ML20245E071
| ML20245E071 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/03/1988 |
| From: | SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY |
| To: | NRC |
| Shared Package | |
| ML20245E074 | List: |
| References | |
| CON-NRC-03-87-029, CON-NRC-3-87-29 SAIC-87-3069, TAC-63461, NUDOCS 8811170078 | |
| Download: ML20245E071 (17) | |
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SAIC-87/3069
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h TECHNICAL EVALUATION REPORT i
INDEPENDENT REVIEW OF UPDATED FIRE HAZARDS ANALYSIS i
AND LICENSE AMENDMENT REVISION SACRAMENTO MUNICIPAL UTILITY DISTRICT RANCHO SECO NUCLEAR GENERATING STATION UNIT I TAC NUMBER 63461
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Prepared for:
U.S. Nuclear Regulatory Comission Washington, D.C. 20555 Contract NRC-03-87-029 Task Order No. 003 L7 f W
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j FOREWORD j
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This Technical Evaluation Report was prepared by Science Applications l
International Corporation (SAIC) under contract with the U.
S.
Nuclear i
Regulatory Connission (Office of Nuclear Reactor Regulation) for ' technical assistance in support of NRC operating reactor licensing actions.
The technical evaluation was conducted in accordance with criteria established by the NRC.
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TABLE OF CONTENTS l
Seetion
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INTRODUCTION.....................
I 1.1 Purpose of Review................
I 1.2 Generic Background................
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1.3 Plant-Specific Background.............
2 1.4 Review Criteria..................
3-2 EVALUATION....................~..
4 2.1 General.....................
14 2.2 Circuit Analysis 2.3 Construction Review................
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2.4 Combustible Loading Calculations 6
2.5 Fire Protection Features 6
2.6 Safe Shutdown Equipment.............
7 2.7 Appendix R Compliance..............
8 2.8 License Amendment Revision............
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CONCLUSION......................
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REFERENCES......................
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1.
INTRODUCTION 1
I 1.1 PURPOSE OF REVIEW This Technical Evaluation Report (TER) documents an independent review of the Updated Fire Hazards Analysis Report for Rancho Seco Nuclear Generating Station Unit 1,
submitted by Sacramento Municipal Utility District. This evaluation was performed with the following objectives:
o To ' assess if -the Updated Fire Hazards Analysis includes the necessary information as required 'by. NRC Staff guidance o
To evaluate the methodology used by the Licensee and determine if it satisfies the requirements as defined by the NRC.
This TER also documents an independent review of a License Amendment Revision submitted separately by the Licensee.
1.2 GENERIC BACKGROUND General Design Criterion 3 (GDC 3), " Fire Protection," of Appendix A to 10CFR50 requires that structures, systems and components important to safety be designed and located to minimize, consistent' with other safety requirements, the probability and effects of fires and explosions.
Noncombustible and heat resistant materials are required to be used whenever practical.
GDC 3 also requires that fire detection and suppression systems of appropriate capacity and capability be provided and designed to minimize the adverse effects of fires on structures, systems and components'important l
to safety. Additionally, fire fighting systems should be designed to ensure that their failure, rupture or inadvertent operation does not significantly impair the safety capabilities of these structures, systems and components.
Either the staff guidance contained in Branch Technical Position (BTP)
CMEB 9.5-1 of NUREG 0800, " Standard Review Plan," or the combination of i
staff guidance contained in Appendix A to 'TP APCSB 9.5-1 and the technical B
requirements set forth in Appendix R to 10CFR50 define the essential elements of an acceptable fire protection program at nuclear power plants 1
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for demonstrating compliance with GDC 3.
The purpose of the fire protection program is to' ensure the capability to shut downLthe reactor and to maintain it in a safe shutdown condition and to minimize radioactive releases to the environment in the event of a fire.
The above guidance implements the philosophy of defense-in-depth protection against the hazards of fire and
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its associated effects on safety-related equipment.
Licensees must detail their program in the Final Safety Analysis Report (FSAR),
including plant design features, organization, and administrative controls.
The FSAR must include a Fire Hazards Analysis (FHA),. which describes plant design and equipment on an area-by-area basis.
~The FHA should identify ' fire area boundaries and demonstrate that a fire in any 3
given area will not prevent the plant from safely shutting down. Where any plant design feature deviates from regulatory
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identified and demonstrated that the deviation does not : adversely affect plant safety.
1 1.3 PLANT-SPECIFIC BACKGROUND l
By letter dated December 2,
- 1986, Sacramento Municipal Utility Dis-
'I trict (the Licensee) submitted.an " Updated Fire Hazards Analysis" for Rancho Seco Nuclear Generating Station Unit 1.
The updated analysis represents a i
re-evaluation of fire areas described in the 1977 " Fire Hazards Analysis".
As a result of this re-evaluation, the Licensee combined several original fire areas into larger areas and subdivided one area (RG2) into two smaller j
The Licensee also incorporated changes in combustible loading that areas.
have occurred since 1977 and any changes in fire protection equipment that have taken place. A fire hazards analysis for the Nuclear Services Electri-
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cal Building has been added along with safe shutdown logic diagrams which identify necessary equipment for safe shutdown for any given area. Based on-
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a preliminary review of this submittal, an RAI'was issued to the Licensee on October 8,.1987. Subsequent to issuing this RAI, the Licensee submitted a
revision to the UFHA by letter dated September 22, 1988.
This revision incorporated plant modifications to date including the addition of the' new Diesel Generator Building.
A preliminary review of this submittal was performed and the original RAI was revised and resubmitted to the Licensee on December 9, 1987. The Licensee responded to questions in this RAI by letter dated September 16, 1988.
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- Also, by letter dated January 16, 1986 the Licensee requested a revision to License Amendment 19. This revision request is based on the re-evaluation of fire areas in the Updated Fire Hazards Analysis, which no longer requires some of the fire doors and dampers described in Amendment 19.
This report represents an evaluation of the September 22, 1987 submittal of the Updated Fire Hazards Analysis including information provided in the September 16, 1988 response to the RAI and the January 16, 1986 request for a license amendment revision.
l 1.4 REVIEW CRITERIA The criteria used in reviewing the Licensee-submitted fire hazards analysis are based on the following documents:
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Appendix R to 10CFR50 2.
Appendix A to BTP APCSB 9.5-1 3.
Generic Letter.,86-10, " Implementation of Fire Protection Requirements," dated April 24, 1986.
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EVALUATION 2.1 GENERAL This section represents review and evaluation of the " Updated Fire Hazards Analysis" dated August 1987 for Rancho Seco Nuclear Generating Station and request for license amendment revisions dated January 16, 1986 submitted by Sacramento Municipal Utility District, the Licensee.
The fire area / zone numbering used in this section corresponds to that used in the Licensee's submittal.
2.2 CIRCUIT ANALYSIS Appendix R,Section III.G.2 defines separation criteria for " cables and equipment, including associated non-safety circuits that could prevent operation or cause maloperation due to hot shorts, open circuits, or shorts to ground, of redundant trains of equipment necessary to achieve and main-tain hot shutdown."
In order to evaluate the spurious operation portion of this requirement a Licensee must first identify the components which are subject to spurious operation and then evaluate the effects this operation might have on safe shutdown.
The NRC provided additional guidance on the evaluation for spurious operations in Generic Letter 86-10.
The Licensee performed a review to determine the effects of fire induced shorts, shorts-to-ground and open circuits on the operation of safe shutdown equipment.
Equipment in high/ low pressure interfaces was sepa-rately identified.
The Licensee also considered hot shorts to 120V AC and 125V DC to be credible while a three-phase 480V AC phase-to-phase hot short between power cables was not considered to be credible and was not analyzed.
This is consistent with guidance in generic letter 86-10 and is therefore acceptable.
The Licensee also performed a breaker coordination study to ensure that a fire induced short on a non-safe shutdown circuit will not cause a trip of the main source breaker, thereby affecting safe shutdown components.
This evaluation also verified that a coordinated Class IE electrical system 4
existed.
Where the Licensee could not demonstrate this, an analysir was performed to ensure that breaker coordination existed for faults outside of i
the fire area in which the protective device is located.
1 As part of the circuit analysis, the Licensee reviewed associated circuits sharing common, enclosures to ensure that these circuits would not allow fire to propagate-from one fire area to another and that appropriate-
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electrical protection 'was provided for associated circuits which share common power supplies with safe shutdown equipment.
The circuit analyses as described in the 1987 UFHA are consistent with J
Staff requirements as described in Appendix R to 10CFR50 and guidance
-l provided in Generic Letters 81-12 and 86-10.
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2.3 CONSTRUCTION REVIEW Section III.G of Appendix R establishes criteria for the separation of safe shutdown equipment within the same fire area.
In order to determine plant fire areas, the Licensee must perform a review of the plant construc-tion and identify fire resistance ratings of assemblies used within the plant.
I As part of the Updated Fire Hazards Analysis the Licensee performed
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review of plant construction.
The Licensee assigned a rating of 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to wall and floor ceiling assemblies having a thickness of at least 6-1/2 inches of concrete as defined in the NFPA Handbook (l'5th edition).
For other types of construction the Licensee used the rating as defined in - the UL Building Construction Fire Resistance Directory or vendor data.
Penetra-tions in rated barriers were identified and ratings were based on the Licen-see's electrical and mechanical firestop schedules.
I The methods used by the Licensee for establishing the fire resistive ratings of plant construction appear to be consistent with guidance estab-lished in Appendix A to BTP APCSB 9.5-1 and Generic Letter 86-10 and are
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therefore acceptable.
However, the 1987 UFHA states that changes in the fire ratings of Appendix R fire barriers have been incorporated. The staff was concerned that a reduction in rating for a fire area boundary may affect i
compliance with Appendix R separation criteria.
The Licensee stated in' 1
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their response to the RAI that the changes in fire barrier ratings resulted from a re-evaluation of fire barriers constructed of metal stud and plaster partitions.
The Licensee included a table identifying areas where changes in fire barrier ratings apply. The Licensee concludes in their response that these barriers are adequate based on the low combustible loading's within the fire areas involved. The staff reviewed the table of barriers in question and agrees with the Licensee that the barriers remain adequate given the low combustible loading's. The changes in barrier ratings as-identified in the 1987 UFHA are therefore acceptable.
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2.4 COMBUSTIBLE LOADING CALCULATIONS l
Part of performing a valid fire hazards analysis is the evaluation of in-situ combustibles in a given fire area and determinations of the impact a fire in the area and adjacent barriers could have on plant safety.
I The Licensee identified the type and quantity of combustibles in each fire area. This information was then converted to area fire loading's by comparing the BTU value of the combustibles per square foot of area and then comparing this number with the standard time-temperature curve from the NFPA Handbook.
The Licensee stated in the 1987 UFHA that changes in combustible loading from previous submittals had been incorporated, however these
" changes" had not been identified. The Staff was concerned that significant increases in combustible loading may affect conclusions made by the Staff in previous SER's or on the Licensee's own conclusions on the adequacy of fire barriers made in previous FHA's.
In the September 16, 1988 response to the RAI, the Licensee provided a comparison of combustible loading's in the recent UFHA and previous submittals.
While increases are noted, none were determined to be of a magnitude that would affect previous NRC evaluations. The Licensee stated in their response that based on the 1987 UFHA, fire area boundaries are adequate given these increases.
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2.5 FIRE PROTECTION FEATURES f
The fire hazards analysis for each area defined fire protection fea-d tures specific to that area.
These features include automatic and manual suppression systems, early warning fire detection', portable hose stations and fire extinguishers.
This information was used by the Licensee to determine compliance with the requirements of Appendix R and, where the area did not comply, to demon-strate that an equivalent level of fire protection existed.
The Licensee statG in the 1987 UFHA that changes to Fire Protection features had been incorporated. The Staff was concerned that any reduc' tion in these features may affect previous compliance with Staff guidance.
The Licensee responded to this concern in their September 1988 submittal by providing a table specifically identify the changes. While several reductions in coverage were noted, the Licensee stated that these changes in the UFHA were simply corrections of errors in previous FHA's and that no actual reductions were made. These corrections were reviewed by the Staff and were not found to affect any previous conclusions made in earlier SER's.
2.6 SAFE SHUTDOWN EQUIPMENT Section III.G of Appendix R establishes criteria for maintaining one train of equipment required for safe plant shutdown free of fire damage. As part of the fire hazards review process, a licensee must establish for each fire area what equipment and circuitry would be necessary to achieve safe j
shutdown.
In the Updated Fire Hazards Analysis Report the Licensee identified the safe shutdown systems present in each fire area.
The required systems are based on the plant's Appendix R Evaluation prepared by Babcock & Wilcox and are included in the Fire Analysis Matrix.
The equipment was divided into three categories for each fire area, that required for hot shutdown, equip-ment necessary for cold shutdown, and equipment or components in high/ low pressure interfaces.
Safe shutdown equipment or circuitry which could potentially spuriously operate in a fire was also identified.
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9, For each fire area, the licensee identified the potential effects of fire on hot and cold shutdown capability on a system by system basis.
The effects of fire on high/ low pressure interfaces and the consequences of spurious operation were also identified.
The September 22, 1987 submittal referenced a number of documents related to the post-fire safe shutdown methodology that were not referenced in the July 1985 UFHA. The Staff was concerned that changes may have been made in the safe shutdown methodology that were not readily apparent and may effect previous NRC SER's. The Licer.see was requested in the RAI to detail any changes in safe shutdown methodology from the 1985 submittal.
The Licensee stated in their September 16, 1988 response to the RAI that a comparison of the 1985 UFHA and the 1987 UFHA was performed to identify any changes in safe shutdown equipment and the basis for that change.
The September 16, 1988 response included a discussion of each difference that was identified. The Licensee stated that these differences were primarily a result of the Emergency Feedwater Instrumentation and Control (EFIC) modifications and design changes associated with the Transamerica Delaval, Inc. (TDI) diesel generators.
These modifications were reviewed by the NRC and-documented in a SER dated December 14, 1987.
Therefore, the safe shutdown methodology and required components as identified in the 1987 UFHA are acceptable.
2.7 APPENDIX R COMPLIANCE For each fire area, the Licens,ee presents a summary of compliance with Appendix R,
Section III.G.
This section of the fire hazards analysis identifies the method of meeting the separation requirements of Appendix R, and where these requirements are not met, reference to the exemption request permitting this configuration is made.
The basis for the NRC granting the specific exemption is also identified.
The 1987 FHA includes several new fire areas and modifications to previously defined areas. The staff was concerned that these new areas may not have been reviewed by either the Licensee or the Staff to verify compliance with BTP APCSB 9.5-1 and that changes in existing areas resulting from an Appendix R re-evaluation may affect compliance with BTP APCSB 9.5-1.
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t, In their response to the RAI, the Licensee specifically identified the new fire areas created since the 1977 FHA. These areas include NSEB Fire Areas (75 through 91.2), NSRW Pump Area (110) and the Transformer Alley (70).
The TDI Diesel Generator Building is also a new fire area, however this facility was independently reviewed by the staff and is not' in I
question. For the new areas identified, the Licensee included references to previous SER's verifying that these fire areas had been evaluated by the Staff for compliance with BTP APCSB 9.5-1.
The Licensee also included a description of fire areas which have been revised.
Generally, these I
modifications consist of combining several smaller areas into a' single larger area. The Licensee states that these changes were made as a result of a review of wall construction, penetration ratings, fire loading's and l
separation requirements. The UFHA includes drawings which identify the new fire areas, however, original fire areas were left in for reference.
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on review of the drawings, it appears that many of the original fire area boundaries did not separate safe shutdown components but were simply 1
composed of interior plant walls. The Licensee chose to eliminate many of l
these interior walls as rated fire boundaries since they do not separate vital equipment. While this is a valid reason for the reconfiguration, it must also be noted that the Licensee is still committed to maintain barriers l
which provide compliance wfth.,BTP APCSB 9.5-1.
2.8 LICENSE AMENDMENT REVISION By Letter dated January 16, 1986 the Licensee requested an Revision to l
License Amendment 19. This request was made because a re-evaluation of fire areas (discussed in the evaluation of the UFHA above) made several of the fire doors and dampers required by License Amendment 19, no longer necessary.
This revision request applies to four specific License Conditions identified in Amendment 19 to the Station License.
The Individual license condition changes are discussed below.
1 2.8.1 License Condition 3.1.5(1)
The original License Condition called for the installation of fire dampers in all duct penetrations in the Turbine Deck Corridor.except the emergency control room ventilation duct. The Licensee had issued LER 85-004 related to missing dampers in these ducts. The re-definition of fire 9
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areas documented in the 1985 UFHA no longer requires dampers in many of the referenced ducts since the barriers they penetrate do not provide separation of safe shutdown components per NRC requirements as documented in the Licensee's UFHA. Specifically, the revision states that dampers should be installed in all duct penetrations to Fire Areas 1, 2, 6, 62, RG1 and RG3 from Fire Area RT1.
Since the License's UFHA documents compliance with separation criteria with newly defined fire areas, the revision to License Condition 3.1.5(1) modifying required dampers is consistent with the UFHA and is therefore acceptable.
2.8.2 License Condition 3.1.30(1)
The original license condition called for the installation of fire dampers in ducts to Fire Areas 46, 58, 59. The Licensee has requested that I
the license condition be modified to exclude the installation of a damper in corridor 045.
The Licensee discussed this issue in exemption request 7 submitted to the NRC on November 7, 1985. By letter dated November 4, 1986 the NRC documented an evaluation of exemption requests and approved the lack of a fire damper in the duct,in Corridor 045.
Therefore, the revision to License Condition 3.1.30(1) as' submitted by the Licensee is acceptable.
2.8.3 License Condition 3.1.25f1)
The original license condition called for a rated door between Fire Areas 34 and 39. The UFHA has combined these areas into new Fire Area RG1 and has concluded that the door referenced in the license condition is no longer necessary. The license revision request is to delete this license condition entirely.
Since the door originally called for is no longer necessary to provide appropriate separation between safe shutdown components, the deletion of License Condition 3.1.25(1) is therefore acceptable.
2.8.4 License Condition 3.1.40f51 The Licensee has requested the requirement to provide a rated door between Fire Areas 58 and 50 be deleted. This is based on the re-evaluation 10
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of fire areas making this door no longer required. These two fire areas have been incorporated into new Fire Area RBI which has been evaluated in the UFHA.
Since the door originally called for in Item (1) to License Condition 3.1.40 is no longer necessary to comply with NRC separation criteria, the revision as requested by the Licensee is acceptable.
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CONCLUSIONS Based on the review of the Updated Fire Hazards Analysis for Rancho Seco Nuclear Generating Station Unit 1,
the Licensee's subrpittal is determined to comply with the requirements outlined in Appendix A to APCSB 9.5-1 and the guidance given in NRC Generic Letter 86-10 and is therefore acceptable.
In addition, the request for revision to License Amendment 19, submitted by the Licensee on January 16, 1986 has been reviewed and found to be consistent with information provided in the UFHA evaluated in this TER. Therefore, the License Amendment revision request is acceptable.
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REFERENCE 5
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Appendix A to BTP APCSB 9.5-1,
" Guidelines for Fire Protection for Nuclear Power Plants Docketed Prior to July 1,1976," August 23, 1976.
2.
Appendix R to 10CFR50,
" Fire Protection Program for Nuclear Power i
Facilities Operating Prior to January 1,1979," November 19, 1980.
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Generic Letter 86-12. " Fire Protection Rule," February 20, 1981.
4.
Generic Letter 86-10 " Implementation of Fire Protection Requirements,"
April 24, 1936.
5.
Task Order No.
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" Review and Evaluation of Operating Reactor Fire Protection Programs" transmitted by P.J.
Edgeworth (NRC) to SAIC, May 15, 1987.
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ENCLOSURE 2 CHEMICAL ENGINEERING BRANCH SALP INPUT RANCHO SEC0 GENERAllhG STATION UNIT NO. 1 Sumary of Review Activities The focus of the review was on an update of the licensee's fire hazards analyses.
This update included: revised fire area boundaries; charges to the combustible loadings "in a number of areas; a new fire hazards analyses for the Nuclear Services Electrical Building along with safe shutdown logic diagrams which identify equipment required for safe shutdown for any given area. Our review also encompassed a licensee request to revise license Amendment 19 to reflect current revisions to the fire protection program. The time frame of our efforts was between September 1987 and the present. Based on our review we conclude that the licensee's revised program conforms with staff fire protection guidelines-and is, therefore, acceptable.
Engineering / Technical Support Throughout the review process, the licensee's activities exhibited evidence of prior planning and assignment of priorities. Decisions were usually made at a level that ensured adequate management review. Management was aware of the importance of fire protection and took steps to see that our review went well.
In the documents submitted in conjunction with the resolution of fire protection issues, the licensee's representatives displayed a clear understanding of our concerns with the level of fire protection. The licensee's additional fire I
protection comitments revealed a conservative approach toward fire safety.
j The licensee provided timely written and oral responses to our requests for infonnation. Most of the proposals offered to resolve our fire protection 1
concerns were viable.
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