ML20214R612
| ML20214R612 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 07/14/1986 |
| From: | Carfagno S, Con V, Triolo S CALSPAN CORP. |
| To: | NRC |
| Shared Package | |
| ML20214R555 | List: |
| References | |
| CON-NRC-03-81-130, CON-NRC-3-81-130 TAC-07938, TAC-7938, TER-C5506-318, NUDOCS 8612080036 | |
| Download: ML20214R612 (20) | |
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SUPPLEENTARY TECHNICAL EVALUATION REPORT e
l NRC DOCKET NO. 50-333 FRC PROJECT C5506 i
i NRCTAC NO. 07938 FRC ASSIGNMENT 12 NRC CONTRACT NO. NRC-03-81 130 FRC TASK 318 in
' li STRUCTURAL EVALUATION OF THE VACUUM BREAKERS (MARK I CONTAINMENT PROGRAM)
"r NEW YORK POWER AUTHORITY
,L JA!!ES A. FITZPATRICK NUCLEAR POWER PLANT
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TER-C5506-318 i
ia Prepared for Nuclear Regulatory Commission FRC Group Leader: V. N. Con Washington, D.C. 20555 NRC Lead Engineer:
H. Shaw P
July 14, 1986 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the Unit 6d States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or i
responsibility for any third party's use, or the results of such use, of any information, appa-ratus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.
Prepared by:
Revic wed by:
Approved by:
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Department Dir I/"/8b Date: 7 -'I - Ib Yb Date:
86 FRANKLIN RESEARCH CENTER AD 03 DIVislON OF ARVIN/ CAL 5 PAN P
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i CONTENTS i
i Section Title Page 1
1 INTRODUCTION 1
l 1.1 Generic Background.
I 1.2 Vacuum Breaker Function 2
2 EVALUATION CRITERIA.
9 3
DESIGN LOADS 10 4
STRESS EVALUATION 11 5
PLANT-SPECIFIC REVIEW: FITZPATRICK.
15 5.1 Background Information.
15 5.2 Results 15 I
6 CONCLUSIONS.
16 6
7 REFERENCES.
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TER-C5506-318 i-4 FOREWORD
'i This Technical Evaluation Report was prepared by Franklin Research Center under a contract with the U.S. Nuclear Regulatory Commission (Office of
,i Nuclear Reactor Regulation, Division of Operating Reactors) for technical I
assistance in support of NRC operating reactor licensing actions. The technical evaluation was conducted in acccrdance with criteria established by the NRC.
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- 1.. INTRODUCTION In a latter state of the generic resolution of the suppression pool dynamic load definition of the Mark I Containment Long-Term Program, a potential failure mode of the vacuum breakers was identified during the chugging and condensation phases of hydrodynamic loadings. To resolve this i
issue, two vacuum breaker owner groups were formed, one for those with General Precision Engineering (GPE) vacuum breakers, the other for those with Atwood-Morrill (AM) vacuum breakers.
The issue was not part of the original scope of the Mark I Containment Long-Term Program as described in NUREG-0661 [1]. However, vacuum breakers have the function of maintaining containment integrity and, therefore, are subject to Nuclear Regulatory Commission (NRC) review. In a generic letter i
dated February 2, 1983 [2), the NRC requested all affected plants either to submit the results of the plant-unique calculations which formed the bases for modifications to the vacuum breakers or to provide the justification for the as-built acceptability of the vacuum breakers.
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Franklin Research Center (FRC) has been retained by the NRC to evaluate the acceptability of the structural analysis techniques and design criteria used in the plant-unique' analysis (PUA) reports of 16 plants. As a part of this review, the structural analysis of the vacuum breakers has been reviewed cnd documented in this report.
The first part of this report (Sections 1 through 4) consists of generic information that is applicable to all affected plants. The' second part of the report (Sections 5 and 6) provides a plant-specific review, which pertains to FitzPatrick.
I 1.1 GENERIC BACKGROUND In 1980, the Mark I owners and the NRC became aware of the vacuum breaker damage during full-scale test facility testing and of the potential for damage during actual LOCAs. Two vacuum breaker owner groups, General Precision Engineering (GPE) and Atwood-Morrill (AM), were formed to develop action plan for resolving this issue. In February 1983, the NRC issued Generic Letter 83-08 (2), requesting commitments from affected utilities to provide ;
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TER-C5506-318 e,
analytical results. The licensees responded to the NRC request by developing appropriate force functions simulating the anticipated hydrodynamic loads, and then performing stress analyses that used these loads. With respect to loading, the NRC has reviewed and issued a staff position as indicated in Section 3.
FRC's function is to review the stress analysis submitted by a licensee.
I 1.2 VACUUM BREAKER FUNCTION During steam condensation tests on BWR Mark I containments, the wetwell-I to-drywell vacuum breakers cycled repeatedly during the transient phase of steam blowdown. This load was not included in the original load combinations
- j used in the design of the vacuum breakers. Consequently, the repeated impact of the pallet on the valve seat and body created stresses that may impair its capability to remain functional.
I A vacuum breaker is a check valve installed between the wetwell and the drywell.
Its primary function is to prevent the formation of a negative 2
pressure on the drywell containment during rapid condensation of steam in the drywell and in the final stages of a LOCA. The vacuum breaker maintains a wetwell pressure less than or equal to the drywell pressure by permitting air flow from the wetwell to the drywell when the wetwell is pressurized and the
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drywell is depressurized slowly.
A vacuum breaker can be internally or externally mounted.
Figures 1 and 1
2 illustrate locations of vacuum breakers.
,a Schematics of typical GPE and AM vacuum breakers are illustrated in Figures 3 and 4.
A typical pressure differential vacuum breaker during a LOCA is provided in Figure 5.
Table 1 lists the various vacuum breaker types and the plants affected by b
them.
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IN TRANM.
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Figure 1.
Internal Vacuum Breaker
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External Vacuum Breaker
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TER-C5506-318 Table 1.
Vacuum Breaker Types and Affected Plant:
Vacuum Breaker Plant GPE 18 In (Internal)
Brown Ferry Units 1, 2, and 3 Pilgrim Unit 1 Brunswick Units 1 and 2 Cooper q
Hatch Units 1 and 2 Peach Bottom Units 2 and 3 iI Duane Arnold Fermi Unit 2 GPE 24 in (Internal)
Hope Creek i
AM 18 in (Internal)
Monticello Quad Cities Units 1 and 2 AM 18 in (Externai)
Dresden Units 2 and 3 Millstone Unit 1 Oyster Creek l
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2.
EVALUATION CRITERIA l
To evaluate the design of the vacuum breakers, the affected licensees follow the general requirements of NUREG-0661 [1] and those of " Mark I Containment Program Structural Acceptance Criteria Plant Unique Analysis Application Guide" [3).
Specifically, the requirements of the ASME Boiler and
<i Pressure Vessel Code,Section III, Subsection NC for Class 2 Components, 1977 Edition, including the summer'1977 addenda (4), have been used to evaluate the structural integrity of the vacuum breakers.
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TER-C5506-318 3.
DESIGN LOADS i
s The loads acting on the Mark I structures and on the vacuum breaker are j
based upon the Mark I Program Load Definition Report [5] and the NRC Acceptance Criteria (1). The loads acting on the vacuum breaker include gravity, seismic,
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and hydrodynamic loads. The hydrodynamic forcing functions were developed by i
Continuum Dynamics, Inc, (CDI). CDI used a dynamic model of a Mark I pressure suppression system, which was capable of predicting pressure transients at specified locations in the vent system. With this dynamic model and the full-scale test facility data, load definition resulting in pressure differential across the vacuum breaker disc was quantified as a function of time. This issue has been reviewed and addressed by the NRC [6).
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STRESS EVALUATION l-t To determine structural integrity of the vacuum breaker, the licensees have employed standard analytical techniques, including the finite element method, to calculate stresses of critical components of the vacuum breaker under various design loadings. Loads resulting from the hydrodynamic phenomenon were compared with those values specified in the ASME Codes (4].
For illustration purposes, a schematic drawing of the moving parts of all components other than the actual disc of the Atwood-Morrill valve and of the corresponding finite element model are shown in Figures 6 and 7, respectively.
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The model in Figure 7 was used to investigate the dynamic response following impact.
A typical model for stress analysis of the vacuum breaker disc is shown in Figure 8.
Loading inputs to this model are the displacement time histories y
that were obtained from the impact model analysis.
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Finite Element Model of Valve Internals.--
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5.
PLANT-SPECIFIC REVIEW: FITZPATRICK PLANT i
5.1 BACKGROUND
INFORMATION i
o Vacuum breaker type:
18 inch Atwood-Morrill Vacuum Breaker (external) i j
o A total of four vacuum breaker valves are mounted on two 30 inch external vacuum rel:ef lines, which connect the wetwell to the
- drywell, o
The vacuum relief lines have been analyzed and the stress results reported in Reference 7.
h 5.2 RESULTS m
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According to the Licensee's review of the Plant Unique Analysis Report
[8), vacuum breaker analysis is not required since the plant-unique load evaluation demonstrated that the valves will not actuate due to Mark I dynamic loads. Therefore, the original design is structurally adequate.
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CONCLUSIONS
'l A review has been conducted to determine the structural integrity of the i
vacuum breakers of the FitzPatrick 1 plant. The design loads associated with the hydrodynamic phenomena have been reviewed and addressed by the NRC in j '
Reference 6.
This review covered only the structural analysis of the vacuum breaker, and the following conclusion is drawn-from the review:
o The plant-unique load evaluation showed that the wetwell to drywell vacuum breakers at the FitzPatrick plant do not actuate due to Mark I dynamic loads. The vacuum breakers, therefore, are structurally
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adequate without modification.
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REFERENCES b
1.
" Safety Evaluation Report, Mark I Containment Long-Term Program l
Resolution of Generic Technical Activity A-7," Office of Nuclear Reactor Regulation, USNRC July 1980 2.
D. G. Eisenhut "USNRC Generic Letter 83-80, Modification of Vacuum Breakers on Mark I i
Containment" February 2, 1983 3.
NEDO-24583-1 7d
" Mark I Containment Program Structural Acceptance Criteria Plant Unique Analysis Application Guide," General Electric Co., San Jose, CA October-1979
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4.
American Society of Machanical Engineers Boiler and Pressure Vessel Code,Section III, Division 1, " Nuclear Powar T
Plant Components," New York, 1977 Edition and Addenda up to Summer 1977 e
5.
NEDO-21888 Revision 2
" Marl I Containment Program Load Definition Report," General Electric
- L,i Co., San Jose, CA November 1981 ll 6.
D. B. Vassallo, NRC
'lj Letter with Attachment to H. C. Pfefferlen, BWR Licensing Programs, GE
" Evaluation of Model for Predicting Drywell to Wetwell Vacuum Breaker i-Valve Dynamics" l
December 24, 1984 7.
" Plant Unique Analysis Report of the Torus Attached Piping for James A.
FitzPatrick Nuclear Power Plant" TR-5321-2 i
Teledyne Engineering Services
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May 1984
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8.
" Review of Plant-Unique Analysis Report for J. A. FitzPatrick Nuclear y
Power Plant"
-l Teledyne Engineering Services June 13, 1984
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