ML18052A761
| ML18052A761 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/03/1986 |
| From: | Wambach T Office of Nuclear Reactor Regulation |
| To: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| Shared Package | |
| ML18052A762 | List: |
| References | |
| TAC-59123, NUDOCS 8611110492 | |
| Download: ML18052A761 (23) | |
Text
(
Docket No. 50-255 Mr. Kenneth W. Berry.
Director, Nu~lear Licen~in~
,Consumers Power Company * **
1945 West Parn~ll Road Jackson, Michi~an 49201
Dear Mr. Berry:
NOV 0 3 1986 Di s_ttib.uti_on _
\\Docket File
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FMiraglia OGC""'.Bethesda EJordan
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-JP art low Gray Fi)_e. 3-:' 6a
- Y:.*.. ;.
NThompson TWambach
- PKreuzter **
ACRS(lO)
- RKendal l (PElSCSB)
SUBJECT:
.. REVIEW (10 tFR 50. 62) REQUES_T. FOR '~DO(rI~NAL. INfQRMATION:
~
4-I You provided.information.. concerning implemen.tat{ori. *~f the ATW~*'.rul*:e'. ~~qlHr.-e ments at Pali sades.by.1 etters dated October* -22,: 1985 'arid. April 23.~ 1~86:
Howeve.r, _the information provided.in these letter~ is*:not s'lifficient'to allow us to determine that the proposed design is in compliarice_with t~e regulation
- {10 C~R 50.62).
The enclosure to. this letter ~dentifi~~the ~ddit~onal :.
i~fo~matio~ ~equired.. Please respond o~~fa *s9h~dule c~nsistent-~itti t~e impl~mentation schedule given in the r,u*le-.allowing 60 days for ~_RC re-vie...,,_>*;
I
- ~
This request for i nformatfon *was approved.by,OMB under cl eara_nce 'number
- 315,0-(lOll whi cti. exp1res Dec.ember 30, 1986.
Comments or :,b_urden _and duplication may be directed -to the Office of Management and. Budget,, Re'pqrts Management, Room 3208, New Executive Office Building, Washington) o:~c~
20503.
Enc.l osure:
_ As stated.
cc:
See next page PBD-~,
P~er 117_) /8_~.
. h" f/JA/
PaD:0:JV1r~
TWambach:jch 11/j/86
- Sfocerely, fs/
Th~mas Y.
Wamb~ch, Proj~tt Man~ge~
PWR Project Directorate #8 Di~ision of.PWR Litensing-B_ *
, PBD-8:
AThadani ny /86
Mr. Kenneth W. Berry Consumers Power Company cc:
M. I. Mi 11 er, Es qui re Isham, Lincoln & Beale Slst Floor Three First National Plaza Chicago, Illinois 60602 Mr. Thomas A. McNish, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Jerry Sarno Township Supervisor Covert Township 36197 M-140 Highway Covert, Michigan 49043 Office of the Governor Room 1 - Capitol Building Lansing, Michigan 48913 Palisades Plant ATTN:
Mr. Joseph F. Firlit Plant General Manager 27780 Bl~e Star Memorial Hwy.
Covert, Michigan 49043 Resident Inspector c/o U.S. NRC Palisades Plant.
27782 Blue Star Memorial Hwy.
Covert, Michigan 49043 Palisades Plant Nuclear Facilities and*
Environmental Monitoring Section Office Division of Radiological Health P.O. Box 30035 Lansing, Michigan 48909
Introduction and Discussion CONSUMERS POWER COMPANY PALISADES 10 CFR 50.62 (ATWS RULE)
.REQUEST FOR INFORMATION TAC 59123 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 offsite power) which is
. accompanied by a failure of the reactor trip system CRTS) to shut down 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 shut down 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 Palisades 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.
The information provided in Consumers Power letters dated October 22, 1985 (Schedule for Compliance with ATWS Rule) and April 23, 1986 (Preliminary System Description for Proposed Diverse ATWS Trip) is not sufficient to allow the staff to determine whether the Palisades plant complies with the hardware diversity, electrical independence, reliability and testability at power requirements of the ATWS rule.
The information identified below is required by the staff to complete the review of implementation of the requirements of the ATWS rule at Palisades.
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.
A method acceptable to the staff for demonstrating that the equipment satisfies the reliability requirements of the ATWS rule is to provide technical specifi-.
cations,.including operability and surveillance requirements, which govern its
- availability and operation, and thereby ensure that the necessary reliability of the equipment is maintained. provides model technical specifica-tions which can be used as an aid to develop plant specific technical specifi-cations.
The model technical specifications are intended to provide guidance in the scope and types of specifications in the areas of equipment and adminis-trative requirements (including actions to be taken when operability require-ments* cannot be-met~ and limiting conditions for operation) considered necessa~
to ensure adequate reliability of ATWS equipment.
The parameters and number of channels listed in the model technical specifications are examples based on preliminary informati-on regarding ATWS equipment designs:~ Prop-osed technical specifications should follow the* same format, but reflect the actual plant design.
The ATWS prevention and mitigation systems should be designed to provide the operator with accurate, complete and timely information pertinent to their own status.
Displays and controls (including those used for operating, test and maintenance bypasses) should be integrated into the main control room through system functional analysis and should conform to good human engineering practices in design and layout.
It is important that the displays and controls added to the control room as a result of the ATWS r.ule not increase the potential for operator error.
A human factor analysis should be performed taking into consideration:
(a) the use of this information and equipment by an op~rator during both normal and abnormal plant conditions, (b) integration into emergency procedures, (c) integration into operator training, and (d) the presence of other alarms during an emergency and need for prioritization of alarms.
Required Information
- 1.
Diversity from the Existing Reactor Trip System (RTS)
The basic premise behind the ATWS rule as documented in SECY-83-293, "Amendments to 10 CFR 50 Related to Anticipated Transients Without Scram (ATWS) Events" is to require systems/equipment that are diverse (and independent) to those portions of the existing reactor trip system (RTS) where only minimal diversity is currently provided, and which are capable of preventing or mitigating the consequences of an ATWS event.
The failure mechanism of concern is a common mode failure of identical components within the RTS (e.g., logic channels, actuation devices and instrument channels excluding sensors).
The diversity required by the ATWS rule is intended to ensure that common mode failures (CMFS) which disable the electrical portion of the existing reactor trip system will not affect the capability of systems/equipment installed in accordance with ATWS rule requirements (to prevent or mitigate the consequences of ATWS events) to perform their design functions.
Therefore, the divers.ity required by the ATWS rule is hardware/component diversity (to prevent CMFs from disablin_g both the existjng RTS and ATWS_prevention/mitigation systems).
Diversity can be achieved by incorporating as many of the following methods as practicable:.
0 0
0 0 use of components from different manufacturers, use of electromechanical devices versus electronic devices, use of AC versus DC power sources, and use of equipment employing different principles of operation.
Components that use different principles of operation and/or different manufacturing processes are considered to provide the best diversity.
Identical components with energize-to-actuate trip status versus deenergize-to-actuate trip status are not considered sufficient to provide an acceptable level of diversity.
Identical components used in both the existing RTS and the diverse scram system or mitigating systems are subject to potential common mode failures, and therefore, are not acceptable.
In those cases where complete hardware/equipment diversity is not provided, and it can be demonstrated that other factors exist that similarly reduce the potential for CMFs to disable both the existing RTS and ATWS prevention/mitigation systems, these considerations and methods for achieving diversity will be review~d.
Equipment diversity to minimize the potential for common mode failures. is required from sensor output to and including the components used to interrupt control rod power (circuit breakers from different manufacturers alone is not sufficient to provide the required diversity for interruption of control rod power) for diverse scram systems, and from sensor output to, but not including, the final actuation device for mitigating systems (e.g., diverse turbine trip and diverse auxiliary feedwater actuation).
Therefore, f6r all diverse scram system and mitigating system instrument channel components (excluding sensors and signal conditioning equipment upstream of the bistables) and logic channel components, and all diverse scram system actuation devices, provide information sufficient to demonstrate compliance with the ATWS rule diversity requirements.
This information should include electrical schematic/elementary diagrams for the diverse scram system, diverse auxiliary feedwater system actuation circuitry and the diverse turbine trip circuits that clearly show all instrument channels, logic, actuation circuits, test circuits, interlocks, bypasses, alarms, and indication.
Also provide information concerning all components involved including manufacturer, model number, design principle, and*power supply, and a diversity comparison of these components with the components used in the existing RTS.
The similarities and differences in the physical and operational characteristics of these components must be analyzed to determine the potential for common mode failure mechanisms that could disable both the RTS and ATWS preventive/mitigative functions.
The evaluation of the adequacy of the diversity provided must be performed at a detailed level to include hardware design considerations and diversity aspects that might not be apparent from a cursory/audit review.
For example, two electromechanical relays from the same manufacturer and having the same voltage/current ratings and energize-to-actuate/deenergize-to-actuate trip status, and therefore, which appear to be unacceptable for satisfying the diversity requirements of the ATWS rule, may actually be acceptable if different materials and different manufacturing processes are used.
-Conversely, two printed-circuit cards from different manufacturers, ahd therefore, which appear to be acceptable for satisfying diversity requirements of the ATWS rule, may not be acceptable if they both use identical components.
- 2.
Electrical Independence from the Existing Reactor Trip System Electrical independence of the diverse scram system (DSS), diverse AFWS actuation circuitry, and diverse turbine trip circuits* from the existing RTS is required from sensor output to, but not including, the final actuation device.
The staff considers a station battery not used to provide power to RTS components to be a preferred source for providing power to those systems/equipment installed per ATWS rule requirements.
The electrical schematic/elementary diagrams provided in response to item 1 above should clearly identify all power sources used.
Electrical indepen-dence of non-safety related ATWS circuits from safety related circuits is required in accordance with the guidance provided in IEEE Standard 384, 11 IEEE Standard Criteria for Independence of Class lE Equipment and Circuits, 11 as supplemented by Regulatory Guide 1.75, Revision 2, 11 Physical Independence of Electric Systems.
11 If RTS power supplies are used, it must be demon-strated that faults within the DSS, diverse AFWS actuation circuits or diverse turbine trip circuits cannot degrade the reliability/integrity of the existing RTS below an acceptable level, and that a common mode failure affecting the RTS power distribution system (including degraded voltage conditions such as overvoltage and undervoltage; the.effects of degraded voltage conditions over time must be considered if.such conditions can go undetected) cannot compromise both the RTS and ATWS prevention/mitigation functions.
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.
The required information is identified*
in Attachment 2.
If the isolation devices are identical to isolation **
devices used in other applications (e.g., safety parameter display system),
and the requested information has been previously submitted for staff review and the isolation devices approved for their applications, the*
- related correspondence should be referenced, and no additional information need be provided.
- 3.
Reliability and Testability at Power 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 opera-bility while at power.
The functions performed by the ATWS equipment/
circuits may be bypassed if necessary to prevent inadvertent actuations during testing.at power.
A 11 bypass conditions should be automatically and continously indicated in the main control room.
\\!. a.
Describe how periodic testing at power of the equipment/circuitry
-required by the ATWS rule wi 11
- be at comp 1 i shed.
- b.
It appears that the 2-out-of-4 energize-to-actuate logic used for the DSS and diverse turbine trip is sufficient to prevent inadver-tent actuations during testing.
Describe the design features of the diverse AFWS actuation circuitry that prevent inadvertent actu-ation *of the AFWS during testing at power.
- c.
If the functions of equipment/circuits required by the ATWS rule are bypassed/rendered inoperable during testing, describe the means used to effect the bypass and the indication provided in the control room of the bypass condition.
- d.
Provide information sufficient to demonstrate that the systems and_equipment required by the ATWS rule will be adequately main-tained and capable of performing their design functions in a reliable manner when required.
If technical specifications are proposed, they should follow the format of the model technical specifications provided in Attachment 1.
- e.
Describe all other bypass features (e.g., maintenance bypasses, operating bypasses, etc.) incorporated into the design of systems/equipment required by the ATWS rule, including the means used to effect the bypass (indicate if the bypass involves undesirable practices such as installing jumpers, lifting leads, pulling fuses, tripping breakers, or blocking relays) and the indication provided in the control room of the bypass condition.
- f.
Discuss how good human factors engineering practices are incor-porated into the design of ATWS prevention/mitigation system components located in the control room for items a through e above as applicable.
Specifically address coordination of displays used to provide the status of ATWS systems/equipment to the operator with existing displays. - Model Technical Specifications for ATWS Systems and Equipment - Information Required to Demonstrate the Adequacy of Isolation Devices Used to Achieve Electrical Independence of 'Non-Safety Related ATWS Circuits from Safety Related Circuits
MODEL TECHNICAL SPECIFICATIONS FOR ATWS SYSTEMS AND EQUIPMENT
INSTRUMENTATION ATWS MITIGATING SYSTEM ACTUATION CIRCUITRY
_{AMSAC) MODEL TECHNICAL-SPECIFICATIONS
{DIVERSE AUXILIARY FEEDWATER SYSTEM ACTUATION AND DIVERSE TURBINE TRIP) 3/4.3.X ATWS MITIGATING SYSTEMS ACTUATION CIRCUITRY LIMITING CONDITION FOR OPERATION 3.3.X The ATWS Mitigating Systems Actuation Circuitry (AMSAC) instrumentation channels shown in Table 3.3.X-1 shall be OPERABLE with their trip setpoints set consistent with the values sh6wn in the Trip Setpoint column of Table 3.3.X-2.
The AMSAC manual and automatic actuation logic and actuation devices shall be OPERABLE.
APPLICABILITY:
Mode 1 ACTION:
- a. With an AMSAC instrumentation channel trip setpoint less conservative than the value shown in the Allowable Values column of Table 3.3.X-~~
declare the channel inoperable until the channel is restored to OPERABLE status with the trip setpoint adjusted consistent with the Trip Setpoint value.
- b.
With the number of OPERABLE instrument channels (one or more) less than the Minimum Number_ of Opera~l~ Chann~ls requirement of Table 3.3.X-1, restore the inoperable channels to OPERABLE status within ~ hours or decrease reactor power to below the bypass trip setpoint within the next~ hours.
- c. With the manual initiation circuits or the automatic actuation logic or actuation device(s) inoperable, restore the operable equipment to OPERABLE status within ~ hours or decrease reactor power to below the bypass trip setpoint within the next hours.
SURVEILLANCE REQUIREMENTS 4.3.X.1 Each AMSAC instrumentation channel and the manual and automatic actuation logic and actuation devices (e.g., master and slave relays) shall be demonstrated OPERABLE by the performance of the ATWS mitigating system actuation circuitry instrumentation surveillance requirements specified in Table 4.3.X-1.
4.3.X.2 An integrated test of all system co~ponents (i.e., all relays and contacts, all trip units, all solid state logic elements, etc.) from sensors through and including actuated devices shall be performed to verify OPERABILITY of the system function(s) at least once per fuel cycle during shutdown.
This test shall include simulated automatic operation of all
- channels.
TABLE 3.3.X-1 ATWS MITIGATING SYSTEMS ACTUATION CIRCUITRY INSTRUMENTATION TOTAL NUMBER NUMBER OF CHANNELS MINIMUM NUMBER OF OPERABLE FUNCTIONAL UNIT OF CHANNELS REQUIRED TO TRIP CHANNELS PER TRIP FUNCTION (a)
- 1. Turbine Trip and Auxiliary Feedwater System Initiation
- a. Manual 1
1
- b. Automatic Actuation logic and Actuation Devices 1
1
- c. Pressurizer Pressure-High*
3(b) 2
- d.
Steam Generator Level-Low**
4(b) 3
- e. Reactor Power Level 1
NA (AMSAC bypass)
(a) A trip channel may be placed in a bypassed (inoperable) status for up to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for required surveillance.
(b) This trip function may be bypassed when reactor power level is less than
% of
. RATED THERMAL POWER.
- The model Technical Specifications for these parameters assumed a 2-out-of-3 energize-to-actuate trip logic. Plant specific-:_technical specifications should provide for similar. instrument operability requirements for the installed AMSAC logic/circuit design.
- The model Technical Specifications for these parameters assumed a 4-loop plant using a 3-out-of-4 trip logic. Plant specific technical specifications should provide for similar instrument operability requirements for th~ actual plant configuration.*
1 1
2 3
NA
TABLE 3.3.X-2 ATWS MITIGATING SYSTEMS ACTUATION CIRCUITRY INSTRUMENTATION TRIP SETPOINTS FUNCTIONAL UN IT TRIP SETPOJNT ALLOWABLE VALUES e
- 1.
TURBINE TRIP, AUXILIARY FEEDWATER INITIATION
- a. Manual Initiation NA NA U'1
- b. Automatic Actuation logic and Actuation Devices NA NA
- c. Pressurizer Pressure--High
< (
) psig
~ ( ) psig
- d.
Steam Generator Level--Low
?: ( ) inches
~ ( ) inches
- e. Reactor Power Level (AMSAC bypass)
~ (. ) %
~ (
) %
TABLE 4.3.X-1 ATWS MITIGATING SYSTEMS ACTUATION CIRCUITRY INSTRUMENTATION SURVEILLANCE REQUIREMENTS FUNCTIONAL UNIT CHANNEL CHECK(a)
CHANNEL FUNCTIONAL TEST(b)
- 1. Turbine Trip and Auxiliary Feedwater System Initiation
- a. Manual Initiactfon NA R.
- b. Automatic.Actuation logic and Actuation Devices
- NA Q
- c. Pressurizer Pressure-High s
Q
- d.
Steam Generator level-Low s
Q
- e. '.Reactor Power Level
- s Q
(AMSAC bypass)
(a*) If the system design prohibits a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Channel Check, then the Channel Functional Test must include physical actuation of the sensor.
(b) Channel Functional. Tests should be performed* on a staggered test basis (e.g., if three instrument ch~nnels are provided, one channel should be tested each month such that all: channels are tested each quarter).
CHANNEL CALIBRATION NA NA R
R R
INSTRUMENTATION BASES 3/4.3.X ATWS MITIGATING SYSTEM ACTUATION CIRCUITRY The OPERABILITY of the ATWS Mitigating Systems Actuation Circuitry (AMSAC) ensures that sufficient means are provided to limit the consequences of anticipated transient without scram (ATWS) ev~nts. The AMSAC is designed to automatically initiate the auxiliary feedwater system (AFWS) and trip the main turbine to prevent the excessively high reactor coolant system pressures which could otherwise result from ATWS events, thus maintaining reactor coolant pressure boundary and containment integrity to ensure plant safety.
The AMSAC is diverse from the existing reactor trip system (RTS) circuitry, and therefore, significantly reduces the consequences of ATWS events caused by common mode failures in the RTS.
The AMSAC is required by the ATWS Rule 10 CFR 50.62, "Requirements for Reduction of Risk From Anticipated Transients Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Plants).
The Technical Specification OPERABILITY requirements ensure that*sufficient instrumentation remains in service to provide adequate protection from ATWS events in accordance with the ATWS Rule.
If the OPERABILITY requirements cannot be met, the plant is placed in a limiting condition for operation (LCD) where appropriate ACTIONS must be taken to restore the inoperable AMSAC instrumentation. to an OPERABLE status within a specified time, or otherwise reactor operation is restricted to safe levels/modes where the AMSAC safety function is no longer required.
The surveillance requirements specified for the AMSAC instrumentation ensures that the overall system functional capability and availability is maintained at a level commensurate with the safety functions to be performed.
The periodic surveillance tests, when performed at the specified intervals, will assure that the necessary quality of systems and components is maintained to accomplish the *desired safety functions when required.
DIVERSE SCRAM SYSTEM (DSS) MODEL TECHNICAL SPECIFICATIONS INSTRUMENTATION 3/4.3.X DIVERSE SCRAM SYSTEM INSTRUMENTATION LIMITING CONDITION FOR OPERATION 3.3.X The Diverse Scram System (DSS) instrumentation channels shown in Table 3.3.X-1 shall be OPERABLE with their trip setpoints set consistent with the values shown in the Trip Setpoint column of Table 3.3.X-2.
The DSS manual and automatic actuation logic and actuation devices shall be OPERABLE.
APPLICABILITY:
Mode 1 ACTION:
- a.
With a DSS instrumentation channel trip setpoint less conservative than the value shown in the Allowable Values column of Table 3.3.X~2, declare the channel inoperable until the channel is restored to OPERABLE status with the trip setpoint adjusted consistent with the Trip Setpoint value.
- b.
With the number of OPERABLE instrument channels (one or more) less than the minimum number of OPERABLE channels requirement of Table 3.3.X-1, restore the inoperable channels to OPERABLE status within hours or decrease reactor power to below the bypass trip setpoint within the next hours.
- c. With the manual initiation circuits or the automatic actuation logic or actuation devices(s) inoperable, restore the inoperable equipment to OPERABLE status within __ hours or decrease reactor power to below the bypass trip setpoint within the next hours.
SURVEILLANCE REQUIREMENTS 4.3.X.l Each DSS instrumentation channel and the manual and automatic actuation logic and actuation devices shall be demonstrated OPERABLE by the performance of the diverse scram system instrumentation surveillance requirements specified in Table 4.3.X-l.
4.3.X.2 An integrated test.of all.system components (i.e., all relays and contacts, all trip units, all solid state logic components, etc.) from sensors through and including actuated devices shall be performed to verify OPERABILITY of the system function(s) at least once per fuel cycle during shutdown.
This test shall include simulated automatic operation of all channels.
~-
TABLE 3.3.X-1 DIVERSE SCRAM SYSTEM INSTRUMENTATION MINIMUM TOTAL NUMBER NUMBER OF CHANNELS NUMBER OF OPERABLE CHANNELS FUNCTIONAL UNIT OF CHANNELS REQUIRED TO TRIP PER TRIP FUNCTION(a)'
- 1. Reactor Scram
- a. Manual 1
1 1
- b. Automatic Actuation Logic and Actuation Devfces 1
1 1
- c. Pressurizer Pressure-High*
3 2
2
- d. Ove.r Tempef'."ature, T-High**
4 3
3 (a) A trip channel may be placed in a bypassed (inoperable) status for up to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for required surveillance.
- The model Technical Specifications for this parameter assumed a 2-out-of-3 energize-to-actuate trip logic.
Plant specific technical specifications should provide for similar instrument operability requirements for the installed DSS logic/circuit design.
- The model Technical Specifications for this parameter assumed 3-out-of-4 trip logic. Plant specific technical specifications should provide for similar instrument operability requirements !or the actual plant configuration.
~
0
~*
TABLE 3.3.X-2 DIVERSE SCRAM SYSTEM INSTRUMENTATION SETPOINTS e
FUNCTIONAL UNIT TRIP SETPOINT ALLOWABLE V~LUE
- 1. Reactor Scram
- a. Manual Initation NA NA.
~
..JI
- b. Automatic Actuation Logic and Actuation Devices NA NA
- c. Pressurizer Pressure--High 5 (
) psig
~ ( ) psig 9*
~.
- d. Over Temperature.~T. High
~ ( ) OF
~ ( ) Of
t*
TABLE 4.3.X-1 DIVERSE SCRAM SYSTEM INSTRUMENTATION SURVEILLANCE REQUIREMENTS FUNCTIONAL UNIT CHANNEL CHECK(a)
CHANNEL FUNCTIONAL*TEST(~)
CHANNEL CALIBRATION
- 1. Reactor Scram
- a. Manual Initation NA R
NA
- b. Automatic Actuation Log~c and Actuation D~vices NA Q
NA
- c. Pressurizer Pressure-High s
Q R
- d. Overtemperature, T-High s
Q R
(a) If the system design prohibits a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> CHANNEL CHECK, then the CHANNEL FUNCTIONAL TEST must include physical actuation of the sensor.
(b). CHANNEL FUNCTIONAL, TESTS should be performed on a sta.ggered test basis (e.g., if three instrument channels are provided, one channel should be tested each month such that all channels are tested each quarter).
~
N*
INSTRUMENTATION BASES 3/4.3.X DIVERSE SCRAM SYSTEM (DSS) INSTRUMENTATION The OPERABILITY of the Diverse Scram System (DSS) ensures that sufficient means are provided to limit the consequences of anticipated transient without scram (ATWS) events.
The diverse scram syste~ is designed to shutdown the reactor independent of the existing reactor trip system (RTS), thus preve~ting the high reactor coolant system pressures associated with an ATWS event.
The diverse scram system is diverse from the existing reactor trip system (RTS) logic and actuation circuitry, and therefore significantly reduces the potential for ATWS events caused by common mode -failures in the RTS.
The DSS is required by the ATWS Rule (10 CFR 50.62, "Requirements for Reduction of Risk From Anticipated Transients Without Scram (ATWS) Events for Light-Water Cooled Nuclear Plants").
The Technical Specification OPERABILITY requirements ensure that sufficient instrumentation remains in service to provide adequate protection from ATWS events in accordance with the ATWS Rule.
If the OPERABILITY requirements cannot be met, the plant is placed in a limiting condition for operation (LCO) where appfopriate ACTIONS must be taken to restore the inoperable DSS instrumentation to an OPERABLE status within a specified time, or otherwise reactor operation is restricted to safe levels/modes where the DSS safety function is no longer required.
The surveillance requirements specified for the DSS instrumentation ensures that the overall system functional capability and availability is maintained at a level commensurate with the safety functions to be performed.
The periodic surveillance tests, when performed at the specified intervals, will assure that the necessary quality of systems and components is maintained to accomplish the desired safety functions when required.
INFORMATION REQUIRED TO DEMONSTRATE THE ADEQUACY OF ISOLATION DEVICES USED TO ACHIEVE ELECTRICAL INDEPENDENCE OF NON-SAFETY RELATED ATWS CIRCUITS FROM SAFETY RELATED CIRCUITS
- a.
For the type of device used to accomplish electrical isolation, describe the specific testing perfonned to demonstrate that the device is acceptable for its application(s). This description should include elementary diagrams when necessary to indicate the test configuration and 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.
- c. Data to verify that the maximum credible faul.t was applied to the output of the device in the transverse mode (between signal and return) and other faults were considered (i.e., open and short circuits).
- d.
Define the pass/fail acceptance criteria,for each type of device.
- e.
Provide a commitment that the isolation devices comply with the environment qualifications (10 CFR 50.49) and with the seismic qualfications which were the basis for plant licensing.
- f. Provide a description of the measures taken,to protect the safety systems from electrical interference (i.e., Electrostatic Coupling, EM!, Common Mode and Crosstalk) that may be generated by the ATWS circuits.
- g.
Provide information to verify that the Class lE isolator is powered from a Class lE source.
\\
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October 15, ~986 Docket No. 50-255 MEMORANDUM FOR:
lt:ro~a-~_ ~~--=--~am~~--,-~~en*for-*-'.PfoJecrM_a*~~*~~t:_~.
P\\iJR ProJect Di rectorate-#8 * --- --.
Divisi~n of PWR-Licensing-B FROM:
SUBJECT:
Dennis *M. Crutchfield, Assistant Director Division of PWR Licensing-B PALISADES 10 CFR_ 50.62 (,ATWS RULE} REVIE.W; REQUEST FOR INFORMATION (TAC NO. 59123)
The ATWS rule (10 CFR 50.62, 11Requirements for-Reduction.. of Risk from Anticipated Transients.Without Scram (ATWS) Events for Light-W~ter-Cbole~ ~
- Nuclear Power Plants) requires improvements tn the design. and operation of commercial nuclear power facilities to reduce th~ likelihood of failure to
.. shutdown the reactor.following anticipated transients~ arid to mitigate.the consequences of an:ATWS event.* Th~ requirements for Conibµstion Engineering plants such as Paltsades a_re to provide'a diverse scram' system (DSS), diverse auxiliary fe~dwater system (AFWS) actuation, and diverse initiation*'of turbine
.. trip. - Paragraph (c)(6) Qf, the rule re.quires tbat informati<m *sufficient to..
.. demonstrate ;compliance w_H_tl the.se r~quirements -be submitted to NRR.
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'!_~-*<~*C.onsu.mers Power provlded. ir)fo~tnation concerning implementat1on of the ATWS
- -_*:
- r::,ule requirements_ a-t... P.aT.i~ades by letters dated October 22, 1985_ and ~pril 23,
- . i986~ ;* H~wev~r~:\\t.he; fnfor,mation provided in these letters. js *not*suffitient.to.
~- aJlow:the~'fl'ant; E.lectr,i,cal; Instrumentation and Control Systems Branch (PEICSB_) * '*
.,, to defermi ne.. cprtlp'l i arc,(.-wi t.~ the -Commission Is regulations. Therefore, in order. *...
' : __ *:.:for the PElCSB to cohtinue:*their review, it is requested that the enclosed,..
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- ~-: **request* for i'nformatfg_n-* be transmitted--to the licensee.
We understand* t_hat.,~--.*
- \\~>-~-:: tb*e lic~hsee:-plans<:tcr complete the.. required A_TWS modifica.ti_ons-during the
_--;~;;_:: *. upco!fling_ r~fUel'.irjg pu*tage (August 1987).
In order. for the PEICSB to meet the
_,_.... :~ ***t!lrget'~conipletibn 'date* fbr.'.safety evaluation report input to PWR Project
......; 'Directorate #8 of :Decemb~r,*n,-)986, the requested information should be
,.--** provided-~to *PEICSB no. iate'r than December 1, 1986.
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~c~Chfield, ssistant Directo"
,*~
Division of PWR Licensing-B
.l-.,,. f Enc.losures::.
- As.stated cc w/enclosures:
- See next page CONTACT:
R. Kendall, PEICSB/NRR 49-28301
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cc w/enclosure:
F. Miraglia C. Rossi G. Lainas A. Thadani J. Calvo F. Rosa E. Butcher W. Regan M. Virgilio J. Mauck.
P. Shemanski L. Beltracchi G.L. Plumlee R. Borgen (INEL)
R. Kenda 11 October 15, 1986
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