ML20214R871

Technical Evaluation Rept Evaluation of Bldg 10 Electrical Mods Fort St Vrain Nuclear Generating Station, Informal Rept

ML20214R871
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/31/1987
From:	Nolan A EG&G IDAHO, INC., IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LABORATORY
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20214R859	List: ML20214R856 ML20214R871
References
CON-FIN-D-6023 EGG-NTA-7607, TAC-55287, NUDOCS 8706090036
Download: ML20214R871 (14)

Text

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iw EGG-NTA-7607 March 1987 INFORMAL REPORT TECHNICAL EVALUATION REPORT EVALUATION OF BUILDING 10 i

/daho ELECTRICAL MODIFICATIONS National FORT ST. VRAIN NUCLEAR GENERATING STATION Engineering.

Laboratory Managed I

by the U.S.

A. E. Nolan Department ofEnergy i

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DOE Contract No. DE-AC07-76tD015?O 8706090036 870306 PDR ADOCK 05000267 P

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s DISCLAIPER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, of any information, apparatus, product or process disclosed in this report or represents that its use by such third party would not infringe privately owned rights.

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EGG-NTA-7607 TECHNICAL EVALUATION REPORT EVALUATION OF BUILDING 10 ELECTRICAL MODIFICATIONS FORT ST. VRAIN NUCLEAR GENERATING STATION DOCKET NO. 50-267 TAC No. 55287 INEL Reviewer - A. Nolan INEL Program Manager - C. L. Nalezny NRC Lead Reviewer - I. Ahmed NRC Project Manager - K. Heitner NRC Program Manager - M. Carrington Published March 1987 1

EG&G Idaho, Inc Idaho Falls, Idaho 83415 Prepared for the U.S. Nuclear Regulatory Commission Washington, D.C.

20555 Under DOE Contract No. DE-AC07-761001570 FIN No. D-6023

ABSTRACT This EG&G Idaho, Inc., report reviews the submittals for the Fort St. Vrain Building 10 electrical modifications. The report concludes that the electrical modifications are acceptable.

D6023--Review of Plant-Specific Licensing Actions for Operating Plants Docket No. 50-267 TAC NO. 55287 11 1

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I j-FORWARD i

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This report is supplied as part of an on-going review of electrical I

modifications made to nuclear power plants in support of the U.S. Nuclear Regulatory Comission, Office of Nuclear Reactor Regulation, Division of PWR Licensing-B, Standardization and Special Projects Directorate by EG&G l

Idaho, Inc.

j The U.S. Nuclear Regulatory Comission funded the work under authorization B&R 20-19-10-11-2, FIN No. D6023.

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1 Docket No. 50-267 l

TAC No. 55287 I

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CONTENTS 4

j ABSTRACT.......................................................

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FORWARD........................................................

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1.0 BACKGROUND

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2.0 DISCUSSION AND EVALUATION.................................

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2.1 Appendix R of 10 CFR 50 Concerns.....................

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2.2 General Clarification................................

3 2.3 Equipment Qualification Concerns.....................

3 2.4 Engineering Design Concerns..........................

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3.0 CONCLUSION

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4.0 REFERENCES

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TECHNICAL EVALUATION REPORT EVALUATION OF BUILDING 10 ELECTRICAL MODIFICATIONS FORT ST. VRAIN NUCLEAR GENERATING STATION

1.0 BACKGROUND

In 1981, Public Service Company of Colorado (PSC), the licensee for l.

Fort St. Vrain (FSV), finalized the design for a new facility known as Building 10. At the same time, the licensee began a project to upgrade the electrical distribution systems to ensure that they could supply the plant's present electrical loads and accommodate future load requirements.

On June 25, 1984, NRC Region IV (RIV) staff met with PSC to review the Building 10 modifications. During the review, it was noted that Building 10 housed some electrical equipment essential to the safe shutdown of the plant.

As a result of this meeting, RIV requested additional information (RAI) by letter dated June 25, 1984 (Ref. 1).

In a letter dated July 25, 1984 (Ref. 2) PSC responded to the RAI.

In their response, PSC stated the review of the Technical Specifications was not affected by the design and construction of Building 10, nor were there any unreviewed safety questions.

The Office of Nuclear Reactor Regulation (NRR), upon being notified of Building 10, raised some concerns, and in a separate letter dated July 25, 1984 (Ref. 3), forwarded their concerns to RIV for review. As a result of these NRR concerns, RIV requested, by letter dated August 18, 1984 (Ref 4), that the staff review the documents related to the modifications i

of the electrical systems at FSV and the relocation of electrical equipment to Building 10.

The documents sent to NRC Headquarters were the Change Notices (CNs) issued by PSC for the work on Building 10. A list of these CNs is included in the reference section of this report (Refs. 8 -

16). The CNs were reviewed by the staff, and a second RAI was forwarded to the licensee on May 1, 1986 (Ref. 5). The licensee responded to the RAI by letter dated June 19, 1986 (Ref. 6).

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The objectives of this technical evaluation are to determine the completeness of the Building 10 electrical modifications, as described by the CNs, and to determine that the modifications are in agreement with the applicable NRC requirements.

2.0 DISCUSSION AND EVALUATION 1

The CNs submitted for review described the Building 10 modifications which include: (1) increasing the capacity of inverters, transformers, batteries, and battery chargers; (2) installing automatic transfer switches, transformers, switch gear, current $1miting reactors, cables, undervoltage relays, cable trays and conduits; (3) relocating transformers and switch gear from inside Building 10 to an outside location; (4) reconfiguring the instrument bus distribution system by adding back-up power transformers; and (5) reconfiguring the DC distribution system by installing new battery chargers and a back-up source of 125VDC.

The Standard Review Plan (SRP) Section 8.3.1, A-C Power systems I

(Onsite), and Section 8.3.2 D-C Power Systems (Onsite), were used as the review criteria for these changes. This was to ensure that the original plant design criteria was still valid with respect to the modifications and that the new electrical equipment was installed in keeping with the l

applicable design criteria as called out by the SRP.

l The review resulted in a set of questions that were forwarded to the licensee in the form of a RAI (Ref 5). The questions were grouped into four categories: (1) 10 CFR 50, Appendix R Concerns, (2) General Clarification, (3) Equipment Qualification, and (4) Engineering Design Concerns. These categories are discussed below.

2.1 10 CFR 50. Appendix R Cogerns The concerns related to Appendix R regarded cables of redundant divisions in the same fire area, emergency lighting, and revisions to the original Fire Study as a result of new equipment installed in Butiding 10.

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These concerns were addressed in a separate NRC staff evaluation and were transmitted to the licensee by letter dated November 18, 1986 (Ref. 7). These concerns will not be readdressed in this TER.

4 2.2 General Clarification J

The General Clarification questions were related to a power system single-line diagram, to bus identification (ID) and bus tie-in, to the

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disposition of old equipment and the rating of new equipment, to the CN l

revisions that were missing from the review package, and to the status of Inverter IC.

The licensee submitted an "as-built" version of the single-line diagram, which clarified the bus ID and tie-in concerns. The response furnished the disposition of the old equipment and ratings of the new equipment and forwarded the missing revisions of the CNs. The response i

also stated that all essential 480-volt switchgear had been replaced with q

new equipment. The review showed that only the old 1C battery, battery i

charger and inverter were retained and re-used as a computer power source.

The licensee responded that the primary power source for Inverter 1C is essential Bus 2 with back-up feed from essential Bus 1.

The inverter feeds non-interruptible Buses 1C and 10-1.

These two buses are i

independent from the other system buses and, as such, are not associated with any of the existing redundant divisions.

2.3 Equipment Concerns 1

The equipment qualification concerns dealt with the ambient i

temperature of the cables, cable ratings, short circuit handling capability of the cables, and protective devices and battery discharge tests.

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i The licensee stated in their response that the worst case conditions, 1.e., failure of the HVAC system in Building 10, the building's 0

temperature would not exceed 120 F and that all Class 1E cables used within Building 10 are rated at 1850F.

The licensee stated that the existing batteries had been in service for 12 years and cell failures were occurring. The replacement batteries were purchased to fit the existing battery racks, and, because of advances in battery technology, the new batteries had an increased capacity for comparable cell dimensions.

The licensee indicated that the discharge testing procedure of the batteries has been revised to correspond to the new battery load profile.

In addition, the new inverter i

and battery charger have been seismically and environmentally qualified to FSV requirements for the Class 1E equipment.

In response to the short circuit current handling capabilities, the licensee stated that the current limiting reactors protected the Motor Control Centers from the higher short circuit currents that are now available as a result of upgrading the main transformer and that additional loads were not added to the existing cables; instead new cables were installed when new loads were added. The upgrade of the electrical system within Building 10 did not affect the existing protective device, cable, and load combinations.

2.4 Engineering Design Concerns The design concerns included: 1) the possibility of single-phasing due to the fused circuit breakers; 2) the possibility of voltage drop caused by the installation of the current limiting reactors; and 3) the application codes, standards, regulatory requirements, and design requirements used in the electrical systems modifications.

In response to the concerns regarding the possibility of single-phasing, the licensee supplied data showing that the fused circuit breakers were equipped with voltage sensors in parallel with the fuses.

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If one or more of the fuses opened, the voltage sensors would then open the breakers. The breakers would lock open, thus eliminating the possibility of single-phasing.

Current limiting reactors are used in power distribution systems to limit short circuit current. The licensee supplied data which shows that the current limiting reactors would cause slightly over 1 percent voltage drop for 600 amperes at a 0.8 power factor. Additionally, this voltage drop will not cause less than rated voltage at the terminals of the associated Class 1E equipment; therefore, the existing voltage regulation is acceptable.

The licensee's response listed the design documents used in the modifications to the electrical systems within Building 10.

In addition, the licensee provided a comparison of the applicable design criteria used for the electrical modification to these of the original plant (Ref. 2).

l The licensee stated that the electrical modifications meet or exceed the i

original plant design criteria and that the current revisions of building codes were used at the time of construction.

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3.0 CONCLUSION

S The review of the licensee's submittals, including the responses to the RAls, has determined that FSV modifications involving safety-related electrical systems / equipment in Building 10 meet the applicable NRC requirements and the original design criteria of the plant. Therefore, it has been-determined that the modifications are acceptable.

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4.0 REFERENCES

1.

Letter dated June 25, 1984, from J. T. Collins (Region IV) to

0. R. Lee (PSC), forwards NRC concerns to Licensee.

2.

Letter dated July 25, 1984, from 0. R. Lee (PSC) to E. H. Johnson (NRC), " Fort St. Vrain Building 10."

3.

Letter dated July 25, 1984, from D. G. Eisenhut (NRC) to R. P. Denise (Region IV), " Fort St. Vrain (FSV)."

4.

Letter dated August 15, 1984, from P. Check (Region IV) to D. E. Eisenhut (NRC), " Request for Review Assistance - Fort St.

Vrain (FSV) Electrical Modifications."

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Letter dated May 1, 1986, from K. L. Heitner (NRC).to R. F. Walker (PCS), " Request for Additional Information - Fort St. Vrain, Building 10 Electrical Modifications (TAC 55287)."

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Letter dated June 19, 1986, from D. W. Warenbourg (PSC) to H. N.

Berkow (NRC), " Additional Information on Equipment Upgrades and Building 10."

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Letter dated November. 18, 1986, from K. L. Heitner.(NRC) to R. O. Williams, Jr., " Draft Fire Protection Safety Evaluation (SE) For Fort St. Vrain (FSV)."

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CN 1255 - Upgraded Instrument Power System 1A and 1B.

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CN 1294 - Upgraded the 480 V Essential Power System.

10.

CN 1332 (All Revisions) - Upgraded Non-Interruptible Instrument Power System IC and Replaced Battery Charger 10.

11. CN 1391 - Upgrade Station Batteries 1A, 1B, and IC.

12. CN 1462 - Install Building 10 Cable Tray System and Fire Protection System.

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CN 1605 - Install 4150/480 Volt Transformers and Associated.

Support Systems.

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CN 1622 - Modified Essential Power Undervoltage Protective Relaying.

15. CN 1629 - Installed Current Limiting Reactors.

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CN 1781 - Installed Cable Tray Wrap.

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BIBUOGRAPHIC DATA SHEET EGG-NTA-7607 sit INSTRUCTIONS ON THE REVERSE 3 LE AVE OLANK

3. TITLE ANO 3USTITLE Evaluation of Building 10 Electrical Modifications Fort St. Vrain Nuclear Generating Station 4 OATE REPORT COMPLETED Marc 1ONTH I 1987 TGAR 5 LutriORist A. E. Nolan

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March l1987 MONTH VEAR F S E APORMING ORGAN #2 ATION N AME AND M AILING ADORE S$ ffac4*e l* C88st S PROJECitT ASK/ WORK UNai NUMSER 1

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' Pe~ oa caAN r NuMaia Idaho Falls, ID 83415 D6023 to SPONSORING ORG ANi2 Af SON N AME AND M AILING ADORES $ ltarbee to Cowes 1to fvPE OP REPORT Division of PWR Licensing - B Informal Office of Nuclear Regulatory Commission -

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Washington, D.C.

20555 N/A 13 SUPPLEMENT ARV NOTES e

13 A85TR ACT f200 eerve er 'essJ This EG&G Idaho, Inc., report reviews the submittals for the Fort St. Vrain Building 10 electrical modifications.

The report concludes that the electrical modifications are acceptable.

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