rev 0 to 'addl verification of circuit separation & single ...by the dcp to ensure that the...
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PACIFIC GAS 6 ELECTRIC COMPANY
DIABLO CANYON NUCLEAR POWER PLANT
INDEPENDENT DESIGN VERIFICATION PROGRAM
INTERIM TECHNICAL REPORT NO. 49
REVISION 0
1
ADDITIONALVERIFICATION OF
CIRCUIT SEPARATION AND SINGLE FAILURE
REVIEW OF SAFETY-RELATED ELECTRICAL EQUIPMENT
PERFORMED BY
STONE 6 WEBSTER ENGINEERING CORPORATION
DOCKET NO. 50"275
LICENSE NO. DPR-76
PROJECT MANAGER
F. Sestak, Jr.
DATE 4 ~3
8307050149 830630PDR ADOCK 05000275R . PDR
PROGRAM MANAGER'S PREFACE
DIABLO CANYON NUCLEAR POWER PLANT - UNIT 1
INDEPENDENT DESIGN VERIFICATION PROGRAM
INTERIM TECHNICAL REPORT
ADDITIONAL VERIFICATION OF CIRCUIT SEPARATION
AND SINGLE FAILURE
REV IEW OF SAFETY-RELATED ELECTRICAL E(UIPMENT.
This is the forty-ninth of a series of Interim Technical Reports preparedby the DCNPP-IDVP for the purpose of providing a conclusion of the program.
This report provi des a des cripti on of the work done,
summary
and
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evaluation of the results, and conclusions of the IDVP with respect to theconcern of circuit separation and single failure review of safety-relatedelectrical equipment.
As IDVP Program Manager, Teledyne Engineering Services has approved thisITR. The methodology foil owed by TES in performing this revi ew andverification is described by Appendix A to this report.
ITR Reviewed and ApprovedIDVP Program ManagerTeledyne ngineeri g Ser vices
D. C. StratoulyAssi stant Project Manager
TABLE OF CONTENTS
Section Title ~Pa e
INTRODUCTION.. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ \ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 1-1
SUMMARY . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 2-1
BASIS OF CONCERN................... ~ ~ ~ ~ ~ 3 1
3.1 EOI FILES. ~ ~ ~ ~ ~ ~ ~ ~ 4 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~'3 1
3.2 SCOPE OF ADDITIONALVERIFICATION........................... 3-2
ANALYSIS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~'
~ ~ ~ 4-1
4.1 CIRCUIT SEPARATION...-....,.................,............... 4-1
4.2 SINGLE FAILURE. 4-2
„4.3 ACCEPTANCE CRITERIA..................... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 4-2
4.4 DOCUMENTATION USED. 4-2
CONC LUSIONS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r 5 1
APPENDIX
PROGRAM MANAGER'S ASSESSMENT
SECTION .1
INTRODUCTION
Interim Technical Report (ITR) No. 34, Revision 1, describes all additional
verification work required to be performed based on the initial sample.
This ITR describes work performed in one of the areas of concern,
specifically, circuit separation and single failure review of safety-related
electrical components.
The Independent Design Verification Program (IDVP) review of the Auxiliary
Feedwater (AFW) System and the Control Room Ventilation and Pressurization
(CRVP) System Class IE electrical control circuits in enclosures (panels,
termination boxes) identified electrical circuits that were not separated by
the methods listed in the FSAR, Section 8.3.3. The IDVP also'dentified an
electrical component in the CRVP,System that did not meet the DCNPP-1 single
failure criteria.
The AFW and CRVP Systems are Design Class I (safety-related) systems. PGSE
agreed to make modifications to these systems to assure that the separation
and single failure criteria would be met. The IDVP recommended additional
verification to assure that similar concerns did not exist for other safety-
related systems. As a result, PGSE performed a review of all PGSE-designed
safety-related systems to ensure that the safety-related electrical circuits
meet FSAR single failure and separation criteria. As a result of the review,
1" 1
PGSE made modifications to comply with FSAR single faj.lure and separation
criteria. The lDVP verified the results of the PGRE review on a sampling
basis by reviewing electrical schematics and inspecting enclosure wiring
of four selected systems.
1-2
SECTION 2
SUMMARY
PG&E reviewed the electrical and control circuitry for all PG&E-designed
safety-related systems required to achieve safe shutdown or mitigate an
accident. The review identified all mutually redundant circuits and their
connection to all devices, including transfer switches. The review included
a field verification to assure that cable/wire separation meets the FSAR
requirements. The IDVP selected a sample of the PG&E work to verify circuit
separation and to verify single failure criteria conformance for mutually
redundant circuits connected to a common device. The IDVP verification
included a field inspection of circuit separation in selected panels and
enclosures.
The results of 'the IDVP verification determined:
~ The PG&E analysis for the four sample systems was thorough and
complete.
~ The PG&E review resulted in the identification of separation and
single failure concerns similar to those addressed in:the initialsample. Modifications were subsequently made to provide consist-
ency with FSAR separation commitments.
2-1
~ The IDVP drawing review and field verification of the four sample
systems upon completion of the PGSE analysis and modifications
indicated that the FSAR separation and single failure criteria
were satisfied.
~ No further additional verification is required based on the satis-
factory results of the IDVP verification.
2-2
1%
SECTION 3
BASIS OF CONCERN
The IDVP review of instrumentation and control of the AFW System and the
CRVP System identified two areas of concern:
~ Several mutually redundant devices and circuits in control panels
for both systems were not separated in accordance with criteria in
the FSAR, Section 8.3.3.
~ An electrical component in the CRVP Control System did not meet
the DCNPP-1 single failure criteria for safety-related systems.
3.1 EOI FILES
Control panels containing AFW and CRVP system control circuits were field-verified for separation of mutually redundant circuits. As committed to in
the FSAR, Section 8.3.3, separation is required to meet the single failure
criteria. This review identified several instances of circuits with a
mutually redundant function connected to the same terminal block, exposed
wiring at end connections to devices and instruments not separated by at
least 5 inches, and mutually redundant circuits not separated by one of the
eight methods listed in the FSAR, Section 8.3.3. The concern is that due to
lack of separation, a single failure may result in the loss of mutually re-
dundant trains of a safety-related system. EOI File 8057 was issued to
address this concern.
3-1
Each redundant train of equipment in the CRVP System is powered from a
separate, redundant Class IE power source. Mutually redundant sources of
power, however, are brought together in one electrical control transfer
switch which is used to select the train to operate. Failure of this switch
could result in loss of electrical power to both trains of the CRVP System.
EOI File 8017 addressed this concern.
3.2 SCOPE OF ADDITIONALVERIFICATION
In response to ITR No. 34, PG&E committed to reviewing all PG&E-designed
safety-related systems and identifying the mutually redundant circuits
within these systems. PG&E then determined if the mutually redundant cir-
cuits and devices within the same enclosures were both properly identified
and noted as requiring separation. In addition, PG&E conducted a field
review of all mutually redundant safety-related circuits located in common
enclosures to ensure that they were separated as required by the methods
stated in the FSAR, Section 8.3.3.
Also, as part of the review, PG&E identified devices which had mutually
redundant circuits connected to them. When identified, a single failure
analysis was performed to determine the ability of the system to perform itsdesign basis function.
SECTION 4
ANALYSIS
Upon completion of the analysis performed by PGSE, the IDVP selected samples
of the PGSE-designed safety-related systems and verified the analyses. The
sample systems selected for verification were:
Component Cooling Water
Auxiliary Saltwater
Auxiliary Building Ventilation
125'V dc Emergency Power
4.1 CIRCUIT SEPARATION
The IDVP reviewed the circuit drawings to determine that PGSE identified
mutually redundant circuits and performed a field inspection of enclosures
in the above systems to determine if the installation of mutually redundant
circuits within the same enclosure met the separation criteria committed to
in the FSAR, Section 8.3.3. The IDVP verification did not identify any
cases where PGRE did not identify the systems'utually redundant circuits
or where separation in the field did not meet FSAR requirements. PG&E did
identify modifications that were required, and they were implemented in the
sample systems to ensure compliance with the FSAR separation methods.
4.2 SINGLE FAILURE
In addition to verifying the circuit separation, the IDVP also reviewed
PG&E's single failure analyses in the above four systems. PGSE provided
drawings marked to show where mutually redundant circuits were connected to
the same device. Where this occurred, PGSE performed a single failure
analysis to determine the ability of the system to perform its design basis
function. The IDVP reviewed these analyses to verify that all mutually
redundant circuits connected to the same device were identified. The IDVP
verification did not identify any cases where a single failure would
adversely affect the operation of these systems.
4.3 ACCEPTANCE CRITERIA
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The sample systems must satisfy the single failure criteria of IEEE Standard
279-1971. These systems must also meet the commitments in the FSAR, Section
8.3.3, regarding circuit separation.
4.4 DOCUMENTATION USED
Documentation required to verify PGRE performed reviews for circuit separa-
tion and single failure of safety-related electrical control equipment
consisted of the following:
4-2
~ DCNPP-1 schematic diagrams and connection 'diagrams for the four
selected sample systems color-coded by PGSE
~ PGSE-performed single failure analyses for those devices that had
mutually redundant circuits connected to them.
I
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SECTION 5
CONCLUSIONS
The conclusions concerning the additional verification of circuit separation
and single failure review of safety-related electrical equipment follow:
The PG&E analysis for the four sample systems was thorough and
complete.
~ The PGSE review resulted in the identification of concerns similar
to those addressed in the initial sample. Modifications were sub-
sequently made to provide consistency with FSAR separation
commitments.
~ The IDVP drawing review and field verification of the four sample
systems upon completion of the PGSE analysis and modifications
indicated that the FSAR separation and single failure criteria
were satisfied.
~ No further additional verification is required based on satis-
factory results of the IDVP verification.
5 "1
APPENDIX A
PROGRAM MANAGER'S ASSESSMENT
APPENDIX A
PROGRAM MANAGER'S ASSESSMENT
Independent review by TES of the tasks performed by SWEC to verify theDiablo Canyon Project (DCP) efforts was done in accordance with the IDVP PhaseII Program Management Plan and ITR-34.
ITR-34, Revision 1, issued on March 24, 1983, identified five (5) areasof concern which required additional verification. The work was performed bythe DCP and the conclusions were verified by SWEC.
This ITR describes the additional verification on circuit separation andsingle failure reviews of safety-related electrical equipment performed bythe IDVP on a sample basis. The sample consisted of four safety-relatedsystems which were drawn from all safety-related systems previously reviewedby the DCP to ensure that the electrical circuits met the FSAR single failureand separation criteria. Included in the verification were a review of theapplicable DCP electrical schematics and an on-site inspection of wiring inenclosures for the sampled systems.
The results of the IDVP verification determined that the DCP review wasthorough and complete, and that the FSAR requirements for separation andsingle failure criteria were satisfied. No EOI files were issued.
The IDVP concluded that the DCP review of circuit separation and singlefailure analysis in safety-related systems is satisfactory. Accordingly, nofurther additional verification is required.
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