ML20151Y465
| ML20151Y465 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/31/1998 |
| From: | Mays J, Sadeghi N, Sanchez R GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20138K996 | List: |
| References | |
| GENE-E21-00143, GENE-E21-00143NP-R1, GENE-E21-143, GENE-E21-143NP-R1, NUDOCS 9809180246 | |
| Download: ML20151Y465 (32) | |
Text
..
GENE-E21-00143 Class III Revision I ECCS Suction Strainer Hydraulic Sizing Report March 31,1998 Prepared for:
OYSTER CREEK NUCLEAR GENERA TING STA TION Prepared by:
/s/
Nader Sadeghi, Senior Engineer Verified by:
/s/
i Rafael Sanchez, Project Engineer i
Approved by:
/s/
John W. Mays / Daryl l Bouchie, Project Manager
/s/
Stanley M. Litwin, Engineering Manager 1
l l
l-1 f
i 9809190246 980914 PDR ADOCK 05000219 B
PDR l
J r
j.
1 I
^
f.(fll60f&>
PROPRIETARY INFORMATION NOTICE This document contains proprietary infon-nation of the General Electric Company (GE) and is furnished to Oyster Creek in confidence solely for the purpose or purposes stated in the transmittal letter. No other use,. direct or indirect, of the document or the infonnation it contains is authorized. The Oyster Creek shall not -publish or otherwise disclose this document or the information it contains to others without the written consent of GE, and shall return the document at the request of GE.
IMPORTANT NOTICE REGARDING CONTENTS OF Tills REPORT Please read carefully The only undertakings of the General Electric Company (GE) respecting information in this document are contained in the contract between Oyster Creek and GE, as identified in Contract Num'er 0702470, and nothing contained in this document shall be construed as changing the contract. The use of this information by anyone other than Oyster Creek, or for any purpose other than that for which it is intended is not authorized; and with respect to any unauthorized use, GE makes no representation or warranty, express or implied, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document, or that its use may not infringe upon privately owned rights.
l i
l 1
GENUCLEAR Energy ABSTRACT ProprietaryInformation Withheld 1
l i
....... ~
-.....-.... ~,.. -. - _ _.
GE Proprietary Infonnation GENE-E2100143 f
TABLE OF CONTENTS Page 1.0 Introduction 5
1.1 Background
5 1.2 BWR Owner's Group R(:ponses 6 2.0 Summary and Conclusions 7
- 3.0 Design Inputs 8 l
3.1 ProprietaryInformation Withheld l
3.2 ProprietaryInformation Withheld 3.3 ProprietaryInformation Withheld 4.0 Overview of Analysis Tecimique 10 4.1 ProprietaryInformation Withheld 4.2 ProprietaryInformation Withheld 4.3 ProprietaryInformation Withheld 4.4 ProprietaryInformation Withheld 5.0.
Detailed Analysis Calculations 12 l
6.0 Oyster Creek Sizing Results And Discussions 14 I
7.0 Conclusions 14 8.0 References 15 i
9.0 Appendices 16 i-l o
J e
l E
GE Nuclear Engrgy 1.0 Introduction ProprietaryInfbrmation Withheld
1.1 Background
in the event of a Loss of Coolant ' Accident (LOCA) in a BWR Nuclear Power Plant, drywell insulation and debris can be transported into the suppression pool which provides a supply of water to the Emergency Core Cooling System (ECCS). This insulation, when combined with corrosion products and other debris, can migrate to and block strainers installed on suction lines supplying the ECCS pumps. In July 1992, an ECCS suction strainer became blocked with mineral woolinsulation at the Barseback 2 plant in Sweden due to insulation dislodged by the discharge of a relief valve in the drywell. The displaced mineral wool insulation eventually migrated into the suppression pool and clogged the strainer, causing cavitation of the spray pumps (Ref. 8.2). In January 1993, during a scheduled outage at Perry Nuclear Power Plant, it was observed tliat an ECCS Residual IIeat Removal Suction Strainer became clogded (Ref. 8.2). These events led the NRC to require BWR cwners to indicate how they would guard against such events in the future.
t
GENE-E21-00143 GE Nuclear Energv 1.2 BWR thrners' Group Responses In response to the NRC's concern, the BWR Owners' Group, using GE as Project Manager, implemented a program to develop a long-term solution to the strainer blockage issue. The BWROG developed and tested alternate ECCS suction strainer designs as a possible means to mitigate the strainer clogging problem. The BWROG efforts led to generation of the Utility Resolution Guidance (URG) document for ECCS Suction Strainer Blockage (NEDO-32686).
ProprietaryInformation Withheld 4
i
GENE-E2100143 GE Nuclear Energy 2.0 Summary and Conclusions 1
The GE strainer has several advantages over the standard disc strainer, such as increased surface area and lower hydraulic losses for a strainer of comparable size.
ProprietaryInformation Withheld The detail design calculations are contained in the Design Record File, Reference 8,1. Reference 8.4 was
)
also used for the hydraulic sizing calculations. The Oyster Creek strainer sizing input and output spreadsheets are included as Appendix B.
i i
i I
1 i
i
_,. = _
GENE-E2l-00143 GE Nucizar Energy j
3.0 Design inputs 3.1 PlantSpecific Configuration Prior to initial sizing calculations, the plant specific configuration must be set up. The majority of this information is supplied by the utility, with verification completed by GE. These inputs include the following:
ProprietaryInformation Withheld 3.2 Singic Failure Mode Criteria Critical to the design of the strainer is the application of DB A and single failure criteria. By selecting an appropriate failure mode that best simulates the events occurring after a postulated LOCA event, the most limiting design conditions can be selected.
ProprietaryInformation Withheld 1
i
)
i j
l GENE-E21-00143 GE Nuclear Energy 3.3 Debris Loading As discussed above, equally important to the design of the strainer is the application of the various debris loads that could be experienced during the LOCA. The BV,,RROG has developed the i
methodology for sizing new ECCS suction strainers. References 8.2 and 8.3 outline the basic methodology for designing GE optimum stacked disk strainers. Typical debris consists of:
Fibrous Debris Corrosion Products e
Reflective Metal Insulation e
Dirt and Dust Paint Chips / Zinc Oxide e
Rust Sand Calcium Silicate Other debris e
ProprietaryInformation Withheld l
1
i l
GENE-E21-00143 GENuclear Energy I
4.0 Overview of Analysis Technique 4.1 Introduction ProprietaryInformation Withheld l
9 i
10 l
I I
I
GENE-E21-00143 GENuclear Energy ProprietaryInformation Withheld 4
1 1I 1
GENE-E21-00143 GE Nuclear Energy ProprietaryInformation Withheld 12
=-,
GENE-E21-00143 GE Nuclear Energy ProprietaryInformation Withhekt 13
.m GENE-E21-00143 GE Nuclear Energy 6.0 Oyster Creek Sizing Results and Discussions.
ProprietaryInformation Withheld 7.0 Conclusions ProprietaryInformation Withheld
^
4 14 1
_ j
GENE-E21-00143 GE Nuclear Energy Proprietary Information IVithheld 4
9 15
)
GENE-E21-00143 GENuc/ car Energy i
TA"tE1 l
ProprietaryInformation Withheld i
l 15A i
l
.._.~.. _ _ _._._ _
8.0 REFERENCES
l 8.1 ProprietaryInformation Withheld l
8.2 Reference 2: NEDO-32686, " Utility Resolution Guidancefor ECCS Suction i
Strainer Blockage ", Volume I, prepared by the BWROG ECCS Suction Strainer l
Committee, Apperulix A: Passive Strainer Head Loss Prediction with Fibrous Debris.
l 8.3 Reference 3: NEDO-32686, " Utility Resolution Guidancefor ECCS Suction l
Strainer Blockage ", Volume I, prepared by the BWROG ECCS Suction Strainer Committee, Appendix B: Calculation afstrainer RMI Capacity.
8.4 ProprietaryInformation Withheld 8.5 ProprietaryInformation Withheld l
6 16
GENE-E21-00143 GE Nuclear Energy 9.0 APPENDICES 9.1 Appendix A: GE ECCS Suction Strainer Si:ing Procedures Appendit B: ECCS Strainer design input and output 17
i l
GENE-E21-00143 GE Nuc/ car Energy GE ECCS Suction Strainer Sizing Head Loss Calculation Methodology with fiber insulation Proprietary Information IVithheld 18
i GENE-E21-00143 GENuclear Energy i
Proprietary Information IVithheld 1
l l
19
\\
GENE-E21-00143 GENuc/ car Energy Proprietary Information IVithheld
+
s 20
GENE-E21-00143 GE Nuclear Energy ProprietaryInformation Withheld l
l 21
GENE-E21-00143 GE Nuclear Energy 1
Definition of the variables and the associated symbols j
ProprietaryInformation Withheld 22
l I
GENE-E21-00143 GENuclear Energy l
GE ECCS Suction Strainer Sizing Head Loss Calculation Methodology with RMI Insulation ProprietaryInformation Withheki l
23 l
GENE-E21-00143 og Nuclear Energy r Pr etary Information Withheld 1
24 i
l I
GENE-E21-00l43 GENuclear Energy ProprietaryInformation Withheki 25
\\
Inputs for ECCS Suction Strainer Design APPENDIX B Plant:
OC l
Design / Load Case:
Calculation Date:
9/23/97 ProprietaryInformation Withheld i
Page1
1 i
l l
l l
l Outputs OC Appendix B i
l l
l ProprietaryInformation Withheld l
l l
Page1
1940-98-20488 Change to the Licensing Basis Attachment IV Answer to Questions 2 - 4 i
- =
1940-98-20488 j
Attachment IV Question 2:
It was rated that the core spray flow docketed in response to Generic Letter 97-04 was 4250 gpm. However, in the Request for a Change to the Licensing Basis, the flow was identified to be 4350 gpm. Explain the difference.
Response 2:
L The original calculation used to support the Generic Letter submittal did identify a core spray main pump flow of 4250 gpm, once a booster pump had been removed from service. At the time of the submittal, the calculation had been completed, but the design verification of the calculation was still in progress. Subsequent to the submittal, the design verification of the main pump flow was completed and revealed that the actual flow was 4350 gpm. As this new number was more conservative that the original submittal, no updated response to the Generic Letter was required. However, when the Request for a Change to the Licensing Basis was submitted, the correct, design verified, value of 4350 gpm was submitted.
l l-Question 3:
Provide a detailed description of the bounding case, including the postulated worst case single failure.
1 1
Response 3:
l The bounding case assumes a large break in a recirculation line below the lowest drywell grating. This maximizes both debris generation and transport to the suppression pool. The containment initial conditions are such that the containment pressure response to the accident is minimized and the suppression pool temperature response is maximized. The full capability of the core (main and booster pumps injecting) and containment spray systems are assumed to be in operation within the first minute of the accident. This maximizes strainer debris loading rates and suction piping system head loss. Consistent with operating procedures, one of the two containment spray pumps is used to reduce the drywell pressure, the other is used to cool the suppression pool. When the drywell pressure drops to 1.25 psig the system in drywell spray mode is aligned to cool the suppression pool.
At the ten-minute point in the accident one of the core spray booster pumps is manually removed from service to ensure adequate NPSH. At the one-hour point the remaining core spray booster pump is manually removed from service to ensure adequate NPSH. At this
_ point credit is no longer taken for containment pressure of 1.25 psig in evaluating the NPSH margin.
1 l
1940-98-20488 Attachment IV Page1 When the design criteria for the new suction strainers were developed, a number of
+ mitivity studies were performed. These studies were intended to identify key issues l
x.sociated with the head loss to the ECCS pumps. From these studies, it was concluded that the maximum strainer flow situations were bounding. As a result, the design basis scenario for the suction strainer was associated with maximum flow through the strainer (Case 8 in our August 3,1998 submittal). It must be noted that this case does not result in the maximum suppression pool temperature, which historically had been used as the bounding case for net positive suction head assessments.
As the maximum flow condition provides the design basis for the suction strainer, the single failure associated with the scenario was not that associated with restricting flow to the core (i.e. diesel generator failure). A diesel generator failure does not result in maximum flow conditions. For the Oyster Creek Nuclear Generating Station, the most limiting core spray pump for suction head loss is the backup pump NZOIC. The NZ01C pump is the backup for l
pump for NZ01 A. NZ01 A is the primary pump in the loop, and if it starts, the NZOIC pump will not be run. Therefore, the worst postulated sing!e failure assumed in the design of the suction strainers is the loss of core spray main pump NZ01 A.
l l
Question 4:
Provide the Net Positive Suction Head requirements for the Containment Spray pumps as a function of flow.
1 Response 4:
Containment Spray Pump Flow Required NPSH' 3850 gpm 18 ft.
4200 gpm 21 ft l
l 2
Reference:
Oyster Creek Final Safety Analysis Report; Figure 6.2-15.
i i
1 i
1940-98-20488 4
Change to the Licensing Basis i
i Attachment V i
Question 5:
i i
Provide the Calculations for Case 8 and Case 9 i
i l
i i
s i
1
.,