ML19249E528
| ML19249E528 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/23/1978 |
| From: | Rosa F Office of Nuclear Reactor Regulation |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7910010635 | |
| Download: ML19249E528 (14) | |
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DOCKET FILE V NRR READIt!G NAY 2 3 073 PS READIllG PSB READIrlG MFIELDS READIflG JVJ10X READIrlG l'.Ef L'RiflDUM FOR:
J. F. Stolz, Chief, Light Uater Reactors Cranch 1, DPli F30M:
FEust Rosa, Chief, Power Systens Branch, DSS SU3 JECT:
ACCEPTAt;CE REVIEU - GP/fl0 GULF !!UCLEAR STATION UtilTS NOS.1 & 2 Plant itane: Crand Gulf 1 & 2 Docket !:os: 50p10/317 Licensing Stage: - Acceptance Review - OL
!:llestone I:o: 010 Responsible Cranch: LUR-1 A Project ISnager:
C. Thooas Pequeste.1 Corupletion Date: l'ay 22,1978 Review Status: Cocplete The enclosed acceptance review regeests for additional inforaation covers thosa portions of Grand Culf Huclear Station for which the Pcwor Syster.s Brench has prirary responsibility. Our review vas t'ased on guidelinas provided by Rcgulatory Guide 1.70 " Standard Format and Content of Safety Analysis T.eports for Nuclear Power Plants", Revision 2, and the Standard Revieu Plans. Based on this review we conclude that the Grand Culf FSAR is approximately 90% complete and therefore recorrend that it should be accepted for docketina.
Ik cnci% requests ideatify specific areas where additional informa-I tion is needed. These areas are: The offsite and onsite emergency power systws, equipr. cat qualification, diesel senerator auxiliary systons, and the ;urbine generator.
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Faust Rosa, Chief Pcwcr Systcas Branch Division of Systeas Safety pC#'(c~
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Acceptance Review Requests for Additional Information Grand Gulf Nuclear Station 1&2 50-416/417 040.
Diesel generator alarms in the control room:
i review of malfunction (8.3) reports of diesel generators at operating nuclear plants has uncovered that in scme cases the information available to the control room operator to indicate the operational status of the diesel generator may be imprecise and could lead to misinterpretation.
This can be caused by the sharing of a single annunciator station to alarm con-l ditior,s + hat render a diesel generator unable to respond to an automatic emergency start signal and to also alarm abnormal, but not disabling, conditions.
Another cause can be the use of wording of an annunciator window that does not specifically say that a diesel generator is in-operable (i.e., unable at the time to respond to an automatic emergency start signal) when in fact it is inoperable for that purpose.
Review and evaluate the alarm and control circuitry logic for the diesel generators at your facility to determine how each condition that renders a diesel generator unable to respond to an automatic emergency start signal is alarmed in the control room.
These con-ditions include not only the trips that lock out the diesel generator start and require manual reset, but also control switch o. mode switch positions that block automatic start, loss of control voltage, insufficient starting air pressure or battery voltage, etc.
This i
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_2 review should consider all aspects of possible diesel generator operational conditions for example test conditions and operation from 3
local control stations.
One area of particular concern is the unreset condition following a manual stop at the local station which terminates a diesel generator test and prior to reseting the diesel generator controls for enabling subsequent automatic operation.
I Provide the details of your evaluation, the results and conclusions, l
and a tabula: ion of the following information:
(a) all conditions that render the diesel generator incapable of responding to an automatic emergency start signal for each operating made as discussed above; (b) the wording on the annunciator window in the control room that is alent.ed for each of the conditions identified in (a);
(c) any other alam signals not included in (a) above that also
,2 i cause the same annunciator to alarm; (d) any condition that renders the diesel generator incapable of responding to an automatic emergency start signal which is not alamed in the control room; and (e) any proposed modifications resulting from this evaluation.
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' 040.x In regard to the physical separation between the preferred power (8.2) sources from the service transfonners and ESF Transfonner to the onsite Class TE power system, sufficient information has not been provided in the FSAR to demonstrate compliance with NRC General Design Criteria 1, 3, 4,17, and 18.
Provide this information.
040.
The staff requires that the following qualification test program (3.11)'
(8.0) infonnation be provided for all Class lE equipment:
I 1.
Identification of Equipment including, a) Manufacturer b) Manufacturer's type model c)
Manufacturer's model number d) All Class lE equipment should be identified including the following, as applicable:
1)
Switchgear
- 2) Motor control centers,
- 3) Valve operators
- 4) Motors
- 5) Logic equipment
- 6) Cable
- 7) Diesel generator cont rol equipment
- 8) Sensors
- 9) Limit Switches
- 10) Heaters i
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Fars
- 12) Control Boards 13)
Instrument racks and panels
- 14) Connectors 15)
Electrical penetrations 16)
Sp'lices
- 17) Terminal blocks l
Equipment c:esign specification requirements, including, 2.
a) The system safety function requirements b) An environmental envelope as a ft
' ion of time which includes all extreme parameters, both maximum and minimum values, ex-pected to occur during plant shutdown, normal operation, abnarmal operation, and any design basis event including LOCA and MSLb.
c) Time required to fulfill its safety function when subjected to any of the extremes of the environmental envelope specified above.
The qualification test plan, test set-up, test procedures, and 3.
acceptability goals and requirements.
For equipment subject to a design basis accident environment, 4.
c a. actual qualification envelope simulated duri..g testing (defin-ing the duration of the hostile environment and the margin in l
excess of the design requirements).
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-5 5.
A summary of test results (or schedule for submission) that demonstrates the adequacy of the, qualification program.
If analysis is used for qualification justification must be provided.
6.
Identification of the qualification documents which contain de-tailed supporting information, ir.cluding test data, for items 3, 4 and 5.
I The information requested in items 1, 2, 4, 5 and 6 shall be provided for all items of Class 1E equipment.
The information in item 3 shall be provided fcr at least one of each group of equipment of item ld (as applicable) which is subject to a design basis accident environ-
. men t The information in item 3 shall also be provided for represen-tative major equipment of item ld which is not subject to a design basis accident environment.
In addition, in accordance with the requirements of Appendix B of 10 CFR 50, the staff requires a statement verifying:
- 1) that all Class lE equipment has been (0L) or will be (CP) qualified to the program described above, and 2) that the detailed qualification information is (or will be) available for an NRC audit.
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Qualification of Safety Related Cable (8.3)
The Regulatory staff is currently requesting, of all plants in OL (3.11) information on the use of poleythelen type cable in safety
- review, These type cables were found to have degraded considerably systems.
af ter many years of installed operation at the Savannah fuel pro-cessing plant.
Identify all safety related cable used in your design that has polyethe-j lene in its construction. Provide the following infonnation for each type of cable identified:
a) Type of cable by name and Cat. tio.
b) Manufacturer c) Type of polyethelene used d) How is the polyethelene used in the cables construction, i.e.,
insulation and/or jacket.
e) Results of environmental qualification tests perfonred.
040.4 Qualification of Penetrations (8.3)
Describe how your d'esign meets the recommendations of Regulatory 7
Guide 1.63, Revision 1.
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Identify each type of electrical circuit that penetrate,s containment.
Describe the primary and backup over current protection systems pro-vided for each type of circuit.
Describe the fault-current-versus-time for which the primary and backup protection systems and the penetrations are designed and qualified.
Provide coordinated curves which deconstrate, for each circuit identified. that the ma>imum fault-current-versus-time condition to j
which the penetration and cable were qualified will not be exceeded.
Describe the provit ;n for periodic testing under simulated fault conditions.
040.5 Potential Problem with Containment Electrical Penetration Assemblies (3.11)
(8.3)
Recent operating experience at Millstone Unit No. 2 has shown that the deterioration of the epoxy insulation between splices has caused electrical shorts between conductors within a containment electrical penetration assembly.
Indicate what tests and/or analysis that have been perfonned to demonstrate the acceptability of the design in this regard.
Provide whatever infonnation is required to perferm an independent evaluation of this aspect of the electrical penetration design.
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P00R BR M 040. 6 Recent-operating experience has shown that adverse effects on the (8.2) safety-related power system and safety related equipment and loads can be caused by sustained low or high grid voltage conditions.
We therefore require that your design of the safety related electrical system meet the fnilowing staff positions.
Supplement the descrip-tion of your design in the FSAR to show how it meets these positions or provide appropriate analyses to justify non-conformance with these positions.
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'We require that an additional level of voltage protection for the 1,
ensite pcwer system be provided and that this additional level of volta;e pr:tection shall satisfy the following criteria:
a) Tne selection of voltage and time set points shall be determined f r:,= an analysis of the voltage requirements of tht safety-relaced loacs at all ensite system distribution levels; b) Tne voltage pro *.ection snali include coincicence logic on a per bus basis to preclude sourious trips of the offsite power source; c) Tne time delay seie:ted shall be based on the following conditions:
(1) ine alicaabie tint delay, including margin, shall not exceed the maxim;m time delay that is assumed in the PSAR accident analyses; 1032
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(2) The time delay sell minimize the effect of short duration disturbances from reducing the availability of the offsite pcwer source (s); and (3) The allowable time duration of a degraded voltag'e condition at all distribution system levels shall not result in failure of safety systems or components; I
i' d) The voltage sensors shall automatically initiate the disconnec -
tion of offsite pcwer sources whehenver the voltage set point and time delay limits have been exceeded; e) The voltage sensors shall be designed to satisfy,the applicable requirements of IEEE Std. 279-1971, " Criteria for Protection Systems for Nuclear Pcwer Generating Stations"; and f) The Technical Specifications shall include limiting condition for operation, surveillance requirerents, trip set points with minimur, and maximum limits, and allewable values for the second-level voltage protection senscr; and associated time delay devices.
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..a We require that the current system designs automatically prevent 2,
lead shedding of the emergency buses once the onsite sources are The supplying pcwer to all sequenced loads on the emergency buses.
design shall also include the capability of the load shedding feature to be automatically reinstated if the onsite source supply breakers are tripped. The automat.ic bypass and reinstatement feature shall be verified during the periodic testing identified in Position 3.
j In the event an adequate basis can be pro'vided for retainir.s the load shed feature when leads are energized by the onsite power system, we will require that the setpoint value in the Technical Specifications, which is currently specific as "... equal to or greater than..." be amended to specify a value having maximum and minimum limits. The licensee' bases #or the setpoints and limits selected must be documented.
We require that the Technical Specifications include a test require-3.
ment to demonstrate the full functional cperability and independence of the onsite pcwer scurces at least once per 18 months during shutdcan. The Technical Specificatiens shall include a require ent for tests:
(1) si.mulating less of offsite pcwer; (2) simulating
'. ass of offsite pc-er in conjunction with a safety feature actuation signal, and (3) simulating interruption and subsequent reconnection of onsite pcwer sources to their respective buses. Proper operation shall be deter ined by:
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-Il-I 4). Verifying that on loss of offsite power the emergency buses have teen de-energized and that the loads have been shed from the er.er;ency buses in accordance with design requirerents.
b) Verifying that on loss of offsite power the diesel, generators start on the autostart signal, the emergency buses are energized with permanently connected loads, the auto-connected shutdown
--- loads are energized through the lesd segncer, and the system 1
operates for five minutes while the generators are loaded with the shutdown loads.
c) Verifying that on a safety features actuation signal (without loss cf offsite pcwer) the diesel generators start on the autostart signal and operate on standby for five minutes.
d) Verifying that on loss of offsite pcwer in conjunction with a safety features actuation signal the diesei generatori sta.t on the autostart signal, tne erergency buses are energized with per.anently connected leads, the auto-connected erergency (accident) 1 cads are energized through the load sequencer, and the system operates for five minutes while the generators are loaded with the emergency loads.
e) Verifying that on interruption of the onsite sources the loads are shed from the emergency buses in accordance with design requirc-ments,and that subsequent loading of the onsite sources a through the load sequencer.
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I The voltage levels at the safety-related buses should be optimized 4.
for the full load and minimum load conditions that are expected throughout the anticipated range of voltage variations of the offsite power source by appropriate adjust. ment of the voltage tap settings of the intervening transformers. We require that the adequacy of the design in this regard be verified by a'ctual measurement and by correlation of measured values with analysis I
results. Provide a description of the method for making this j
verification, before initial reactor power operation, provide-the--
I documentation required to establish that this vurificatic.) has i
been accomplished.
Provide in Section 9.5.4 the means for indicating, controlling and 040.
(9.5.4) monitoring the emergency diesel engine fuel oil tempe;oture (SRP 9.5.4,PartIII, Item 1).
The diesel engine generator sets should be capable of operation at 040.
(9.5.5) less than full load for extended periods without degradation of per-formance or reliability.
Provide a discussion of your diesel engine operating parameters, including minimum load requirerants, and relate this to anticipate minimum loads under accident recovery conditions and during accident standby operation when offsite power is available (SRP 9.5.5, Part III, Item 7).
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Section 9.5.8 states that the diesel gener ttor combustion air intake (9.5.8) and exhaust system is missile protected. Provide further description (with the aid of drawings) explaining how the openings in tre diesel generator building for the air exhaust are protected from tornado borne missiles.
040.
Discuss what protection will be provided the turbine overspeed con-(10.2) trol system equipment and associated electrical wiring and hydraulic l
lines from the effects of a high or moderate energy pipe failure so that the turbine overspeed protection system will not be damaged to preclude its safety function.
(SRP 10.2, Part III, Item 8).
040.
Describe with the aid of drawings, the bulk hydrogen storage facility (10. 2) including its location and distribution system.
Include the protective measures considered in the design to prevent fires and explosions during operations such as filling and purging the generator, as well as during normal operations.
040.
The FSAR discusses the main steam stop and control, and reheat stop (10.2) and intercept valves. Show that a single failure of any of the above valves cannot disable thr: turbine overspeed trip functions.
(SRP 10.2, Part III, Item 3).
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