ML20062L830

Proposed Tech Spec Pages 61,63 & 93a Re Main Steam Line Tunnel Exhaust High Temp Instrumentation Setpoint

ML20062L830
Person / Time
Site:	Peach Bottom
Issue date:	06/29/1981
From:	PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
Shared Package
ML20008G101	List: ML20008G100 ML20062L827 ML20062L830
References
NUDOCS 8107020250
Download: ML20062L830 (3)

Text

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TABLE 3.2.A

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N ca INSTRUMESTATION THAT INITIATES PRIMARY CONTAINMENT ISOLATION .

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!"? Hinimun No. l  !

of Operable l Number of Instrument -

(A Instruraent Instrument . Trip Level Setting l Channels Provided Action gfj Channels per Trip System (1)

By Design (2)

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2 (6) Reactor Low Water t.0" Indicated 4 Inst. Channels A Level Level (3) 1 Reactor High Pressure 1 75 psig 2 Inst. Channels D (Shutdcwn Cooling Isolation) -

2 Reactor Low-Low at or above -49" 4 Inst. Channel $s A Water Level indicated level (4) 2 (6) High Drywell Pressure 1 2 psig 4 Inst. Channels A Y 2 High Radiation Hain 13 X Normal Rated (8) 4 Inst. Channels B Steam Line Tunnel Full Power Background 2 Low Pressure Main 1 850 psig (7) 4 Inst.. Channels B Stean Line 2 (5) High Flow Hain 1 140% of Rated Steam Line Steam Flow 4 Inst. Channels B 2 Hain Steam Line 1200 deg. F (9) 4 Inst. Channels B Tunnel Exhaust Duct High Temperature

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PDAPS NOTES FOR TABLE 3.2.A

l. L.hanuver Primary Containment integrity is required by ,

Section 3.7, there shall be two operable or tripped trip systems for cach function.

2. If the first column cannot be met for one of the trip systems, that trip system shall be tripped or the appropriate action -

listed below shall be taken.

A. Initiate an orderly shutdown and have the reactor in Cold Shutdown Condition in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

B. Initiate an orderly load' reduction and have Main Steam Lines isolated within eight hours. .

C. Isolate Reactor Watcr Cleanup System.

D. Isolate Shutdown Cooling.

3. Instrument set point ccrresponds to 177.7" above top of active fuel.

4. Inst;ument set point corresponds to 129.7" above top of active fuel,

b. Two required for each steam line. ,

6. These signals also start SBGTS and initiate secondary contain-ment isolation.

7. Only required in Run Mode (interlocked with Mode Switch).

S. At a radiation Icyc1 of 1.5 times the normal rated power background an alarm will be tripped 'in the control room to alert the control room operators to an increase in the main steam line tunnel radiation Icycl. g

9. In the event of a loss of ventilation in the main steam line tunnel area, the main steam line tunnel exhaust duct high temperature setpoint may be raised up to 2500F for a period not to exceed 30 minutes to permit '

restoration of the ventilation flow.

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PBAPS 3.2 BASES (Cont'd)

In the event of a loss of the reactor building ventilation system, radiant heating in'the vicinity of the main steam lines raises the ambient temperature above 200 degrees F.

' Restoration of the main steam line tunnel ventilation flow momentarily exposes.the temperature sensors to high gas temperatures. The momentary temperature increase can cause an unnecessary main steam line isolation and reactor scram.

Permission is provided to increase the temperature trip setpoint to 250 degrees F for 30 minutes during restoration of ventilation system to avoid an unnecessary plant transient.

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UNITED STATES l 5]

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NUCLEAR REGULATORY COMMISSION WASHING TON, D. C. 20555 t Tsw "4 June 19, 1981 .. . _ - 7 . -., q3

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Dockets Nos. 50-277

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~: JUN 2 31981* C Mr. Edward G. Bauer, Jr. - usmuon 42 Vice President and Genera'i Counsel S ,,,, ,m cc SSS Philadelphia Electric Company 7 2S01 Parket Street 4 Philadelphia, Pennsylvania 19101

Dear Mr. Bauer:

Our letter of May 15, 1981 transmitted requests for additional infomation needed by us to complete our review of the Peach Bottom Station problems related to degraded grid voltage and station electric distribution voltages.

As a result of telephone calls between our staffs, subsequent to May 15, we require the additional informtion supplied in the enclosure to this letter.

We request that the additional information be provided within 30 days of ,

your receipt of this letter.

Sincerely, John F. Stol2f Chief Operating Reactors Branch #4 Division of Licensing

Enclosure:

Request for Additional Infomation cc w/o enclosure:

See next page f)

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' Philadelphia Electric Company Eugene J. Bradley U. S. Environmental Protection Agency Philadelphia Electric Company Region III Office -

Assistant General Counsel ATTN: EIS COORDINATOR -

t 2301 Market Street C"etis Building (Sixth Floor)

Philadelphia, Pennsylvania 19101 6th and Walnut Streets Philadelphia, Pennsylvania 19106 Troy B. Conner, Jr.

1747 Pennsylvania Avenue, N.W. M. J. Cooney, Superintendent Washington, D. C. 20006 Generation Division - Nuclear Philadelphia Electric Company Raymond L. Hovis, Esq. 2301 Market Street 35 South Duke Street Philadelphia, Pennsylvania 19101 York, Pennsylvania 17401 Government Publications Section Warren K. Rich, Esq. State Library of Pennsylvania Assistant Attorney General Education Building

< Department of Natural Resources Commonwealth and Walnut Streets

! Annapolis, Maryland 21401 Harrisburg, Pennsylvania 17126 Philadelphia Electric Company ATTN: Mr. W. T. Ullrich Peach Bottom Atomic Power Station Mr. R. A. Heiss, Coordinator Delta, Pennsylvania 17314 Pennsylvania State Clearinghouse Gqvernor'c Office of State Planning Albert R. Steel, Chairman and Development Board of Supervisors P. O. Box 1323 Peach Bottom Township Harrisburg, Pennsylvania 17120 R. D. #1 Delta, Pennsylvania 17314 Curt Cowgill U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Peach Bottom Atomic Power Station P. O. Box 399 Delta, Pennsylvania 17314 l

REQUEST FOR ADDITIONAL INFORMATION PEACli BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-277, 50-278

SUBJECT:

GRID VOLTAGE DEGRADATION

REFERENCES:

(1) NRC letter to all power reactor licensees, dated June 2, 1977.

Reference (1), Enclosure 1, page 2,- Position 1.c,(1) requests that the ... -

" time delay, including margin, shall not exceed the maximum time delay that -

is assumed in the FSAR accident analyses...." The degraded voltage logic l

l scheme for Peach Bottom Units 2 and 3 transfers' the Class 1E buses to a second off-site source should the first off-site source be degradea. The licensee 7

should show that for all possible voltage levels and logic schemes, the time delay would not exceed or add to the time assumed in the FSAR accident analyses due to insufficient voltage for Class IE equipment to start or operate.

l Since it appears, the proposed 2nd level undervoltage protection logic does l not meet this requirement, enclosed is a recently revised Power Systems Branch Technical Position (PSB 1) which outlines an alternate approach acceptable to the NRC.

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April 17,1981 .

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NOTE TO: PSB Members FROM: F. Rosa, Acting Chief, PSB

SUBJECT:

BRANCH TECHNICAL POSITION PSB 1 " ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES"

REFERENCE:

Memorandum to PSB Members from R. Fitzpatrick, dated

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March 11, 1981 '

/ 01osed is the finalized branch technical position (BTP) on the above subject.

ank you for your input in response to the above reference in enabling us to finalize the position in a timely fashion.

This BTP is effective immediately. It is a preferred method over the old PSB Review Reminder #3 but it in no way jotracts from the acceptability of designs in accordance with Review Remincer #3.

, The guidance of part 4 concerning an acceptable verification testing program should be applied across-the-board to all plants [0Rs, OLs & cps] that have not already either provided or proposed an accepted verification testing program.

You should bring the revised criteria of part 1 to the attention of those licensees / applicants that have designs now under review simaly for their information and inform them that they may opt for the revised design criteria

they so choose. However, this should not become a mechanism to astantially delay implementation of a final design.

This BTP will be part of our Chapter 8 submittal of revised SRPs scheduled for completion by May 1,1981.

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Faust Rosa Acting Chief i Power Systems Branch, DSI ,

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cc: R. Mattson P. Check

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Contact:

R. Fitzpatrick x28350 -

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BRANCH' TECHNICAL POSITION PSB 1 ADEQUACY OF STATION ELECTRIC DISTRIBUTION SYSTEM VOLTAGES A. BACKGROUND Events at the Millstone station have shown that adverse effects on the Class'lE loads can be caused by sustained low grid voltage conditions

, m when the Class IE buses are connected to offsite power. These low voltage I

, conditions will not be detectet ._ loss of- voltage relays (loss of off-site power) whose low voltage pickup setting is generally in the range of

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.7 per unit voltage or less.

The above events also demonstrated that improper voltage protection logic can itself cause adverse effects o 'the Class lE systems and equipment such as spurious load shedding of Class lE loads from the standby diesel generators and spurious separation of Class 1E systems from offsite power -

due to normal motor starting transients.

A ncre recent event at Arkansas Nucle'ar One (ANO) station and the subsequent analysis performed disclosed the possibility of degraded voltage conditions existing on the Class lE buses even with normal grid voltages, due to deficiencies in equipment between the grid and the Class 1E buses or by the starting transients experienced during certain accident events not originally considered in the sizing of these circuits.

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8. BRA';CH TECH.'!! cat. POSITION '

l. Irr addition to the undervoltag'e scheme provided to detect loss of o'ffsite power at the Class 1E buses, a second level of undervoltage protection with time delay should also be provided to protect the Class lE equipment'; this second level of undervoltage protection shall satisfy the following criteria:

a) The selection of undervoltage and time delay setpoint3 shall be determined from an analysis of the voltage requirements of the Class lE loads at all onsite system distribution levels; "

b) Two separate time delays shall be selected for the second level of 1

undervoltage protection based on the following con,ditions:

1) The first time delay should be of a duration that establishes i the existance of a sustained degraded voltage condition (i.e.,

something longer than a motor starting transient). Following this delay, an alarm in the control room should alert the operator to the degraded condition. The subsequent occurrence of a safety injection actuation signal (SIAS) should immediately separate the Class lE distribution system from the offsite power 1 system.

2) The second time delay should be of a limited duration such that the permanently connected Class 1E loads will not be damaged.

Following this delay, if the operator has failed to restore /

adequate voltages, the Class lE distribution system should be O

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automatically separated from the offsite power system. Bases and justification must be provided in support of the actual delay chosen.

c) The voltage sensors shall be designed to satisfy the following

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applicable requirements derived from IEEE Std. 279-1971, .,

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" Criteria for Protection Systems for Nuclear Power Generating Statiens": -

, 1) Class 1E equipment shall be utilized and shall be physically located at and electrically connected to the Class 1E switchgear.

2) An independent schems shall be provided for each division of the Class 1E power system. "- .

3) The undervoltage protection shall include coincidence logic on a per bus basis to preclude spurious trips of the offsite power <

source;

4) The voltage sensors shall autaratically initiate the disconnection of offsite power sources whenever the voltace set point and time delay limits, (cited in item 1.b.2 above) have been exceeded; 4

5) Capability for test and calibration during power operation shall be provided. "

. 6) Annunciation must be provided in the centrol room for any hypasses

. . . _. incorporated in the design. -

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I d). The Technical Specifications shall include limiting conditions for l

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l operations, surveillance requirements, trip setpoints with minimum and maximum limits, and allowable values for the second-level voltage protection sensors and associated time delay devices.

2. The Class 1[ bus load shedding scheme should automatically prevent .

shedding during sequencing of the emergency loads to the bus. The load shedding feature should, however, be reinstated upon completion of the load sequencing action. The technical specifications must include a test requirement to demonstrate the operability of the automatic bypass and reinstatement features at least once per 18 months during shutdo vn. -

In the event an adequate basis can be provided for retaining the load shed feature during the above transient conditions, the setpoint value in the Technical Specifications for the first level of undervoltage f

protection (loss of offsite power) must specify a value having maximum and minimum limits. The basis for the setpoints and limits selected must be documented.

3. The voltage levels at the safety-related buses stuuld be optimized for

. the maximum and minimum load conditions that are expected throughout l the anticipated range of vol' cage variations of the offsite power sources by appropriate adjustment of the volta 2e tap settings of the intervening . _ _

trkns formers. The tap settings selected should be based on an analysis e i l

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- 5-of the voltage at the terminals of the Class 1E loads. The analyses performed to determine minimum operating voltages should typically consider maximum unit steady state and transient loads for events such as a unit trip, loss of coolant accident, startup or shutdown; with the offsite power supply (grid) at minimum anticipated voltage and only the offsite source being considered available. Maximum volteges should be analyzed with the offsite power supply { grid) at zaximum expected voltage _

concurrent with minimum unit loads (e.g. cold shutdown, refueling). A separate set"of the above analyses should be performed for each available connection to the offsite power supply.

4. The analytical techniques and assumptions used in the' voltage analyses cited in item 3.above must be verified by actual measurement. ' The ,

verification and test should be ' performed prior to initial full power -

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reactor operation on all sources of offsite power by:

a) loading the station distribution buses, including all Class 1E buses down to the 120/208 v level, to at least 30%;

b) recording the existing grid and Class 1E bus voltages and bus loading  ;

down to the 120/208 volt level at steady state conditions and during the starting of both a large Class 1E and non-Class 1E motor (not concurrently); -

Note: To minimize the number of instrumented locations.

(recorders) during the motor starting transient tests, the bus voltages and loading need only be

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recorded on that string of buses which previously -

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showed the lowest analyzed voltages from item 3 above.

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c) using the analytical techniques and assumptions of the previous voltage analyses cited in item 3 above, and the iceasured existing grid voltage and bus loading conditions recorded during conduct of the test, calculate a new set of voltages for all the Class lE buses down to the 120/2.08 volt levelg d) compare the analytically derived voltage values against the

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test results. l With good correlation between the analytical results and the test results, the test verification requirement will be met. That is, the validity of the mathematical model used in perfomance of the analyses of item 3 will have been established; therefore, the validity of the results of the analyses is also established. In general th'e test results should not be more than 3% lower than the analytical results; however, the difference between the two when subtracted from the voltage levels detemined in the original analyses should never be less than the Class 1E equipment rated voltages.

I C. REFERENCES

1. General Design Criterion 17

2. IEEE Std. 279, " Criteria for Protaction Systems for Nuclear Power Stations" 3.

Millstone Unit No. 2. Safety Evaluation Supporting Annendment No.16 to license No. DPR-65 4.

NRC Sumary of Meeting for Arkansas Nuclear One Incident of September 16...

1978, dated February 9,1979.

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