ML17222A263
| ML17222A263 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 05/18/1988 |
| From: | Tourigny E Office of Nuclear Reactor Regulation |
| To: | Conway W FLORIDA POWER & LIGHT CO. |
| References | |
| TAC-59144, TAC-59145, NUDOCS 8806030081 | |
| Download: ML17222A263 (13) | |
Text
May 18, 1988 Docket:.Nos.
50-335 and 50-389 Mr. kl. F.
Conway Senior Vice President - Nuclear Florida Power and Light Company P.O.
Box 14000 Juno Beach, Florida 33408
Dear Mr. Conway:
DISTRIBUTION
. NRC-8 Local PDRs PD22 Reading S.
Varga G. Lainas D. Miller E. Tourigny OGC-HF E. Jordon J. Partlow ACRS (10)
Gray File R. Kendall
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - ST.
LUCIE UNIT NOS. I AND 2 - 10 CFR 50.62 - ATMS RULE (TAC NOS.
59144 AND 59145)
In conducting our review of your July 15, 1987 submittal relating to the above subject at the St. Lucie Plant, Unit Nos.
1 and 2, we have determined that we wi 11 need additional information identified in the enclosure to continue our review.
In order for us to maintain our review schedule, your response is requested within 45 days of the date of this letter.
If you cannot provide a full response within the requested time, please provide your full response schedule within 30 days of the date of this letter.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than 10 respondents; therefore, OMB clearance is not required u'nder P.L.96-511.
Please contact me at (301) 492-1474 if'ou have any questions concerning this letter.
Sincerely,
Enclosure:
As stated cc w/enclosure:
See next page E.
G. Tourigny, Project Manager Project Directorate II-2 Division of Reactor Projects-I/II Office of Nuclear Reactor Regulation
- See previous concurrence
- LA:PD II'-2 DMi 1 le r 5/16 /88
- pDI 2
u gny: bg HBerkow 5//g/88 5/fg/88 8806030081 880518 PDR ADOCl( 05000335 P
Docket.Nos.
50-335 and 50-389 Mr.
W. F.
Conway Yice President
- Nuclear Florida Power and Light Company P.O.
Box 14000 Juno Beach, Florida 33408 I
Dear Mr. Conway:
SUBJECT:
RE(VEST FOR ADDITIONAL INFORMATION UNIT NOS.
1 AND 2 - 10 CFR 50.12-(TAC NOS.
59144 AND 59145)
DISTRIBUTION ACRS tlo)
'RC
& Local PDRs 'ray File PD22 Reading R. Kendall S.
Varga G. Lainas D. Miller E. Tourigny OGC-WF E. Jordon J. Partlow
- ST.
LUGIE ATWS RULE In conducting our review of your July 15, 1987 submittal relating to the above subject at the St. Lucie Plant, Unit Nos.
1 and 2, we have determined that we will need additional information identified in the enclosure to continue our review.
In order for us to maintain our review schedule, your response is requested within 45 days of the date of this letter: If you cannot provide a full response within the requested time, please provide your full response schedule within 30 days of the date of this letter.
The reporting and/or recordkeeping requirements contained in this letter affect fewer than 10 respondents; therefore, OMB clearance is not required under P.L.96-511.
Please contact me at (301) 492-1474 if you have any questions concerning this letter.
S incere ly,
Enclosure:
As stated cc w/enclosure:
See next page E.
G. Tourigny, Project Manager Project Directorate II-2 Division of Reactor Projects-I/II Office of Nuclear Reactor Regulation 1-2 er 5/I'Ig 88 PM: PDI I-2 ETourigny:bg 5/
/88 D:PDII-2 HBerkow 5/
/88
Mr.
W. F.
Conway Florida Power
& Light Company St. Lucie Plant CC:
" Mr. Jack Shreve Office of the Public Counsel Room 4, Holland Building Ta 1 1ahassee, Florida 32304 Resident Inspector c/o U.S.
NRC 7585 S.
Hwy A1A Jensen Beach, Florida 34957 State Planning
& Development Clearinghouse Office of Planning
& Budget Executive Office of the Governor The Capitol Building Tallahassee, Florida 32301 Harold F. Reis, Esq.
Newman
& Holtzinger 1615 L Street, N.W.
Washington, DC 20036 John T. Butler, Esq.
- Steel, Hector and Davis 4000 Southeast Financial Center Miami, Florida 33131-2398 Administrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Mr. Weldon B. Lewis, County Administrator St. Lucie County 2300 Virginia Avenue, Room 104 Fort Pierce, Florida 33450 Mr. Charles B. Brinkman, Manager Washington - Nuclea~ Operations Combustion Engineering, Inc.
7910 Woodmont Avenue
- Bethesda, Maryland 20814 Jacob Daniel Nash Office of Radiation Control Department of Health and
.Rehabilitative Services 1317 Winewood Blvd.
Tallahassee, Florida 32399-0700 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street N.W., Suite 2900 Atlanta, Georgia 30323
I~
ENCLOSURE ST.
LUCIE UNITS 1 AND 2 10 CFR 50.62 ATWS RULE)
RE VEST FOR INFORMATION TACS 59144 AND 59145 INTRODUCTION AND DISCUSSION On July 26, 1984 the Code of Federal Regulations (CFR) was amended to include the ATWS rule (Section 10 CFR 50.62, "Requirements for Reduction of Risk from Anticipated Transients Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Power Plants" ).
An ATWS is an expected operational transient (such as loss of feedwater, loss of condenser vacuum, or loss of'ffsite power) which is accompanied by a failure of the reactor trip system (RTS) to shutdown the reactor.
The ATWS rule requires specific improvements in the design and operation of commercial nuclear power facilities to reduce the likelihood of failure to shutdown the reactor following anticipated transients, and to mitigate the consequences of an ATWS event.
Paragraph (c)(6) of the rule requires that information sufficient to demonstrate compliance with the requirements of the rule be submitted to the Director, Office of Nuclear Reactor Regulation.
The ATWS rule requirements for Combustion Engineering (CE) plants such as St. Lucie Units 152 are to provide a diverse scram system (DSS), diverse (from the existing reactor trip system) auxiliary feedwater system (AFWS) actuation, and diverse (from the existing reactor trip system) initiation of turbine trip.
Information in addition to that provided in Florida Power and Light (FPL) letter L-87-301 is needed to allow the staff to determine whether St. Lucie Units 152 comply with the hardware diversity, electrical independence, reliability and testabi lity at power requirements of the ATWS rule.
The information identified below is required by the staff to complete the review of implementation of the ATWS rule requirements at St. Lucie Units 152.
1.
The St. Lucie Units 182 diverse scram system (DSS) design uses the existing reactor protection system (RPS) pressurizer pressure iransmitter instrument loops.
The bistables and logic circuitry are part of the existing engineered safety features actuation system (ESFAS).
It is the staff's understanding that the DSS circuitry from the sensors, through the logic, up to and including the isolation devices (that provide the DSS output signals to the CEA drive MG set output breakers and control room annunciators) is safety related Class 1E.
a)
Is the staff's understanding correct.
If not, please explain.
b)
Please provide electrical schematic/elementary diagrams for the DSS that clearly show all instrument channels (including bistables),
logic, actuation circuits, test circuits, interlocks,
- bypasses, alarms and indications.
Also, provide electrical one-line diagrams showing the CEA drive NG sets and DSS actuated output breakers, and power distribution to the RPS and ESFAS/DSS, including vital buses, inverters, batteries and chargers.
2.
Electrical independence is required between the existing RPS and the ATWS prevention/mitigation systems required by the rule.
The electrical schematic/elementary diagrams provided in response to Item 1 above should clearly identify all power sources used.
Where RPS power supplies are used, it must be demonstrated that
- 1) faults within the DSS, diverse AFW actuation circuits or diverse turbine trip (DTT) circuits cannot degrade the reliability/integrity of the existing RPS below an acceptable
- level, and 2) that a
common mode failure affecting the RPS power distribution system (including degraded voltage and/or frequency conditions, e.g.,
overvoltage and undervoltage; the effects of degraded voltage conditions over time must be considered if such conditions can go undetected) cannot compromi e both the RPS and ATWS prevention/mitigation functions.
If the St. Lucie Units 182 design shares common power supplies for the RPS and
equipment installed per ATWS rule requirements (i.e.,
DSS excluding
- sensors, and diverse AFWS actuation and DTT excluding sensors and actuation devices),
provide the information for items 1 and 2 above.
3.
Electrical independence of non-safety related ATWS circuits from safety related circuits is required in accordance with the guidance provided in IEEE Standard
- 384, "IEEE Standard Criteria for Independence of Class lE Equipment and Circuits," as supplemented by Regulatory Guide 1.75, Revision 2, "Physical Independence of Electrical Systems."
a)
Information must be provided to demonstrate the adequacy of all isolation devices used to protect the integrity of safety related circuits from non-safety related ATWS circuits'he required information is identified in Attachment 1. If the isolation devices are identical to isolation devices used in other applications (e.g.,
to isolate the safety parameter display system from safety related circuits), and the requested information has been previously submitted for staff review, and the isolation devices have been approved for their applications, the related correspondence should be referenced, and no additional information need be provided.
bj Attachment 6 of FPL's July 15, 1987 letter is a block diagram of the St. Lucie Units 1&2 DSS.
The DSS is shown to provide isolated output signals to the CEA drive YiG set output breakers,
- however, there is no isolation shown between the DSS and the control room annunciator.
Is the diagram correct in this regards 4.
Using circuit breakers from different manufacturers is generally not considered sufficient to provide the required diversity for interruption of control rod power.
In general, circuit breakers from different manufacturers are considered susceptible to common mode failures (CtlF) because of common design features such as mechanical linkages (consisting
of springs, pivots, latches,
- pins, cams, etc.) that are subject to binding/malfunction from a number of causes (e.g., dirt, corrosion, improper lubrication, etc.)
as has been demonstrated through operating experience.
Please provide information that demonstrates physical hardware diversity of the CEA drive MG set output breakers from the reactor trip breakers actuated by the RPS.
5.
During the life of a commercial light-water -cooled nuclear power plant many components reach their end of life and must be replaced, including components installed in the
Provide a
description of the measures/programs implemented at St. Lucie to assure that the equipment diversity provided in accordance with the ATWS rule will be maintained during component repair, replacement, modifications and/or design changes etc. throughout the life of the plant.
6.
Discuss how good human factors engineering practices are incorporated into the design of ATWS prevention/mitigation system components located in the control room.
Specifically address coordination of displays used to provide the status of ATWS systems/equipment to the operator with existing displays.
'7.
FPL's July 15, 1987 letter states that inherent to the DSS design is a
turbine trip independent and diverse from the RPS, which is initiated by undervoltage conditions sensed in the CEA drive control system.
Explain in detail how this arrangement satisfies the ATWS rule requirements for a diverse turbine trip.
Please provide electrical schematic/elementary diagrams of the DTT circuits.
8.
The equipment required by 10 CFR 50.62 to reduce the risk associated with an ATWS event must be designed to perform its functions in a reliable manner.
The DSS, diverse AFWS actuation circuitry, and diverse turbine trip circuits must be designed to allow periodic testing to verify operability while at power.
All bypass conditions should be automatically and continuously indicated in the main control room.
a)
Describe the scope and intent of the various surveillance tests (e.g.
sensor/channel
- checks, instrument channel functional tests, logic channel and actuation device tests, channel/system calibrations, overall system functional tests, etc.) that FPL intends to use to periodically verify operability of the DSS and DTT equipment/
circuitry installed at St. Lucie Units 182.
Indicate the frequency for which each surveillance test is conducted.
Also discuss the controls/programs (e.g., technical specifications) to be used to ensure that the equipment/circuitry installed in accordance with the ATWS rule will be properly tested and maintained in an operable condition.
The controls/programs would provide reasonable assurance that the ATWS equipment/circuitry will perform its design functions when required, and therefore, satisfy the reliability requirements of the ATWS rule.
b)
Please indicate whether the test procedures involve undesirable practices such as installing jumpers, lifting leads, pulling fuses, tripping breakers, blocking relays, or other circuit alterations.
c)
Describe the specific indication provided in the control room of the bypass condition when equipment/circuits required by the ATWS rule are bypassed/rendered inoperable during testing (including use of the bistable bypass switches).
ATTACHMENT 1
AMSAC ISOLATION DEVICE-RE(VEST FOR ADDITIONAL INFORMATION Each light-water-cooled nuclear reactor shall be provided with a system for the mitigation of the effects from anticipated transients without scram (ATWS).
The Commission-approved requirements for the ATWS are defined in the Code of Federal Regulations (CFR) Section 10 paragraph 50.62.
The staff has reviewed the functional AMSAC designs for compliance with the ATWS Rule.
As a result, the staff has determined that the use of isolators within AMSAC will be reviewed on a plant-specific basis.
The following additional information is required to continue and complete the plant-specific isolator review:
Isolation Devices Please provide the following:
a.
For the type of device used to accomplish electrical isolation, describe the specific testing performed to demonstrate that the device is acceptable for its applications(s).
This description should include elementary
- diagrams, when necessary, to indicate the test configuration and should describe how the maximum credible faults were applied to the devices.
b.
Data to verify that the maximum credible faults applied during the test were the maximum voltage/current to which the device could be
- exposed, and define how the maximum voltage/current was determined.
P g
c.
Data to verify that the maximum credible fault was applied to the non-Class 1E side of the device in the transverse mode (between signal and return) and that other faults were considered (i.e.,
open and short circuits.
d.
Define the pass/fail acceptance criteria for each type of device.
e.
A commitment that the isolation devices comply with the environmental qualifications (10 CFR 50.49) and seismic qualifications that were the basis for plant licensing.
f.
A description of the measures taken to protect the safety systems from electrical interference (i.e., Electrostatic
g.
Information to verify that the Class 1E isolator is powered from a Class lE source.
fi J