ML19337A426

From kanterella
Jump to navigation Jump to search
Testimony in Response to Ucs Contention 4 Re Connection of Pressurizer Heater to Diesel.Presents Provisions Assuring Protection of Onsite Emergency Power Supplies.Prof Qualifications Encl.Related Correspondence
ML19337A426
Person / Time
Site: Three Mile Island Constellation icon.png
Issue date: 09/15/1980
From: Shipper P, Torcivia J
METROPOLITAN EDISON CO.
To:
Shared Package
ML19332B231 List:
References
ISSUANCES-SP, NUDOCS 8009260407
Download: ML19337A426 (15)
v • d • e


Text

9 s

i

g. O RELATED CORREspONDM O g renr3 LIC 9/15/80

, ' c .g

~ -

y c..y]p y 11980 >

5

  • s UNITED STATES OF AMERICA k, , NUCLEAR REGULATORY COMMISSION M s 1

i BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of )

)

METROPOLITAN EDISON COMPANY ) Docket No. 50-289

) (Restart)

(Three Mile Island Nuclear )

Station, Unit No. 1) )

LICENSEE'S TESTIMONY OF JOSEPH A. TORCIVIA AND PAUL J. SHIPPER, JR.

IN RESPONSE TO UCS CONTENTION NO. 4 (CONNECTION OF PRESSURIZER HEATER TO DIESEL)

/

0 '

999'p 6 l

i OUTLINE j The purposes and objectives of this tesimony are to respond to UCS Contention No. 4 which asserts that design provisions to enable pressurizer deaters to be added to on-site er gency (diesel) power supplies in the event of postulated loss of off-site power events have not been demonstrated to no t degrade these emergency power supplies. This testimony presents the provisions that assure that on-site emergency power supplies are protected by the proper application of design features, administrative procedures and protective 1

devices.

l l

\

l f

1

-i-I

, I

INTRODUCTION ,

This testimony, by Mr. Joseph A. Torcivia , GPU, Senior Project Engineer , and Mr. Paul J. Shipper, Jr., Project Electrical Engineer , Gilbert Associates, Inc., is addressed to the following contention:

UCS CONTENTION NO. 4 Rather than classifying the pressurizer heaters as safety-grade, the staff has proposed simply to add the pressurizer heaters to the on-site emergency power supplies. It has not been demonstrated that this will not degrade the capacity, capability and reliability of these power supplies in violation of GDC 17. Such a demonstration is required to assure protection of public health and safety.

RESPONSE TO UCS CONTENTION NO. 4 BY WITNESSES TORCIVIA AND SHIPPER:

l NUREG-0578, Section 2.1 requires that a limited number of pressurizer heaters shall have the capability of being connec-ted to the emergency buses under loss of off-site power events in a manner that will provide redundant power supply capabil-ity.

Adding heaters to the emergency buses provides additional assurance that the pressurizer heaters will be available. The use of the pressurizer heaters is the normal and, therefore, the most desirable means for maintaining the pressure of the reactor coolant system during natural circulation.

Licensee's testimony in response to UCS Contention 3 (Safety Classification) explains why it is not necessary for the pressurizer heaters to be qualified as a safety-grade Emergency Core Cooling System (ECCS) .

Pressurizer heaters are normally supplied from two  !

non-essential, Balance of Plant (BOP), 480 volt electrical  !

buses. Power to these buses would be lost, however,( Jring postulated loss of off-site power events. Ther efore , the two 480 volt buses supplied by emergency diesel generators can be "tilized to provide emergency power to the pressurizer heaters.

The electrical arrangement of the design is shown in Figure 1. The design provides the means to: l

a. Normally supply all pressurizer heaters from BOP buses.
b. Manually connect pressurizer heater group 8 to emergency " bus" "lP", but not to emergency bus "1S".
c. Manually connect pressurizer heater group 9 to emergency bus "lS", but not to emergency bus "lP".
d. Prevent any possible interconnection of emergency bus "lP" with emergency bus "lS".

e.

Prevent the interconnection of a BOP bus with l an emergency bus. l l

l 1

l .

i t

Contrary to UCS Contention 4, this modification does not degrade the emergency buses in violation of GDC 17. Normally, the heaters would be supplied from off-site power and would not be connected to the emergency diesel buses. In the event of a Itss of off-site power, the operator may make the manual transfer of power supplies to restore portions of the pressurizer heaters. This transfer process employs a number of different kirk key interlocks that force a step by step process in a fixed sequence which requires an individual to obtain and utilize keys and specific electrical devices to:

1

a. Trip the breaker at the BOP bus .
b. Open the disconnect device enclosure in the l

Turbine Building and remove the disconnect l assembly.

c. Carry the disconnect assembly to the 480 volt ES switchgear room in the Control Building.
d. Insert the disconnect assembly in the disconnect device enclosure in the Control Building.
e. Engage the pressurizer heater emergency power feeder breaker into its compartment.
f. Operate the control switch to close the associated feeder breaker if conditions permit.

The manual transfer, therefore, is controlled by design, administrative procedure, kirk key interlocks and protective devices that prevent paralleling or degrading redundant power supplies.

TMI-l Emergency Procedures specify that only one group of pressurizer heaters be connected to an emergency bus at any one

~

time, and that sufficient capacity be available for the emergency diesel generator to handle the pressurizer heater loads as verified by wattmeter indication. Further , the rated I capacity of the diesel has been verified as being capable of handling the heaters in addition to the safety related loads required during loss of off-site power events.

Diverse means of tripping the pressurizer heater loads from the safety-related buses are provided to assure that the capacity, capability and reliability of the safety bus to supply power to safety loads is not degraded. These diverse

, trips are:

i

1. Automatic safety features actuation signal trip (ESFAS) - There are three separate and independent signals that produce this safety l action (accident) signal which will trip the pressurizer heater loads.
2. Low emergency bus voltage trip - Emergency bus voltage is an indicator of the capability of the emergency bus to supply power to safety loads. Three (3) under-voltage relays

are provided, any one of which will trip the pressurizer heater load from the emergency bus when the voltage level indicates that that capability is jeopardized.

3. The distribution breaker thermal magnetic overload trip elements - One of the three (3) distribution breakers will trip the pressurizer heater elements it powers if a fault exists on those elements.
4. Main feeder breaker overcurrent trip elements

- This breaker , which is in series with the breakers mentioned in Item 3 above, will also provide a backup trip for a fault on the pressurizer heater elements.

5. Manual trip.

i Regulatory Guide 1.75, dated September 1978, presents the I basis for isolation of non-Class lE loads from Class lE power supplies (emergency buses) in Paragraph Cl:

Also, the susceptability of non-Class lE loads energized from redundant Class lE power sources to design basis events (e.g., seismic events) could similarly threaten the redundant main (bus) circuit breakers.

This establishes the basis for providing isolation of the pressurizer heater loads from the emergency buses. It al so i

implies that the purpose of this isolation is to prevent a fault on the pressurizer heaters from causing the main l

emergency bus circuit breaker to trip and thereby remove

i electrical power from safety loads during the performance of l

their safety function. The Regulatory Guide further states:

It is recognized that proper breaker or fuse coordination would preclude such an event.

However, because the main (bus) breakers are in series with the fault and could experience momentary currents above their setpoints, it is prudent to l';eclude the use of interrupting devices actuated only by fault current. . . . '

The con ern is that while a breaker in the supply chain to the .

non-Class r* od would isolate the fault if properly coordi-nated, that breaker may fail to respond to an above normal I current and thereby force the main bus breaker to function to isolate the fault. The electrical supply feeder to the pressurizer heater loads has two circuit breakers ( refer to Items 3 and 4 in the preceeding paragraph) in series, and each has coordinated overcurrent tripping elements. Therefore, a failure of either breaker overcurrent element to operate does not prevent the other from successfully isolating the fault before the time-current setting of the main emergency bus .

breaker is reached. Voltage on the emergency bus for a fault on the pressurizer heaters would also cause the under voltage relays (refer to Item 2 in the preceeding paragraph) to cause opening of the main pressurizer heater supply breaker to isolate the fault by a shunt trip independent of the overcur-rent tr ip.

It should be noted that while an overcurrc . v ic e requires sensing of a condition above normal to trip, unuervol-tage relays require a normal value to restrain them from tripping and trip for a value below normal. Therefore, in this

( ,

l

application the undervoltage relay can be considered as fail-safe in that a failure in its sensing circuit would produce a trip.

It also stated in the Regulatory Guide that:

Breakers that trip on receipt of a signal other than one derived from the fault current or its effects (e.g., an accident signal) are accept-able....

As previously stated, (refer to Item 1 above) this design does also incorporate an ESFAS signal trip.

In conclusion, and as stated in the Regulatory Guide, "The standard defines ' isolation device' in terms of preventing malfunctions in one section of circuit from causing unaccept-able influe:nces in other sections of the circuit." At TMI-1, the pressurizer heater loads are:

a. Normally not connected to the emergency buses. The disconnect means is manual with a visable break.
b. When required, only one group of pressurizer heaters are powered from one emergency bus at one time. The connection means precludes interconnection of emergency buaes and/or interconnection of a BOP bus with an emergency bus.
c. Automatically tripped front the emergency bus by diverse signals: A failure of any one of the signals below does not prevent the I

l

successful isolation of a fault on the l pressurizer heaters.

1. Accident signals.
2. Undervoltage signals.
3. Overcurrent trip signals of two breaP'rs in series.

It is concluded tha t the addition of pressurizer heaters i

to the emergency buses when required does not degrade the capacity, capability and reliability of these power supplies and complies with GDC 17.

l l

l l

i

_ di s )W. C .?s. tatl*. B D _

, 4 e rs O V. F..i 9*'3", 9 F.

I L 's 9 iJ' 3.

L '<.f Ef.5" 9

~ <2eu,,r e<oi.

. s so, ,, . ...ies ce...ur.: ., , ,-: Im..-.tR 4eov. t.s. eux. o c W.c)

)t"t* anov, t.3. co: is (c.rtanu) -

i i i i I -1 i i i i H

') )- ) II ) El ) vp ,...) miu rr.rtat g ., - ens ..cx i) i) 3y _.) +i.a.r.tetc= en oc ') )

g o c= recsunene O&ies. .

os cit e.scincuits B&1 ts.2 orurn e.s.cincuit s M DEEAf t3! EVMW certculf S

. < 'A '

A 6 4 84 M

  • E'r!$"r'.'" c O O m s w

a w a M q 3 6 9 a _,

(c DetTRIBUT eo6J $3rtEAWEst

, _ -_ _ , F^*3El S ~.

--1 MEcseAtticAq. MattK s(LY IDJTEt(Lccn l - @ unoasavoi.vac.e. nei.ny l l i > > i , ) > > i e i t I cu.Soe un4:Aine en _ , _

$NS800 C0 4I AINM&64I L._ . , _

c' c' t~' c' c' c' ent3suustty rerosuniten setAT Eis:8 C#!Oot* 8 HEA1ER G'.DOP 9 9 to MW 424 KW s

Tii~re,s..<,sh i. c ietn uie =e n., emm a,e FIGURE I ol en. o. I nna '

warm cee e

JOSEPH A. TORCIVIA Business Address: GPU Service Corporation 100 Interpace Parkway Parsippany, New Jersey 07054 Education: B.S.E.E., Pratt Institute, 1936.

Post-graduate courses in: protective relaying including extensive experience in coordination and ground fault studies; process control and instrumentation for industrial plants; industrial electronics; cathodic protection; and, switchgear and motor controls in all voltage classifications.

Expe rience : Lead Senior Electrical Engineer, GPU Service Corporation, 1972 to present.

Responsible for the design, documentation, and review of all power. equipment for the nuclear powered electric generating stations of the GPU system. Responsible for the major studies and responses to the NRC related to the electric power equipment.

Engineer, C.F. Braun Architectural Engineering Corp., 1971 to 1972.

Responsible for performing process control engineering projects for chemical and electrical industrial organizations.

Plant Manager, Federal Pacific Electric Company, 1970 to 1971.

Overall responsibility for manufacturing of power equipment.

Engineer, A.G. McKee Architectural Engineering Company, 1969 to 1970.

Responsible for process control applications for the petrochemical ind us try.

Westinghouse International, 1968 to 1969, consulting sales applications overseas.

i

Engineering Manager, Westinghouse Electric Corporation, 1936 to 1968. Responsible for engineering of manufactured switchgear motor control and all types of power equipment for Manufacturing Division.

Professional Affiliations: Member, IEEE - IAS Group.

Registered Professional Engineer, New Jersey and Massachusetts.

1 PAUL J. SHIPPER, JR.

Business Address: Gilbert Associates, Inc.

525 Lancaster Avenue Reading, Pennsylvania 19603 Education: B.S.E.E., The Pennsylvania University, 1966 Experience: Project Electrical Engineer, Gilbert Associates, Inc., 1979 to present.

Responsible for Metropolitan Edison Company's Three Mile Island Unit 1 Continuing Services Restart Program; and assisted Three Mile Island Unit 2 plant staff during accident and recovery.

Project Electrical Engineer, Gilbert Associates, Inc., 1974 to 1979.

Responsible for continuing engineering services for Metropolitan Edison j Company's Three Mile Island Nuclear l

Station, Unit 1; coordinator of Three l Mile Island Nuclear Station Unit 2 I cable routing data processing program- l and electrical design for all volatile l treatment condensate demineralizer installations for Rochester Gas and Electric Corporation's R.E. Ginna Nuclear Power Plant, Unit 1.

Project Electrical Engineer, Gilbert Associates, Inc., 1971 to 1974.

Responsible for completion of the engineering design and licensing of Metropolitan Edison Company's Three Mile Island Nuclear Station, Unit 1, and provided coordination for Unit 1 with Unit 2 design interface problems.

Also assisted in balance of plant studies for Gulf General Atomic for their standard 1140 MW HTGR Nuclear Generating Station.

l

Project Electrical Engineer, Gilbert Associates, Inc., 1969 to 1971.

Responsible for the design of gas '

turbine generating stations, including short circuit studies, plant layout, physical electrical distribution, application of equipment, electrical construction specification, underg-round ducts, review of purchased tur-bine package, and substation work on various generating plants.

Junior Electrical Engineer, Gilbert Associates, Inc., 1966 to 1969.

Involved in design of control systems, cabling and physical wire checking; application, evaluation and purchase of equipment; and startup of 2 mine-mouth coal-fired units for Pennsylvania Electric Company's Homer City Generating Station.

Engineering Trainee, Metropolitan Edison Company, 1965. Worked on conversion of Metropolitan Edison Eastern Division Load Flow Study from a-c network analyzer to digital computer.

Professional Affiliations: Registered Professional Engineer, Pennsylvania.

Publications: " Review of Cable Installation at Three Mile Island, Unit 1," GAI Report No.

2042.

- - -- --, - - , . -

Retrieved from "https://kanterella.com/w/index.php?title=ML19337A426&oldid=2483359"