ML20043F633
| ML20043F633 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 06/11/1990 |
| From: | SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY |
| To: | NRC |
| Shared Package | |
| ML17348A308 | List: |
| References | |
| CON-FIN-D-1311 SAIC-89-1642, TAC-M68250, TAC-M68251, NUDOCS 9006150187 | |
| Download: ML20043F633 (32) | |
Text
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h TECMICAL EVALUATION REPORT TURKEY POINT UNITS 3 A2 4 i
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STATION BLACK 0LTT EVALUATION s
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,l TAC Nos. N68250 and N68251 An Employee Owned Company Final June 11, 1990
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.I, Prepared for:
U.S. Nuclear Regulatory Comission Washington, D.C. 20555 Contract NRC-03-87-029 rje r
Task Order No. 38 A
1710 Goodndge Drive, P.O. Box 1303, McLaon, Viminia 22102 (703) 8214300 on ame om m som em W o.ma. u ma ta w a t Aw on w owen % an sei omen s.nua av rwe.a
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TABLE OF CONTENTS Section hga
1.0 BACKGROUND
1
)
2.0 REVIEW PROCESS 3
3.0 EVALUAT!0N 6
3.1 Proposed Station Blackout Duration 6
3.2 Alternate AC (AAC) Power source..................
13 3.3 Station Blackout Coping Capability 17 3.4 Proposed Procedure and Training..................
22 3.5 Proposed Nodification 23 3.6 Quality Assurance and Technical $pecifications...
24 4.0 CONCLU$10NS 25
5.0 REFERENCES
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11
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TECHNICAL EVALUATION REPORT TURKEY P0 INT UNITS 3 AS 4 STATION BLACK 0UT EVALUATION 1.0 BACK8R00ND f
On July 21, 1988, the Nuclear Regulatory Commission (NRC) amended its regulations in 10 CFR Part 50 by adding a new section, 50.63, " Loss of All Alternating Current Power" (1). The objective of this requirement is to assure that all nuclear power plants are capable of withstanding a station j
blackout (SBO) and maintaining adequate reactor core cooling and appropriate containment integrity for a required duration.
This requirement is based on i
information developed under the commission study of Unresolved Safety Issue l
A 44, " Station Blackout" (2 6).
The staff issued Regulatory Guide (RG) 1.155, ' Station Blackout," to provide guidance for meeting the requirements of 10 CFR 50.63 (7).
Concurrent with the development of this regulatory guide, the Nuclear Utility Management and Resource Council (NUMARC) developed a document entitled, " Guidelines and Technical Basis for NUMARC Initiatives Addressing Station Blackout at light Water Reactors," NUMARC 87 00 (8). This document provides detailed guidelines and procedures on how to assess each plant's capabilities to comply with the station blackout rule. The NRC staff reviewed the guidelines and analysis methodology in NUMARC 87-00 and concluded that the NUMARC document provides an acceptable guidance for addressing the 10 CFR 50.63 requirements._ The application of this method results in selecting a minimum acceptable station I
blackout duration capability from two to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> depending on the plant's l
characteristics and vulnerabilities to the risk from station blackout. The i
plant's characteristics affecting the required coping capability are: the redundancy of the onsite emergency AC power sources, the reliability of onsite emergency power sources, the frequency of loss of offsite power (LOOP), and the probable time to restore offsite power.
I 1
In order to achieve a consistent systematic response from licensees to the station blackout rule and to expedite the staff review process, NUMARC developed two generic response documents.
These documents were reviewed and endorsed by the NRC staff (9) for the purposes of plant specific submittals.
The documents are titled:
1.
" Generic Response to Station Blackout Rule for Plants Using Alternate AC Power," and 2.
" Generic Response to Station Blackout Rule for Plants Using AC Independent Station Blackout Response Power."
Plant specific submittals, using one of the above generic formats, provide only summary of results of the analysis of the plants' station blackout coping capability.
Licensees are expected to ensure that the baseline assumptions used in NUMARC 87 00 are applicable to their plants and to verify the accuracy of the stated results.
Compliance with the station blackout rule requirements is verified by review and evaluation of the licensee's submittal and audit review of the supporting documents as I
necessary.
Follow us NRC inspections assure that the licensee has implemented the necessary changes as required to meet the $80 rule.
In 1989, a joint NRC/SAIC team headed by an NRC staff member performed i
audit reviews of the methodology and documentation supporting the licensee's submittals for several plants. These audits revealed several deficiencies which were not apparent from the review of the licensee submittals using the agreed upon generic response format. These deficiencies raised a generic question regarding the degree of licensee's conformance to the requirements of the SB0 rule.
To resolve this question, on January 4, 1990, NUMARC issued additional guidance as NUMARC 87 00 Supplemental Questions / Answers (15) addressing the NRC's concerns regarding the deficiencies. NUMARC requested that the licensees send their supplemental responses to the NRC addressing these concerns by Narch 30, 1990.
2
2.0 REVIEW PROCESS The review of the licensee's submittal is focused on the following areas consistent with the positions of RG 1.155:
A.
Minimum acceptable station blackout duration (Section 3.1),
B.
Station blackout coping capability (Section 3.2),
C.
Procedures and training for station blackout (Section 3.4),
D.
Proposed modifications (Section 3.3), and E.
Quality assurance and technical specifications for station blackoutequipment(Section3.5).
For the determination of the proposed minimum acceptable station blackout duration, the following factors in the licensee's submittal are reviewed:
a) offsite power design characteristics, b) emergency ac power system configuration, c) determination of the emergency diesel generator (EDG) l-reliability consistent with NSAC 108 criteria (10), and d) determinatien of the accepted EDG target reliability. Once these factors are known, Table 3 8 of NUMARC 87 00 or Table 2 of Regulatory Guide 1.155 provides a matrix for determining the required coping duration.
For the $80 coping capability, the licensee's submittal is reviewed to assess the availability, adequacy and capability of the plant systems and components needed to achieve and maintain a safe shutdown condition and j
recover from an 580 of acceptable duration which is determined above.
The review process follows the guidelines given in RG 1.155, Section 3.2, to assure:
I a.
availability of sufficient condensate inventory for decay heat
- removal, 3
1
j b.
adequacy of the class IE battery capacity to support safe
- shutdown, c.
availability of adequate compressed air for air operated valves necessary for safe shutdown, d.
adequacy of the ventilation systems in the vital and/or dominant areas that include equipment necessary for safe shutdown of the
- plant, ability to provide appropriate containment integrity, and e.
f.
ability of the plant to maintain adequate reactor coolant system inventory to ensure core cooling for the required coping duration.
The licensee's submittal is reviewed to verify that required procedures (i.e., revised existing and new) for coping with SB0 are identified and that i
appropriate oper'stor training will be provided, i
The licensee's submittal for any proposed modifications to emergency AC sources, battery capacity, condensate capacity, compressed air capacity, I
appropriate containment integrity and primary coolant make up capability is reviewed. Technical Specifications and.1uality assurance set forth by the licensee to ensure high reliability of '.he equipment, specifically added or l
assigned to meet the requirements of the station blackout rule, are assessed l-for their adequacy.
i The licensee's proposed use of an alternate AC power source is reviewed to determine whether it' meets the criteria and guidelines of Section 3.3.5 of RG 1.155 and Appendix 8 of NUMARC 87 00.
A normal SB0 review is limited to the review of the licensee submittal:
it does not include a concurrent site audit review of the supporting I
L documentation.
Such an audit may be warranted as an additional confirmatory 4
)
action. This determination would be made and the audit would be scheduled and performed by the NRC staff at some later date.
)
However, a limited number of concurrent site audit reviews were performed in order to obtain a benchmark for licensee conformance with the documentation requirements of the 5B0 rule. The Turkey Point site was one of the plants selected by the NRC for a concurrent audit review of the SB0 support',ng documentation.
This audit was performed by a joint NRC/SAIC team, headed by an NRC staff member, on October 17 19, 1989 at Florida Power and Light's Juno Beach offices.
The following evaluation was written in coordination with NRC staff and encompasses review of the licensee's submittal (11) and the licensee's response to questions raised during the site audit review (16).
The licensee did not respond to the NUMARC 87 00 Supplemental Questions / Answers. The licensee claimed similar information had been provided in his submittal (16).
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3.0 EVALUATION 3.1 Proposed $tation Blackout Duration j
Licensee submittal' The licensee, Florida Power and Light (FPL), calculated (11) a mittimum acceptable station blackout duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for the Turkey Point Units 3 and 4.
The licensee stated that a modification is necessary to attain this proposed coping duration. This modification is described in Section 3.5.
The plant factors used to estimate the proposed SB0 duration are:
1.
Offsite Power Design Characteristics
)
I The plant AC power design characteristic group is "P2", based on:
)
a.
Independence of the plant offsite power system characteristics of "!!",
- b.
Expected frequency of grid related LOOP events of less than one per 20 years, c.
Estimated frequencies of LOOPS due to extremely severe weather (ESW)of6.25E-3or4.9E3pecyear(11).
Either estimate places the plant in ESW group "4",
d.
Estimated frequency of LOOPS due to severe weather (SW) of 1.8E-3 per year which places the plant in SW group "1",
2.
Emergency AC (EAC) Power Configuration Group The licensee stated that once the modification is completed, the EAC power configuration of the plant will be "A."
Turkey Point site will be equipped with four emergency diesel generators and 6
they will normally be available to either unit's safe shutdown equipment.
The licensee stated that one EAC power supply is necessary to operate safe shutdown equipment for both units following a LOOP.
3.
Target Emergency Diesel Generator (EDG) Reliability The licensee has selected a target EDG reliability of 0.95 based on having an average EDG reliability of greater than 0.95 for the last 100 demands consistent with NUMARC 87 00 selection criterion.
The licensees provided (16) the following EDG failure counts:
Last 20 Last 50 Last 100 IQG Damands atmandi Demands A
0 0
0 8
0 1
2 l
i Review of Licensee submittal i
(
The factors which affect the estimation of the 580 coping daration are:
the estimated frequancy of LOOPS due to the severe and extremely severe
[
weather' conditions. the classification of EAC group, and the selection of EDG target reliability. The licensee's estimation of the frequency of LOOP due to severe weather (SW) is consistent with the data provided in Table 3.2 of NUMARC 87 00.
The licensee's estimation of remaining t
factors were not consistent with the guidance provided in RG 1.155 and NUMARC 87 00. The following summarizes our findings:
Indenandance of Offsite Power (I) Groun -- The licensee claimed to be in group '!!" based on two electrically independent switchyards and separate incoming transmission lines. This assessment is not consistent with the guidance as documented under question 3.2 in NUMARC 87 00 supplemental Questions / Answers (15). Turkey Point has one switchyard, L
with a ring bus containing several circuit breakers that can be opened to provide independent offsite power sources.
However, this assessment 7
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is not consistent with the definition of independent switchyards given in Table 5 of RG 1.155.
The guidance in NUMARC 87 00 Supplemental Questions / Answers states that multiple switchyards 'must be physfcally and electrically Independent.' The electrical separation should be provided by two or more normally open breakers.
Physical independence requires that the switchyards be separate and distinct, and each bounded by a perimeter fence.
Although, Turkey Point may operate the ring bus as if there are two electrically independent circuits, they are co-J located in a sinale switchyard.
Therefore, we conclude that the Turkey-Point site does not have multiple independent switchyards necessary for it to be categorized as "II".
During the site audit review, the licensee stated that Turkey Point can be considered either as "12" or "!!" grouping.
Figure 1 was supplied by the licensee (16) to show the AC power configuration system down to the 4160Vsafetybusses(3A,3B,4Aand48). The licensee stated that after the loss of the normal AC power source (the main generator), there is an automatic transfer of emergency safety feature (ESF) busses to the preferred alternate power source (offsite power through the start up transformer).
If the startup transformer fails, a manual transfer can be made to power one of the safety busses (3A or 4A) from '.he opposite unit's startup transformer and the other safety bus (38 or 48) car be energized by additional manual breaker actions. The licensee added that l
with the installation of the safety grade intertie an additional method e
l' of supplying AC power to safety bus 38 or 48 will be available.. The licensee's action to provide power to the safety bus 3B or 48 in order to comply with the RG 1.155 requirement that all ESF buses are powered after the transfer requires the following clarifications: 1)the licensee needs to identify the exact nature of the manual breaker operation and the offsite power sources for powering the safety bus 3B or 48, at 2) the licensee needs to verify that each of the unit startup transformers has sufficient capacity to support the loads on the ESF buses of both units. The first clarification is needed to ensure that the equipment and the power source are properly identified and covered by an appropriate procedure and quality assurance program. Figure 1 8
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indicates that the plant appears to have capability to power safety Bus 3B and 48 from "C" transformers. However, this needs to be verified.
Only an affirmative answer to one of the above clarifications is 1
required for the unit to be classified as "12" grouping.
Otherwise, it should tie classified as "!3."
Emeroenev'AC Power Confiauration (EAC) Groun -- The license there are four redundant EDGs (after the addition of two new EDGs), and only one is required to achieve and maintain safe shutdown at both units, therefore, the EAC power configuration is group "A'.
However this assessment does not conform to the NUMARC 87-00, Iart 2A and 2B guidance, since at Turkey Point one of the EDGs is being proposed as an AAC.
In accordance with NUMARC 87 00 guidance there will be three EDGs (instead of four) available for the determination of the EAC Group.
After the installation of the two new EDGs, Turkey Point will have two normally dedicated EDGs per unit, which automatically respond to the LOOP needs'of the connected unit. Thu ena out of two EDG cJnfiguration per unit results in an EAC classification of group 'C " The EAC classification can also be dctermined on a shared EDG basis.Since one EDG is to be used as at AAC source, as stated in the licenroe's submittel, this must be subtracted from the total nun.oer available in accordance with NUMARC 87 00, Section 3.2.2. Part 2A, Paragraph B.
This configuration results in 3 shared EDGs available with one required for safe shutdown.
From Table 3-7 of NUMARC 87 00, the resulting classification is "C.*
Extremelv Severe Weather - The licensee's estimation of ESW group 4 4
for the Turkey Point site is based on the results of two studies; one wasperformedfortheNRCbySandiaNationalLaboratory(SNL)as documented in NUREG/CR 4762 (12) using wind data from WASH-1300 report, and the second one was performed by Dames and Moore, a consultant to FPL, using wind data from four separate studies:
The National Hurricane Center (NHC), the National Bureau of Standards (NBS), the University of Western Ontario (UWO), and the Federal Emergency Nanagement Agency 10
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(FEMA)-asdocumentedinReference(13).
The results of these two studies indicate that the frequency of hurricane wind speeds of greater
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than 125 mph to range between 6E 4/Yr. (FEMA data) and 7.3E-3/Yr. (UWO data) with the WASH 1300 and the NHC data resulting in a range from
)
6.3E 3/Yr. to 2.1E-?!Yr., respectively.
The above results were obtained by linear interpolation of the data which was provided to us by the L
licensee on two selected tables (16).
These data indicate that the site.
should be in ESW group 4.
However, if the licensee were to use the National Oceanic and Atmospheric Administration (NOAA) data, which is given in Table 3 2 of NUMARC 87 00 and is based on 100 years weather data, the site would be in ESW group 5, with an estimated frequency of hurricane wind speeds of greater than 125 mph of 2.3E 2/Yr.
This 1
frequency (2.3E 2/Yr.) is three times larger than the highest frequency estimated by the licensee.
The licensee needs to resolve the difference between these results, or, use ESW group 5 for the Turkey Point site per NUMARC 87 00 Table 3 2.
Qff, tite Power Desian Charnetaristic (P) Groun -- Turkey Point has experienced two grid-related LOOPS of greater than 1/2 hour in duration in the last 20 years in addition to several shorter events.
Occurrence of only one such event could olt.ce the plant in the "P3" group.
Both h
NUMARC 87 00 and HUREG 1032 consider the Turkey Point site to be vulnerable to grid-related LOOP events. This would place the plant in
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Group "P3" without further analysis (Reference 7. Table 4).
- However, l
_the licensee claims'that in the last 10 years the southeastern. Florida i
grid has been significantly strengthened by improved recovery procedures, additional 500 kV lines, and improved interconnections to l
gas turbines in the general area. Table 4 of RG 1.155 allows exemption from this automatic "P3" categorization of plants experiencing frequent l
LOOPS if the site has procedures to recover offsite power from a reliable source within approximately 1/2 hour following a grid failure, Florida Power & Light has grid wide offsite power restoration procedures for' supplying power to the Turkey Point site following a grid failure.
The grid can be powered from several sources, including several gas turbine sites in southern Florida. Based on these improvements, the 11 i
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. licensee claims that-Turkey Point should not to be categorized as a "P3" site' solely due to the past grid-instability problems.
q We believe southern Florida is exposed to the most severe hurricanes and U
the site geographic limitations hamper the availability of offsite power from multiple sources. (Turkey Point cannot get power from the east and essentially cannot get power from the south.) Turkey Point is 4
susceptible to both weather related (ESW 5) And grid-related events, I
therefore, it automatically falls into the "P3" group.. Since the licensee stated that the existing procedures will be modified to include criteria for shutdown of the units two hours prior to the arrival of hurricanes (16) consistent with the guidance provided in NUMARC 87-00, the site can be categorized as "P3*."
i a
EDG Taraet Reliability / Conina Duration - The licensee stated-that the assignment of the EDG target reliability of 0.95 is supported by the diesel reliability analysis performed by the FPL staff.
A review of the information in NSAC-108 indicates that EDGs A and B (which will be renamed to 3A and 3B once the new EDGs are installed) have an average of
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70 and 67' valid demands per calendar year and had reliability levels of 1
-higher than 0.975.
The licensee's a dfysis showed that EDG A q
L experienced six failures in 1987, but aas improved since then. No l
failures have occurred since January 1988 (through June 1989). EDG B has
/
experienced two failures since January 1987, both in 1988. Although l
[
exact demand courits-are not available, the EDGs are apparently p
. performing adequately for selecting either 0.95 or 0.975 as a
- reliability goal. The licensee expects continued high diesel reliability.because the EDGs are continually pre-lubricated and warmed and'the fcrmalized EDG preventive maintenance program has been effective.
The licensee believes that the present EDG reliability program is b
sufficient to sati. sty the guidelines of Regulatory Guide 1.155, Section
.l.2 and NUMARC 87-00, Appendix D.
The licensee stated that, following the closure of the NRC/ industry initiatives on EDG reliability (the 1
12
c.,
generic safety issue B 56) the new guidance will be reviewed and appropriate enhancement will be made to the current program (16),
n' The results of our review indicate that the offsite power characteristic and the EAC configuration grouping of the site'are "P3*" and "C",
respectively. Using Table 3 8 of NUMARC 87-00, the site required coping duration would be four hours with an EDG target reliability of 0.975, or
.eight hours with an EDG target reliability of 0.95. The licensee's l
coping analysis was performed for a 4-hour SB0 coping duration. We reviewed the licensee's submittal for a coping duration of eight hours as' required for an EDG-target reliability of 0.95. The licensee was informed by the NRC staff that the plant's offsite power characteristic is "P3*" and should cope-for eight -hours, if a target EDG reliability of 0.95 is selected.
In response the licensee stated (17) that, they do not agree with the NRC's assessment but-will stay with 0.95 EDG target reliability, and that the plant can cope with an SB0 for eight hours satisfactorily.
3.2 Alternate AC (AAC) power-source Licensee submittal:
The licensee stated that the AAC. power source is a class 1E emergency diesel generator (EDG). The EDG used as an AAC source could be any one of the four onsite EDGs providing power from the non blacked out unit to the blacked out unit through the new proposed intertie described in
'Section 3.6.
The licensee stated that one EDG has adequate power to successfully power both units during an SB0 event. The licensee stated that the AAC line-up will be completed 10 minutes after the operators perform the immediate steps in the Emergency Operating Procedures (EOPs) to verify the scram and other primary system parameters and attempt to restore offsite power and start the failed EDGs-from the control room.
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Review of Licensee Submittal:
The licensee is using the existing EDG as an AAC power source; The p
guidance on the use of existing emergency diesel generators.(EDGs) as L
-alternate AC (AAC) power sources is documented in RG 1.155, Position C.3.3.5, NUMARC 87-00; Section 2.3.1(3), and it is further explained under questions 3.4 and B.3 in NUMARC 87 00 Supplemental Questions and l!
Answers.
The station blackout rule states (1):
"At multi-unit sites, where the combination of emergency AC power
-sources exceeds the minimum redundancy requirements for safe shutdown (non DBA) of all units, the remaining emergency ac power sources may be used as alternate AC power sources provided they meet the applicable requirements."
The guidance provided by the staff (1) indicates that in order for an EDG to qualify as an AAC power source, there must be an EDG available in the non blacked out (NBO) unit that is in addition to the number of EDGs required to meet the minimum EDG redundancy requirement for powering a normal safe shutdown for a loss of offsite power (LOOP) event.
Thus a
plants with two dedicated EDGs per unit could not claim credit for an AAC source because the two EDGs per unit just meet.the minimum 4
redundancy requirement, i.e., there is no' excess EDG.
However, there are some plants at multi-unit sites which have-EDGs that just meet the minimum redundancy but.each EDG has sufficient capacity to fully power all the normal LOOP loads of the NB0 unit and also has sufficient excess capacity to power the required safe shutdown loads of-U the SB0 unit.
In recognition of the existence of this type of situation, the NRC staff has interpreted the '1/teral' excess EDG redundancy requirement of the SB0 rule to allow large EDGs to qualify as AAC sources, provided other applicable requirements are met.
In order to take credit for this' interpretation, the NRC staff's position has been (18, 20 and 21) that:
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1.
No action should be taken that would exacerbate the already difficult situation in the NB0 unit.
Each unit must meet the SB0 rule:on its own merits without reducing another unit's capability to respond to its own potential problems.
Load switching or disablement of information readouts or alarms in the control roo:n are considered to be a degradation of normal safe shutdown capability for LOOP in the NB0 unit.
2.
The excess capacity of the EDG being designated as an AAC source should not be the capacity made available by shedding or not l
powering the normally available capability for safe shutdown LOOP loads in the NB0 unit.
These loads include RHR pumps, HVAC loads,
(
component cooling water pumps, the power supply of the plant L
computer, and annunciator panels, and one or more sets of redundant instrumentation.
The shedding of such loads constitutes i
degradation of the normal safe shutdown capability of the NB0 unit.
The excess capacity of the EDG in the h30 unit is, therefore,
'only that availabic capacity within the nomal continuous rating I
but above the EDG iosd represented by the complete contingent of safety related and non-safety related loads normally expected to be available to the NB0 unit for the LOOP condition.'
The licensee stated that each EDG has sufficient capacity to. power the.
required loads at both units.
In support of this statement the licensee
[
provided the following load parameters indicating the required load to l
power both units (both LOOP and SB0 loads), and the different ratings of each EDG'(in KW):
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[M LOADING
- CONT. RATING 2000 Hr. R&U E 3A 2475.
2500 2850 38 2300.
2500 2850 4A 2565 2874 3095 4A 2390 2874 3095 t
The loading differences are caused by differences in the EDO i
auxiliary loads.
The licensee also provided a breakdown of loads on each EDG (16). On this list,the represented loads are those which are required to keep both plants at' hot standby conditions. The licensee, however, did not consider the RHR pump loading (214 KW) which is required for the NB0 I
unit to be consistent with the NRC's guidance. -The licensee, presently under existing procedures, is permitted to cycle the load required for the' charging pump (125 KW) and the pressurizer heater (150 KW) (19).
In addition, there is apparently a discrepancy in the battery charger
' loading calculation between that given in the plant UFSAR-(revision 7 dated 7/89) (194 KW) and that given in reference 16 (a difference of 44 KW). The sum of tha RHR pump load (214.KW for one pump), the difference between the pressuriter heater and the charging pump load (25 KW), and:
r the difference in the battery charger loads (44 KW), would result in a
-total-of 283 KW load more than that estimated by the licensee.
It L
should be noted that this is not the: final loading on an EDG (used as an l-
- AAC) because it may not include all of the HVAC loads other tha'n those for the control room, computer room /cabit spreading room in both unit, and the battery room in one unit.
If we were to use the licensee's i
estimated loading requirements of 2565 KW (for EUG 4A) and add 283 KW, l
then we would need at least 2848 KW; the corresponding load on-the EDG i
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3A would be 2758. This loading is within the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of these hi
.EDGs. The loading on the EDG 4A (2848 KW) is within its continuous i
rating.
Based on this evaluation, it appears that the EDGs would have sufficient capacity to power the equipment required at both units. The minimum 16 m
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1 excess capacity available is 92 KW (ie. 2850 2758).
The licensee needs to verify that the total HVAC loading in both units for enclosure areas other than the control room, cable spreading room, and battery room is less than 92 KW.
Additionally, the licensee needs to demonstrate by a test that the AAC power source can power the shutdown busses within 10 minutes of the onset of an SBO, in accordance with NUMARC 87 00 Section 7.1.2 and RG 1.155, Section 3.3.5.3.
Daring the site audit review, the licensee stated that this test would be performed as part of the modification.
3.3 Station Blackout Coping Capability-i The licensee's submittal does not document the plant's ability to cope with an SB0 for the required duration.
During the site audit review, the
- licensee stated that since the AAC power source is assumed'to be available c
within 10 minutes from the onset of an SB0 and the coping analysis is not i
required in accordance with 10 CFR 50.63(c)(2).
It is assumed that since the L
AAC is available within 10 minutes the functions needed to cope with an SB0
.are available and adequately powered for the required duration.
L This'section addresses each of the six major areas identified-in SB0
. guidance as being important to cope with an S80.
The plant coping capability with an SB0 for the required direction of eight hours is assessed based on the f
following results:
1.
Condensate inventory for decay heat removal L-Licensee submittal:
During the site audit review the licensee stated that the Turkey Point technical specifications require that each plant maintains a minimum condensate storage level equivalent to 185,000 gallons.
L The plant UFSAR (13) shows that this quantity of water is adequate to keep a unit in hot standby for about 23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br />. This volume of 17 L
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o i
water exceeds ~the quantity required to cope with an SB0 of 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> duration. The licensee indicated that no plant modifications or j
procedure changes are needed'to use this water source.
Review of Licensee Submittal 1
The licensee stated that the turbine driven AFW pumps will supply the steam generators with condensate water to keep the plant at hot standby conditions (no significant cooldown will occur).
Using NUMARC 87-00, Section 7.2.1, and core therm:,1 power of 2296 j
MW, each unit would need 81,630 gallons of condensate to cope with an SB0 event with a duration of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> while removing decay heat only. -the licensee stated that Turkey Point maintains a minimum condensate storage level equivalent to 185,000 gallons for each i
unit per plant technical specification.
Therefore, we agree with i
the licensee that both units have adequate condensate inventory to cope for the required SB0 duration.
The excess inventory available in the CST can be used to assist in $80 recovery, i
2.
Class 1E Battery Capacity Licensee submittal:
c During the audit review, the licensee stated that the class lE
-batteries.at Turkey Point must function for only 10 minutes following the onset of an SB0 event. After the initial 10 minutes.:the AAC source will be operable and it will supply power to all battery chargers.
The licensee added that a11' battery chargers are available as soon as the AAC source is available.
Review of Licensee Submittal:
The battery chargers are available as soon as the AAC source is on line, thus the licensee will have adequate DC power to cope with an SB0 with a duration of eight hours. The licensee stated that 18 i
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3 they are not shedding any DC loads in the non blacked out unit or L
the blacked out unit-that could degrade that units' safe shutdown capability.
-1 3.
Compressed Air
?
Licensee Submittal:
During the audit review, the licensee stated that the air operated valves needed to cope with a station blackout for a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> SB0 y
coping duration are normally supported.by diesel engine driven air L
compressors which will continue to operate during an SB0 event.
Review of Licensee Submittal:
The instrument air system will be available throughout the event, i
We agree with the licensee that adequate instrument air is available to cope with an SBO.
4.
Effects of Loss of Ventilation q
Licensee Submittal:
The licensee did not perform a formal-coping analysis since AAC power is available within 10 minutes.
The licensee assessed the.
availability of ventilation during an SBO,.and reported the following results (16):
1.
The split air conditioning unit for the control building annex is included as a load in the SB0 evaluation. This unit will provide-heat removal from batteries, battery chargers and inverters.
2.
Thecurrentloadcenterandswitchgearrooms(LC-SWGR) air conditioning system is being enhanced as part of the 19
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Emergency Power System (EPS) upgrade. As part of the design i
process, adequate ventilation during station blackout will i
be verified.
U
' 3.'
The current plant design allows for manually re-energizing j
the auxiliary building fans upon restoration of power.
Heat-up of the charger pump rooms or any electrical l
equipment in the. auxiliary buildings, from unit blackout, I
will be avoided by loading these fans on the AAC source after power is restored to the emergency buses.
Review of Licensee submittal:
I The EDG loading estimates provided by the licensee (16) did not include the HVAC loading-for all the areas where a heat generating source is present. This applies to both the NB0 and SB0' units..
The list of the EDG loads provided by the licensee included only the HVAC loads for the control room, and computer / cable spreading room for each unit and the battery room for one unit. Our review of the required-loads on EDGs indicates that the total loads are less than the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the existing EDGs by 92 KW.
The licensee needs-.to verify that with the above additional air
. conditioning loads romain below 92 KW, or provide assurance that the equipment operability is not degraded in the NB0 and SB0 units.
' 5.
Containment Isolation l-L Licensee submittal l
Containment isolation was not addressed in the submittal. During the site audit review, the licensee stated that all busses would be energized upon the availability of AAC power. The licensee stated that this would allow for the normal establishment and verification of appropriate containment integrity.
20
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1 Review of Licensee submittalt-
)
The unit intertie allows the licensee to power both' division of l
safety buses in the blacked out unit uring one of the EDGs in the NB0 unit.
Since this power, AAC power source, is available within 10 minutes to these buses, containment integrity is assured.
6.
Reactor Coolant Inventory Licensee Submittal:
During the audit review, the' licensee stated that the AAC source powers the~necessary make up systems including one charging pump
^
for adequate reactor coolant inventory to ensure that the core is covered for the required SB0 duration of four hours.
Review of Licensee Submittals i
The reactor coolant system (RCS) losses which the licensee needs to consider are:
1.
25 gpm per pump losses through reactor coolant pump seals' per NUMARC guidelines, 4
2.
maximum allowable RCS leakage per plant technical specifications.
l L
Turkey Point has three reactor coolant pumps resulting in an L
assumed 75 gpm seal leakage from the reactor coolant system (RCS).
The maximum allowed RCS leakage is assumed to be 25 gpa.
l:
Therefore, a total of 100 gpm leakage from the RCS must be made up in order to maintain inventory.
Turkey Point has three positive displacement charging pumps, each is capable of delivering 75 gpm each. The licensee stated that there would be no significant 21
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cooldown;- only decay heat would be removed.
From our analytic experience of similar plants, using a not RCS leakage of 25 gpm would not result in core uncovering during an 580 with a duration of eight hours, provided that no RCS shrinkage occurs.
3.4~
Proposed Procedure and Training Licensee Submittal:
The licensee stated that existing plant policies and guidelines for training will be used upon issuance of new and revised procedures.
The licensee also stated that these policies will ensure that operators are i
adequately _ prepared to cope with station blackout events.
The licensee stated-(11) that the procedures that will be used to cope with a station blackout event are:
1.
New emergency procedure to cross-connect any EDG to it's bus and a bus'on the other unit. Loss of all AC power on Units 3 and 4 will be precluded by deveioping a procedure which will allow the l;
operators to use any one of the four EDGs in the enhanced system
. design to safely shut,down and maintain both nuclear units in hot i
g standby conditions for the required SB0 duration. The licensee stated that the procedure (s) will include containment isolation J-cnd'AC recovery.
2.
Existing-procedures which allow use of the five blackstart diesel l
generators will be modified to accommodate the two new EDG's.-
4 y
3.
The existing emergency procedure will be modified to' include additional criteria for unit shutdown for hurricanes.
1 Review of Licensee Submittal:
Our review did not examine the affected procedures or training. These-procedures are plant specific actions concerning the required activities 22 4
. j l.
i to cope with an SB0 event.
The licensee identified the procedures that need to be modified and/or created to cope with an SB0 event.
It is the
. licensee's responsibility to revise and implement these procedures, as needed, to mitigate an SB0 event and to assure that these procedures are complete and correct in their contents and that the associated training needs are carried out accordingly, f '
- 3.5 Proposed Modifications f
Licensee submittal:
FPL~is presently, in an effort separate from SB0 requirements, adding two new EDGs along with new 4.16 KV switchgear, 480V-load centers, motor i
control centers, battery chargers and 125 VDC distribution panels.
In order to meet the SB0 requirements, FPL proposes to intertie Units 3 and 4 via the new swing switchgear (buses 30/40)._ This approach, as illustrated in Figure 1, will utilize a new tie between 30 and 40. -The licensee states that since each swing switchgear has the capability to receive power from its A or B EDG, at least one swing switchgear is i
L always assured a source of power.
The licensee claims that a safety bus
'on the blacked out unit could then be re-energized via the 30 and 4D switchgear within ten minutes from the control room.
Tii current integrated schedule completion date is the end of 1990 (Unit 3 Diesel Tie-in and Unit 4 Cycle 13 Refueling Outages).
Review of Licensse' Submittal:
The licensee stated that this design change will be implemented in accordance with the applicable design and licensing requirements to comply with the guidance of RG 1.155 and NUMARC 87-00.
If properly implemented, this design change will significantly improve the reliability of the site AC power system.
l 23 l
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9:.
m 3.6 Quality Assurance And Technical Specifications
.0uality Assurance 1
.The licensee stuted that:
"FPL resolution of Station Blackout encompasses procurement and use of n].y safety grade equipment housed in'setsnically qualified buildings."
0 Bastd on our audit, it appears that all equipment necessary to cope with i
a station blackout is covered by a QA program that is consistent with the guidance of Appendices A and B of RG 1.155.
Technical Soecification The licensee did not identify any changes to current technical-specification for the involved SB0 equipment.. Our review of the licensee's approach indicates that the equipment necessary to cope with an SB0 (EDGs, AFW, CST, batteries, etc.) is already covered by technical specification.
24
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3; +.
4.0' CONCLUSIONS:
Based on our review of the licensee's submittal and the related supporting documents and discussions during a site audit for the Turkey Point Units 3 'and 4'we find that the submittal conforms to' the station blackout rule 4
and the guidance of RG 1.155 with the following exceptions:
1.
Proposed Station Blackout Duration a.
Offsite Power Desian Characteristic Groun I
The Turkey Point site has experienced several grid related LOOPS in the last 20 years, and based on NRC data it is categorized as j
ESW group 5.
Either the grid-related LOOP frequency of greater pu than one in 20 or the ESW group 5, in conjunction with the plants pre hurricane shutdown procedures, would place the plant in group h
"P3*."' The licensee claims that the site is in ESW group 4 and L4 requests an exemption from the grid related LOOP frequency h
criterion' based on grid improvements.
Howeyw, the preponderance of evidence indicates that the plant is in group "P3*" (see Section3.1).
1 L
b.
Emeraency AC Power Confiauration (EAC) Groun g
The licensee claims that the EAC configuration is "A."
Our review indicates that it should be classified as an EAC group "C" based on the proposed modification (see Section 3.1).
The licensee can.
not take credit for one EDG to serve both as an EAC and an AAC source..
c.
Indeoendence of Offsite Power (I) Groun l
l The licensee claims that Turkey Point can be considered either as "II" or "I2" grouping. Our review indicates that they can not be classified as "II"'because the site does not have multiple 25 l
t
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L:,[ -
- f...
- switchyards which are physically and electrically independent.
For the site to be considered as "12" the licensee needs to verify-that each of the unit startup transformers has sufficient capacity to support the loads on the ESF buses of both units, or.if other i
sources are used for the alternate preferred power source the-licensee needs to state the exact nature of the manual breaker I
operation and the capacity of the power source.
Otherwise, it should be classified as "I3."
However, the "I" classification does not change the determination of "P3*."
d.
SB0 Conino Duration and EDG Taraat Reliability Based on.. items a and b,-the licensee can claim a required coping duration of four hours with an EDG target reliability of 0.975 or a required coping duration of eight hours with an EDG target reliability of 0.95. Although the coping analysis was performed for a ~4-hour 580 duration, the licensee stated that the plant can adequately cope with an eight hour SBO.
2.
Effects of-Loss of Ventilation The licensee stated that.HVAC systems will be available to all l
dominant areas of concern. Our evaluations indicates that, as E
long'as-the additional HVAC loads does not exceed 92 KW, the total required. loads will remain within the 2000 hr rating of the smaller EDGs. The licensee needs to verify that the total load including HVAC loads remain within the rating of the EDG (2850 KW)-
i or. provide assurance that'the equipment operability is not L
degraded in the NB0 and-SB0 unit.
L 3.
Alternate AC Power Source I
The licensee needs to demonstrate, by a test, that the AAC power source can power the shutdown busses within 10 minutes of the onset of an SBO, in accordance with RG 1.155, Section 3.3.5.3.-
L 26 1
i l
1-
4- [.k,
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' s 4.
Emergency Diesel Generator Reliability Program The licensee's submittals do not document the conformance of the
]
plant's EDG reliability program with the guidelines of Regulatory Guide 1.155, Section 1.2 and NUMARC 87-00, Appendix 0.
The I
licensee stated that the present EDG' reliability program is 1
sufficient to satisfy the above guidance.
The licensee stated, however,- that a reliability program will be evaluated against the above guidance and will be adjusted to. meet the intent, r
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a J
5.0 REFERENCES
z 1.
The Office of Federal Register, " Code of Federal Regulations Title 10 Part 50.63," 10 CFR 50.63, January 1, 1989.
l 2.
U.S. Nuclear Regulatory Comission, " Evaluation of Station Blackout Accidents at Nuclear Power Plants - Technical Findings Related To Unresolved. Safety Issue A 44," NUREG-1032, Baranowsky, P. W., June 1988.
3.
U.S. Nuclear Regulatory Comission, " Collection and Evaluation of Complete and Partial losses of Offsite Power at Nuclear Power Plants,"
NUREG/CR 3992, February 1985.
4.
U.S. Nuclear Regulatory Comission, " Reliability of Emergency AC Power
. System at Nuclear Power Plants," NUREG/CR-2989, July 1983.
5.
U.S. Nuclear Regulatory Comission, " Emergency Diesel Generator i
Operating Experience, 1981-1983," NUREG/CR 4347, December 1985.
6.
U.S. Nuclear Regulatory Comission, " Station Blackout Accident Analyses (Part of NRC Task Action Plan A 44)," NUREG/CR-3226, May 1983.
7.
' U,S. Nuclear Regulatory Comission Office of Nuclear Regulatory Research, " Regulatory Guide 1.155 Station Blackout," > August 1988.
E
.8.
Nuclear Management and Resources Council, Inc., " Guidelines and L
Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors," NUMARC 87-00, November 1987.
9.
Thadani, A. C., letter to W. H. Raisin of NUMARC, " Approval of NUMARC Documents on Station Blackout (TAC-40577)," dated October 7, 1988, 10.
Nuclear Safety Analysis Center, "The Reliability of Emergency Diesel l
Generators at U.S. Nuclear Power Plants," NSAC-108, Wyckoff, H.,
September 1986.-
28
tr..
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,3 q.e i
11.
Conway,.W. F., letter to the Document Control Center of the U. S.
Nuclear Regulatory Commission, " Turkey Point Units 3 and 4, Docket Nos.
4 50-250 and 50-251, Information to Resolve Station Blackout," FPL L 89 144, 10 CFR 50.63, dated April-17, 1989.
12.
U.S. Nuclear Regulatory Commission, " Shutdown Decay Heat Removal Analysis of a Westinghouse 3-Loop Pressurized Water Reactor Case t
Study," NUREG/CR-4762, dated 1986, 13.
Dames & Moore, " Updated Report - Probabilistic Hurricane Analyses.
1 Methodology Development - Turkey Point and St. Lucie Nuclear Power Plants for Florida Power & Light Company", January 1989.
14.
Florida Power & Light, " Updated Final Safety Analysis Report - Turkey Point Units 3 and 4".
15.
- Thadani, A. C., letter to Marion A., of NUMARC, " Publicly-Noticed Meeting December 27, 1989," dated January 3, 1990 (confirming "NUMARC 1
87-00 Supplemental Questions / Answers", December 27,1989).
I i
.16.
Harris, K. N., letter with attachment to the Document Control Desk of the U. S. Nuclear Regulatory Commission, " Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251, Information to Resolve Station Blackout",
~
L-90-56, March 29,'1990.
l 17.
Telecon from Remo Gritz of FPL to Argil Toalston of NRC dated May 2,.
1990.
18.
Tam, P. S., Memorandum for, " Daily Highlight-Forthcoming Meeting with -
NUMARC on Station Blackout (SBO) Issues-(TAC 40577)," (providing a Draft Staff Position Regarding Use of Emergency AC Power Sources (EDGs) as l.
Alternate AC (AAC) Power Sources, dated April 24,1990), dated April 25, L
1990.
L 1
29
.,s
.",[*
19.
Woody,C.O.(FPL)letterwithattachmenttoL.S.RubensteinofNRC,
" Turkey Point Units 3 and 4. Docket Nos. 50 250 and 50 251. Emergency l
Diesel Generator load Evaluation," L 86 243, dated June 12, 1986.
20.
Rosa, F. letter to Duquesne Light Company - Beaver Valley Units 1 and 2
" Meeting Summary - Meeting of February 22, 1990, on Station Blackout issues (TAC 68510/68511)," Docket Nos. 50-334 and 50 412, dated-March 6, 1990.
21.
Russell, W. T. (NRC) letter to W. Raisen of NUMARC, " STATION BLACKOUT,"
dated June 6, 1990.
30
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