy (near 1 tiirn-cown ratio) Small Shield or sove flow transmitters to reduce radiation induced error Small j . Increase survelliance fr % scy to reduce drift error Reduce Required ECCS and/or RBS NPSH Small-Medium l ' Request pump vandor to_ justify lower required NPSH Install pump impeller inlet inducers ' Large 89R-1006-02

1 u_

( n

• * ~ ~

89R-1006-02 i 89R-1006-02 TABLE 2 ANO-1 ECCS PUMP NPSH DbRING POST-LOCA RB SUMP RECIRCULATION REQUIRED ~ AVAILABLE EXCESS l ' Pump Train Flow (gpm) NPSH(ft) NPSH(ft) NPSH(ft) RBS A 1320 gpm 11.69 12.68 0.99 g RBS B 1320 gpm 11.69 12.09 0.40 LPI A* 3820 gpm 10.37 11.21 C.84 LPI B* 3820'gpm 10.37 11.21' O.84 A bounding assessment was made for both trains. I NOTE: No-credit was taken for the feet of additional NPSH'available ~ due to.the RB pressure exceeding the RB sump saturation pressure (as shown in-Table 3). Based upon References 5 and 6. .,..,i....,,.,,,, n ii y i

89R-1906-02 89R-1006-02 TABLE 3 Post LOCA RB Pressure and Sump Saturation Pressure Comparison Transient Analysis R8 Pressure RB Temperature RB Sump Sat. R8 Pressure in Excess time (sec) (psig) (*F) Pressure (psig) of Susp Sat. Pressure (psig)- 3670 (recirc.) 18.03 256.6 33.4-14.7=18.73 0.10 4,100 19.12 254.3 32.14-14.7=17.43 1.69 4,600 20.47 253.6 31.75-14.7=17.05 3.4 6,325 22.37 252.8 31.0-14.7=16.3 6.0 16,900 17.3 247.0 28.3-14.7=13.6 3.7 38,524 10.03 227.6 '19.8-14.7=5.1 5.0 125,024 4.68 184.5 8.3-14.7=-6.4-11.0 262,024 3.09 165.0 5.3-14.7=-9.4 12.4 2,600,993 0.08 122.8 1.8-14.7=-12.9-12.8 This data is taken from reference ~17 for the D8A large Break LOCA. 14,499 (recirc.) 15.31 227.65 19.89-14.7=5.19 10.12 18,999 25.27 240.8 '25.33-14.7=10.63 14.6 27,499 24.03 248.0 28.79-14.7=14.1 9.94 38,499 19.67 243.0 26.25-14.7=11.55 8.12 95,024 8.4 '211.7 14.6-14.7=-0.1 8.5 1,219,018 1.0 142.5 3.08-14.7=-11.61 12.61 This data is taken from reference 26 for a 0.02 f t.2 Small Break LOCA. ....._.............m __.s..._... .....,,..,. - _. _. ~....

mI 6-j 89R-1006-02 89R-1006 TABLE 4 i B&W PLANT SUMP REALIGNMENT COMPARISON i (FOR INFORMATION ONLY) l E0P ACTION AT OR PRIOR TO B&W PLANT RB SUMP SUCTION ALIGNMENT j Oconee-Units 1, 2, & 3(1) throttle RBS flow to 1000 gpn throttle LPI. flow to 3000 gpm TMI(2) e throttle RBS to 1300-1400 gpm-throttle.LPI to approximately 3300 gpm Davis-Besse(3) e auto-interlock on recirculation-actuation-signal to reposition RBS valves to preset i throttle position LPI cooler-outlet valves have travel stops to limit flow to approximately-1 3800 gpm CR-3(4) no. throttling-required e transfer on R8 sump level vs. BWST level due to maximum flooding concerns throttle RBS to 1050 to 1200 gpm Proposad ANO-1 o' LPI cavitating ventaris limit' flow is approximately 3820 gpm i Note: This comparison is provided for information only l Points of contact: 1. Dave-Deatherage (803) 885-3000 ext. 3074 2. Henry Shipman (717) 948-8014. 3. Louis Simon (419) 321-7524'

4..

Paul.Flemming (904) 795-6486,-ext. 4196' .- i i i i 1

TABLE 5 IMPORTANT ANALYSIS INPUT ASSUMPTIONS ~ 88E-0098 88E-0098-10 88E-0098-14 88E-0098-14 88E-0098-14 'i ~ Assumptions Case 2 Case 1 Case 2 Case 3 1) Net Free Volume (fts) 1.865 x 108 1.83 x 108 1.83 x 10s 1.83 x 10s-1.83 x los 2) Corrected Decay Heat No Yes Yes Yes Yes 3) Reduced Cooler No No Yes' Yes Yes. Performance 4) 8WST: Temperature (*F) 85 110 110 110 110 5). Hydrogen Recombiner No Yes Yes Yes-Yes Heat Loads l' 6) Time to Recirculation 3800 3670 4128 3745 4257 (seconds) 7) Recirculation Time No No Yes Yes Yes l Properly Accounts for l ECCS Injection Flow 8) BWST Instrument Errors .No Yes Yes Yes Yes Accounted for 9) ECCS Flow Before/After '3500/3000 3500/3000-3500/3000 3500/3000 3500/3000 Recirculation (gun)

10) RBS Flow Before/

1506/120 1500/1500 1000/1000 1500/1000-1000/1000 After Recirculation (gpe) l

11) BWST Volume Assumed 291,463 280,463

-302,574 302,574 312,210 (gal). 89R-1006-02 i

• I s

.n

TA8LE 6 l CONTAll0EENT PRESSURE / TEMPERATURE ANALYSIS RESULTS 88E-0098-02 88E-0098-14 88E-0098-14 M-T!9-14 4 Original (reference 11) 88E-0098-10 (reference 10) (reference 10) 4 reference 10) Results __SAR Case 2 (reference 17) Case 1 Case 2 Case 3 1) Peak Temperature (*F) 280 282 283 283 283 283 2) Peak Pressure (psig) 53.1 52.4 53.4 53.4 53.4 53.4 i 3) Maximum R8 Sump (*F) ~220 250 256 256 255 254 Temperature after Injection 4) Return to below ~3.5 7.9 6.4 5.2 5.2 5.2 140*F (days) j i i b l i l I 89R-10%-02 l l

Figure 1 Containment Temperature Versus Time 300- = = EO Profile = 88E-OO98-02 Case 2-280 - = - 88E-0098-14 Case 3' (New DBA) 260 - n 3, k 240- \\. v ~ t O 220- = t L $s ] [ f200-u 180- ~Eqj 160 - 1, 140-120 - M ,ime (sec)

Figure 1 Containment Temperature Versus Time 300-

: Eo Profile

= = = - = 88E -0098-02 Case 2

=

= 88E -0098-14 Case 3 280-V (New DBA) ~ k 260 - i T k 240 - k l 0 220 - 1

3 L

J y ]200- -8 e U 180-g E i 160 g l 'q i 140-i %4 120-100 .. o inii .... am i runni . i n nii i i nnur , nni i . > > n"ii i i a "">i i i i iinii i i i i am i 10 ~3 10~2 10 ~' i 10 10 2 10 10 10 ' 10 '- 10 ' 3 -ime (sec) i.._

Figure 2 "U" 60-88E-0098-02 Case 2

=

88E-0098-14 ' Case 3

== == 50h ^ . 2 40 ~ m O v a, A 30i qy s t T J i 8 m CD ~ q) 20 5 t n 10 ~ 0 ~ i i iiiiii i i i m u r i i e iii>>i i i i iiiiii i i 'r rr m ni i, i iiii,, ,.. ii-i rrnuii - i i iiii i

10. ~'

10 ~ '1 0 -' i 10 10 10 10

• 10 '

10 '- 10 ' 2 5 Ime sec 'I

Figure 3 i Containment Temperature Versus Time 300-

= EO Profile ^ = 88E-0098-10 280- = = = = = 88E-0098-14 Case 1 88E-0098-14 Case 2 g

'f 260-n f.

L'- 2 4 0 - I. O 220- ~ 1 E J i 200-o o L 1-1 O 180-E ~ \\ i 160-g I i 140-l ~ l 120-l ~ l l 100 i i i iiiiii i i i niur r rinnri > > > > > nii i i rmnr r i iinnt > > > i i iii i i > > > > > >i i i i i i > >>i i i i inni 10 ~' 10 -' 10~' i 10 10 10 10 ' 10 10 ' 10 2 5 - ime (w) u

^4. e 20 * ~, t 4 i l 'l i F 4 1 1 89R-1006-02 ATTACHMENT 1 1 + =

g. yn Ba -s _._ bcock & Wilcox P.0 to 138dL tecNips. We 24905 feep w e m aiak 5111 June 11. 1973 ECE!y! j. - n gir. W. Cesensegh j l-Projoet Emmager 4 Arhannes Peser & Light ca. Jyg.,ap P. O. Ben 551 Little Bad. Arbammaa 72203 l %.88*.4! q subseets aska-ama w i== % ?sa ! '"' CL [F (Csegiin iset Baselas " OT ) 898 befseende 3155-4 l ) Daar IIr. Ce==ma=ght Per voor sequest. se ese attamhing a short writag en Cavitataas Teateri Test reen;.ts. We treet this will be estfia&amt for yee se respeed to the AEC. la additismal infessataea is sequised, please aertaa. E Dery temly years. N'

s... ela.

Senter Project Ilmanger l ....-r g g v.3 Aseeciate Prcject Manager GmataB/ pal L CC: f J. E. Andersom 1 C. G. m R. T. Belmas J. R. Jennetas C. Estanaea w!1 att L P. Lachett j

t. m it e R. R. Beere J. E. Usoessed I

8 W k 89R-1006-02

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Engineering Report Data Sheet (Cont.) Report Noi 89 R - ICCG- 02 Uniti l Rev. Noi I Verification Methodi Design Reviewi r Alternate Calculation Qualification Testingt j Poqes Revised and/or Added j Purpose of Revisioni M 5e Ns tka +b-c,C FAS A iu+<u-, i+ e rv. 1 l 1 Cross References Initiating Documents Resulting Document (s) Reference Docs, Supercedes Report (s) ~/'/# Byi LL bl /J.A /Mlle /9*w / 6h/vo Rvw'di A*nunlx)saW+aF1C/ N / h!D Apv'diY$Alb5/ Nom lOld/2'3-9* Chk'di emt ma.> cats) s.t.) ennt u.a.> amts) u.t.> Rev, Noi Verification Methodi Dr

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