PLA-6561, Amendment Request No. 296 to Unit 1 and Amendment Request No. 266 to Unit 2 Re Emergency Core Cooling System Instrumentation - Technical Specification (TS) Table 3.3.5.1-1 and Editorial Change to TS 3.10.8.F, Response to RAI

From kanterella
(Redirected from ML092580088)
Jump to navigation Jump to search

Amendment Request No. 296 to Unit 1 and Amendment Request No. 266 to Unit 2 Re Emergency Core Cooling System Instrumentation - Technical Specification (TS) Table 3.3.5.1-1 and Editorial Change to TS 3.10.8.F, Response to RAI
ML092580088
Person / Time
Site: Susquehanna  
Issue date: 09/11/2009
From: Rausch T
Susquehanna
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-6561
Download: ML092580088 (66)


Text

Timothy S. Rausch Sr. Vice President & Chief Nuclear Officer PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3445 Fax 570.542.1504 tsrausch @ pplweb.com

  • 1
  1. VIP P1' SEP11 20091 U. S. Nuclear Regulatory Commission Document Control Desk Mail Stop OP1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION AMENDMENT REQUEST NO. 296 TO UNIT 1 LICENSE NPF-14 AND AMENDMENT REQUEST NO. 266 TO UNIT 2 LICENSE NPF-22:

EMERGENCY CORE COOLING SYSTEM INSTRUMENTATION -

TECHNICAL SPECIFICATION (TS) TABLE 3.3.5.1-1 AND EDITORIAL CHANGE TO TS 3.10.8.F RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION Docket N PLA-6561 a

os. 50-387 nd 50-388 Reference. 1)

PLA-6235, Mr. W. H. Spence (PPL) to Document Control Desk (USNRC),

"Susquehanna Steam Electric Station Amendment Request No. 296 to Unit 1 License NPF-14 and Amendment Request No. 266 to Unit 2 License NPF-22:

Emergency Core Cooling System Instrumentation - Technical Specification (TS)

Table 3.3.5.1-1 and Editorial Change to TS 3.10.8.F," dated March 24, 2009.

2) E-mail from B. Vaidya (NRC) to D. L. Filchner (PPL), "TA C Nos. ME0933 and ME0934, Draft RAIs RE: Changes Related to ECCS TSs 3.3.5.1-1 and 3.10. 8.f, " (Instrumentation and Controls Branch), dated May 4, 2009.
3) E-mail from B. Vaidya (NRC) to D. L. Filchner (PPL), "Susquehanna Units 1 and 2 TAC Nos. ME0933 and ME0934, IAis (SRXB)for Amendment Request RE: Changes to TS Table 3.3.5.1 -1 and TS 3.10.8.f " dated May 29, 2009
4) PLA-6501, Mr. W. H. Spence (PPL) to Document Control Desk (USNRC),

"Susquehanna Steam Electric Station Amendment Request No. 296 to Unit 1 License NPF-14 and Amendment Request No. 266 to Unit 2 License NPF-22:

Emergency Core Cooling System Instrumentation - Technical Specification (TS)

Table 3.3.5.1 -1 and Editorial Change to TS 3.10.8.F Supplemental Information,"

dated April 24, 2009.

In accordance with the provisions of 10 CFR 50.90, PPL Susquehanna, LLC (PPL) submitted a request for amendment to the Technical Specifications (TS) for Susquehanna Units 1 and 2 in Reference 1.

References 2 and 3 are Requests for Addition Information (RAI) from the Nuclear Regulatory Commission (NRC) Instrumentation and Controls Branch and Reactor Systems Branch. These RAts were discussed with the NRC staff on June 22, 2009.

Document Control Desk PLA-6561 Reference 4 provided supplemental information as requested by the NRC staff during teleconferences on April 6 and April 8, 2009.

The attachments provide the PPL responses to the NRC RAIs in References 2 and 3. addresses the Instrumentation and Controls Branch RAIs. Attachment 2 responds to the Reactor System Branch RAIs. Attachment 3 provides the revised No Significant Hazards Consideration Determination. Attachment 4 is PPL calculation EC-052-1055 in response to Reactor Systems Branch RAI. No. 1.

There are no new or revised regulatory commitments contained herein.

If you have any questions regarding these responses, please contact Mr. D. L. Filchner -

Nuclear Regulatory Affairs at (610) 774-7819.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on:

Lk 0a, T. S. Rausc Attachments:

1) Response to the Instrumentation and Controls Branch RAIs
2) Response to the Reactor System Branch RAIs
3) Revised No Significant Hazards Consideration Determination
4) PPL Calculation EC-052-1055 Copy: NRC Region I Mr. R. Janati, DEP/BRP Mr. F. W. Jaxheimer, NRC Sr. Resident Inspector Mr. B. K. Vaidya, NRC Project Manager to PLA-6561 Response to the Instrumentation and Controls Branch RAIs to PLA-6561 Page 1 of 4 The NRC review of References 1 and 4 by the Instrumentation and Controls Branch (EICB) concluded that additional information is needed, as described in the RAIs below:

NRC EICB RAI No. 1:

The licensee is not adding any footnotes for the proposed condensate storage tank low-level allowable value changes in the technical specifications (TS) because the Magnetrol float switches used are of the mechanical type. The Magnetrol float switch catalog the licensee gave to the U.S. Nuclear Regulatory Commission does not indicate any provision for adjusting the setpoint. However, clause 6.1.8 of licensee plant procedure SI-152-308, page 6, describes adjusting the setpoint if the as-found trip setpoint is greater than or equal to the allowable value. Furthermore, in calculation EC-037-1001, page 14, the licensee specified +1 inch as the calibration accuracy for these switches.

Please provide the details regarding how the setpoint adjustments are performed in the field.

PPL Response:

PPL surveillance procedures SI-152-308 (Unit 1) and SI-252-308 (Unit 2) provide identical instructions to perform and document the quarterly calibration of the condensate storage tank low level channels LSLL-E41-1N002 and LSLL-E41-1N003 (Unit 1), and LSLL-E41-2N002 and LSLL-E41-2N003 (Unit 2). Unit 1 procedure SI-152-308 was previously submitted in Reference 4.

Setpoint adjustments are not normally required for these level switches to meet the surveillance acceptance criteria. The +1 inch calibration accuracy on page 13 and 14 of calculation EC-037-1001 was established based on the original GE documentation for these switches. The surveillance results from 2003 to 2006, as documented on pages 9 and 10 of EC-03 7-1001, show that the limit switches did not require adjustment because the "as found" setting was within the "Final" tolerance band. Discussions with PPL I&C personnel familiar with this surveillance confirmed that the Magnetrol float level switches did not require any adjustment to the float setpoint to maintain the "Final" tolerance band. Although the limit switch manufacturer's information provided in Reference 4 provides an illustration for adjusting the jam nuts that support the float, these jam nuts have not required adjustment because of the consistent results documented in the surveillances. In order to perform the surveillance, the procedure provides direction to isolate the level switch from the tank, raise the water level in the sight glass, and allow the water to drain from the sight glass to obtain the channel trip.

to PLA-6561 Page 2 of 4 NRC EICB RAI No. 2:

Page 11 of setpoint calculation EC-037-1001 states, "There is no Analytical Value for this setpoint." The applicant also stated on page 4 of this calculation that to avoid vortex formation in the high-pressure coolant injection suction piping, the high pressure coolant injection suction transfer from the condensate storage tank to the suppression pool should take place with the condensate storage tank water level above 36 inches. The staff believes that this setpoint calculation should comply with this analytical limit to avoid vortex formation.

Please provide the justification for the lack of an analytical limit for this setpoint calculation.

PPL Response:

There is no safety analysis that credits this setpoint for protection against any reactor core Safety Limit or a reactor coolant system pressure Safety Limit. Therefore, an analytical limit has not been specified for the High Pressure Coolant Injection (HPCI) suction transfer from the condensate storage tank (CST) to the suppression pool (SP). This position is consistent with the GE documentation for establishing TS limits that do not have analytical limits and PPL Susquehanna's existing TS. The TS limit for the "CST Level-Low" function has a specified design basis limit which assures adequate Net Positive Suction Head to the HPCI pumps while preventing unacceptable vortex formation in the pump suction piping. The proposed TS allowable value of 40.5" assures that the HPCI suction transfer design basis is maintained.

NRC EICB RAI No. 3:

Plant procedure SI-152-308, page 6, clause 6.1.6, refers to the Required Action section in the Data Form if the trip setting is not greater than or equal to the allowable value.

Please provide the details regarding the required actions, specifically when the as-found values are (a) beyond the acceptable as-found tolerance, or (b) beyond allowable value, or (c) cannot be set within the acceptable as-left values.

PPL Response:

As-left trip settings are controlled under the PPL programs for Surveillance Testing and Preventative Maintenance. As-found settings that are outside acceptable tolerances are controlled through the SSES 10 CFR 50, Appendix B, Criterion XVI, corrective action program. Operability and Reportability determinations are integral to the corrective action program.

to PLA-6561 Page 3 of 4 The as-found and as-left tolerances specified in calculations are incorporated into appropriate surveillance procedures. The Surveillance Testing program establishes the administrative controls for Surveillance Testing which includes the following:

Specifying requirements for preparation and control of surveillance test procedures.

Specifying the requirement to generate a Condition Report for any failed calibration activity that references a surveillance procedure.

The maintenance and calibration of installed plant instrumentation procedure defines the responsibilities and controls for I&C activities affecting installed plant instrumentation.

This process applies to activities associated with testing, calibration, corrective maintenance, and modification.

Calibration corrective action is controlled under this procedure which includes the following requirements:

" If an instrument is found outside of the as-found tolerance, it shall be calibrated and left within the final tolerance, and

" An Action Request (AR) shall be generated for any equipment exceeding as-found tolerances or any other condition considered adverse to quality.

" The AR is processed as required by the corrective action process, "Action Request and Condition Report Process."

NRC EICB RAI No. 4:

On page 8 of calculation EC-037-1001, TS Allowable Value & TRM Trip Setpoint (New) has been specified as 36 inches for LSL-E51-1N035A, LSL-E51-1N035, LSL-E51-2N035A, and LSL-E51-2N035E instruments.

Please explain how you derived the allowable value of 36 inches and justify why it is not specified in the TS.

PPL Response:

The TS Allowable Value and TRM trip setpoint of 36 inches for the RCIC LSL-E5 1-1N035A, LSL-E51-1N035E, LSL-E51-2N035A, and LSL-E51-2N035E was calculated from the same flow model in PPL calculation EC-052-1055 utilized to determine the HPCI trip setpoint of 40.5 inches. Calculation EC-052-1055 is provided in Attachment 4 and demonstrates that a RCIC suction transfer setpoint of 36 inches maintains adequate RCIC pump suction to remain above the CST vortex limit. Therefore, it is concluded that to PLA-6561 Page 4 of 4 the existing Allowable Value of 36 inches for RCIC is acceptable and therefore no change to the TS is required.

NRC EICB RAI No. 5:

The analysis of No Significant Hazards Consideration Determination in your application dated March 24, 2009, as supplemented by letter dated April 24, 2009, does not address the analysis of the proposed changes in TS 3.10.8.f.

Please provide the revised analysis of NSHCD that addresses the analysis of the proposed changes in TS 3.10.8.f.

PPL Response:

The revised NSHCD is provided in Attachment 3 in its entirety. Text that has been added to address the proposed changes to TS 3.10.8.f is shown in bold italics. Text that has been deleted is shown as strikethrough.

to PLA-6561 Response to the Reactor System Branch RAls to PLA-6561 Page 1 of 2 The NRC Reactor Systems Branch (SRXB) requested the following additional information to complete the review of References 1 and 4:

NRC SRXB RAI No. 1:

Please provide the flow analysis as documented in EC-052-1055 to determine the new TS allowable value of 40.5 inches for the CST low level.

PPL Response:

See PPL Calculation EC-052-1055 (Attachment 4) for the flow analysis used to determine the new TS allowable value of 40.5 inches.

NRC SRXB RAI No. 2:

Please clarify whether the float type level switches are safety-related or not? If they are not safety-related then justify its operability during transient and accident conditions.

PPL Response:

The float type level switches are safety-related as confirmed by review of design documents.

NRC SRXB RAI No. 3:

Provide operating history of these float type level switches.

PPL Response:

The operating history of these float type level switches has been very reliable and their "as found" settings have been consistently within the "as left" final tolerance as demonstrated by the quarterly surveillance results. A review of the work order history for both the Unit 1 and 2 HPCI and RCIC CS Tank low level switches (8 total) indicated the following:

" LSLL-E41-1N002, LSLL-E41-2N002, LSLL-E41-2N003, LSL-E51-2N035A, and LSL-E51-2N035E indicated no surveillance failures going back to 1990.

" LSLL-E41-1N003, LSL-E51-1N035A, and LSL-E51-1N035E experienced a total of six surveillance failures during the same period. These failures were due to micro-switch problems which were resolved by either adjustment or replacement.

to PLA-6561 Page 2 of 2 There were 32 surveillance opportunities per year (8 switches receiving quarterly surveillances) for a total of 624 surveillances over the last 19.5 years. These six failures constitute a failure rate of less than 1%.

to PLA-6561 Revised No Significant Hazards Consideration Determination to PLA-6561 Page 1 of 3 Added text is shown in bold italics. Text that has been deleted is shown as ot,-kethfogh.

No Significant Hazards Consideration The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

PPL proposes changes to Appendix A, Technical Specifications (TS), of Facility Operating License Nos. NPF-14 and NPF-22 for the Susquehanna Steam Electric Station Units 1 and 2 respectively.

Thefirst proposed change revises TS Table 3.3.5.1-1 to increase the technical specification allowable value for the high pressure coolant injection (HPCI) suction low level automatic transfer from the condensate storage tank (CST) to the suppression pool (SP).

Additionally, an editorial /administrative change is proposed which corrects a typographical error in the SSES Units 1 and 2 TS Section 3.10.8.f. No further discussion of this editorial!/ administrative ehange is provided hereafter-because it does not inivolve a signifiant incr-ease in the pr-obability or-consequences of an accident pr-eviously evaluated; it does not cr-eate the possibility of a new or-differ-ent kind of accident fro any accident pr-eviously evaluated; and it does not involve a significant reduction in a-mar-gin f safety.

In accordance with the criteria set forth in 10 CFR 50.92, PPL has evaluated the proposed TS changes and determined it they does not represent a significant hazards consideration.

The following is provided in support of this conclusion.

1.

Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

No. The proposed change to TS Table 3.3.5.1-1 increases the Technical Specification allowable value for the HPCI suction low level automatic transfer function from > 36 inches to > 40.5 inches above the CST bottom. There are no process setpoint changes associated with this TS allowable value change. This TS change does not introduce the possibility of an increase in the probability or consequences of an accident because the HPCI automatic transfer function is not an initiator of any new accidents nor does it introduce any new failure modes. The to PLA-6561 Page 2 of 3 CST is not safety related and therefore not credited in any design basis accident analyses. However, the CST reserve volume is credited in anticipated transients without scram (ATWS), Appendix R and station blackout (SBO) evaluations. The reserve volume available in the CST at the proposed allowable value of 40.5 inches above the CST bottom remains adequate to fully support these HPCI system support functions and the change fully supports HPCI system operation.

The reserve volume is not reduced as a result of the proposed change in the TS allowable value since the transfer will still occur at the CST low level instrument setpoint of 43.5 inches above tank bottom, which remains unchanged.

The HPCI system automatic transfer function occurs at the point in a design basis accident (DBA) when the CST level reaches the low level transfer setpoint. This proposed change will require the HPCI pump suction to be transferred from the CST to the SP at 40.5 inches versus 36 inches above the CST bottom. Currently, the TS allow this transfer to occur at 36 inches. This proposed change is conservative because it assures the suction transfer will occur while there is more water in the tank, thus eliminating the possibility of vortex formation and air intrusion to the HPCI pump suction. Since this proposed change ensures the HPCI system automatic suction transfer function occurs without adversely impacting HPCI system operation, it does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed editorial ladministrative change is necessary to correct a typographical error in the SSES Units 1 and 2 TS Section 3.10.8.f. This editorial change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

No. As discussed above, the proposed change to TS Table 3.3.5.1-1 involves increasing the TS allowable value for the HPCI low level automatic transfer function from the CST to the SP at > 36 inches to > 40.5 inches above the CST tank bottom. This change ensures the HPCI automatic transfer function occurs without introducing the possibility of vortex formation or air intrusion in the HPCI pump suction path. All HPCI system support functions remain unaffected by this change. This TS change does not introduce the possibility of a new accident because the HPCI automatic transfer function is not an initiator of any accident and no new failure modes are introduced. There are no new types of failures or new or different kinds of accidents or transients that could be created by these changes. Therefore, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

to PLA-6561 Page 3 of 3 The proposed editorial ladministrative change only corrects a typographical error in the SSES Units 1 and 2 TS Section 3.10.8.f. This editorial change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3.

Does the proposed change involve a significant reduction in a margin of safety?

No. The margin of safety is established through equipment design, operating parameters, and the setpoints at which automatic actions are initiated. The proposed change to TS Table 3.3.5.1-1 involves increasing the allowable level at which the HPCI automatic suction transfer from the CST to the SP must occur to avoid the possibility of vortex formation or air intrusion into the HPCI pump.

This change does not result in a change to the level switch setpoint, which initiates the HPCI suction transfer from the CST to the SP. Although the allowable value for the transfer is now closer to the process setpoint for activation of the level switch, this reduction in operating margin was reviewed and determined to be acceptable. The level switch setpoint tolerances were established based on historical instrument data and instrument characteristics. These tolerances provide adequate margin to the proposed TS allowable value of 40.5 inches above the CST bottom. The tolerances further ensure the transfer will occur prior to level reaching the technical specification allowable value. Therefore, the proposed change does not result in a significant reduction in a margin of safety The proposed editorial ladministrative change only corrects a typographical error in the SSES Units 1 and 2 TS Section 3.10.8.f. This editorial change does not result in a significant reduction in a margin of safety.

to PLA-6561 PPL Calculation EC-052-1055

.For Information Only PCAF 42007-1057 Page 9 of 10 NUCLEAR ENGINEERING CALCULATION COVER SHEET 1go NEPM-QA-0221-1 1t Page Sof/

Total Pages 5-/

>-2. TYPE:

CALC

>3. NUMBER:

EC-052-1055

  • >5. UNIT 3
  • >6. QUALITY CLASS:

0

>7. DESCRIPTION:

CST Water Level for HPCI Suction Transfer

>4. REVISION:

1

8. SUPERSEDED BY:

NA

9. Alternate Number:

NA

10. Cycle:

NA

11. Computer Code/Model used:
12. Discipline:

M

>13. Are any results of this calculation described in the Licensing Documents?

G]

Yes, Refer to NDAP-QA-0730 and NDAP-OA-0731 rl No

>14. Is this calculation changing any method of evaluation described in the FSAR and using the results to support or change the FSAR? (Refer to PPL Resource Manual for Definition of FSAR) 0 Yes, 50.59 screen or evaluation required.

Ii No

>15. Is this calculation Prepared by an External Organization?

nl Yes 0

No EG771 Qualifications may not be required for individuals from external organizations (see Section 7.4.3).

> 16. Prepared byI:

> 17. Reviewed by':

> 18. Verified by:

>-19. Approved by:

>20. Accepted by:

M. A. Chaiko Pnnt Name (EG771 Qualification Required)

, pnature Date R. M. Centenaro

.?.

10, 7/02 Print Name (EG771 Qualification Required) ature pate R. M. Centenaro A -M O/

7/o7 Print Name (EG771& QADR Qualification Required)

Signa I

'eDate D. G. Kostelnik

(

4 If

-1./- 7 Print Name (Qualified per NEPM-OA-0241 and Signature Date comply with Section 78 of NEPM-QA-0221)

Print Name (E6771 Qualification Required) and comply with Section 7.9 of NEPM-QA-0221 Signature Date IFor Fire Protection related calculations see Section 7.4.3.14 tor additional qualification requirements ADD A NEW COVER PAGE FOR EACH REVISION FORM NEPM-QA-0221-1, Revision 10, Page 1 of 1. ELECTRONIC FORM II

  • Verified Fields

> REQUIRED FIELDS

.For Information Only Page la CALCULATION REVISION DESCRIPTION SHEET NEPM-QA-0221-2 REVISION NO:

1 CALCULATION NUMBER:

EC-052-1055 0

FULL REVISION El SUPERSEDED El PAGE FOR PAGE El VOIDED A

R R

Revised d

R m

Description Pages d

I t

of Revision on the Listed Pages All

[]

N E]

Replace all Rev. 0 pages with Rev. 1 pages.

_ ] E l

E El El Ch 1

El El El1: El I

S[1 E l E

El El E

[I 1

El o

El El0 El

_~

[ El El E

[ E

]

El FORM NEPM-OA-0221-2, Revision 5, Page 1 of 1, ELECTRONIC FORM

.For Information Only Page lb TECHNICAL CHANGE

SUMMARY

PAGE NEPM-QA-0221-5 Calculation: Number:

EC-052-1055 Revision No.

1 This form shall be used to (1) record the Technical Scope of the revision and (2) record the scope of verification if the calculation was verified. It should not be more than one page. Its purpose is to provide summary information to the reviewer, verifier, approver, and acceptor about the technical purpose of the change. For non-technical revisions, state the purpose or reason for the revision.

Scope of Revision: Revision I includes an evaluation of Net Positive Suction Head (NPSH) during the HPCI suction transfer from the CST to the suppression pool. For the design case (Case 1), there is no reduction in the available margin. NPSH is also evaluated based on minimum acceptable surveillance stroke times for HPCI and RCIC CST suction valves and design maximum values, including degraded voltage conditions, for the suppression pool suction valves (Case 5). This highly conservative combination of valve stroke times maximizes the flow resistance associated with the HPCI and RCIC suction paths.

Even for this extreme case there is still significant margin (4.5 ft) in the available NPSH.

The hydraulic model was modified to prevent the occurrence of reverse flow in the RCIC suppression pool suction line. For the valve stroke times used in the NPSH evaluation (Case 5 in Table 6-1), the potential exists for reverse flow in this line; however, flow from the CST to the suppression pool is prevented by check valve 149F030. The effect of 149F030 on system flow was included in the computer model by adding a large resistance (lx1012) to the RCIC suppression pool suction path if the onset of reverse flow is detected during the flow iteration.

A Computer Case Summary, Table 6-1, was added to define the case-specific stroke times used for the HPCI and RCIC CST and suppression pool suction valves.

The assumption that no vortex formation will occur with tank level above the vortex breaker is validated in. Preoperational test data, which shows no vortex formation at 6000 gpm and tank level of 34' is used along with the onset-of-air-ingestion curve provided in §5.3 to demonstrate that no vortex formation will occur with water level above the vortex breaker.

Scope of Verification (If verification applies): Technical changes associated with Revision 1 are to be verified. Revision 1 changes are indicated using rev. bars.

FORM NEPM-QA-0221-5, Revision 0, Page 1 of 1, ELECTRONIC FORM

-For Information Only EC-052-1055 Page 2 Table of Contents

1.

O bjective.............................................................................................................

3

2.

Conclusions........................................................................................................

3

3.

Assum ptions.....................................................................................................

3

4.

Inputs.........................................................................................................................

5 4.1 Valve Stroke Tim es........................................................................................

5 4.2 Flow Rates.....................................................................................................

5 4.3 Tank Data and Elevations...............................................................................

6 4.4 Valve Flow Coefficients.................................................................................

6 4.5 Unit I Pipe Data..............................................................................................

7 4.6 Net Positive Suction Head............................................................................

7

5.

M ethod......................................................................................................................

7 5.1 Governing Equations.....................................................................................

8 5.2 Friction Coeffi cients.........................................................

..................... 10 5.3 Vortex Lim it.................................................................................................

14 5.4 N et Positive Suction Head............................................................................

14 5.4.1 HPCI.....................................................................................................

15 5.4.2 RCIC.....................................................................................................

17 5.5 Num erical Solution M ethod...........................................................................

18 5.6.

Verification of Results.................................................................................

19

6.

Results...............................................................................................................

21

7.

References........................................................................................................

29 : FORTRAN Program Used to Solve Eqs. in §5.1...................

31 : Verification of FORTRAN Results............................................

41 : Peer Check of FORTRAN Results............................................

46 : Validation of Acceptance Criteria for Vortex Formation....... 48

,For Information Only EC-052-1055 Page 3

1.

Objective The purpose of this calculation is to determine the initial CST level required to maintain adequate HPCI/RCIC pump suction conditions in the event of an automatic suction transfer from the CST to the suppression pool. This will serve as the basis for the revision of TS (Technical Specification) 3.3.5.1 (Ref. 17) for the allowable value of the HPCI suction transfer trip function (Function 3.d of TS Table 3.3.5.1-1). This calculation also evaluates the impact on HPCI pump NPSH available during an automatic suction transfer with the CST and suppression pool suction valves operating in parallel.

f< I

2.

Conclusions This evaluation determined that the new allowable value for CST level required for satisfactory pump operation during a HPCI suction transfer is 40.5 inches. This is above the current TS Table 3.3.5. 1-1 value of 36.0 inches. Therefore, a TS change will be necessary.

The design case (Case 1) demonstrates that there is no impact on pump NPSH available during the transfer with suction valves operating in parallel. Even in an extreme case with regard to pump NPSH (Case 5), where HPCI suction flow resistances from the CST and suppression pool are maximized by selectively applying degraded voltage conditions to the suppression pool suction valves, but not to the CST suction valves, significant margin (4.5 ft) exists between NPSHA and NPSHR.

3.

Assumptions I. The CST and suppression pool suction valves for the HPCI system operate in parallel rather than in series as currently designed. A modification to the HPCI suction transfer logic will be required to support this assumption (Ref. CRA 685368, EC 823975, and EC 823991).

2. Both HPCI and RCIC are assumed to be in operation in order to simulate "worst case" conditions during a suction transfer. Total HPCI and RCIC flow is constant during the transfer.
3. The RCIC suction set point will remain at the current TS value of 36.0 inches (Ref. 2).
4. The Unit 1 HPCI and RCIC systems are modeled. Differences between the suction piping on Units 1 and 2 are relatively small (Ref. 4 and 5). Results based on the Unit I model should conservatively bound Unit 2 for purposes of evaluating the potential for vortex formation because the distance from the CST to HPCI and RCIC pumps on Unit 1 is less than on Unit
2. Smaller CST suction line losses on Unit 1 would result in slightly higher flow from the CST during the suction transfer which would tend to minimize CST level thus reducing margin to the onset of vortex formation.

.For Information Only EC-052-1055 Page 4

5. Pressure in the suppression chamber air space is I atm. This minimizes HPCI and RCIC suction flow from the suppression pool during the HPCI suction transfer evolution, which results in a greater flow from the CST and a faster drop in CST level.
6. Owing to the large size of the suppression pool and the short time for the transfer

(<3 minutes), pressure and level in the suppression chamber are taken as constant during the suction transfer.

7. Suppression pool water is assumed to be at 140'F, the maximum temperature for HPCI operation with suction from the pool (Ref. 18). Using a maximum temperature minimizes suppression pool water density which in turn minimizes HPCI suction from the pool during the transfer. Pool density is 61.38 Lbm/ft3 (Ref. 27).
8. Height of the pool is assumed to be at the TS minimum value of 22 feet (Ref. 1). The normal band is 22 ft to 24 ft with a typical operating height of 23 ft. This assumption tends to minimize HPCI suction flow from the pool during the transfer which results in greater suction from the CST.
9. CST is at atmospheric pressure.
10. CST water temperature is 100°F (Ref. 19). Density is 62.00 Lbm/ft3 (Ref. 27). This water temperature is conservative relative to 140°F (the maximum temperature for HPCI operation) because it provides a greater coolant density which tends to maximize flow from the CST during the suction transfer.
11. CST water level at the time HPCI suction transfer initiates is adjusted in the model until acceptable HPCI/RCIC pump suction conditions with regard to vortex formation are obtained. This determines the TS allowable value for the HPCI suction transfer trip function (Function 3.d of TS Table 3.3.5.1-1).
12. Valve stroke times for the HV 1 (2)55F042 valve is adjusted for degraded DC voltage under dynamic loading (Ref. 3). The fraction that the valve is open is assumed to be a linear function of the valve stroke time.
13. Acceptance criteria is based on final CST level remaining above the vortex breaker or above the level associated with the onset of air ingestion, as described in Ref. 16. (Refer to for validation of this acceptance criteria.) Note that no credit is taken for the CST vortex breaker when establishing the onset-of-air-ingestion curve.
14. The most limiting condition for HPCI NPSH available occurs at the instant the HPCI CST suction valve HVl(2)55F004 goes closed and pump suction is aligned exclusively on the suppression pool. Suction line elevation head and friction losses are essentially independent of Unit when HPCI suction is aligned to the suppression pool (see Attachment 1 of Ref. 29);

therefore, the minimum NPSHA margin, which is obtained using a Unit 1 hydraulic model (see Assumption 4), applies also to Unit 2.

"For Information Only EC-052-1055 Page 5

4.

Inputs 4.1 Valve Stroke Times Reference 3 was used to determine dynamic stroke times for each valve. These are the design stroke times for the valves, which consider maximum design loadings, and also consider degraded voltage conditions (AR 667984667984. In evaluating vortex formation, the following stroke times were obtained by using the higher of Unit 1 and Unit 2 dynamic stroke times and rounding the "worst case" stroke time up to the nearest second:

HPCI HVl(2)55F042 = 115 seconds (Open) = tF042 HIPCI HV1(2)55F004 = 108 seconds (Close)= t=,

RCIC HVI(2)49F031 = 44 seconds (Open) = tF031, and RCIC HVI(2)49F010 = 44 seconds (Close) = t1010.

For purposes of evaluating NPSHA (Net Positive Suction Head Available), the minimum acceptable surveillance stroke times for HPCI and RCIC CST suction valves HVI (2)55F004 and HVI(2)49FO10 are used in order to maximize pump suction path resistance from the CST.

These values as specified in HPCI and RCIC quarterly surveillance procedures SO-1 52/252-004 and SO-150/250-004, respectively, are HPCI HV I(2)55F004 = 53.6 seconds (Close) = tFOO4, and RCIC HV1 (2)49F010 = 25.5 seconds (Close) = t FO10.

Opening stroke times for HPCI and RCIC suppression pool suction valves HVI(2)55F042 and HVl(2)49F031 are maintained at their design maximum values for degraded voltage conditions (115 seconds and 44 seconds, respectively). This maximizes the flow resistance associated with the suppression pool suction path.

Combining stroke times in this manner is extremely conservative since a degraded voltage condition is selectively applied to the suppression pool suction valves, but not to the CST suction valves.

4.2 Flow Rates According to Calculations EC-052-0002 (Ref. 4) and EC-050-0001 (Ref 5), the flow rates for HPCI and RCIC are 5000 and 600 gpm respectively. However, the flow rates used for the calculations were 5100 and 625 gpm to account for flow controller tolerances (EWR 686614, SO-150-001, and SO-152-001). Note that both HPCI and RCIC are assumed to be in operation in order to simulate "worst case" conditions during a suction transfer, i.e., maximum rate of CST level decrease.

For Information Only EC-052-1055 Page 6 4.3 Tank Data and Elevations Condensate Storage tank parameters and piping elevations are summarized in the following table.

Table 4-1 Elevation and CST Data Parameter Value Reference Elevation at bottom (floor) of CST 672.10 ft 6

CST volume per unit height 9,350 gal/ft 6, 23 Free cross-sectional area of CST 1,250 ft' 6, 23 Elevation at inside bottom of CST suction pipe relative to 0.84 ft 20, 21 tank floor Elevation at bottom of suppression pool 648 ft 7

Elevation at HPCI Node 3 on Fig. 1 653.25 ft 8

Elevation at RCIC Node 4 on Fig. 1 648.7 ft 9

Elevation at top of vortex breaker relative to tank floor 30.875 inches 10 CST volume =er unit height Tank diameter = 40.0 ft - (2)(0.375)/12 = 39.94 ft (Ref. 6, 23)

Free cross-sectional area = T(39.94 ft) 2 /4-1,250 ft2.

Volume per height = 9350 gal/ft Elevation at bottom (inside) of CST suction Ripe relative to bottom of tank Suction pipe is 20" HCD/HCB Schedule 10 Pipe (Ref. 13, 20)

ID = 19.5" = 1.625 ft (Ref. 14)

Centerline elevation of suction pipe = 673'-9" = 673.75 ft (Ref. 21)

Elevation at inside bottom of suction pipe = 673.75' - 1.625'/2 = 672.94 ft Elevation at bottom of pipe relative to bottom of tank = 672.94' - 672.10' = 0.84 ft 4.4 Valve Flow Coefficients Values of the valve flow coefficients at full open is supplied by the vendor (see Table 4-2 below). The vendor has also supplied a generic curve for a gate valve C, (as a fraction of max CQ) vs. percent open (Ref. 15). This curve is represented by the polynomial, C,(x) = C, (0.9602x4 -0.1689x 3 -0.1857x 2 + 0.3952x),

where x is the fraction that the valve is open. The fraction x is assumed to be linear through the valve stroke time. The initial system configuration has the HPCI F004 and RCIC FO10 valves fully open and the HPCI F042 and RCIC F031 valves fully closed. For calculational purposes, the HPCI F042 valves starts to open at t = 0+. The RCIC F031 valve starts to open after CST level drops to its TS allowable value of 36.0 inches relative to the tank bottom (Assumption 3).

HPCI system valves will be run in parallel such that the HPCI F004 valve starts closing when the HPCI F042 begins to open. The original logic was a series configuration and will be modified to

-For Information Only EC-052-1055 Page 7 a parallel operation. RCIC system valves remain functioning in series, such that the RCIC FOO valve starts closing after the RCIC F031 reaches full open.

Table 4-2 Full-open Valve Cv Data Valve Flow Coefficient, Cv Reference HPCI Valve HVI(2)55F042 20,700 gpm 11 HPCI Valve HVI(2)55F0G4 20,700 gpm 11 RCIC valve HV1(2)49F031 2,300 gpm 12 RCIC valve HV 1(2)49F0 10 2,300 gpm 12 4.5 Unit 1 Pipe Data The common HPCI/RCIC suction from the CST (downstream of node 1 in Fig. 1) is 20" Schedule 10 pipe (Ref. 13, 20).

A I = 2.074 fi, D, = 19.5 in = 1.625 ft (Ref. 14)

HPCI suction pipe from the CST and SP at node 3 on Fig. 1 consists of 16" Schedule 30 pipe (Ref. 20, 24).

A3 = 1.2684 f12, D3 = 15.250 in = 1.271 ft (Ref. 14)

Per Ref. 20 and 26, RCIC suction piping from the CST and SP at node 4 consists of 6" Schedule 40 pipe.

A 4 - 0.2006 W, D 4 = 6.065 in = 0.5054 ft (Ref. 14) 4.6 Net Positive Suction Head The following FSAR NPSH requirements and results are taken from EC-059-1036, Rev. 2 (See FSAR Sections 6.3.2.2.1.1, 6.3.2.2.1.2, and 5.4.6.2.2.2.)

Unit Suction NPSHR NPSHR NPSHA NPSHA Source HPCI RCIC HPCl RCIC (if)

(if)

(if)

(ft) 1 CST 21.0 21.3 47.32 49.10 2

CST 21.0 21.3 42.26 44.43 1or 2 SP 21.0 21.3 31.4 39.52

5.

Method A hydraulic model of the HPCI and RCIC Pump suction piping has been developed based on conservation of mass and mechanical energy. The model is used to determine CST level versus time during a HPCI suction transfer from the CST to the suppression pool. Suction valves at the CST and the suppression pool are assumed to function in parallel for the HPCI system (i.e., at

For Information Only EC-052-1055 Page 8 t=0, the HPCI CST suction valve HVI(2)55F004 begins to close and the suppression pool suction valve HVI(2)55F042 begins to open). Pressure drop relations were developed for the suction piping in order to predict the change in flow in each line with the changing valve positions. The model incrementally calculates the change in flow in each line and the corresponding change in CST level until the suction valves complete their position change (from open to close or close to open). Initial CST level assumed in the model is adjusted until the final level in the CST is at an acceptable value after a suction transfer. The level can not drop below the point where air intrusion would be introduced from vortex formation in the suction piping.

Acceptable results are achieved when the final level is determined to be at or above the vortex breaker elevation in the CST or the level is determined to be above the onset of air ingestion curve as described in Ref. 16. This acceptance criterion is incorporated into the hydraulic model.

In order to determine the reduction in CST level during a suction swap, it is necessary to determine separate flow rates from the CST and suppression pool while both valves are open.

This is accomplished by balancing the suction heads and flow losses at the point where the two suction flow paths meet (Nodes 3 and 4 on Figure 5-1).

5.1 Governing Equations Bernoulli's equation is used to calculate the flow rates from the CST and suppression pool as a function of time. Governing equations are solved at specific time steps to simulate the transient response of CST level.

Based on Fig. 5-1, the Bernoulli equations for the CST and suppression pool suction paths consist of (Ref. 28, pp. 16-3 and 17-7)

S Pc+

Zgc Pc 2gcA)

+-2 2gCA 2g+ A' I

_,-QHpc)Igc 4

2

+ K 2-3 Q (Q) 2c Pc 2gcA 4 2

A 2gc A(

Z 4 +__t

+ K-+

K2 2-(3)

Ps)

P C2 Ps 2gc AA 3 )

2g cA and

=--

+

9

+_f 24 (gc~

PSX) g p s 2gc A'i 2gc A"

For Information Only EC-052-1055 Page 9 By conservation of mass, the following two relations also hold (total HPCI and RCIC flow rates are constant per Assumption 2 and §4.2)

QHC +

=~

loo) sec (5)

  • ,449 see' and

=(625 ]11 3

QRC +QRS (21) I (6) k4491 sec The elevation Z, of the water surface in the CST is determined from AcZ = -Qc - QRC (7) dt Equations (1)-(7) are sufficient to determine the unknowns Z, InQHC Q

,RC QHs, Qs, P3, and P4.

Variables are defined according to Ac

= free cross-sectional area in CST = 1,250 ft2 (§4.3),

A1

= flow area of 20" common CST suction pipe = 2.074 ft2 (§4.5),

A3

= flow area of 16" HPCI CST and SP suction pipe at node 3 = 1.268 ft2 (§4.5),

A 4

= flow area of 6" RCIC CST and SP suction pipe at node 4 = 0.2006 ft2 (§4.5),

g

= acceleration due to gravity = 32.2 ft/sec2, gc

= 32.2 ft-Lbm/Lbf-see, KI.2

= friction loss coefficient for path from CST to node 2, K2 3(t) = friction loss coefficient for path from node 2 to node 3, K2 4() = friction loss coefficient for path from node 2 to node 4, K 5-3(t) = friction loss coefficient for path from SP to node 3, K5_4(t) = friction loss coefficient for path from SP to node 4, Pl

= pressure in CST above water surface = 2116.8 psfa (Assumption 9),

P3(t)

= pressure at node 3 (psfa),

P4(t)

= pressure at node 4 (psfa),

P5

= pressure in SP above water surface = 2116.8 psfa (Assumption 5),

QHc(t) = HPCI suction flow from CST (ft3/sec),

QHs(t) = HPCI suction flow from SP (ft3/sec),

QRc(t) = RCIC suction flow from CST (ft3/sec),

Q{s(t) = RCIC suction flow from SP (ft3/sec),

t

= time (see),

Z1(t) = elevation of water surface in CST = 672.10 ft + tank level (ft) (§4.3),

Z3

= elevation at node 3 = 653.25 ft (§4.3),

Z4

= elevation at node 4 = 648.7 ft (§4.3),

Z5

= elevation of water surface in SP = 648 ft + 22 = 670 ft (§4.3 and Assumption 8),

ps

= density of water in suppression pool = 61.38 Lbm/ft3 (Assumption 7), and pc

= density of water in CST = 62.00 Lbd/ft3 (Assumption 10).

,For Information Only EC-052-1055 Page 10 In both the CST and SP suction lines, the friction coefficient K has two components: the loss due to the suction valve, which is expressed in terms of the valve Cv and the loss due to piping friction K'. These losses can be expressed as (Ref. 14, p. 3-4)

K2-3 -K2'3 891(12D 3)4 K 4

-K '

+/-891(12D4 ) 4 K5-3

=K L3 + 891(12D 3) 4

_[Cv,F042 OTC and K

4 = K'

+ 891(12D 4)4 where the pipe diameters D3 and D4 are expressed in units of ft. The loss coefficient K5.4 accounts for flow resistance in the RCIC suppression pool suction line. In some cases, a potential exists for reverse flow in this line; however, this would not occur owing to the presence of check valve 149F030. In order to prevent the development of reverse flow in the RCIC suppression pool suction line, a large flow resistance (lxI0 2 ) is added to K5-4 if the onset of reverse flow is detected during the flow iteration. This simulates closure of check valve 149F030.

5.2 Friction Coefficients Friction coefficients K1_2, K_3, K_4, K2-3, and K', are determined from data provided in Ref. 4 and 5.

From Ref. 4, pp. 24 and 45, loss coefficient K1, 2 is equivalent to 290.51 ft of 20" pipe (ID=19.5",f=0.0131) plus 116.63 ft of 16" pipe (ID=15.5",f=O.0133). Basing the total equivalent length on 19.5" ID pipe gives 16 3X0"0133 V19"5'\\s L

= 290.51ft+(U16 63

,0.013 1 9.5) =(290.51+373.2)ft =663.7ft, and K,-2 is given by (0"013(19.5/12)ft 5.35 (Based on pipe DL= 19.5")

-For Information Only EC-052-1055 Page 11 Based on Ref. 4, pp. 24 and 45, loss coefficient K;-3 is equivalent to 43.83 ft of 16" pipe (ID=-I 5.5",f=0.0133) and 164.9 ft of 16" pipe (ID=1 5.25",fJ0.0134).

Converting the entire equivalent length to 15.25" ID pipe gives (l{0.0133" ( 15.25

  • Lq= 164.9ft+(43.83 ft 0.-

( I

_ =(164.9+ 40.1)fR = 205.0 ft

)(0.0l34 ).

5.51 Therefore, 2-3 (0.015.25/12) ft

= 216 (Based on pipe ID= 15.25")

The loss coefficient K'24 is equivalent to 123.87 fR of 6" pipe (ID=6.357",f=0.0164) and 62.78 ft of 6" pipe (ID=6.065",f=0.0163); see pp. 24 and 64 of Ref. 5).

Converting the entire equivalent length to 6.065" ID pipe leads to

+

[(0.0164)6.065f Lq =62.78 ft + (123.87 fk) 0.01 64)(6.65

=)(62.78 + 98.52)fl = 161.3 ft This gives K,_- as K2P-

= (0.0163)(161"3ft) =520 (BasedonpipeID

= 6.0651)

(6.065 /12) ft (BsdopieD=605" For the HPCI suppression pool suction path, the loss coefficient K,_3 consists of the suction strainer loss coefficient,KH,,s,.i., and a loss equivalent to (136.26+270.21-10.90) = 395.6 ft of 16" pipe (ID=-15.25"=1.271 ft, A=1.268 ft2,f-O.013 1); see Ref. 4, pp. 24, 25, and 49. The suction strainer has a pressure drop of 2.80 psi (403 Lbdft2) at 5,000 gpm (11.14 ft3/sec) and suction water temperature equal to N40TF (Ref. 4, p. 49), which yields a loss coefficient of 2gcA'AP (2)(32.2)ftLb.

1.268ft 2 2(403Lb, )(

ft3 I

se 2

KHPCI.Sramcr pQI Lbf see' 1

),

-2

),61.38Lbm J

.-14ft')

KHPCIsa*.= 5.48 (Based on pipe ID = 15.25")

K'

= 5 4 8 +(0.013I)(395.6ft) = 9.56

(

K _

(1.271 ft')

(Based on pipe ID=-I 5.25")

,For Information Only EC-052-1055 Page 12 With regard to the RCIC suppression pool suction path, the loss coefficient K,, consists of the suction strainer loss coefficient, KRCIC,Striner, and a loss equivalent to (63.04+7.08+10.11+7.08+12.10+5.01+5.85+7.08+5.42+7.08+64.15+10.11)

= 204.11 ft of 6" pipe (ID=6.065" = 0.5054 ft, A=0.2006 ft2,f=0.0160); see Ref. 5, pp. 26, 27, and 70. The suction strainer has a pressure drop of 0.90 psi (130 Lb~tft2) at 600 gpm (1.34 ft3/sec) and suction water temperature equal to 140'F (Ref. 5, p. 70), which yields a loss coefficient of KRIwaf 2gcA'AP -(2)(32.2)ftLb.

0.2006ft12 f130Lbf~r[ft, -)(.3 ___2 pQ 2 Lbf see2 I*ft2

)(61.38Lb mA 1.34ftt)

KRccSm.im,

= 3.06 (Based on pipe ID = 6.065")

K

= 3.06 (0.0160)(204.11 ft)= 9.521 (Based on pipe ID = 6.065")

(0.5054 ft) 9 Loss coefficients for the HPCI and RCIC suction lines are summarized in Table 5-1

Eor Information Only EC-052-1055 Page 13 Table 5-1 Summary of Loss Coefficients for HPCI and RCIC Suction Pipe Path Loss Coefficient Value HPCI and RCIC KI_2 5.35 (Based on pipe ID= 19.5")

CST suction HPCI CST suction 891(12D3 )4 K'_3 = 2.16 (Based on pipe ID = 15.25")

K-3 + [C D3 = 1.271 ft CFO(t Cv,)I2 (t) = (20,700X0.9602 x 4 -0.1689 x

- 0. 1857 x2 + 0.3952 x) x I - t /tFoo4 for 1 <! tFoD4 x =0 for t > tFoo4 RCIC CST suction 891(12D.) 4 K2_4 =5.20 (Based on pipe ID = 6.065")

K_-4

=K2-4 + C

)

D4 = 0.5054 ft C-.F01o (t) = (2,300)(0.9602 x4 - 0.1689 x3

- 0.1857x' + 0.3952x) x=1 for t <t x=1-(t-t 2 )/t1o10 for t2 < t :t2 +tF0oo x = 0 for t >t2 +tf0,o t2 = tI +tF01o A = time (sec) when RCIC CST-to-SP suction transfer set point of 36.0" is reached HPC SP suction891(12D)

K'-3 = 9.56 (Based on pipe ID=15.25")

K S_,

K 5-3 + [C

-~~

t]

D 3 = 1.27 1 ft C F#o42 (W)

= (20,700)(0.9602 x4

- 0.1689 x'

-0.1857x 2 +0.3952x) x =O+1ttFO4 2 fort _ t F04z x = 1 for t >to42 RCIC SP suction 891(12D 4)4 K5 4 = 9.52 (Based on pipe ID = 6.065")

K5-4 K-(t)K D 4 = 0.5054 ft CvFo31 (1) = (2,300)(0.9602 x 4 -0.1689 x

-0.1857 x2 + 0.3952x) x =O for t <51 x =1O+(t-t,)/t,, fort <t< t+ +t x =1 for t> t, + tFo31*

,For Information Only EC-052-1055 Page 14 5.3 Vortex Limit Acceptable results are determined by meeting one of two criteria:

1. CST level is at or above 32". This level is higher than the vortex breaker to account for field installation tolerances. With the CST level higher than the vortex breaker, there will be no vortex created in the suction pipe (Ref. 10). See Attachment 4 for validation of this assumption using field test data.
2. CST suction pipe submergence is at or above the onset of air ingestion curve provided in Ref. 16. As described in Ref. 16, the onset of air ingestion curve gives the required submergence of the suction pipe as a function of Froude number. Maintaining suction pipe submergence above the ingestion curve will ensure satisfactory pump operation.

The onset of air ingestion curve (Eqs. 9 and 10 in Ref. 16) is given by S = 2.087(Fr)0 '670 for 0 _< Fr < 0.35 S = 1.363(Fr)0 26' for 0.35 < Fr S 1.40 where Fr Froude number for 20" CST suction pipe = V / g--D V

=

CST suction pipe velocity based on the full pipe.flow area (fl/sec)

(QHc +QRc)/(2.074ft'),

D

=

inside diameter of 20" CST suction pipe = 1.625 ft, S

=

dimensionless submergence of suction pipe = H/D, H

submergence of pipe entrance measured with respect to the inside bottom of the suction pipe (fl)

Z, - (672.10 + 0.84) ft = Z, - 672.94 fl 5.4 Net Positive Suction Head The NPSHA (Net Positive Suction Head Available) for HIPCI and RCIC is computed for case of parallel operation of HPCI CST and suppression pool suction valves. The most restrictive situation occurs when the closure times for the HPCI and RCIC CST suction valves HVI(2)55F004 and HV1 (2)49F010 are at their minimum values while the opening times for the suppression pool suction valves HVI (2)55F042 and HV I (2)49F031 are at their maximum values as discussed in §4.1.

For Information Only EC-052-1055 Page 15 5.4.1 HPCI The NPSHA (ft) for HPCI is calculated as described in FSAR Section 6.3.2.2.1.1.

NPSHA = hk - hf + ha -

where hs is the static head, hfdenotes the friction head, ha is the atmospheric pressure head, and h~pa is the head equivalent of vapor pressure. In terms of the variables defined in this calculation, the HPCI NPSHA can be calculated as (see Fig. 5-1)

NPSHA I =

-c + 1.75 F -qT-h(

(8) g

[42g where P3

=

pressure at node 3 in Fig. 5-1 (psfa),

/3

=

flow-weighted density at node 3 = (Pc QHC + Ps Q1,s) (Lb/ft3),

atc + QHs

=

flow area of 16" HBB 107 pipe = r(15.25")2 /4 = 182.65 in2 = 1.27 ft2 (EC-052-0002, Rev. 2, p. 24),

4t4-

=

flow area of 14" HBBI07 pipe = ir(13.25") 2 /4 = 137.89 in2 = 0.958 ft2 (EC-052-0002, Rev. 2, p. 24),

K16.

=

resistance coefficient for 16" HBB piping in flow path from node 3 to HPCI pump suction, K,1.4 resistance coefficient for 14" HBB piping in flow path from node 3 to HPCI pump suction, and hv~a

=

vapor pressure of water at HPCI pump inlet (ft).

Other variables in Eq. (8) have been defined previously. Node 3 in Fig. 5-1 corresponds to the pipe junction at the 16"xI6"x16" tee shown on Isometric HBB107-1 (Elevation 653'-3"). In Eq.

(8), an elevation head of 1.75 ft is added to account for the fact that the HPCI suction piping drops this amount in elevation between node 3 and the pump center line elevation (Ref.

HBB 107-1). The vapor pressure of the water at the HPCI pump suction is determined by flow weighting the suction flows from the CST and suppression pool as follows:

TFor Information Only EC-052-1055 Page 16 hva = (h~,c QHc + h.,.,s Qns )

QHC + QHS (9) where hvpa~c is the vapor pressure of 100IF CST water (0.94924 psia = 2.2 ft), and h,.s is the vapor pressure of 140TF suppression pool water (2.8892 psia = 6.8 fi). From Isometric HBB107-1, the flow resistance terms are K16.

= [tee branch]+ [area contraction] + [90 deg elbow]

+[16"x14" reducer]+[4' of 16" HBBPipe]

and K14" = [4.4ftofl4"HBBpipe]

For the 16-inch pipe,

[tee branch]

= 60 f= 60x0.013 = 0.78 (Ref. 14, pp. A-26 and A-29)

[area contraction]

= contraction from two 16" pipes into a single 16" pipe.

_0.51-,5)= (0.5)(1-0.5) = 1.0

  1. 4 (0.50)2 p2 = A = 1 = 0.50 A22

[90 deg elbow]

[1 6"x 14" reducer]

= 14 f= 14x0.013 = 0.18 0.5(1-f2)= (0.5)(1 - 0.75) -022

,p4 (0.75)2 P 2 = 0.958 ft2 = 0.75 1.27 ft2

[4' of 16" HBB Pipe] = (0.0 13) (4.0 f)/ (1.27 ft) = 0.041 K16.

=0.78+1.0+0.18+0.22+0.041 =2.2 For the 14-inch pipe, K,4. = (O.013)(4.4')/(1.104') = 0.052

-For Information Only EC-052-1055 Page 17 5.4.2 RCIC The NPSHA (ft) for RCIC is calculated as described in EC-050-0001, Rev. 2, p. 149.

NPSHA = hs - hf + h. - h,;.

where hs is the static head, hf denotes the friction head, ha is the atmospheric pressure head, and hvp, is the head equivalent of vapor pressure. In terms of the variables defined in this calculation, the RCIC NPSHA can be calculated as (see Fig. 5-1)

NPSHA =

gc 1K. (QRc+Q) 2 -hV, (10) jig 2g where P4

=

pressure at node 4 in Fig. 5-1 (psfa),

=

flow-weighted density at node 4 = (Pc QRC + PS QS) (Lbmft3),

QRC +

A6.

=

flow area of 6" HBBI03 pipe = ;r(6.065") 2 /4 28.89 in2 = 0.201 ft2 (Ref. 14, 20),

K6.

=

resistance coefficient for 6" HBB piping in flow path from node 4 to RCIC pump suction,

h.

=

vapor pressure of water at RCIC pump inlet (ft).

Other variables in Eq. (10) have been defined previously. Node 4 in Fig. 5-1 corresponds to the pipe junction at the 6"x6"x6" tee shown on HBB 103-1. The node corresponds to elevation 648.7 ft. Isometric HBB 103-1 shows that the RCIC pump centerline elevation and the elevation of node 4 are essentially equal; therefore, no elevation correction is included in Eq. (10). The vapor pressure of the water at the RCIC pump suction is determined by flow weighting the suction flows from the CST and suppression pool as follows:

h~,

_ (h,,Pc QRc + hy,.s Qs)

QRC + QR1 where hpc is the vapor pressure of 100'F CST water (0.94924 psia = 2.2 ft), and h,,,s is the vapor pressure of 140PF suppression pool water (2.8892 psia = 6.8 ft). From Isometric HBB103-1, the flow resistance terms are

TFor Information Only EC-052-1055 Page 18 K6.

= [tee branch] + [area contraction]+ [90 deg elbow]

+[6"gate valve 150F016]+[6.5' of 6" HBBPipe]

The individual loss coefficients are computed as follows:

[tee branch]

= 60 f= 6040.015 = 0.9 (Ref. 14, pp. A-26 and A-29)

[area contraction]

[90 deg elbow)

[6" gate valve]

= contraction from two 6" pipes into a single 6" pipe.

0.5 (1 _

)82 (0.5)(1-0.5) -10

/4 (0.50)2

)6 A2

=

- 0.50 A2 2

= 14 f= 14x0.015 = 0.21

= 8 f= 8x0.015 =0.12

[6.5' of 6" HBB Pipe] = (0.015) (6.5 ft)/ (0.505 ft) = 0.19 K 6.

=0.9+1.0+0.21+0.19--2.5 5.5 Numerical Solution Method Bernoulli Equations (1)-(4) were solved by means of functional iteration with under-relaxation on pressures P 3 and P 4 tosupport convergence. The mass balance on CST inventory, Eq. 7, was solved with first-order explicit integration with a time step size of 0.1 seconds. The FORTRAN program used to carry out the solution is provided in Attachment I and on CD. Sensitivity of the solution to time step size and convergence criterion was investigated and the results are summarized in Table 5-2.

For Information Only EC-052-1055 Page 19 Table 5-2 Sensitivity of Calculation Results to Time Step Size and Convergence Criterion Case Time Step (sec)

Convergence CST Level (Inches)

Criterion at t = 100 seconds 1

0.1 10"7 31.3109 2

0.1 104 31.3109 3

0.5 10"'

31.2937 4

1.0 10"7 31.2733 Results in Table 5-2 show that the numerical error in Case I results is on the order of 0.02 inches, which is acceptable. Computer output for Cases 1-4 is included on CD.

5.6 Verification of Results Computer results for Case 1 are verified by substituting numerical results at a particular time step back into Eqs. (1)-(6) to demonstrate that the governing equations are satisfied (see Attachment 2). An additional peer check of the results is provided in Attachment 3 through comparison of the present calculations against an independently developed Excel spreadsheet model of CST water level response.

EC-052-1055 Page 20 0

H o

0 0D CST 20", D=1 9.5" A1 = 2.074 ft2 HV155F004 QHC HV149F01 16", D3=15.250" A3 = 1.268 ft2 QRC 10 6", D4=6.065" A.4 = 0.2006 ft2 0

RCIC Suction 625 gpm HVI55F042 0

QHS QRS HPCI Suction 5,100 gpm Figure 5-1 Schematic of HPCI and RCIC CST and suppression pool suction flow paths.

For Information Only EC-052-1055 Page 21

6.

Results A computer case summary is provided in Table 6-1. Case I is the design case for evaluation of CST vortex formation during transfer of HPCI and RCIC suction from the CST to the suppression pool on low CST water level. Case 5 provides a highly conservative calculation of the NPSHA for HPCI and RCIC pumps during the transfer. As discussed in §5.5, Cases 2 through 4 demonstrate an acceptable level of error in the numerical calculations.

Calculation results for Case 01 presented in Fig. 6-1 demonstrate that a HPCI suction transfer set point of 40.5 inches maintains adequate HPCLIRCIC pump suction conditions in that CST water level remains above the vortex limit. The vortex limit line is a combination of the two acceptance criteria specified in §5.3. CST level must stay above the vortex limit line at all times in order to satisfy the acceptance criteria of not introducing air into the HPCIRCIC pump suction line. The specified initial water level in the CST was adjusted to achieve a depletion curve that remained above the vortex limit. The initial CST level that was required is greater than the current technical specification value of 36.0 inches; therefore, a technical specification change will be necessary in order to prevent vortex formation in this application. The computed HPCI and RCIC CST and suppression pool suction flows are shown in Fig. 6-2 and the calculated loss coefficients are plotted in Fig. 6-3 in order to provide indication of valve position.

Available NPSH for Case 1 during the transfer is plotted in Fig. 6-4 where it is compared to the NPSH required. As can be seen from Fig. 6-4, there is no reduction in the available margin during the suction transfer for the design case (Case 1).

Case 5 provides a bounding assessment of NPSHA during the HPCI suction transfer. As discussed previously in §4.1, the choice of valve stroke times maximizes pump suction path resistance from the CST and the suppression pool. Results in Fig. 6-6 show that the minimum available margin in NPSHA for HPCI is 25.45 ft - 21.0 ft = 4.5 ft, even in this extreme case. As expected, the minimum in the available margin occurs at the point where the HPCI CST suction valve [HVl(2)55F004] goes closed at 53.6 seconds. At this instant, the HPCI SP suction valve

[HVI (2)55F042] is in an intermediate position during its opening stroke of 115 seconds. Suction line elevation head and friction losses are essentially independent of Unit when HPCI suction is aligned to the suppression pool; therefore, the minimum NPSHA margin shown in Fig. 6-6, which was obtained using a Unit 1 hydraulic model (see Assumption 4), applies also to Unit 2 (see Attachment 1 of Ref. 29).

'For Information Only EC-052-1055 Page 22 Table 6-1 Computer Case Summaryt t FO42 tFOO t Fo31 t Fo1Ti eS p Co v r nc Case (sec)

(see)

(se)

(see)

Time Step Convergence (sec)

Criteron UIPCI SP HPCI CST RCIC SP RCIC CST 1

115 108 44 44 0.1 10-I 2

115 108 44 44 0.1 10.-

3 115 108 44 44 0.5 10.'

4 115 108 44 44 1.0 10-7 5

115 53.6 44 25.5 0.1 10i In all Cases, suction transfer set points are 40.5" for HPCI and 36.0" for RCIC.

included on CD.

All input and output files are

Tor Information Only EC-052-1055 Page 23 I-35 00

-1530 C

0 25 0

10

'U 20 0

"- 15 0

-J 10 0

20 40 60 80 100 120 140 160 Time, sec Fig. 6-1 FORTRAN calculation of CST water level vs. vortex limit for Case 1.

set points are 40.5" for HPCI and 36.0" for RCIC.

Suction transfer

,For Information Only EC-052-1055 Page 24 r:

a.o 3

C,!

U-0 E

0l.

0 20 40 60 80 100 120 140 160 Time, sec Fig. 6-2 FORTRAN calculation of HPCI and RCIC suction flow for Case 1. Suction transfer set points are 40.5" for HPCI and 36.0" for RCIC.

ý I

For Information Only EC-052-1055 Page 25 1.E+20 1.E+18 1.E+16 I.E+14 1.E+12 U

  • 1.E+10 a

a

  • 1.E-)B 1.E.06 1.E+04 1.E+02 1.E+00 a

20 40 60 80 100 120 140 160 Time, sec Fig. 6-3 FORTRAN calculation of HPCI and RCIC suction path loss coefficients for Case 1.

Suction transfer set points are 40.5" for HPCI and 36.0" for RCIC.

For Information Only EC-052-1055 Page 26 U) z 60 55 50 45 40 35 30 25 20 15 10 0

20 40 60 80 Time, sec 100 120 140 160 Fig. 6-4 FORTRAN calculation of HPCI and RCIC NPSHA for Case 1. Suction transfer set points are 40.5" for HPCI and 36.0" for RCIC.

For Information Only EC-052-1055 Page 27 6000 5000 4000 E

CL 3000 0C 2000 C.

E 1000 0

-1000 0

20 40 60 80 100 120 140 160 Time, sec Fig. 6-5 FORTRAN calculation of HPCI and RCIC suction flow for Case 5. Suction transfer set points are 40.5" for HPCI and 36.0" for RCIC.

-For Information Only EC-052-1055 Page 28 60 55 50 45 40 35 30 25 20 15 10 0

20 40 60 80 100 120 Time, sec Fig. 6-6 FORTRAN calculation of HPCI and RCIC NPSHA for Case 5.

points are 40.5" for HPCI and 36.0" for RCIC.

140 160 Suction transfer set

'For Information Only EC-052-1055 Page 29

7.

References I. Tech Spec 3.6.2.2, "Containment Systems-Suppression Pool Water Level."

2. Technical Specification 3.3.5.2, "Reactor Core Isolation Cooling (RCIC) System Instrumentation," and Table 3.3.5.2-1, "Reactor Core Isolation Cooling System Instrumentation.
3. Calculation EC-VALV-1072, "Actuator Sizing & Diagnostic Test Acceptance Criteria for GL 89-10 DC Rising-Stem MOVs, Rev. 29.
4. Calculation EC-052-0002, "High Pressure Coolant Injection DP Calculations," Rev. 2.
5. Calculation EC-050-0001, "Reactor Core Isolation Cooling Pressure Drop Calculations,"

Rev. 2.

6. Drawing J-653, Sheet 21, "Level Settings Diagram Condensate Storage Tank 0T522A &

0T522B."

7. Drawing C-1932, Sheet 4, "Reactor Primary Containment Reactor Building Composite Overview," Rev. 0.
8. Drawing HBB 107-1, Sheet 1, "Isometric Reactor Building High Pressure Coolant Injection,"

Rev. 3.

9. Drawing HBB 103-1, Sheet 1, "Isometric Reactor Building Reactor Core Isolation Cooling,"

Rev. 4F6.

10. Calculation EC-037-0013, "Technical Specification Limit For 0T522A," Rev 0.
11. Vendor Drawing FF 110120, Sheet 7901, "1 6-inch, 150-pound Weld Ends Carbon Steel Flex Wedge Gate Valves with SMB-00-7 1/2 Limitorque Operator," Rev. 3.
12. Vendor Drawing FF 110120, Sheet 1601, "6-inch 150-pound Weld Ends Pressure Seal Flex Wedge Carbon Steel Gate Valves 1 SMB-000-2 Limitorque Operator Forged," Rev. 6
13. M-108, Sheets 1 & 2, "P&ID Condensate & Refueling Water Storage."
14. Crane Technical paper No. 410, 1982 printing.
15. Calculation EC-052-0500, "Motor Operated Valve Data Detail Calculation for HV255F006,"

Rev. 14.

I6. Sanders, R.R., Smith, L.A., Padmanabhaw, M., Johansson, A., and Hafer, D.R., "Air Entrainment in a Partially Filled Horizontal Pump Suction Line," Proceedings of 2001

,For Information Only EC-052-1055 Page 30 International Joint Power Generation Conference, New Orleans, June 4-7, 2001.

17. Technical Specification 3.3.5.1, "Emergency Core Cooling System (ECCS) Instrumentation,"

and Table 3.3.5.1-1, "Emergency Core Cooling System Instrumentation."

18. FSAR Section 6.3.2.2.1.2, "High Pressure Coolant Injection (HPCI) System-NPSH Available with Suction from the Suppression Pool."
19. FSAR Section 6.3.2.2.1.1, "High Pressure Coolant Injection (HPCI) System--NPSH Available with Suction from the Condensate Storage Tank."
20. M-199, Sheet A, "Piping Class Sheets Summary Sheets & Standards," Rev. 66.
21. Drawing HCB 1 -2, "Isometric Condensate Storage," Rev. 4F 12..
22. Vendor Drawing FF101270, Sheet 3 101, "General Plan 30-foot Outside Diameter by 100-foot High Dome Roof Tank," Rev. 8.
23. Vendor Drawing FF101270, Sheet 7901, "General Plan 40 Feet Diameter by 36 Feet High Condensate Storage Tank 0T522A."
24. Drawing M-155, Sheet 1, "P&ID High Pressure Coolant Injection."
25. Drawing M-150, Sheet 1, "P&ID RCIC Turbine Pump."
26. M-149, "P&ID Reactor Core Isolation Cooling."
27. ASME Steam Tables, 5th Edition.
28. Lindeburg, M.R., Mechanical Engineering Reference Manual, Professional Publications, Belmont, CA, 2001.
29. EC-059-1036, "Bases for ECCS & RCIC FSAR Net Positive Suction Head Calculations,"

Rev. 2.

(^ '.

-For Information Only EC-052-1055 Page 31 : FORTRAN Program Used to Solve Eqs. in §5.1 IMPLICIT REAL*8(A-H,O-Z)

REAL,*8 kl2,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SET1/

ala3,a4,acst,cvfO42,cvfOO4,cvf03l,cvfOlO, dl,d3,d4,efcst,ebcstsp,ebsp,etvb, g,gc, k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc.qhs,qrc,qrs,tl,t2,tf042, tf004,tfO3l,tfOlO,zlcstL,z3,z4,z5, rcictr,rhoc,rhos,errO,vxL C

OPEN (UNIT=5,FILE='c:\\documents and settings\\hp-owner\\my documents C

&\\mark\\vortex\\cstl.out',STATUS='OLD')

C OPEN (UNIT=7,FILE='c:\\documents and settings\\hp-owner\\my documents C

&\\mark\\vortex\\cst2.out',STATUS='OLD')

C OPEN (UNIT=8,FILE='c:\\documents and settings\\hpowner\\my documents C

&\\mark\\vortex\\cst3.out',STATUS='OLD')

C OPEN (UNIT=9,FTLE='c:kdocuments and settings\\hp-owner\\my documents C

&\\mark\\vortex\\cst4.out',STATUS='OLD')

OPEN (UNIT=5,FILE='cstl.out',STATUS='NEW')

OPEN (UNIT=7,FILE='cst2.out',STATUS='NEW')

OPEN (UNIT=8,FILE='cst3.out',STATUS='NEW')

OPEN (UNIT=9,FILE='cst4.out',STATUS='NEW')

C....

Nomenclature C

al

= flow area of 20" common CST suction pipe (ft**2)

C a3

= flow area of HPCI CST and SP suction pipe at node 3 (ft**2)

C a4

= flow area of RCIC CST and SP suction pipe at node 4 (ft**2)

C acst

= free cross-sectional area of cst (ft**2)

C cstL

= level in CST relative to floor of CST (inches)

C cvf004

= full-open cv for HV155F004 (gpm)

C cvf010

= full-open cv for HV149FO10 (gpm)

C cvf042

= full-open cv for HV155F042 (gpm)

C cvf03l

= full-open cv for HV149F031 (gpm)

C dl

= diameter of 20* CST suction pipe (ft)

C d3

= diameter of HPCI CST and SP suction piping at node 3 (ft)

C d4

= diameter of RCIC CST and SP suction piping at node 4 (ft)

C efcst

= elev at floor of CST (ft)

C ebcstsp = elevation at inside bottom of CST suction pipe relative C

to tank floor (ft)

C ebsp

= elevation at bottom of SP (ft)

C etvb

= elevation at top of vortex breaker relative to tank floor (ft)

C g

= acceleration due to gravity (ft/sec**2)

C gc

= 32.2 ft-Lbm/Lbf-sec**2 C

k12

= friction coeff for path from CST to node 2 C

k23

= friction coeff for path from nodes 2 to 3 C

k24

= friction coeff for path from nodes 2 to 4 C

k53

= friction coeff for path from SP to node 3 C

k54

= friction coeff for path from SP to node 4 C

k23p

= friction coeff for path from nodes 2 to 3 excluding F004 valve C

k24p

= friction coeff for path from nodes 2 to 4 excluding F010 valve C

k53p

= friction coeff for path from SP to node 3 excluding F042 valve C

k54p

= friction coeff for path from SP to node 4 excluding F031 valve C

pl

= press in CST above water surface (psfa)

C p3

= press at node 3 (psfa)

C p4

= press at node 4 (psfa)

C p5

= press in SP above water surface (psfa)

C qhc

= HPCI suction flow from CST (ft**3/sec)

C qhs

= HPCI suction flow from SP (ft**3/sec)

C qrc

= RCIC suction flow from CST (ft**3/sec)

C qrs

= RCIC suction flow from SP (ft**3/sec)

C t

= tine (sec)

\\

-For Information Only EC-052-1055 Page 32 C

C C

C C

C C

C C

C C

C C

tl t2 tf042 tf004 tf03l tfOlO zl z3 z4 z5 rcictr rhoc rhos time at which HV149FO31 begins to open (sec) time at which HV149F010 begins to close (sec) stroke time (open) for HV155F042 valve (sec) stroke time (close) for HV155F004 valve (sec) stroke time (open) for HV149F031 valve (sec) stroke time (close) for HV149F010 valve (sec) elevation at water surface in CST (ft) elevation at node 3 (ft) elevation at node 4 (ft) elevation at water surface of SP (ft)

RCIC suction transfer setpoint (inches) density of water in CST (Lbm/ft**3) density of water in SP (Lkm/ft**3)

C....

INPUT DATA al

=

2.074 a3

=

1.268 a4

=

0.2006 acst

=

1250.0 cvf042

= 20700.0 cvf004

= 20700.0 cvf031

=

2300.0 cvf010

=

2300.0 dl

=

1.625 d3

=

1.271 d4 0.5054 efcst ebcstsp ebsp etvb g

gc k12 k23p k24p k53p k54p p1 p 5 z3 z4 z5 rhos rhoc rcictr tf042 tf03l

=

672.10

=

0.84

=

648.0

=

2.573 32.2

=

32.2

=

5.35

=

2.16

=

5.20

=

9.56

=

9.52

=

2116.8

=

2116.8

=

653.25

=

648.7

=

670.0

=

61.38

=

62.00

=

36.0

=

115.

=

44.

C....

Design Case for Vortex Formation C

tf004 108.

C tfOlO

=

44.

C....

Limiting Case for NPSH Evaluation tf004

=

53.6 tfOlo

=

25.5 C....

specify convergence criterion errO = l.E-07 C....

specify the time step size (sec) dt

= 0.1DO C....

specify initial CST water level (inches) cstL = 40.5 C....

specify initial time, end time, and time step size (sec) t

= 0.Do tend = 150.0

,For Information Only EC-052-1055 Page 33 npr

= DINT( dt/dt np

= 0 C....

Initialize tank level, loss coefficients,flow rates, C....

and pressures k23 = fk23(t) k24 = fk24(t) k53 = fk53Ct) k54 = fk54(t) z1 efcst + cstL/12.0 qhc = 5100./449.

qrc = 625./449.

qhs = 0.0 qrs = 0.0 p3

= g*zl/gc + pl/rhoc g*z3/gc - qhc**2/(2*gc*a3**2)

- kl2*(qhc+qrc)**2/(2*gc*al**2) k23*qhc**2/(2*gc*a3**2) p3

= p3*rhoc p4

= g*zl/gc + pl/rhoc g*z4/gc - qrc**2/(2*gc*a4**2)

- kl2*(qhc+qrc)**2/(2*gc*al**2)

- k24*qrc**2/(2*gc*a4**2) p4

= p4*rhoc C..

C C

C C

C C

initialize tl and t2 (sec) tl

= time at which F031 valve starts to open (sec)

= time when CST level drops to allowable value (36.0")

for RCIC suction transfer

= t at instant when cstL = 36.0 t2 = time when F010 valve starts to close (sec)

= tl

+ tf031 (FO10 starts to close when F031 is full open) tl

= I.D+09 t2 = l.D+09 C....

set RCIC suction transfer flag C

irtr

= 0 prior to transfer C

irtr

= 1 after transfer irtr

= 0 C....

print the initial conditions C....

calculate flows and pressures CALL flow(t)

C....

compute vortex limit CALL vortex WRITE(5,111)

WRITE(5,113)

WRITE(5,101) t,cstL,vxL,qhc*449,qhs*449,qrc*449,qrs*449 WRITE(*,101) t,cstL,vxL,qhc*449,qhs*449,qrc*449,qrs*449 WRITE(7,115)

WRITE(7,117)

WRITE(7,103) t,k12,k23,k24,k53,k54,p3/144.,p4/144.

WRITE(9,119)

WRITE(9,120) 101 FORMAT(3F12.4,4F12.2) 103 FORMAT(FI2.4,1P5E12.4,0P2F12.4) 105 FORMAT(Fl2.4,F12.2,5X,F12.2) 111 FORMAT(8X,'t',9X,'cstL',8X,'vxL',BX, Qhc',9X, Qhs',

9X,'Qrcl,9X,'Qrs')

113 FORMAAT(7X,'sec',9X,Iinl,9X,'in;,9X,'gpm',9X,'gpm',

9X,'gpm',9X,'gpm')

115 FORMAT(8X,'t',9X,'K12 '0SX,'K23',8X,'K24',9X,'K53-,

9X,'K54',9X,'P3

,9x,'P4 ')

-For Information Only EC-052-1055 Page 34 117 FORMAT(7X,'sec',9X,

,9X,'

',9X,'

',9X,'

9X,'

',9X,1psia1,8X,'psia')

119 FORMAT(8X, 't',5X, 'NPSHAHPCI',9X, 'NPSHARCIC')

120 FORMAT(8X,'sec',5X,'

(ft)

(ft)

')

20 CONTINUE C.... Calculate the hpci and rcic flows and pressures p3, p4 CALL flow(t)

C....

Integrate the CST mass balance z1 = zl - dt*( qhc + qrc )/acst t

= t

+ dt cstL = (zl-efcst)*12.

C.... check if RCIC suction transfer should initiate IF

( cstL.LT.

rcictr.AND.

irtr

.EQ.

0 ) THEN ti

= t t2

= tl

+ tf031 irtr

= 1 WRITE(8,151) tl WRITE(8,153) t2 151 FORMAT('

tl(sec) =

, F15.5,3X,'F031 begins to open, 153 FORMAT('

t2(sec) = ',

F15.5,3X,'F010 begins to close' END IF C....

print the results CALL vortex CALL hnpsh ( t, hnpsha)

CALL rnpsh(t, rnpsha) np np + 1 IF (np

.EQ.

npr ) THEN IF

( vxL.GE. cstL ) THEN PAUSE 'CST level less than Vortex Limit--STOP' STOP END IF WRITE(5,101) t,cstL,vxL,qhc*449,qhs*449,qrc*449,qrs*449 WRITE(*, 101) t,cstL,vxL,qhc*449,qhs*449,qrc*449,qrs*449 WRITE(7,103) t,k12,k23,k24,k53,k54,p3/144.,p4/144.

WRITE(9,105) t,hnpsha,rnpsha np= 0 END IF IF

( t

.LT.

tend ) GOTO 20 STOP END SUBROUTINE flow (t)

IMPLICIT REAL*8(A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23p,k24p,k53pk54p COMMON /SET1/

al,a3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvfO1O, dl,d3,d4, efcst, ebcstsp, ebsp, etvb,g,gc, kl2,k23,k24,k53.k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc,qhs,qrc,qrs, tl,t2,tf042, tf004, tf031,tf0l0,zl,cstLz3,z4,z5, rcictr, rhoc, rhos, errO, vxL KOUNT = 0 10 CONTINUE C.... calculate time-dependent loss coeff k23,

k24, k53, and k54

-For Information Only EC-052-1055 Page 35 k23 = fk23(t) k24 = fk24(t) k53 = fk53(t) k54 = fk54(t)

KOUNT = KOUNT + 1 IF

( KOUNT

_GT.

1500 ) THEN C....

WRITE(*,*)

KOUNT,qrs END IF IF

( KOUNT.GT.

75000 ) THEN PAUSE 'iter failed in f low--STOPI STOP END IF C....

save p3 and p4 in order to apply under-relaxation y2 = qhc y3 = qrc y4 = qhs y5 = qrs y6 = p3 y7 = p4 C....

check size of k's to maintain stable interation scheme IF

( k53

.GE.

k23 ) THEN C....

calc qhs from Eq.

3 qhs = g*(z5-z3)/gc + (p5-p3)/rhos qhs = qhs*(2*gc*a3**2)/(l.D0+k53) qhs = DSQRT(qhs)

C....

calc qhc from Eq. 5 qhc = 5100./449.

qhs C....

calculate p3 from Eq.

1 p3 = g*(zl-z3)/gc + pl/rhoc qhc**2/(2*gc*a3**2)

- k12*(qhc+qrc)**2/(2*gc*al**2)

- k23*qhc**2/(2*gc*a3**2) p3

= p3*rhoc ELSE IF

( k53.LT.

k23 ) THEN C....

calc qhc from Eq.

1 qhc = g*(zl-z3)/gc + (pl-p3)/rhoc

- kl2*(qhc+qrc)**2/(2*gc*al**2) qhc = qhc*(2*gc*a3**2)/(l+k23) qhc = DSQRT(qhc)

C....

calc qhs from Eq.

5 qhs = 5100./449.

qhc C....

calc p3 from Eq. 3 p3 = g*(z5-z3)/gc + p5/rhos (l.DO+k53)*qhs**2/(2*gc*a3**2) p3 = p3*rhos END IF IF

( k54.GT.

k24 ) THEN C....

calc qrs from Eq. 4 C....

Look for solution with qrs > 0 qrs = g*(z5-z4)/gc + (p5-p4)/rhos qrs = qrs*(2*gc*a4**2)/(l.DO+k54)

IF

( qrs.LT.

0.DO ) THEN k54 = fk54(t) qrs = g*(z5-z4)/gc + (p5-p4)/rhos qrs = qrs*(2*gc*a4**2)/(l.D0-k54) qrs = -DSQRTlqrs)

GOTO 50 END IF qrs = DSQRT(qrs)

'For Information Only EC-052-1055 Page 36 50 CONTINUE C....

calc qrc from Eq.

6 qrc = 625./449.

qrs C....

calculate p4 from Eq.

2 p4

- g*(zl-z4)/gc + pl/rhoc

- qrc**2/(2*gc*a4**2) kl2*(qhc+qrc)**2/(2*gc*al**2) k24*qrc**2/(2*gc*a4**2) p4 = p4*rhoc ELSE IF

( k54.LE.

k24 ) THEN C....

calc qrc from Eq. 2 qrc = g*(zl-z4)/gc + (pl-p4)/rhoc kl2*(qhc+qrc)**2/(2*gc*al**2) qrc = qrc*(2*gc*a4**2)/(l.DO+k24) qrc = DSQRT(qrc)

C....

calc qrs from Eq. 6 qrs = 625./449.

- qrc C....

calc p4 from Eq. 4 p4

= g*(zS-z4)/gc + p5/rhos l.D0*qrs**2/(2*gc*a4**2) k54*qrs*DABS(qrs)/(2*gc*a4**2) p4 = p4*rhos ELSE END IF C....

compute the error err

= ferr(t)

C....

apply under-relaxation IF

( err.GT.

errO ) THEN ep = 5.E-04 qhc = ep*qhc + (l.D0-ep)*y2 qrc = ep*qrc + (l.D0-ep)*y3 qhs = ep*qhs + (l.D0-ep)*y4 qrs = ep*qrs + (I.D0-ep)*y5 p3 = ep*p3 + (l.D0-ep)*y6 p4 = ep*p4 + (l.DO-ep)*y7 GOTO 10 END IF C....

Solution has converged--return to Main RETURN END FUNCTION ferr(t)

C....

computes rms error for governing equations IMPLICIT REAL*8(A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SETI/

al,a3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvfOO, dl,d3,d4,efcstebcstsp,ebsp,etvb,g,gc, k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhcqhs,qrc,qrs,tl,t2,tf042, tf004,tf031,tf010,zlcstL,z3,z4,z5, rcictr,rhoc,rhos,errO,vxL C....

Equation 1 erl

= g*zl/gc

+ pl/rhoc

- g*z3/gc

- p3/rhoc

- qhc**2/(2*gc*a3k*2)

- kl2*(qhc+qrc)**2/(2*gc*al**2) k23*qhc**2/(2*gc*a3**2)

C.... Equation 2

,or Information Only EC-052-1055 Page 37 er2 = g*zl/gc

+ pl/rhoc

- g*z4/gc

- p4/rhoc

- qrc**2/(2*gc*a4**2)

- k12*(qhc+qrc)**2/(2*gc*al**2)

- k24*qrc**2/(2*gc*a4**2)

C....

Equation 3 er3 = g*z5/gc

+ p5/rhos

- g*z3/gc p3/rhos qhs**2/(2*gc*a3**2)

- k53*qhs**2/(2*gc*a3**2)

C....

Equation 4 er4 = g*z5/gc

+ p5/rhos

- g*z4/gc p4/rhos

- qrs**2/(2*gc*a4**2) k54*qrs*DABS(qrs)/(2*gc*a4**2)

C....

Equation 5 er5 = qhc + qhs -

5100./449.

C....

Equation 6 er6 = qrc + qrs - 625./449.

ferr =DSQRT(

(erl**2 + er2**2 + er3**2

+ er4**2 + er5**2 + er6**2)/6.DO RETURN END FUNCTION fk23(t)

IMPLICIT REAL*8(A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23pk24p, k53pk54p COMMON /SET1/

al,a3.a4,acst,cvfO42,cvfOO4,cvfO3l,cvfolo, dl.d3,d4,efcst,ebcstsp,ebsp, etvb,g,gc, k12,k23,k24,k53.k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc,qhs,qrc,qrstl,t2, tf0420 f004. tfO3l, tfOlO,zl,cstLz3,z4,z5, rcictr,rhoc,rhos,errO,vxL C....

F004 valve starts to close at t=O C....

and is fully closed at t=tf004 IF ( t

.LE.

tf004 ) THEN x = I.DO -

t/tf004 ELSE x = O.DO END IF cv = cvf004*( 0.9602"x**4 -

0.1689*x**3 0.1857*x**2 + 0.3952*x )

cv DMAXl(

cv, 1.D-06 )

k23 =k23p + 891.*(12.*d3)**4/cv**2 fk23 = k23 RETURN END FUNCTION fk24(t)

IMPLICIT REAL*8(A-H,O-Z)

REAL-8 k12,k23,k24,k53,k54,k23p,k24p,k53pk54p COMMON /SETI/

ala3,a4,acst,cvfO42,cvfOO4,cvfO31,cvfOIO, dl,d3,d4,efcst,ebcstsp,ebsp,etvb,g,gc, k12,k23,k24,Jk53,k54,k23p,k24p,k53p,k54p, plp3,p4,p5,qhc,qhs,qrc,qrs,tl,t2,tfO42,

For Information Only EC-052-1055 Page 38 tf004,tfO3l,tfO0O,zl,cstL,z3,z4,z5, rcictr,rhoc,rhos,err0,vxL C.... F010 valve starts to close at t=t2 and is fully C....

closed at t=t2+tf0l0 IF

( t

.LE.

t2 ) THEN x=

.D0 ELSE IF

( t

.GT.

t2.AND.

t

.LE.

t2+tfOlO ) THEN x = l.D0 -

(t-t2)/tfOlO ELSE IF

( t

.GT.

t2+tfOlO ) THEN x = 0.DO END IF cv cvfO0O*( 0.9602*x**4 0.1689*x**3 0.1857*x**2 + 0.3952*x cv DMAXI( cv, 1.D-06 )

k24 k24p + 891.*(12.*d4)**4/cv**2 fk24= k24 RETURN END FUNCTION fk53(t)

IMPLICIT REAL*8(A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SET1/

ala3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvfO1O, dl,d3,d4,efcst,ebcstspebsp,etvbg,gc, k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc,qhs,qrc,qrstl,t2,tf042, tf004,tfO3l,tfOlO,zl,cstL,z3,z4,z5, rcictr,rhoc,rhos,err0,vxL C....

F042 valve starts to open at t=0 and is C....

fully open at tf042 IF ( t

.LE.

tf042 ) THEN x = 0.D0

+ t/tf042 ELSE x = I.D0 END IF cv = cvf042*( 0.9602*x**4 - 0.1689*x**3 0.1857*x**2 + 0.3952*x cv = DMAXI( cv, 1.D-06 )

k53 = k53p + 891.*(12.*d3)**4/cv**2 fk53

= k53 RETURN END FUNCTION fk54(t)

IMPLICIT REAL*8(A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SET1/

ala3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvfOlO, dl,d3,d4,efcst,ebcstsp,ebsp,etvb,g,gc, k12,k23,k24,k53,k54,k23p,k24p,k53pk54p, pl,p3,p4,p5,qhc,qhs,qrc,qrstl,t2,tf042, tf004,tf031,tfOlO,zl,cstL,z3,z4,z5, rcictr,rhoc,rhos,errO,vxL C....

F031 valve starts to open at t=tl and is fully C....

open at t=tl+tf031 IF ( t

.LE.

tl

) THEN x

0.D0 ELSE IF

( t

.GT.

tl

.AND.

t

.LE.

tl+tf03l ) THEN x = 0.D0

+ (t-tl)/tf03l ELSE IF ( t

.GT.

tl+tf03l ) THEN x = I.D0 END IF

For Information Only EC-052-1055 Page 39 cv cvf03l*( 0.9602*x**4 -

0.1689*x**3 0.1857*x**2 + 0.3952"x cv DMAXl(

cv, I.D-06 )

k54 k54p + 891.*(12.*d4)**4/cv**2 fk54 k54 C....

If reverse flow in RCIC SP suction line add large C....

resistance to simulate closure of check valve 149F030 IF

( qrs.LT.

0.D0

) fk54 = k54 + I.D+12 RETURN END SUBROUTINE vortex IMPLICIT REAL*8(A-H,O-Z)

REAL*8 kl2,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SETl/

al,a3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvf01O, dl,d3,d4,efcst,ebcstsp,ebsp,etvb,g,gc, k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc,qhs,qrc,qrs,tl,t2,tf042, tf004,tfO3l,tfOlO,zl,cstL,z3,z4,zS, rcictrrhoc rhoserrO,vvxL C.... compute the vortex limit Fr

( (qhc+qrc)/al )/DSQRT(g*dl)

IF

( Fr.GE.

0.DO

.AND.

Fr.LT.

0.35D0 ) THEN s = 2.087*Fr**(0.670) hh =s*dl vxL = (hh + 672.94 - efcst)*12.

vxL = DMINI( vxL, 32.D0

)

ELSE IF

( Fr.GE.

0.35D0

.AND.

Fr.LE.

1.40D0 ) THEN s

1.363*Fr**(0.261) hh =s'dl vxL = (hh + 672.94 - efcst)*12.

vxL = DMINl(

vxL, 32.D0 ELSE vxL = 32.0 write(*,*) Fr PAUSE 'froude # out of range--STOP' STOP END IF RETURN END SUBROUTINE hnpsh ( t, hnpsha)

IMPLICIT REAL*8 (A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p COMMON /SET1/

al,a3.a4,acst,cvfO42,cvfOO4,cvfO31,cvfO1O, dl,d3,d4,efcstebcstsp,ebsp,etvb,g,gc, k12,k23,k24,k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,qhc,qhsqrc,qrs,tl,t2,tf042, tf004, tfO31,tfOlO,zl,cstL,z3,z4,z5, rcictr,rhoc,rhos,errO,vxL rhobar = (rhoc*qhc + rhos*qhs)/(qhc + qhs hvpac = 2.2 hvpas = 6.8 hvpa

= (hvpac'qhc + hvpas*qhs)/(qhc + qhs a16 = 1.27 a14 = 0.958 akl6 = 2.2 akl4 = 0.052 hnpsha = p3/rhobar

+ 1.75

( akl6/Al6**2 + akl4/A14**2

Vor Information Only EC-052-1055 Page 40

  • (

C qhc + qhs )**2 )/(2*g) hvpa RETURN END SUBROUTINE rnpsh(t, rnpsha)

IMPLICIT REAL*8 (A-H,O-Z)

REAL*8 k12,k23,k24,k53,k54,k23pk24p,k53p,k54p COMMON /SET1/

al,a3,a4,acst,cvfO42,cvfOO4,cvfO3l,cvfOlO, dl,d3,d4,efcst,ebcstsp,ebsp,etvbg,gc, k12,k23,k24,1k53,k54,k23p,k24p,k53p,k54p, pl,p3,p4,p5,cqhc,qhs,qrcqrs, tl,t2,tf042, tf004, tf031,tf010,z1,cstL,z3,z4,z5, rcictr,rhoc,rhos,errO,vxL rhobar = Crhoc*qrc + rhos*qrs)/(qrc + qrs hvpac = 2.2 hvpas = 6.8 hvpa

= (hvpac*qrc + hvpas*qrs)/(qrc + qrs a6 = 0.201 ak6 = 2.5 rnpsha = p4/rhobar

( ak6/A6**2 )*( ( qrc + qrs )**2 )/(2*g)

- hvpa RETURN END

-For Information Only EC-052-1055 Page 41 : Verification of FORTRAN Results Calculations for Case 1 are vcrificd by substituting numerical results at a particular time (t= 100 see) back into Eqs. (1)-(6) to demonstrate that the governing equations are satisfied. From the FORTRAN output for Case 01 included on CD, the CST level and the HPCI and RCIC suction flows at t= 100 seconds are (Note: because temporal integration is first-order explicit, FORTRAN output at any particular time actually corresponds to the indicated time minus one time step except for CST water level which corresponds to the actual indicated time.)

CST Level = 31.3109 inches CST Level at previous time step = 31.3149 inches HPCI suction from CST =

1324.8012 gpm =

2.95056 ft3/sec HPCI suction from SP =

3775.1990 gpm =

8.40802 ft3/sec RCIC suction from CST =

537.0097 gpm 1.19601 ft3/sec RCIC suction from SP =

87.9903 gpm =

0.195969 f 3/sec Ac,= 1,250 W P3 = 18.6864 psia = 2690.84 psfa P4 = 23.7112 psia = 3414.41 psfa KK12 = 5.3500E+00 K2-3 = 1.4016E+02 K24 = 7.6021E+00 K 5-3 = 9.8354E+00 K54 = 9.7475E+00 tt = 40.70000 sec dt 0.1 sec (time step)

ZI = 672.10 ft + (31.3109 inches)/12.0 = 674.7092 ft z = 672.10 ft + (31.3149 inches)/12.0 = 674.7096 ft (at previous time step)

Other input data consist of P, = 2116.8 psfa P5 = 2116.8 psfa A I

= 2.074fW A3

= 1.268 W1 K,_2 = 5.35 K 2 -

891(12 xl.271)4 K2_,=

2.6+

CV.Foo4 (t) r x,,04 = I -t/108sec for t _< 108sec xF004 = 1-99.9/108=0.075 Cvo4 (t) = (20,700) [0.9602(0.075)4 -0.1689(0.075)3 -0.1857(0.075)'

+ 0.3952(0.075)]

C""" (t) = 591.079 891(12 xl.271)4 K2-3 = 2.16 +

[591.07912 140.165

0

'For Information Only EC-052-1055 Page 42 K 891(12 xO.5054) 4 K2 4 = 5.20-

.C.F.. (0 2 t 2 =t + 44sec = 40.7 + 44 = 84.7 sec x =1-(t -t 2)/44sec forO <t-t 2 < 44sec x =1 -(99.9 -84.7)/44 = 0.6545 C,.rFOlo(t) = (2,300)[0.9602(0.6545)4 - 0.1689 (0.6545)' - 0.1857(0.6545)2 + 0.3952 (0.6545)]

708.293 K2-4 =5 891(12x0.5054) 4 = 7.6028

[708.293]2 KI-3 = 9.56 + 891(12 x1.271)4 K[CvF42 (t) x=O+t/ll5sec for t <ll5sec x = 0+/-+99.9 /115 =0.86870 CvF042 (t) = (20,700)[0.9602(0.86870)4 - 0.1689(0.86870)' - 0.1857(0.86870)2 + 0.3952(0.86870)]

CvFo42 (t)=

13232.81 K5- =9.56+ 891(12 x1.27) W

= 9.8353

[13232.81]I 891(12 xO.5054) 4 IF031 (01) x = 1 for t - ti > 44sec CV.Fo31 (t) = (2,300)[0.9602 (1)4 -0.1689 (1)3 -0.1857 (1)2 + 0.3952(l)]

CVF 0 31 (W) = 2301.84 K5 -

=9.52+

(12x.5054)4

=

[2301.8412 Check of Eq. (1):

z_(KZ3 + P___K (QHc +QRc) 2 K 2 3 (9

c p,)

-( c pc 2gcA3)'

2 g

2gc A3

( g 2116.8

-Z 1 ++/- -=674.7096+

=708.8515 Pc) 62.00 g

+P+

__*c2

+.2690.84 (2-95056)2 g-Z 3 +P3

+

60312

+

=696.7347 (9gc pc 2 gc A' 532 62.00 (2)X32.2)X1.268)

I I

TFor Information Only EC-052-1055 Page 43 K

(Qc + Qc)2 = (5.35)(2.95056 +1.19601)

-0.332069 2gc At (2)(32.2)(2.074)2 K2-3 Qc (140.165)

(2.95056)2

- 11.78485 2gc A3 (2)(32.2)(1.26 708.8515 - 696.7347 - 0.332069 - 11.78485 = -0.0001 (Eq. 1 is satisfied)

Check of Eq. (2):

'3/4 ~

1 _(QHC + QRC) 2 Yc Pc )

c 2 gc A4 2gc A*

-K-2gcQA' Ig-ZI +

=674.7096+ 2116.8 =708.8515 9c PC P) 62.00 4

+P QAc

)

6487+3414.41 (1.19601)2 Z4 Pc 2gc A' 62.00 (2)(32.2)(0.2006)2 KI-2 (QHC + QRC) 2 = (5.35)(2.95056 +1.19601)2 -0.332069 2gc A

='

(2)(32.2)(2.074)2 K 2 -4 QC

= 7.6028 (L.19601)2

=4.19658 2gc A4, (2)(32.2)(0.2006)2 708.8515-704.3231-0.332069-4.19658 = -0.00025 (Eq. 2 is satisfied)

Check of Eq. (3):

9Z 5 + _5 9Z3

+

p3+'

2____

HS2 (c PS)-9 Ps 2gc A3 2gc A3

-Zz 5 + P=

670+ 2116.8 = 704.4868 (9gc Ps ) =

61.38 r g Z3 +P- ÷ 2s

+653.25+

2690.84 (8.40802)2

.- c ps 2gc A3 61.38 (2)(32.2)(1.268)2

v For Information Only EC-052-1055 Page 44 K O-3-2S

= (9-8353)

(8.40802)2

=6.71507 2 gc A'

.8..3(2)(3.)=268 704.4868-697.7718-6.71507 = -0.00007 (Eq. 3 is satisfied)

Check of Eq. (4):

Ps 2gc-4+

5 2g 3

()3.2(.00A=0432 211 6..8 0.48-70.32- 0.44 5 +.01 (Eq.

4 is s4+

r 542cAtisied O

Q

-=

704.4868 L~QZs+Q-fi,--6700 gc PS 61.38 9 Z + -i +_____

68.7 3414.41 +

(0.195969)2

-704.3422 (9 p 2gc A)648. + 61.38 +(2)(32.2)(0.200)

K 5 -4 QRS2= (9.7475)

(0.195969)2

-0. 14445 2gc A4 (2)(32.2)(0.2006)2 704.4868-704.3422-0.14445 = 0.00015 (Eq. 4 is satisfied)

Check of Eqi. (5):

QHC + Q115 -

44~190 2.95056+8.40802-5100/449 = 5.4E-06 (Eq. 5 is satisfied)

Check of Eg. (6):

-C625)=

1.

19601+0.195969-625/449 = -0.000003 (Eq. 6 is satisfied)

Check of EA. (7:

Ac -LZ-+ QHC + QRC = 0 dt

4 W For Information Only EC-052-1055 Page 45 Validation of the solution to Eq. 7 is accomplished by checking numerical integration consistency against Euler's method for one time step. From FORTRAN output for Case 01 at t=99.9 seconds and t-=100 seconds, t --99.9000 sec, CST Level = 31.3149 in, Z, = 672.10 ft + (31.3149 in)/12.0 = 674.7096 ft t = 100.0000 see, CST Level = 31.3109 in, QHC = 1324.8012 gpm = 2.95056 ft3/sec, QRc = 537.0097 gpm = 1.19601 ft3/sec, ZI = 672.10 ft + (31.3109 in)/12.0 = 674.7092 ft Integrating Eq. 7 from t-= 100 sec - At to t=100 see gives Z, (100) = Z, (99.9) - (0. 1)[Q,,, (99.9) + QRc (99.9)]/1250 Z, (100) = 674.7096 - (0.1)[2.95056 + 1.19601]/1250 = 674.7093 This value is consistent (to within the number of available significant digits) with the computer code calculated value of 674.7092 ft.

Note: As discussed above, because temporal integration is first-order explicit, FORTRAN output at any particular time actually corresponds to the indicated time minus one time step except for CST water level which corresponds to the actual indicated time.

For Information Only EC-052-1055 Page 46 : Peer Check of FORTRAN Results An additional peer check of the results is provided in this Attachment by comparison of the results presented in §6 against an independently developed, but unverified, Excel spreadsheet model of CST level response during HPCI/RCIC suction transfer. The Excel model was developed by Station system engineer John Vandenberg. The Excel model and associated documentation is included on CD. Basic assumptions used in the Excel model consist of Condensate storage tank water is 100'F.

Suppression Pool water is 140'F.

Suppression pool level is constant through the transient.

Suppression Pool pressure is constant through the transient.

The RCIC CST set point is lower than the HPCI CST set point.

Total HPCI and RCIC flow is constant.

The valve stroke times are taken from EC-VALV-0509 for the limiting stroke time. These inputs are HPCI F042 = 115 seconds HPCI F004 = 108 seconds RCIC F031 = 44 seconds RCIC FOI0 = 44 seconds HPCI and RCIC suction line loss coefficients are derived from pressure drops given in Calculations EC-052-0002, "High Pressure Coolant Injection DP Calculations," Rev. 2 and EC-050-0001, "Reactor Core Isolation Cooling Pressure Drop Calculations," Rev. 2.

As shown by comparison of the following plots, results obtained with the FORTRAN code listed in Attachment I are slightly conservative with respect to the independently developed Excel model, but overall the two models show good agreement.

t

-For Information Only EC-052-1055 Page 47 Excel Calculation of CST Water Level vs Vortex Limit Suction Transfer Setpolnt: 40.5" (HPCI), 36.0" (RCIC) 45 40-

=.35 00 M 30 C

125 0

.0 n20 10

_ 15 0

CST Level Vortex Umit Setlpxnt 40.0" 3B.0O HPCI: 5100 gpm RCIC: 625 gpm SP Press: 0 psig SP Level: 22 Feet F042: 115sec F004:108sec F031: 44sec F010: 44sec 80 100 120 140 160 0

20 40 60 Time, sec FORTRAN Calculation of CST Water Level vs Vortex Limit Suction Transfer Setpolnts: 40.5" (HPCIl), 36.0" (RCIC)

U.

IM 20 40 60 80 100 120 140 160 Time, sec

  • For Information Only EC-052-1055 Page 48 : Validation of Acceptance Criteria for Vortex Formation Per FSAR Section 6.3.2.2.1, preoperational testing demonstrated that vortex formation did not occur in the CST under low water level conditions and suction flow equal to 6000 gpm. TP 2.18 (microfilm Roll G5393, Frame 316) and QCIR No. 81-3263 (microfilm Roll 4065, Frame 705) verified by visual inspection that no vortex formation occurred with water level 3" above the vortex breaker.

It is therefore given that vortex formation will not occur at a flow rate of 6000 gpm, as long as CST water level is maintained 3" above the top of the vortex breaker, which is located 30.875" 31" above the CST floor (see Table 4-1). In the present analysis it is assumed that vortex formation does not occur as long as CST level is greater than or equal to 32" (see Assumption 13 and discussion in §5.3). As discussed below, the preoperational test result can be used in conjunction with the vortex correlation in §5.3 to validate this assumption.

Inputs:

Based on test data, vortex formation does not occur with CST water level at 31" + 39 = 34" and CST suction flow equal to 6,000 gpm.

From the computer output for Case 1, the suction flow from the CST is 3,050 gpm when water level drops to 32".

Method:

The Froude number at the test condition (34" and 6000 gpm) and at the low-level operating condition (32" and 3050 gpm) will be calculated (see §5.3). Based on the range of calculated Froude numbers, the appropriate correlation from section 5.3 will be selected. A first-order Taylor series expansion for the dimensionless suction pipe submergence S, corresponding to the onset of air ingestion, will then be developed about the test condition, and the value of S corresponding to 3050 gpm will be calculated. If the tank level associated with this value of S is less than or equal to 32", then the assumption of no vortex formation with tank level > 32" (Assumption 13) is validated.

Fluid velocities and Froude numbers are (Refer to §5.3)

Vat 6000 gpm = 6000gal I

x

-n I

= 6.45 ft nin 60sec 7.48 gal 2.074 ft 2 sec Vat 3050 gpm = 3050gal I minx W

x 1

= 3.28-t min 60sec 7.48 gal 2.074t 2 sec Fr at 6000 gpm - 6.45ft 3 2.

2

. 1.62 5 ft =0.89 sec sec2

  • For Information Only EC-052-1055 Page 49 3.28t1 / 32.2ftx Fr at 3050 gpm-Iec/

2 x1.625ft =0.45 sec se Se 2 For this range of Froude numbers, the appropriate air-ingestion correlation is S = 1.363(Fr)°1 61.

At the test condition (Fr = 0.89) the value of S = 1.32. The first derivative of S with respect to Fr is dS

= 0.356Fr O.739 d(Fr)

Evaluating this derivative at the test condition (Fr = 0.89) gives dS

0.356Fr-7 3 9 = 0.388 d(Fdr) Fr=0.89

Evaluating S at Fr = 0.45, the Froude number when CST water level falls to 32", gives Si,= 0.5 S s

+

(0.45 -0.89) = 1.32 + 0.388x (0.45- 0.89) = 1.15.

=

d(ýFr) Fr=0.89 The change in S corresponding to a change in Froude number from 0.89 to 0.45 is AS = 1.15 - 1.32 =-0.17.

Since H = D S, where H = submergence of CST suction pipe entrance (see §5.3) and D is the CST suction pipe diameter, AH = DAS = (1.625 ft)x(-0.17) = -0.28 ft =-3.4 inches.

Therefore, the water level at which vortex formation could occur is 34 inches - 3.4 inches = 30.6 inches, which is significantly below the assumed value of 32 inches. Therefore, the assumption of no vortex formation with tank level > 32" is valid.

Note that the assessment provided in this Attachment implicitly assumes that the test condition (tank level of 34" and suction flow of 6000 gpm) corresponds to the threshold of vortex formation.