ML20100R486
| ML20100R486 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/04/1996 |
| From: | NORTHEAST NUCLEAR ENERGY CO. |
| To: | |
| Shared Package | |
| ML20100R468 | List: |
| References | |
| NUDOCS 9603120433 | |
| Download: ML20100R486 (16) | |
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l Docket No. 50-423 B15508 i
a 1
1 l
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i Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources Marked Up Pages March 1996 9603120433 960304 PDR ADOCK 05000423 P
4
- g. _ y etrernte.at povra s m rus SURYt!LLANCE REQUIRDIDfts (Continued) b)
Simulated less-of-effsite power by itself, or c)
Simulated less-of.effsite power in eenjunction with an ESF Actuation test sipal, or d)
An ESF Actuation test sipal by itselfeg gg Verifying the generator is synchronized and gradus 11 reloaded _in -.
8) secordance W th the manufacturer's recommendations (to tre snan er eeua' (equal to assu sW)for at least 80 minutes, and Verifying the diesel generator is a11 ped to provide standby 7) power to the associated energency busses.
At least once per 184 days, verify that the diesel generator starts and attains generator voltage and frequency of 4160 t430 volts and 60 t b.
The generater shall_
0.8 N within 11 seconds after the start sipal.
be synchrenhed to the assectated emergency bus loadedTo arenter shar0 Se eeual to asas MDin accordance with the manufactur r
for at least 80 minutes. The diesel gtnerator shal' he started fer
@his test using one of the sipals in Surveillance Requirement 4.8.1.1.t.a.5. This test, if it is perfereed so it coincides with the t
testine required by Surveillance Requirement 4.8.1.
l
' At least once per' 31 days and after each operation of the diesel where the period of operation was greater than er equal to I hour by f
c.
checking for and removing accumulated water from the day tanks j
At least once per 31 days by checking for and removing accumulated i
d.
water from the fuel ett storage tanks By sampling new fuel oil in accordance with ASTM 04037 prior to e.
addition to storage tanks and in accordance with the tests specified in ASTN-f 1)
By verifyiNr to addition to the storage tanks that the sample D975-81 pr i
has:
An Ap1 travity of within 0.3 degrees at 80'F. er a l
a) specific gravity of within 0.0015 at 60/60'F. when compared to the supplier's certificate, or an absolute specific gravity at 60/60'F of greater than er equal to 0.83 but less than er equal to c.89, or an API grairity of greater than er equal to 27 degrees but less than er equal
').
to 39 degrees:
Momentary f the diesel.
- The operating band is meant as guidance to avoid routine overloading o transients outside the load range shall not f.nvalidate the test AmendmentNo.J. fig 3/4 8 4 R1.L.L5foltE - 1st!T 3
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ELECTRICAL POWER SYSTEMS l
RRVEILLANCE REQUIRDIDffs (continued)
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p$
5)
Verifying that en an ESF Actuation test signal, without loss-of-J offsite power, the diesel generator starts from standby l
fj conditions en the auto start si al and operates on standby for reater than er val to 5 minu es. The nerator voltage and l
requency shall 4160 1 420 volts and 6 10.8 Nr within 11 seconds after the auto start signal; the steady state generator l
volta e and frequency shall be maintained within these lietts j
duri this test; y
i a
i y
6)
Simulating a less-of offsite power in conjunction with an ESF Actuation test signal, and:
j 3,
I; a)
Vcrifying doenergitation of the emergency busses and load
~3 shedding from the emergency busses; g!
b)
Verifying the diesel starts from standby conditions on the l j
auto-start signal, one ites the emergency busses with l
jj permanently connected 1 ads within 11 seconds, energizes
~::
the auto connected emergency (accident) leads through the 3i load sequencer and operates for greater than er equal to 5 l
l-minutes while its generator is leaded with the emergency loads. After energizstion, the stead state volta e and
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frequency of the see ency busses sha 1 he maintai d at lg 4150 6 420 volts and 0 1 0,8 Hz during this test; and
.a.
c)
\\ferifying that all automatic diesel generator trips, except g *I engine overc fed, lobe oil pressure low Iof3 logic)and i
generator di forential, are automatica11 bypassed upon il loss of volta e on the emergency bus concurrent with a 1-Safety Inject on Actuation sianal.
.I C5etween 5400-5500 kwd 7)
Verifying the diesel ' generator operates for/at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
~"
3 Duri tte first I hours of this test. thefdiesel generator shall 3 i be 1 ded(to arenter than er anua' to 54s5 kloand duri the 3
remaining EZ Ours of this test. She d' anal generator all be I
ji leadedfte eres'.or snan er eeval to seah The generator g.t,
voltage anc fnquency shall be 4160 of volts and 60 1 0.8 Hz 4
E within 11 srconds after the start si al; the steady-state j3 senerator voltage and frequency shal be malatained within these limits durt this test.* Within 5 minutes after completing this 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> tast, perfors Specification l
(4.3.1.1.1.a.5);"
,,,,,,,,,33 3,,,,, g l
- Diesel generatM' loadings may include gradual leading as recommended bY the l.
nanufacturer.
! **1f Surveillance Requirement 4.8.1.1.2.a.5) is not satisfactorily completed, it is l
met necessary to repeat the precedi 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test. Instead. the diesel generator may be operated 7 u e for hours er until operating temperature has l
{ted.
fbchitta yT00-5000 XW 8
R,1.95 TORE-WIIT3 3/4 8-5 Amendment No. W. N.
W 17 - : f'
-May12,1995 3/4.8 ELECTRICAL POWER SYSTEMS BASES t
3/4.8:'. 3/4.8.2. and 3/4.8.3 A.C. SOURCES. D.C. SOURCES. and DNSITE POWER DISTRIl l0 TION
/
Technical Specification # 3.8.1.1.b.16d 3.8.1.2.b} requirera minimum volume of 278JaMons be contained in each of the diesei generatorAay tanks / This 2
capacity ensur_es that a minimum usable volume or 159 gallons is avaHable to permit operation of each of the diesel generators for approximately 27 minutes with the diesel generators loaded to the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating of 5335 kW. The shutoff level for the (two) fuel oil transfer pumps is 4g3 gallons (413 gallons usable volume) which corresponds to approximately 60 minutes of i
engine operation at the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating. The first pump has a make up setpoint of 372 gallons (284 gallons usable volume) which correspands to approximately 42 minutes of operation at the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating. The 278 k
gallon day tank low level value corresponds to the auto make-up setpoint of the second pump and is therefore the lowest value of fuel oil with auto make-up capability. Loss of the two redundant pumps would cause day tank level to drop below the minimum value.
3-Technical Specificationb.8.1.1.b.2 &ndT~Ei.2.b.2 requirasa minimum volume of 32,760 gallons be contained in each of the diesel generator's fuel storage systems.f This capacity ensures that a minimum usable volume (2g 180 gallons)
(
1s avanable to permit operation of each of the diesel generators for approximately three days with the diesel generators loaded to the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating of 5335 kW.
The ability to cross-tie the diesel generator fuel oil supply tanks ensures that one diesel generator may operate up to approximately six days. Additional fuel oil can be supplied to the site within twenty-four hours after contacting a fuet oil supplier.
am a A'i m% ve\\%
" Tec M c J Spec 4c., b. 3 2 t. 2 b. (
M 4 278 piow s %. c.o w u_4 A, % ggQ pcoci p m.Wy dy %k.
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C AmendmentNo.#f)f M.,ILLSTONE - UNIT 3 8 3/4 8-lb n
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.-3-11F55-INSERT'C'TOPAGEB3/48-lb Surveillance Reauirements 4.8.1.1.2.a.6 (monthlv) and 4.8.1.1.2.b f once ner 184 days) and 4.8.1.1.2.a.7 (18 months test)
The Surveillances 4.8.1.1.2.a.6 and 4.8.1.1.2.b verify that the diesel generators are capable of synchronizing with the offsite electrical system and loaded to greater than or equal to continuous rating of the machine. A minimum time of 60 minutes is required to stabilize engine temperatures, while minimizing the time that the diesel generator is connected to the offsite source. Surveillance Requirement 4.8.1.1.2.g.7 requires demonstration once per 18 months that the diesel generator can start and run continuously at full load capability for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />,12 hours of which are at a load equivalent to 110% of the continuous duty rating and the remainder of the time at a load equivalent to the continuous duty rating of the diesel generator. The load band is provided to avoid routine overbading of the diesel generator.
Routine overloading may result in more frequent teardown inspections in accordance with vendor recommendations in order to maintain diesel generator operability. The load band specified accounts for instrumentation inaccuracies using plant computer and for the operational control capabilities and human factor characteristics. The note (*, ***) acknowledges that momentary transient outside the load range shall not invalidate the test.
4 Docket No. 50-423 B15508 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources Retyped Pages March 1996
1 l
l ELECTRICAL POWER SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) b)
Simulated loss-of-offsite power by itself, or 1
c)
Simulated loss-of-offsite power in conjunction with an ESF Actuation test signal, or d)
An ESF Actuation test signal by itself.
6)
Verifying the generator is synchronized and gradually loaded in accordance with the manufacturer's recommendations between 4800-5000 kW* and operates with a load between 4800-5000 kW* for at least 60 minutes, and 7)
Verifying the diesel generator is aligned to provide standby power to the associated emergency busses.
b.
At least once per 184 days, verify that the diesel generator starts and attains generator voltage and frequency of 4160 t 420 volts and 601 0.8 Hz within 11. seconds after the start signal. The generator shall be synchronized to the associated emergency bus, loaded between 4800-l 5000 kW* in accordance with the manufacturer's recommendations, and operate with a load between 4800-5000 kW* for at least 60 minutes. The l diesel generator shall be started for this test using one of the signals in Surveillance Requirement 4.8.1.1.2.a.5.
This test, if it is performed so it coincides with the testing required by Surveillance Requirement 4.8.1.1.2.a.5, may also serve to concurrently meet those requirements as well.
c.
At least once per 31 days and after each operation of the diesel where the period of operation was greater than or equal to I hour by checking for and removing accumulated water from the day tank; d.
At least once per 31 days by checking for and removing accumulated water from the fuel oil storage tanks; e.
By sampling new fuel oil in accordance with ASTM-D4057 prior to addition to storage tanks and:
1)
By verifying in accordance with the tests specified in ASTM-D975-81 prior to addition to the storage tanks that the sample has:
a)
AnAPIGravityofwithin0.3degreesat60*F, ora specific gravity of within 0.0046 at 60/60*F, when compared to the supplier's certificate, or an absolute specific gravity at 60/60*F of greater than or equal to 0.83 but less than or equal to 0.89, or an API gravity of greater than or equal to 27 degrees but less than or equal to 39 degrees;
- The operating band is meant as guidance to avoid routine overloading of the diesel.
Momentary transients outside the load range shall not invalidate the test.
MILLSTONE - UNIT 3 3/4 8-4 Amendment No. J. JJ. JJ7, ous
o ELECTRICAk.POWERSYSTEMS SURVEILLANCE REQUIRENENTS (Continued) l 5)
Verifying that on an ESF Actuation test signal, without loss-of-offsite power, the diesel generator starts from standby conditions on the auto-start signal and operates on standby for greater than or equal to 5 minutes. The generator voltage and frequency shall be 4160 1 420 volts and 60 1 0.8 Hz within 11 seconds after the auto-start signal; the steady-state generator voltage and frequency shall be maintained within these limits during this test; 6)
Simulating a loss-of-offsite power in conjunction with an ESF Actuation test signal, and:
a)
Verifying deenergization of the emergency busses and load shedding from the emergency busses; b)
Verifying the diesel starts from standby conditions on the auto-start signal, energizes the emergency busses with permanently connected loads within 11 seconds, energizes the auto-connected emergency (accident) loads through the load sequencer and operates for greater than or equal to 5 minutes while its generator is loaded with the emergency loads. After energization, the steady-state voltage and frequency of the emergency busses shall be maintained at 4160 1 420 volts and 60 1 0.8 Hz during this test; and c)
Verifying that all automatic diesel generator trips, except engine overspeed, lube oil pressure low (2 of 3 logic) and generator differential, are automatically bypassed upon loss of voltage on the emergency bus concurrent with a Safety Injection Actuation signal.
7)
Verifying the diesel generator operates for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
During the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of this test, the diesel generator shall be loaded between 5400-5500 kW*** and during the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of this test, the diesel generator shall be loaded between 4800-5000 kW***.
The generator voltage and frequency shall be 4160 1 420 volts and 6010.8 Hz within 11 seconds after the start signal; the steady-state generator voltage and frequency shall be maintained within these limits during this test.*
Within 5 minutes after completing this 24-hour test, perform Specification 4.8.1.1.2.a.5);**
- Diesel generator loadings may include gradual loading as recommended by the manufacturer.
- If Surveillance Requirement 4.8.1.1.2.a.5) is not satisfactorily completed, it is not necessary to repeat the preceding 24-hour test.
Instead, the diesel generator may be operated between 4800-5000 kW for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or until operating temperature l
has stabilized.
- The operating band is meant as guidance to avoid routine overloading of the diesel.
i Momentary transients outside the load range shall not invalidate the test.
1 NILLSTONE - UNIT 3 3/4 8-6 Amendment No. Jp, M. J#,
ou:
3/4.8 ELECTRICAL POWER SYSTEMS BASES 3/4.8.1. 3/4.8.2. and 3/4.8.3~ A.C. SOURCES. D.C. SOURCES. and ONSITE POWER DISTRIBUTION Technical Specification 3.8.1.1.b.1 requires a minimum volume of 278 gallons be contained in each of the diesel generator day tanks. Technical Specification 3.8.1.2.b.1 requires a minimum volume of 278 gallons he contained in the required diesel generator day tank. This capacity ensures that a minimum usable volume of 189 gallons is available to permit operation of each of the diesel generators for approximately 27 minutes with the diesel generators loaded to the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating of 5335 kW.
The shutoff level for the (two) fuel oil transfer pumps is 493 gallons (413 gallons usable volume) which corresponds to approximately 60 minutes of engine operation at the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating. The first pump has a make-up setpoint of 372 gallons (284 gallons usable volume) which corresponds to approximately 42 minutes of operation at the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating. The 278 gallon day tank low level value corresponds to the auto make-up setpoint of the second pump and is therefore the lowest value of fuel oil with auto make-up capability.
Loss of the two redundant pumps would cause day tank level to drop below the minimum value.
Technical Specification 3.8.1.1.b.2 requires a minimum volume of 32,760 l
gallons be contained in each of the diesel generator's fuel storage systems.
Technical Specification 3.8.1.2.b.2 requires a minimum volume of 32,760 gallons be contained in the required diesel generator's fuel storage system.
This capacity ensures that a minimum usable volume (29,180 gallons) is available to permit operation of each of the diesel generators for approximately three days with the diesel generators loaded to the 2,000 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> rating of 5335 kW. The ability to cross-tie the diesel generator fuel oil supply tanks ensures that one diesel generator may operate up to approximately six days. Additional fuel oil can be supplied to the site within twenty-four hours after contacting a fuel oil supplier.
Surveillance Reauirements 4.8.1.1.2.a.6 (monthlv) and 4.8.1.1.2.b (once oer 184 days) and 4.8.1.1.2.a.7 (18 months test)
The Surveillances 4.8.1.1.2.a.6 and 4.8.1.1.2.b verify that the diesel generators are capable of synchronizing with the offsite electrical system and loaded to greater than or equal to continuous rating of the machine. A minimum time of 60 minutes is required to stabilize engine temperatures, while minimizing the time that the diesel generator is connected to the offsite source. Surveillance Requirement 4.8.1.1.2.g.7 requires demonstration once per 18 months that the diesel generator can start and run continuously at full load capability for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, ;t 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of which are at a load equivalent to 110% of the continuous duty rating and the remainder of the time at a load equivalent to the continuous duty rating of the diesel generator. The load band is provided to avoid routine overloading of the diesel generator. Routine overloading may result in more frequent teardown inspections in accordance with vendor recommendations in order to maintain diesel generator operability. The load band specified accounts for instrumentation inaccuracies using plant computer and for the operational control capabilities and human factor characteristics. The note (*, ***)
acknowledges that momentary transient outside the load range shall not invalidate the test.
NILLSTONE - UNIT 3 B 3/4 8-lb Amendment No. U, JJJ.
0441
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4 Docket No. 50-423 B15508 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources Description of Proposed Changes March 1996 l
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U. S. Nuclear Regulatory Commission B15508/ Attachment 3/Page 1 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources Description of Proposed Changes Surveillance Requirements 4.8.1.1.2.a.6 (monthly) and 4.8.1.1.2.b (once per 184 days) verify that the DGs are capable of synchronizing with the offsite electrical system and loaded to greater than or equal to continuous rating of the machine.
NNECO is proposing to modify these surveillance requirements by specifying load bands in loading the DG in lieu of the present requirement to load the DG greater than or equal to a given value.
For continuous load rating, the value specified is 4800 - 5000 kW (continuous rating accounting for instrumentation inaccuracies using the plant computer).
Surveillance Requirement 4.8.1.1.2.g.7 requires demonstration, once per 18 months, that the DG can start and run continuously at full load capacity for an interval not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of which are at a load equivalent to 110%
of the continuous duty rating and the remainder of the time at a load equivalent to the continuous duty rating of the DG, NNECO proposes that the required loads for the 18-month load run be between 5400 - 5500 kW for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and between 4800 - 5000 kW for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> as indicated on the plant computer.
In addition, a footnote is being added to Surveillance Requirements 4.8.1.1.2.a.6 (monthly),
- 4. 8.1.1.2.b (once per 184 days), and 4.8.1.1.2.g.7 (18-month test) to indicate that a momentary transient outside the load range shall not invalidate the test.
Bases Sections 3/4.8.1, 3/4.8.2, and 3/4.8.3 have been revised to reflect the above changes.
In addition, Bases Section 3/4.8.1 (page B3/4 8-1b) has been revised to clarify the fuel oil requirements for the DG day tank and DG fuel storage tank for applicable modes.
Specifically, the change will make the bases sections consistent with Technical Specification Sections 3.8.1.1.b.1, 3.8.1.1.b.2, 3.8.1.2.b.1, and 3.8.1.2.b.2.
This change is administrative in nature and has no impact on plant safety.
+
Docket No. 50-423 B15508 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources Safety Assessment and Significant Hazards Consideration March 1996 d
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c U. S. Nuclear Regulatory Commission B15508/ Attachment 4/Page 1 Millstone Nuclear Power Station, Unit No. 3 Proposed Revision to Technical Specifications Electrical Power Systems -- A.C. Sources safety Assessment and Significant Hazards Consideration Safety Assessment Use of open-ended language such as " greater than or equal to" has the potential for routine overloading of the DGs.
Specifying an upper limit would eliminate this potential and possibly improve DG availability and reliability.
The proposed changes specify a loading, using the plant computer which accounts for instrument error, by lowering the specified limit to ensure the upper value does not exceed the manufacturer's recommended values during testing for continuous rating or 110 percent of continuous (160 hours0.00185 days <br />0.0444 hours <br />2.645503e-4 weeks <br />6.088e-5 months <br />) rating.
While it does not exceed the manufacturer's recommended value at 110 percent of continuous rating, the lower limit envelopes the accident load requirements.
The manufacturer's allowable values for testing are 5086 (~5100) kW for continuous rating and 5585 (~5600) kW for 160 hours0.00185 days <br />0.0444 hours <br />2.645503e-4 weeks <br />6.088e-5 months <br /> rating.
Additionally, the proposed changes take into account the operational control capabilities and human factor characteristics by providing the operating band of 200 kW (4800-5000 kW) for continuous loading and 100 kW (5400-5500 kW) for 110 percent of the continuous rating.
For the 4986 kW (~5000 kW) continuous load rating and for the 110 percent of continuous load rating 5485 kW (~5500 kW), the proposed specified loads are determined as calculated in NNECO's Calculation No. NL-041GE, Rev.
2, using the plant computer.
For continuous rating of 5000 kW, the calculated range with inaccuracies is between 4826-5091 kW.
The selected band is 4800-5000 kW.
Selecting the 4800-5000 kW band may result in the actual load span from approximately 4600 to 5100 kW which corresponds to 92.3 to 102.3 percent of the 4986 kW continuous rating.
The load limit provided by the manufacturer for continuous rating during testing is 5086 kW (~5100 kW).
Selecting an upper limit of 5000 kW will keep the actual upper load limit below the manufacturer's recommended limit.
For 110 percent of continuous load rating of 5500 kW, the calculated range with the inaccuracies is 5320-5587 kW.
The selected band is 5400-5500 kW.
Selecting the 5400-5500 kW band may result in the actual load span from approximately 5220 to 5600 kW which corresponds to 95.2 to 102.1 percent of the 5485 kW (110 percent of continuous rating) and 104.7 to 112.3 percent of the 4986 kW continuous rating.
The load limit provided by the
- O a
U. S. Nuclear Regulatory Commission B15500/ Attachment 4/Page 2 manufacturer for 110 percent of continuous rating (5485 kW) during testing is 5585 kW (~5600 kW).
Selecting an upper limit of 5500 kW will keep the actual upper load limit below the manufacturer's recommended limit and the actual lower limit of 5220 kW envelopes the accident load requirements (i.e., 5184 kW).
The general requirements for periodic surveillance testing are established by Regulatory Guide 1.108.
It specifies that, during the monthly test, the DG is to be loaded to the continuous duty rating.
Further, during the 24-hour load run conducted on an 18-month basis, the DG is to be loaded to the 2-hour rating for the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, followed by 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> at the continuous duty rating.
For the monthly test, the intent is to avoid exceeding the continuous duty rating on a
frequent basis but to detect performance degradation prior to a failure.
During 18-month
- testing, test loads envelope the calculated accident loads.
However, during the accident situation, the larger electrical loads are typically required only for a short time and the load decreases significantly for the remaining time.
The sizing of the DG is acceptable if the short-term 2-hour rating of the DG is greater than the peak accident loads and if the long-term 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the DG is greater than the long-term accident loads.
The 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the DGs is 5335 kW which is greater than the long-term accident loads at Millstone Unit No. 3.
Since the exact value of the load during the monthly test is not critical and since overloading has been identified as a possible cause of DG engine failures, it is appropriate that the specified load should be the continuous duty value less the amount approximating the uncertainties.
Therefore, the band of 4800-5000 kW for the monthly test and longer portion of the 18-month load run is acceptable.
It is noted that the application of an operating band is meant as guidance to avoid routine overloading of the DGs during surveillance testing.
Although the load will be monitored visually, a momentary variation of bus loads may result in an associated momentary deviation of the operating band.
The intent of this change is not to limit the operating range as to result in frequent invalidation of tests due to anticipated momentary variations in load.
Such a consequence would be counter productive in that it would result in additional DG starts.
Therefore, NNECO i
proposes to include a control band as an operating target with the additional flexibility referenced by the asterisk footnote to account for anticipated operational conditions and events.
U. S. Nuclear Regulatory Commission B15508/ Attachment 4/Page 3 The proposed changes will keep the actual upper load limit of the DG below the manufacturer's recommended limit and the actual lower limit enveloping the accident load requirements.
The proposed changes will reduce unnecessary engine stress and wear, while potentially improving overall DG reliability and longevity.
Therefore, the proposed changes are safe and acceptable and do not adversely affect or endanger the health or safety of the public.
Significant Hazards Consideration NNECO has reviewed the proposed changes in accordance with 10CFR50.92 and has concluded that the changes do not involve a significant hazards consideration (SHC).
The basis for this conclusion is that the three criteria of 10CFR50. 92 (c) are not compromised.
The proposed changes do not involve an SHC because the changes would not:
1.
Involve a
significant increase in the probability or consequences of an accident previously evaluated.
The purpose of the proposed changes to Surveillance Requirements 4.8.1.1.2.a.6, 4.8.1.1.2.b, and 4.8.1.1.2.g.7 is to provide the load bands for loading the DG during the monthly, 184 days and 18-month surveillances.
Specifically, for monthly (Surveillance 4.8.1.1.2.a.6) and once per 184 days (Surveillance 4.8.1.1.2.b) surveillances, the load band is between 4800-5000 kW.
For the 18-month surveillance (Surveillance 4.8.1.1.2.g.7),
the load band is between 5400-5500 kW during the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and between 4800-5000 kW during the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />.
The specified load bands account for instrumentation inaccuracies using the plant computer and for the operational control capabilities and human factor characteristics.
The proposed changes will keep the actual upper load limit of the DG helow the manufacturer's recommended limit and the actual lower limit enveloping the accident load requirements.
The proposed changes will reduce unnecessary engine stress and
- wear, while potentially improving overall diesel generator reliability and availability.
The changes to the Bases section reflect the changes made to the surveillance requirements and, therefore, have no adverse impact on plant safety.
Since the proposed changes serve to enhance overall safety, these changes do not increase the probability or consequences of any accident previously evaluated.
.. _ s U. S. Nuclear Regulatory Commission B15508/ Attachment 4/Page 4 2.
Create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed changes regarding the load band for the DGs do not affect the operation or response of any plant equipment, including the DG, or introduce any new failure mechanism.
The proposed changes will reduce unnecessary engine stress and wear, while potentially improving overall DG reliability and availability.
Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
Involve a significant reduction in a margin of safety.
The proposed changes specifying the load bands for diesel testing will keep the actual upper load limit of the DG below the manufacturer's recommended limit, and the actual lower l
limit enveloping the accident load requirements.
Therefore, the proposed changes do not affect the capability of the diesel to perform its intended function.
The purpose of these changes is to increase the overall DG reliability.
The proposed changes do not impact the consequences of any design basis accidents.
There is no direct impact on any of the protective boundaries.
For these reasons, the changes do not involve a reduction in the margin of safety.
l The Commission has provided guidance concerning the application of the standards of 10CFR50.92 by providing certain examples (51FR7751, March 6, 1986) of amendments that are considered not likely to involve an SHC.
Although the changes proposed herein are not enveloped by a specific example, the proposed changes would not involve an SHC.
The proposed changes specify load bands in loading the DG in lieu of the present requirements to load the DG greater than or equal to a given value.
The proposed changes will keep the actual upper load limit of the DG below the manufacturer's recommended limit and the actual lower limit enveloping the accident load requirements.
The proposed changes will reduce unnecessary engine stress and wear, while potentially improving overall DG reliability and longevity.
As previously discussed, the proposed changes do not involve an SHC.
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