ML20043G369
| ML20043G369 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, McGuire  |
| Issue date: | 06/07/1990 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML20043G366 | List: |
| References | |
| NUDOCS 9006200200 | |
| Download: ML20043G369 (45) | |
Text
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McGuire Units 1 and 2 Technical Specifications Changes Requests j f
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CONTAINMENT SYSTEMS
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3/4.6.5 ICE CONDENSER ICE-BED LIMITING CONDITION FOR OPERATION s
3.6.5.1 The ice bed shall be OPERABLE with:
- a. The stored ice having a boron concentration of at least 1800 ppe boron as sodium tetraborate and a pH of 9.0 to 9.5,
- b. . Flow channels through the ice condenser, L c. A maximum ice bed temperature of less than or equal to 27'F, l 1,ons,,9e
- d. A total ice weight of at least.2,'!!,020 pounds at a 95% level }
of confidence, and e.. 1944 ice baskets.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
With the ice bed inoperable, restore the ice' bed to OPERA 8LE status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />'or be in at least HOT STANC8Y within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUT-DOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />, i
SURVEILLANCE REQUIREMENTS t-4.6.5.1 The ice condenser shall be determined OPERABLE:
- a. At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by using' the Ice Bed Temperature Monitoring System to verify-that the maximum ice bed temperature is less than or equal to 27'F,
- b. At least once per 9 months by:
- 1) Chemical analyses which verify that at least nine representative samples of stored ice have a boron concentration of at least 1800 ppe as sodium tetraborate and a pH of 9.0 to 9.5 at 20'C; tost
- 2) Weighing a representative sample of at least 144 ic baskets and verifying that each basket contains at least 1bs of l
[ ice. The representative sample shall include 6 baskets from each of the 24 ice condenser bays and shall be constituted of i
McGUIRE - UNITS 1 and 2 3/4 6-34 A ncy,mcy, N., (w.,, o A ncy, n e-, N.. (u-ru
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l CONTAIMENT SYSTEMS 7
SURVEILLANCE REQUIREMENTS (Continued) loff J c 1 basket each from Radial Rows 1, 2, ,4, 6,/8, and 9 (or from.
the same row of an adjacent bay if a bas t from a designated row cannot be obtained for weighing) wi in each bay. If any basket is found to contain less than pounds of ice, a l representative sample of 20 additional baskets. from the same l bay shall be weighed. The minimum average weight of ice from the 20' additional-baskets and the discrepant basket shall not '
~ be less than.1369 pounds / basket at a 95% level of confidence.- l t e ti The ice condenser shall also be subdivided into 3 groups of baskets, as follows: Group 1 - Bays 1 through 8. Group 2 -
o Bays 9 through 16, and Group 3 - Bays 17 through 24.. The' '
minimum' average ice weight of the sample baskets from Radial Rows-1, 2, 4, 6, 8, and 9 in each group shall not be less than
.4269" pounds / basket at a 95% level of confidence. ,
j to8I The minimum total ice condenser ice weight at a 95% level of confidence shall be calcu1Ated using all ice basket weights determined during this weighing program and shall not be less than.2,466742trpounds; and I 4 2., o e 9,7 9 o ;
- 3) Verifying, by a visual inspection of at least two flow passages
! m per. ice condenser bay, that the accumulation of frost.or ice on flow passages between ice barkets, past lattice frames, through
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the intermediate and top deck floor grating, or past the lower inlet plenum support structures and turning vanes is restricted to a thickness of less than or equal to 0.38 inch. If one flow passage per bay is found to have an accumulation of frost or ice with a thickness of greater than or equal to 0.38 inch, a representative sample of 20 additional flow passages from the same bay shall be visually inspected. If these additional '
flow passages are found acceptable, the surveillance program may proceed considering the single deficiency as unique and accept-able. More than one restricted flow passage per bay is evidence l
l.
of abnormal degradation of the ice condenser.
- c. At least once per 40 months by lifting and visually inspecting the accessible portions of at least two ice baskets from each one-third of the' ice condenser and verifying that the ice baskets are free of detrimental structural wear, cracks, corrosion, or other damage.
The ice baskets shall be raised at least 12 feet for this inspection.
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McGUIRE - UNITS 1 and 2 3/4 6-35 gg Q {"J'l0
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CONTAIMENT SYSTEMS BASES 3/4.6.5 ICE CONDENSER The requirements associated with each of the components of the ice con-denser ensure that the overall system will be available to provide sufficient
, pressure suppression capability to limit the containment peak pressure tran-4 sient to less than 14.8 psig during LOCA conditions.
3/4.6.5.1 ICE BE0 The OPERABILITY of the ice bed ensures that the requ' ired ice inventory will: (1) be distributed evenly through the containment bays, (2) contain sufficient boron to preclude dilution of the containment sump following the LOCA, and (3) contain sufficient heat removal capability to condense the Reactor Coolant Syste.m volume released during a LOCA. These conditions-are consistent'with the assumptions used in the accident analyses.
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The minimum weight figure of la69 pounds of ice per basket contains afl0% l conservative allowance for ice loss through sublimation hich is a factor of 10 higher than assumed for the ice condenser design. T e minimum weight figure V"d" oPA466T420' pounds of ice also contains an additional conservative allowance l to account for systematic error in weighing instruments. In the event that y observed sublimation rai.es are equal to or lower than design predictions after 3 years of operation, the minimum ice baskets weight may be adjusted downward.
In addition, the number of ice baskets required to be weighed each 9 months may be reduced after 3 years of operation if such a reduction is supported by-observed sublimation data.
3/4.6.5.2 ICE BED TEMPERATURE MONITORING SYSTEM The OPERABILITY of the Ice Bed Temperature Monitoring System ensures that the capability is available for monitoring the ice temperature. In the event the system is inoperable, the ACTION requirements provide assurance that the
- ice bed heat removal capacity will be retained within the specified time k limits.
3/4.6.5.3 ICE CONDENSER 000RS The OPERABILITY of the ice condenser doors and the requirement that they
- be maintained closed ensures that the Reactor Coolant System fluid released during a LOCA will be diverted through the ice condenser bays for heat removal and that excessive sublimation of the ice bed will not occur because of warm air intrusion.
If an. ice condenser door is not capable of opening automatically, then . ;
system function is seriously degraded ed immediate action must be taken to j restore the opening capability of the door. Not capable of opening automati- 9(
cally is defined as those conditions in which a door is physically blocked from opening by installation of a blocking device or by obstruction from temporary b "
or permanent installed equipment or is othenvise inhibited from opening such as may result from ice, frost, debris or increased door opening torque. G Amendment No. (Unit 2) l McGUIRE - UNITS 1 and 2 B 3/4 G-S Amendment No. (Unit 1) i k
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ATTACHMENT 2 Justification and Safety Analysis
Introduction:
The requested changes to McGuire Nuclear Station Technical Specification (T.S.' 3/4.6.5.1 reduce the required ice bed ice weight (total ice bed and per i ice basket) of the containment ice condenser, and correct an error in the T.S.'s Bases Section. These changes would provide needed additional flexi-bility in maintaining required ice bed ice weight.
Background /Justi fication:
As discussed in FSAR Section 6.2.1.1.1, the primary function of the Ice l Condenser (NF) system is the absorption of thermal energy released abruptly in the event of a Loss of Coolant Accident (LOCA) for the purpose of limiting the initial peak pressure in Containment. One of the secondary functions of the NF system is the further absorption of energy after the initial incident L causing Containment pressure to be reduced and held at a lower level for a l period of time.
l The Ice Condenser is subdivided into 24 bays which contain 1944 ice baskets that are 12 inches in diameter and 48 feet long. Each bay consists of 9-l columns and 9 rows of ice baskets. The Ice Condenser is also subdivided into 3 groups of baskets with Group I consisting of bays 1 through 8, Group 2 consisting of bays 9 through 16, and Group 3 consisting of bays 17 through 24.
l The ice baskets ensure that ice inventory will be distributed evenly and i contain suf fic' mt heat removal capability.
4 Technical Specification 3/4.6.5.1 specifies that the ice bed shall be operable i with a total ice weight of at least 2,466,420 pounds at a 95% level of confi- '
dence (LOC) with 1944 ice baskets. This is the minimum amount of ice to be' l maintained in the ice condenser to control the anticipated heat load during a large scale LOCA. These conditions are applicable in Mode 1, Power Operation, Mode 2, Start-up, Mode 3, Hot Standby, and Mode 4, Hot Shutdown. The T.S.
action statement specifies that with the ice bed inoperable, restore the-ice bed to operable status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or the unit must be in at least Hot l Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the fo110 wing 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
Per FSAR Section 6.2.1.1.3.1, Containment Fcoctional Design Evaluation for the Loss of Coolant Accident (as updated via Attachment 2A, "McGuire Nuclear Station FSAR 1989 Containment Pressure Calculation", which has not yet been incorporated into the FSAR), the " Peak Containment Pressure Transient" analysis assumes 2,220,000 pounds of ice initially in the ice condenser (basis for the Technical Specification Limit). The minimum T.S. specified ice bed ice weight of 2,466,420 pounds contains a 10% conservative allowance for ice loss through sublimation which is conservatively a factor of 10 higher than assumed for the ice condenser design (Westinghouse has stated that the ice l condenser has an assumed sublimation rate of 1% per cycle), and also contains an additional 1.1% conservative allowance to account for systematic error in weighing instruments (Note that T.S. 3/4.6.5.1's Bases Section incorrectly
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states that the instrument error is 1% rather than the actual value of 1.1%).
These conservative allowances are intended to ensure that actual total ice bed ice weight remains above the value assumed in the FSAR analysis for the duration of the fuel cycle. Thus, the T.S. minimum ice bed ice weight is calculated as 2,220,000 lbs. plus 11.1% (246,420 lbs.) equals 2,466,420 lbs.
.T.S. 4.6.5.1 requires that at least once per 9 months a representative sample of at -least 144 ice baskets be weighed to verify a 95% LOC minimum average weight for bay and row group ice baskets of 1269 lbs. (i.e., 2,466,420 lbs.
T.S. total ice bed ice weight divided by 1944 required ice baskets in ice condenser equals 1268.73 lbs, per ice basket, conse .atively rounded up to
-1269) and ice bed total of 2,466,420 lbs. If any basket is found to contain less than 1269 lbs. of ice, a representative sample of 20 additional baskets from the same bay shall be weighed. The minimum average weight of ice from the 20 additional baskets and the discrepant basket shall not be less than 1269 lbs. per basket at a 95% confidence level. The basis for this require-ment recognizes that ice basket degradation (e.g., sublimation) will occur during unit operation resulting in lowered ice weights (some possibly below 1269 lbs.), and it is not meant to impose this weight limit for all baskets at all times as long as the total ice bed ice weight can be shown to be not less than 2,466,420 lbs. at a 95% LOC (i.e., the ice condenser does not have to be declared inoperable just because a surveilled ice basket weighs less than 1269 lbs.).
As noted above the T.S. limiting condition for operation (LCO) total ice bed ice weight specified was determined / calculated to ensure the actual ice bed ice weight remains above the value assumed in the FSAR analysis for the duration of the fuel cycle. Therefore, the T.S. surveillance requirements were written to ensure that the actual minimum average ice weight for any statistical sub group always remains above 1141.98 lbs. (i.e., the FSAR analysis assumed ice weight per ice basket, 2,220,000 lbs. divided by 1944 ice
-baskets), and-thus the actual total ice bed ice weight above 2,220,000 lbs.,
for the duration of the surveillance interval. The surveillance requires that ice weight be measured at a point in time (i.e., at least once per 9 months),
and assumes the 10% conservative allowance added will account for expected sublimation until the next required surveillance, and the 1.1% conservative allowance added will account for any instrument weighing errors. Thus, as long as the measured average ice basket ice weight is at least 1269 lbs. when the surveillance is performed, the actual ice bed ice weight should remain above the weight assumed in the FSAR analysis until the next required surveil-lance (at which time ice could be added if needed). Therefore, normal degrad-
-ation of the ice bed following surveillance is not considered an operability concern. Note that the minimum average ice weight for the duration of the surveillance interval for any statistical sub group based on r asured (weighed) values is 1155 lbs./ basket (i.e. , 1141.98 plus the 1% instrument weighing uncertainty equals 1154.54, conservatively rounded up), and is referred to as the " safety margin".
Past operating experience indicates that for Unit 1 Cycle 7 (which will be an extended fuel cycle), all group 1 row 9 95% LOC ice weights will be below T.S.
limits and only marginally above safety margin at the end of the cycle.
Consequently, Unit 1 may be unable to operate full cycle under the current T.S.'s without shutting down to reload ice. The 95% LOC weights are significantly influenced by the small population of accessible baskets.
1 However, the available baskets are believed to have a slightly lower weight relative to the balance of row baskets. It is postulated this is a result of a greater surface area exposed to dry air currents from a lesser amount of surrounding frost. The greater exposed area corresponds to a greater sublimation rate potential. Although the condition of Unit 1 is more critical, Unit 2 is not far behind. Accordingly, to ensure ice condenser availability attention must be devoted to this problem immediately. As virtually all row 9 ice baskets are replenished each outage greater replenishment criteria cannot help this specific problem. .
Current McGuire Nuclear Station containment pressure analysis calculate a peak l pressure during a design basis accident of approximately 12.4 psig (see Attachment 2A - Note that subdivision, table, reference and figure numbers referenced in this that aren't included refer to those in the current McGuire FSAR). T.S. 3/4.6.1.1 requires the Type A test (Ref.10CFR50, Appendix J) to be performed at 14.8 psig, resulting in a 2.4 psig operational margin (note that the FSAR analysis assumed containment design pressure is 15.0 psig, thus providing a 0.2 psig margin of safety). During the previous Unit 1 EOC 5 refueling outage Integrated Leak Rate Test, acceptable leakage was demonstrated up to the1T.S. 3/4.6.1.1 requirement of 14.8 psig. Previous ,
analyses have demonstrated the effects of individual safety systems on containment peak pressure. A variance in total ice weight of 160,000 lbs. :
will inversely vary peak pressure by approximately 1 psig. By allowing an i increase in the calculated peak pressure the minimum required ice weight may be' reduced. The corresponding safety margin and T.S. requirements could thus be appropriately adjusted, and several months of additional basket life could be realized. Therefore, to resolve this issue a change in the T.S. 3/4.6.5.1-required Ice weights can be pursued, which would require an analysis be
_ performed raising the analytical peak containment pressure during a design basis analysts.
Description of Requested Technical Specifications Change:
The requested amendments incorporate the results of a reanalysis of the containm nt pressure calculation following a LOCA (FSAR Section 6.2.1.1.3.1, as updated.via Attachment 2A) into the Technical Specifications. The required ice condenser total. ice bed ice weight specified in T.S. LCO 3.6.5.1.d is '
reduced from 2,466,420 to 2,099,790 lbs., along with its use in associated surveillance requirement 4.6.5.1.b.2 and T.S. 3/4.6 b.1's Bases Section.
Correspondingly, the minimum ice basket ice weight specified (in 4 places) in surveillance requirement 4.6.5.1.b.2, and in T.S. 3/4.6.5.1's Bases Section, is also reduced from 1269 to 1081 lbs.
In addition, the conservative allowance specified in T.S. 3/4.6.5.1's Bases Section to account for systematic error in weighing instruments is revised to reflect the correct value of 1.1% rather than 1%.
Bases / Safety Analysis:
i Duke Power Company requested Westinghouse perform for McGuire Units 1 and 2 a LOTIC-1 analysis for peak containment pressure using a reduced Ice bed ice
= weight of 1,890,000 lbs., rather than the current 2,220,000 lbs. (other input parameters, including heat sink data, were to remain unchanged). This would allow a reduction in required ice basket ice weight (which should enable ice basket ice weights to exceed the new safety margin and T.S. values throughout the fuel cycle), with peak pressure operational margin remaining for future Janalyses to obtain relief for such things as heat exchanger fouling, r Attachment 28 is the resultant LOTIC-1 ice weight reduction analysis for McGuire Units 1 and 2 with an ice mass of 1,890,000 lbs. (note that these i changes are to the FSAR 1989 containment pressure calculation of Attachment 2A). It should be noted that the core temperature transient is over rela-tively early (within 400 :econds) during a LOCA event and the core temperature considerations have no bearing on the containment pressure calculation. This peak pressure. reanalysis provides figures showing the containment pressure, temperature, and ice melt response to the design basis transient, and esta-blishes that the design-basis containment pressure transient-can be effec-
~
tively controlled using a reduced ice weight without any reduction in the pressure safety margin. The peak containment design basis accident pressure increases from the current value of approximately 12.4 psig to approximately 14.1 psig (which is within the maximum allowable value of 14.8 psig specified by T.S. 3/4.6.1.1). Therefore, essentially, some of the operational margin available in T.S. 's for one parameter (peak pressure of T.S. 3/4.6.1.1) is traded of f to add safety margin to another T.S. parameter (ice weight of T.S.
L 3/4.6.5.1). This additional safety margin can then be utilized to reduce the K T.S. limit. Note that this reanalysis is not cycle specific, and thus applies for future cycles also.
This Westinghouse reanalysis of the Containment Pressure Calculation provides ,
the supporting basis for reducing the T.S. specified total ice bed ice weight in containment to 2,099,790 lbs. (i.e. , the FSAR reanalysis assumed value of 1,890,000 lbs. plus 11.1% (209,790 lbs.) for the sublimation and instruments conservative allowances), while maintaining the same total margin (11.1%) in the T.S. from the analysis value as was previously in the T S., including the
-same safety margin (1.1%). Accordingly, the T.S. required ice basket ice weight becomes 1081 lbs. (i.e., 2,099,790 lbs. T.S. total ice bed ice weight divided by 1944 required ice baskets in ice condenser equals 1080.14 lbs, per ice basket, conservatively rounded up to 1081). Likewise, the new ice basket safety margin ice weight becomes 983 lbs. (i.e., 1,890,000 divided by 1944 equals 972.22 lbs. FSAR analysis assumed ice weight per ice basket, plus the 1.1% instrument weighing uncertainty equals 982.92, conservatively rounded up). These requested changes are based on a conservative analysis and would not have any adverse safety implications.
1 The incorrect conservative allowance value of 1% stated in T.S. 3/4.6.5.1's Bases Section to account for systematic error in weighing instruments is probably due to rounding off or perceived level of accuracy used when the T.S.'s Bases section was originally written. The correct value originally supplied by Westinghouse, the manufacturer of the ice weighing instruments initially used at McGuire, is 1.1% (although the currently used instruments are not Westinghouse's, they are at least as accurate, and probably more so).
This 1.1% value is more conservative / restrictive than the 1% value stated in the current bases (note that the values of 2,466,420 and 1269 lbs. used in the current specification were calculated using the correct value of 1.1%, not the stated 1%). Correcting this error will prevent possible future calculations / applications from using the wrong value.
The McGuire FSAR will be revised to reflect this reanalysis (in- addition to the FSAR 1989 containment pressure calculation and error correction) in the applicable annual FSAR update following NRC approval of these requested amendments. Appropriate changes in station procedures to reflect the new weight limits will be implemented upon approval of these requested amendments.
Conclusions:
These requested Technical Specifications changes reduce the required ice condenser ice bed total (and ice basket) ice weight, and correct a value stated in the Bases Section. Based upon the preceding justification, Duke Power Company concludes that the requested amendments are necessary to provide needed additional flexibility in maintaining the required ice we1 ht 9 for the containment ice condenser. Based upon the preceding safety analysis, Duke Power Company concludes that the requested amendments will not be inimical to the health and safety of company personnel or the public. Further, similar amendments on other Westinghouse ice condenser plants have been granted by the NRC in the past (Ref. Sequoyah Nuclear Plant Facility Operating License Nos.
OPR-77 and DPR-79 Amendment Nos. 131 (Unit 1)/118 (Unit 2)).
5-
I ATTAc1DIENT 2A Cccuire C c100r Station U0its 1 c:d 2 ,
FSAR 1989 Contcinnut PrG30;ro C01Sulctica LOTIC CODE . LONG TERM ANALYS15 Early in the ice condenser development program it was recognized that there was a need for modeling of long term ice condenser performance.
It was realized that the model would have to have capabilities comparable to those of the dry containment (C0CO) model. These +
capabilities would permit the model to be used to solve problems of containment design and optimize the containment and safeguards '
systems. This has been accomplished in the development of the LOTIC Code (Reference 20). ,
The model of the containment consists of five distinct control '
volumes, the upper compartment, the lower compartment, the portion of the ice bed from which the ice has melted, the portion of the ice bed containing unselted ice, and the dead ended compartment. The ice condenser control volume with unmelted and melted ice is further subdivided into six subcompartments to allow for maldistribution of ,
break flow to the ice bed.
The conditions in these compartments are obtained as a function of '
time by the use of fundamental equations solved through numerical :
techniques. These equations are solved for three phases in time. ;
Each phase corresponds to a distinct physical characteristic of the problem. Each of these phases has a unique set of simplifying assumptions based on test results from the ice condenser test facility. These phases are the blowdown period, the depressurization period, and the long term.
The most significant simplification of the problem is the assumption >
that the total pressure in the containment is uniform. This assumption is justified by the fact that the initial blowdown of the l Reactor Coolant System, after the remaining mass and energy release l
from this system into the containment are small and very slowly
- changing. The resulting flow rates between the cor. trol volumes will
! also be relatively small. These flow rates then are unable to maintain significant pressure differences between the compartments.
- In the control volumes, which are always assbmed to be saturated, steam and air are assumed to be uniformly mixed and at the control volume temperature. The air is considered a perfect gas, and the thermodynamic properties of steam are taken from the ASME steam table.
The condensation of steam is assumed to take place in a condensing node located, for the purpose of ca!culation, between the two control volumes in the ice storage compartment. The exit temperature of the air leaving this node is set equal to a specific value which is equal to the temperature of the ice filled control volume of the ice storage compartment. Lower compartment exit temperature is used if the ice bed section is' melted. ;
. o I
CONTAINMENT PRES $URE CALCUL ATION The following are the major input assumptions used in the LOTIC analysis for the pump suction pipe rupture case with the steam ;
~
generators considered as an active heat source for the McGuire Nuclear Station Containment: ,
- 1. Minimum s'afeguards are employed in all calculations, e.g., one of !
two spray pumps and one of two spray heat exchangersi one of two ?
RHR pumps and one of two RHR heat exchangers providing flow to the ;
core; one of two safety injection pumps and one of two centrifugal charging pumpst and one of two air return fans.
2, 2.22
- 106 lbs. of ice initially in the ice condenser (Basis for i Technical Specification limit).
- 3. The blowdown, reflood, and post reflood mass and energy releases I cescribed in Subdivision 6.2.1.3.6 are used.
- 4. Blowdown and gost blowdown ice condenser drain temperature et 1900 F and 130 F are used. (These numbers are based on :
Reference 22). ;
- 5. Mitrogen from the accumulators in the amount of 5870 lbs. is included in the calculations.
- 6. Nuclear service water temperature of 820F is used on the spray heat exchanger and the component cooling heat exchanger.
- 7. Tha air return fan is # )ctive, 10 minutes after the transient is initiated.
- 8. No maldistribution of steam flow to the ice bed is assumed.
- 9. No ice condenser bypass is assumed. '(This assumption depletes the ice in the shortest time and is thus conservative.)
- 10. The initial conditions in the containment are a temperature of l 1000 F in the lower and dead ended volumes and a temperature of i 75 F in the upper volume. All volumes are at a pressure of 0.3 0
psig.
- 11. Pump flow rates versus time given in Table 6.2.1-13C were used, [
- 12. Containment structural heat sinks are assumed with conservatively #
low heat transfer rates. (See Table 6.2.1 14) e e 1
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I 13.Theoperationo{onecongainmentsprayheatexchanger I (UA . 1.47
- 10 Btu /hr. F) for containment cooling and the 6
operatignofoneRHRheatexchanger(UA=1,64*10 Stu/hr F) for core cooling. ,
. exchanger was modeled at 1.6 *TheemponengF.
106 Btu /hr- cooling heat l
- 14. The air return fan returns air at a rate of 30,000 cfm from the upper to the lower compartment, i
- 15. An active sump volume of 90,000 ft 3 is used.
16,102% of rated themel power is used in the calculations. ;
- 18. Nuclear service water flow to the containment spray heat exchanger 'f was modeled as 3800 gpm. Also the nuclear service water flow to the component cooling heat exchanger was modeled as 5500 gpm. ,
,. The minimum time at which the RHR pumps can be diverted to the RHR sprays will be specified in the plant operating procedures as 50 t
minutes after the accident. A discussion of the core cooling capability of the ECCS is given in Section 6.3.1 for this mode of operation. .
With these assumptions, the heat removal capability of the containment is sufficient to absorb the energy releases and still keep the maximum calculated pressure well below the design.
.The following plots are provided.
Figure 6.2.1 15, Containment Pressure Transient figure 6.2.1 16, Upper Compartment Temperature Transient figure 6.2.1-17 Lower Compartment Temperature Transient figure 6.2.1-18 Active and Inactive Sump Temperature Transient Figure 6.2.1 43, Ice Melt Transient Tables 6.2.1 12 and 6.2.1 13 give energy accountings at various points in the transient. ;
As can be seen from Figure 6.2.1 15 the maximum calculated containment pressure is 12.36 psig, occurring at approximately 7356 seconds. >
Table 6.2.1 13A gives total sump volume versus time. Comparing this
< table with Table 6.2.1-13B, which gives the total sump volume versus elevation, the sump elevation versus time can be determined.
l L
11rystural Heat Removal Provision is made in the containment pressure analysis for heat ,
storage in interior and exterior walls. Each wall is divided into a ,
number of nodes. For each node, a conservation of energy equation expressed infinite difference forms accounts for transient conduction into and out of the containment structural heat sinks used in the analysis. The material property data used is found in Table 6.2.1 15. ;
The heat transfer coefficient to the containment structure is based primarily on the work of Tagami. An explanation of the manner of '
application is given in Reference 24. When applying the Tagami 4 correlations, a conservative limit was placed on the lower compartment .
stagnant heat transfer coefficients. They were limited to a steam air !
ratio of 1.4 according to the Tagami correlation. The imposition of ,
this limitation is to restrict the use of the Tagami correlation '
within the test range of steam air ratios where the correlation was derived.
k 6
l l
l l
L L
l TABLE 6.2.1-12 ENERGY ACCOUNTING IN MILLIONS OF BTU 1
Approx. End Approx. End ;
of Blowdewn of Reflooi .
i I
(t - 10.0 sec.) (t = 299 sec.)
(BTV) (BTV) i
- Ice Heat Removal 176.6 225.4 j
l
- Structural Heat Sinks 21.2 64.4
- RHR Heat Exchanger Heat Removal 0 0
- Spray Heat Exchanger Heat Removal 0 0 l Energy Content of Sump 163.4 237.7 1 Ice Melted (Pounds) 0.57 (106 ) 0.76 (106 ) 1 i !
- Integrated Energies
?
l s
l -.
t f
1 l .
l <
- ' e. ..
l
! TABLE 6.2-13 ENERGY ACCOUNTING IN MILLIONS OF BTU t
Approx. Time of Approx. Tinie of Ice Melt Out Peak Pressure (t-5348sec.) (t = 7356 sec.)
(BTV) (BTV)
- Ice Heat Removal 588.7 588.7
- St.'uctural Heat Sinks 106.5 146.6
- RHR Heat Exchanger Heat Removal 92.6 159.5
- Spray Heat Exchanger Heat Removal 69.7 162.9 Energy Content of Sump 636.4 656.2 6
Ice Melted (Pounds x 10 ) 2.22 2.22 l
- Integrated Energies !
1 4
L l
< 4 .
TABLE 6.2.1 - 13A CONTAINMENT SUMP VOLUME VS. TIME Time fsee) Volume (Ft I,},
25.0 16786.
51.5 ,
18399.
8).1 19684.
129.7 21143.
i 189.7 22981.
259.7 24979.
l 409.3 28787.
599.3 33538.
809.3 38947.
I 1009.3 44089.
1509.3 56783.
1 --
2002.5 68246.
2402.4 74460. ;
2804.8 78475.
3002.3 80675.
3202.3 82871.
3409.8 84445.
I
360k.8 85068.
3802.3 85685, t
4009.1 86320.
4209.1 86927. ,
4409.1 87528.
4609.1 88123, 4809.1 88712.
5100.0 89555.
5384,8 89784.
5258.7 89968.
5298.5 90000.
End of Transient 89848.
I Notes on McGuire sump volume calculation:
l The two sump model was created because of the insufficient capacity of the active sump to contain all the water of the RCS system, the melted-ice, and the RWST.
Worst Case: Double Ended Pump Suction Guillotine, with Minimum Safeguards 1
Maximum volume of the active lower compartment sump = 90000 ft 3 l
-Time in seconds to fill active sump (approx.) = 5298.5 seconds.
u - -e., - , -
p- -
se wy v -e y y -
TABLE 6.2.1-17 (Page 1)
Structural Heat Sinks ;
A. Upper Compartment i
2 Area (ft ) Thickness (ft) l I
- 1. Slab 1: Crane Wall; ice Condenser End Wall; CRDM Missile Shield and I Cate; PRZR and SG Doghouse 1 l
19749 0.001167 Paint 1.3593 Concrete
- 2. Slab 2: Containment Vessel Dome; Shell 23436 0.00059 Paint l 0.05797 Carbon Steel :
- 3. Slab 3: SG Doghouse; Polar Crane; Platforms; Electrical Equipment 34706 0.00059 Paint 1 0.02755 Carbon Steel
- 4. Slab 4
- Internals Storage Stand, Upper and Lower; Reactor Vessel ,
Head Stand ,
i 1156 0.03125 Stainless Steel
( 5. Slab 5: Refueling Canal; floor Slab 4821 0.1563 Stainless Steel 1.5 Concrete ,
- 6. Slab 6: Operating Floor; Refueling Canal; Crane Wall; SG Doghouse;' '
Accumulator Wells; CRDM Gate; HX and Ceiling 41154 0.001167 Paint 1.825 Concrete '
Entire Page Revised i
I t
e
. c t
TABLE 6.2.1 17 (Page 2)
Structural Heat Sinks B. Lower Compartment Area (ft2 ) Thickness (ft)
- 1. Slab 7: SG Supports; Main Steamline Restraints; Pressurizer Supports; Platforms; Steel Columns *; Mechanical and Electrical Equipment 33763 0.00059 Paint 0.03388 Carbon Steel
- 2. Slab 8: Containment Shell 13879 0.00059 Paint 0.0625 Carbon Steel
- 3. Slab 9: Refueling Canal 2269 0.01563 Stainless Steel 1.5 Concrete
- 4. Slab 10:- CROM Missile Shield 738 0.00059 Paint.
0.04208 Carbon Steel 1.5 Concrete
- 5. Slab 11: Dead Ended Compartment Slabs 3403 0.001167 Paint 2.5 Concrete
- In contact with sump Entire Page Revised
TABLE 6.2.1-17 (Page 3)
Structural Heat Sinks l
B. Lower Compartment (cont'd) i Area (ft2) Thickness (ft) 1
- 6. Slab 12: Primary Shield Wall; incore Instrumentation Tunnel; Slabs; )
Floors 20407 0.001167 Paint 1.6686 Concrete .
l
- 7. Slab 13: Duct Work 31360 0.002625 Stainless Steel
- 8. 51kb 14: ;ooling coils 49000 0.0004167 Copper C. Ice Condenser
- 1. Slab 15: Ice Baskets 180,628 0.00663 Steel
- 2. Slab 16: Lattice Frames 76,650 0.0217 Steel Entire Page Revised
TABLE 6.2.1-17 (Page 4)
Structural Heat Sinks C. l'e Condenser (cont'd)
Area (ft2) Thickness (ft)
- 3. Slab 17: Lower Support Structure 28,670 0.0267 Steel
- 4. Slab 18: Ice Condenser Floor 3,336 0.000833 Paint 0.33 Concrete
- 5. Slab 19: Containment Wall Panels & Contain#ent Shell 19,100 1.0 Steel & Insulation 0.625 Steel Shell
- 6. Slab 20: Crane Wall Panels and Crane' Wall 13,055 1.0 Steel & Insulation 1.0 Concrete Entire Page Revised w
P TABLE 6.2.1-21 8 LOWDOWN MASS AND ENERGY RELEASES TIME BREAK PATH NO. 1 FLOW BREAK PATH NO. 2 FLOW >
THOUSAND THOUSAND SECONDS LBM/SEC BTV/SEC LBM/SEC BTV/SEC 0.000 0.0 0.0 0.0 0.0 0.101 41848.7 23251.0 22257.9 12311.1 0.200 42335.3 23668.6 23974.2 13266.4 0.401 44122.2 25216.9 23413.2 12991.0 0.600 44004.7 25724.1 21324.1 11890.4 1.00 39552.8 24045.4 19335.4 10838.8 1.40 33391.0 21442.3 17325.9 9723.5 '
2.10 27440.7 18545.1 16922.3 9495.5 2.50 21192.7 14710.8 16486.9 9251.1 ,
3.40 16604.8 11717.9 14682.1 8239.4 1 3.90 14972.4 10528.1 13944.1 7824.3 4.80 14586.3 9969.3 13087.6 7343.6 5.20 10839.1 8531.1 13104.1 7346.4 5.40 11548.8 8852.9 13011.9 7291.7 6.00 17249.3 11879.5 12675.4 7100.8 l
6.60- 19773.6 13086.2 12218.7 6853.8 7.00 26448.6 17042.8 11631.3 6519.4 8.20 25981.2 16258.1 10206.3 5715.8 8.80 24601.3 15409.5 9571.4 5354.1 9.20 10090.6 6456.8 9735.8 5447.5
'9.40 8289.9 5520.9 9485.3 5296.7 10.0- 8348.2 5451.2 9818.1 5485.7 10.2 9510.8 6118.5 9654.1 5390.4 10.6 9526.7 6449.7 9661.3 5393.6 11.0 6637.2 5398.0 9562.9 5334.7 11.5 7190.8 5494.1 9355.3 5213.3 13.) 6123.9 4904.2 '8733.3 4851.7 14.l 5539.5 4429.0 8093.4 4646.0 15.5 4797.0 4061.2 6603.0 3791.4 16.5 4029.9 3827.2 6025.3 3158.8 i 18.4 1799.4 2228.6 3347.7 1481.9 19.4 1013.5 1272.5 2352.8 1167.9 19.8 769.5 969.1 1252.6 982.6 22.4 119.8 152.9 253.8' 274.0 25.2 33.9 43.8 36.0 46.8 l
l 2D55v.10/081189-1
- .= 'o i
TABLE 6.2.1-22 i
REFLOOD MASS AND ENERGY RELEASES
]
TIME BREAK PATH NO. 1 FLOW BREAK PATH NO. 2 FLOW l THOUSAND THOUSAND :
SECONDS LBM/SEC BTU /SEC LBM/SEC BTU /SEC 25.2 0.0 0.0 0.0 0.0 '
25.7 0.0 0.0 167.7 12.2 '
26.4 5.7 6.6 167.7 12.2 29.3 68.3 79.7 167.7 12.2 e 33.3 110.3 128.8 167.7 12.2- l 34.3 285.3 335.2 4096.0 497.7 ,
35.3 336.7 396.4 4768.0 609.0 '
36.3 336.1 395.7 4760.9 611.2 37.3 331.8 390.6 4707.3 605.5 40.3 318.4 374.6 4539.4 586.5 i
43.3 306.0 359.9 4380.6 568.4 46.3 294.9 346.7 4235.1 551.7 i 49.3 284.9 334.8 4102.2 536.5 >
51.8 277.1 325.5 3995.7 524.4 52.3 275.9 324.1 3980.5 522.5 55.3 267.8 314.4 3868.7 509.7 58.3 260.3 305.6 3765.1 497.9 59.3 135.3 158.0 1444.9 253.2 62.4 134.8 157.5 1412.0 249.5 ,
63.4 254.9 299.2 271.4 128.4 67.4 255.3 299.7 274.0 128.7 86.4 249.9 293.3 290.1 126.3 102.4 245.1 287.6 301.9 124.4 ,
134.4 234.5 275.0 324.8 120.9 '
136.4 233.7 274.0 326.2 120.7 150.4 227.5 266.8 335.6 118.9 182.4 211.2 247.5 361.4 115.4 184.4 210.1 246.2 363.2 115.2 214.4 190.5 223.0 391.1 112.6 ,
224.4 183.1 214.3 402.4 112.1 248.4 163.2 190.9 433.4 111.8 262.4 149.7 174.9 453.2 112.1 ,
272.4 139.0 162.4 468.8 112.7 288.4 120.0 140.1 497.0 114.4 292.6 114.5 133.7 505.1 115.1 h
2055r1D/081189-2
TABLE 6.2.1-23 POST REFLOOD MASS AND ENERGY RELEASES ;
TIME BREAK PATH NO. 1 FLOW PREAK PATH NO. 2 FLOW THOUSAND THOUSAND SECONDS LBM/SEC BTU /SEC LBM/SEC BTU /SEC 292.7 103.3 128.0 567.7 123.1 6 397.7 101.5 125.8 569.5 121.7 .
432.7 102.1 126.6 568.8 121.0 I 462.7 101.0 125.2 570.0 120.7 t 467.7 101.8 126.2 569.2 120.5 .
120.2 ;
497.7 100.6 124.7 570.4 532.7 101.2 125.5 569.7 119.5 '
562.7 100.0 124.0 570.9 119.2 567.7 100.B 125.0 570.2 119.0 632.7 99.5 123.3 571.5 118.2 637.7 100.3 124.3 570.7 117.9 672.7 99.2 123.0 571.8 117.6 712.7 99.8 123.7 571.1 116.8 -
747.7 98.7 122.3 572.3 116.4 752.7 99.5 123.3 571.5 116.2 817.7 98.3 121.8 572.7 115.3 822.7 99.0 122.8 571.9 115.0 862.7 98.8 122.4 572.2 114.4 927.7 97.6 121.0 573.3 113.5 962.7 98.2 121.8 572.7 112.7 1032.7 96.9 120.1 574.1 117.5 !
1037.7 97.5 120.9 573.4 117.2 1127.7 96.3 119.4 574.6 115.6 -
1157.7 96.8 120.0 574.2 114.9 ,
1247.7 95.5 118.4 575.5 113.2
- 1267.7 96.0 119.0 575.0 112.7 L 1467.7 94.1 116.7 576.8 113.5 l 1886.9 94.1 116.7 576.8 113.5 -
1887.0 95.2 117.9 575.7 113.5 2302.7 95.2 117.9 575.7 113.5 2302.8 67.3 82.7 603.6 125.7 2536.5 67.4 77.5 603.6 60.6 l
l' 2055v 10/081489-3
TABLE 6.2.1-25 MASS BALANCE TIME (SECONDS) 0.00 25.20 25.20 292.60 2307.70 2535.80 RASS (TNOUSAND LBM)
INITIAL IN RCS AND ACC 733.33 733.33 733.33 733.33 733.33 733.33 ADDED MAS 3 PUMPED INJECTION 0.00 0.00 0.00 173.74 1525.72 1679.43 TOTAL ADDED 0.00 0.00 0.00 173.74 1525.72 1579.43
- TOTAL AVAILABLE *** 733.33 733.33 733.33 907.07 2259.04 2412.76 DISTRIBUTION REACTOR COOLANT 496,91 90.69 90.73 171.53 171.53 171.53 ACCUMULATOR 236.42 160.84 160.80 0.00 0.00 0.00-TOTAL CONTENTS 733.33 251.53 251.53 171.53 171.53 171.53 EFFLUENT BREAK FLOW 0.00 481.79 481.79 735.53 2087.50 2241.21 ECCS SPILL 0.00 0.00 0.00 0.00 0.00 0.00 TOTAL EFFLUENT 0.00 481.79 481.79 735.53 2087.50 2241.21
- TOTAL ACCOUNTABLE *" 733.33 733.32 733.32 907.06 2259.04 2412.75 ENERGY BALANCE TIME (SECONDS) 0.00 25.20 ?S.20 292.60 2307.70 2535.80 ENERGY (MILLION BTV)
INITIAL EKERGY IN RCS,ACC.S GEN 848.43 848.43 848.43 848.43 848.43 848.0 ADDED ENER5Y PUMPED INJECTION 0.00 0.00 0.00 12.68 117.01 131.31 DECAY HEAT 0.00 8.39 8.39 38.35 181.78 195.11 HEAT FROM SECONDAR 0.00 -5.28 -5.28 -5.23 3.82 4.04 TOTAL ADDED 0.00 3.10 3.10 45.75 302.61 330.46
- TOTAL AVAILABLE = 848.43 851.53 851.53 894.18 1151.04 1178.33 DISTRIBUTION REACTOR COOLANT 293.17 18.29 18.30 38.84 38.84 3B.34 ACCUMULATOR 14.10 9.59 9.59 0.00 0.00 0.0:
Cr.RE STORED 23.12 12.12 12.12 4.04 3.88 3. M PetlMARY METAL 169.34 161.29 161.29 137.57 70.08 65.33
'iECONDARY METAL 95.46 93.95 93.95 84.64 44.60 40.5' STEAM GENERATOR 253.24 253.28 253.28 223.07 117.14 107.5i TOTAL CONTENTS 848.43 548.54 548.54 488.15 274.54 255.3C EFFLUENT BREAK FLOW 0.00 303.09 303.09 410.10 880.56 925.55 ECCS SPILL 0.00 0.00 0.00 0.0 0.00 0.00 TOTAL EFFLUENT 0.00 303.09 303.09 410.10 880.56 925.55
= TOTAL ACCO'JNTABLE *** 848.43 851.62 851.62 898.24 1155.10 1182.95 2096v.10/041489-4 i
A e , -s. -- - -A.a,- _m _-...,a#h#c a g.4...a. _ > . - ---4. -+_- --
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-1 I IEMBIE Mtl.Em STATIGI l UPPER CofrARTMENT TEMPERATURE YnMislElli l
l FIGullE 6.2.1-16 I
l l
-26E 5 ;
i l i i '
l .24E-5 - -
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u owO waanE'w,rw- .
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KQlIK NUCLEAR STATION ACTIE AND INACTin SUMP TEMPERATURE TRAN51ENI FIGURE 6.2.1-18
.26C*5 i .
.24[ 5 - -
i t
.22C*5 l u
o ,pgt.5 w t a w m i
, w at
.180 5 - --- - '
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103 102 105 jg4 gg5 TIME SEC
,. , - . . , , - . . _ . . . , w ~ - .-, --w... , _. - . ., -, -- _-___e--____ ______m .___m_-___m__ _ - um_--
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ATTACBERNT 25 NS-0PLS-OPL-II-90 080 l tecatro Nuclser section Units 1 cnd 2 Peak Prsseuro R3 n: lysis With R:ducsd Ic3 W2ight i
LOTIC mnt . tw- TERM ANALYSIS
. Early in the ice condenser development program it was recognized that there was a need for modeling of long term ice condenser performance. It was g
realized that the model would have to have capabilities comparable to those of l L
p the dry containment (C0CO) model. These capabilities would permit the model l to be used to solve problems of containment design and optimize the i containment and safeguards systems. This has been accomplished in the .
l development of the LOTIC Code (Reference 20). 1 1
l The model of the containment consists of five distinct control volumes, the ,
upper compartment, the lower compartment, the portion of the ice bed from which the ice has melted, the portion of the ice bed containing unmelted ice, and the dead ended compartment. The ice condenser control volume with unselted and melted ice is further subdivided into six subcompartments to l allow for maldistribution of break flow to the ice bed.
The conditions in these compartments are obtained as a function of time by the I use of fundamental equations solved through numerical techniques. These
- equations are solved for three phases in time. Each phase corresponds to a '
(- distinct physical characteristic of the problem. Each of these phases has a '
l unique set of simplifying assumptions based on test results from the ice condenser test facility. These phases are the blowdown period, the depressurization period, and the long term.
The most significant simplification of the problem is the assumption that the i total pressure in the containment is uniform. This assumption is justified by the fact that the mass and energy releases remaining in the containment after the initial blowdown of the Reactor Coolant System are small and very slowly changing. The resulting flow rates between the control volumes will also be relatively small. These flow rates then are unable to maintain significant pressure differences between the compartments.
2eS5v:10/e13e90-5
NS-0PLS-0PL-II.90 080 In the control volumes, which are always assumed to be saturated, steam and air are assumed to be uniformly mixed and at the control volume temperature.
The air is considered a perfect gas, and the thermodynamic properties of steam are taken from the ASME steam table.
The condensation of steam is assumed to take place in a condensing node located, for the purpose of calculation, between the two control volumes in the ice storage compartment. The exit temperature of the air leaving this
. node is set equal to a specific value which is equal to the temperature of the ice filled control volume of the ice storage compartment. Lower compartment exit temperature is used if the ice bed section is melted.
CONTAINMENT PRESEURE CALCULATION The following are the major input assumptions used in the LOTIC analysis for the pump suction pipe rupture case with the steam generators considered as an active heat source for the McGuire Nuclear Station Containment: ,
- 1. Minimum safeguards are employed in all calculations, e.g., one of two spray pumps and one of two spray heat exchangers; one of two RHR pumps and one of two RHR heat exchangers providing flow to the core; one of two safety injection pumps and one of two centrifugal charging pumps; and one of two air return fans.
- 2. 1.89
- 100 lbs, of ice initially in the ice condenser (Basis for Technical Specification limit).
l
- 3. The blowdown, reflood, and post reflood mass and energy releasts described in Subdivision 6.2.1.3.6 are used. .
- 4. Blowdown and post-blowdown ice condenser drain temperature of 190'F and 130'F are used. (These numbers are based on Reference 22).
- 5. Nitrogen from the ac';umulators in the amount of 5870 lbs is included in the calculations.
l 20s5v:10/00090-6
_ _ _ _ . _ _ _ ___ . . _ . ._____ ~ . _ _ _ _. __ _- -.-._ _ _ _ _ .
. e .
NS-0PLS-0PL-83-90-0B0 i
- 6. Nuclear service water temperature of $2'F is used on tite spray heat j exchanger and the component cooling heat exchanger.
- 7. The air return fan is effective 10 minutes af ter the transient is initiated.
- 8. No maldistribution of steam flow to the ice bed is assumed.
~
- 9. No ice condenser bypass is assumed. (This assumption depletes the ice in the shortest time and is thus conservative.)
- 10. The initial conditions in the containment are a temperature of 100*F in the lower and dead-ended volumes and a temperature of 75'F in the upper volume. All volumes are at a pressure of 0.3 psig.
- 11. Pump flow rates versus time given in Table 6.2.1-13C were used.
- 12. Containment structural heat sinks are assumed with conservatively. low heat transfer rates. (See Table 6.2.1-14) ,
6
- 13. The operation of one containment spray heat exchanger (UA . 1.47
- 10 Btu /hr 'F) for containment cooling and the operation of one RHR heat-6 The component exchanger (UA = 1.64
- 10 Btu /hr 'F) for core cooling.
6 cooling heat exchanger was modeled at 1.60
- 10 Btu /hr 'F.
l l
- 14. The air return fan returns air at a rate of 30.000 cfm from the upper to the lower compartment.
- 15. An active sump volume of 90.000 ft3 is used.
- 16. 102% of rated thermal power is used in the calculations.
I l
_u- - --___ _ _ __. , _ , _ _ . , , , _ _ _ , , . _ . , , . , _ , , _,
. . l i
NS-OPLS-0PL-II-90-080 j
- 18. Nuclear service water flow to the containment spray heat exchanger was modeled as 3800 gpm. Also the nuclear service water flow to the component cooling heat exchanger was modeled as 5500 gpm.
The minimum time at which the RHR pumps can be diverted to the RHR sprays will be specified in the plant operating procedures as 50 minutes after the accident. A discussion of the core cooling capability of the ECCS is given in ;
Section 6.3.1 for this mode of operation. ;
With these assumptions the heat removal capability of the containment is '
sufficient to absorb the energy releases and still keep the maximum calculated pressure well below the design. .,
The following plots are provided.
Figure 6.2.1-15. Containment Pressure Transient Figure 6.2.1-16, Upper Compartment Temperature Transient Figure 6.2.1-17, Lower Compartment Temperature Transient I
j Figure 6.2.1-18 Active Sump Temperature Transient j Figure 6.2.1-43, Ice Melt Transient .
l Tables 6.2.1-12 and 6.2.1-13 give energy accountings at various points in the
! transient.
l -
i l As can be seen from Figure 6.2.1-15 the w ximum calculated containment pressure is 14.07 psig, occurring at ap9toximately 6454 seconds. Table ,
6.2.1-13A gives total sump volume versus time. Comparing this table with i Table 6.2.1-138, which gives the total sump volume versus elevation, the sump clevation versus time can be determined.
f I
o .
NS-0PLS-0PL-17-90-080 STRUCTURAL. NEAT REMOVAL Provision is made in the containment pressure analysis for heat storage in interior and exterior walls. Each wall is divided into a number of nodes.
For each node, a conservation of energy equation expressed in finite difference form accounts for transient conduction into and out of the ;
containment structural heat sinks used in the analysis. The material property data used is found in Table 6.2.1-15.
- i The heat transfer coefficient to the containment structure is based primarily ,
on the work of Tagami. An explanation of the manner of application is given ,
l in Reference 24. When applying the Tagami correlations, a conservative limit ,
I
' was placed on the lower compartment stagnant heat transfer coefficients. They were limited to a steam-air ratio of 1.4 according to the Tagami correlation.
The imposition of this limitation is to restrict th6 use of the Tagamt correlation within the test range of steam-air ratios where the correlation was derived.
l- \
l 9
I 1
2es5v:1D/e13e9e-10
. . _ _ . _ _ _ . . _ _ _ ~ _ _ _ _ _ . . _ _ _. _ . _ _ _ ._ _ _ _ . ___.
o .
i NS-0PLS-0PloI8-90-080 1
TABLE 6.2-13 i ENERGY ACCOUNTING IN MILLIONS OF BTU App"ox. Time of Approx. Time of ice Melt Out Peak Pretture (t - 3569 sec.) (t - 6454 sec.) I (BTU) (BTU)
]
l
- Ice Heat Removal 506.3 506.3 i
' Structural Heat Sinks 88.3 152.4
- RHR Heat Exchanger Heat Removal 43.6 136.6
- Spray Heat Exchanger Heat R6moval 2.2 131.8 i
Energy Content of Sump 655.7 667.9 6
Ice Melted (Pounds x 10 ) 1.89 1.89 ;
' Integrated Energies
-i r
20$5v:1D/013090-11 . _ . - _
. . l NS-OPLS-0PL-II-90-080 TABLE 6.2.1-13A CONTAINMENT SUMP VOLUME VS. TIME ,
Tine (sec) Volume (Ft3 )
27.2 16804, 53.0 18512.
82.7 19703.
131.2 21163.
191.2 22998.
261.2 24990, 410.8 28795.
600.8 33547.
810.8 38958.
1010.8 44100.
1510.8 56795.
2002.6 68225. p 2402.4 74644, 2804.8 79587. .
L 3002.3 81786.
3202.3 83982.
3409.8 85553.
3474.8 85747, g
3487.3 85782.
3497.3 85808.
l I 3507.3 85835.
3524.8 85878.
3549.8 85933.
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End of Transient 85415.
j Note on McGuire sump volure calculation:
The two sump model was created because of the insufficient capacity of the active sump to contain all the water of the RCS system, the melted ice, and the RHST.
1 Horst Case:. Double Ended Pump Suction Guillotine, with Minimum Safeguards .
3 Maximum volume of the active lower compartment sump - 900C0 Ft 1
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l ATTACHMENT 3 Analysis of Significant Hazards Consideration
Introduction:
As required by 10CFR 50.91, this analysis is provided concerning whether the requested amendments involve significant hazards considerations, as defined by 10CFR 50.92. Standards for determination that an amendment request involves no significant hazards considerations are if operation of the facility in accordance with the requested amendment would not: 1) involve a significant increase in the probability or consequences of an accident previously evalu-ated; or 2) create the possibility of a new or different kind of accident from any accident previously evaluated; or 3) involve a significant reduction in a margin of safety.
The requested amendments for Technical Specification (T,S.) 3/4.6.5.1 reduce the required ice bed ice weight (total ice bed and per ice basket) of the containment ice condenser, and correct an error in the T.S.'s Bases Section.
Analysis:
The requested amendments incorporate the results of a conservative reanalysis (see Attachment 28) of the containment pressure calculation following a LOCA (FSAR Section 6.2.1.1.3.1, as updated by the FSAR 1989 containment pressure calculation of Attachment 2A) into the Technical Specifications. This reanalysis was performed using a reduced ice bed ice weight, with all other input parameters remaining unchanged, and resulted in an increase in the peak containment design basis accident pressure (but which is still within the maxinum allowable value specified by T.S.'s). Therefore, essentially, some of ths-operational margin available in T.S.'s for one parameter (peak pressure of T.S. 3/4.6.1.1) is traded off to add safety margin to another T.S. parameter (ice weight of T.S. 3/4.6.5.1), which is then utilized to reduce the T.S. I limit.
-The requested amendments would not involve any increase in the probability of an accident previously evaluated. The changes are only to the limiting values provided in the Technical Specifications, and do not involve any plant hardware changes or the manner / procedural method in which plant equipment is operated. The changes to the limiting values in the T.S.'s could not increase . f.
the probability of an accident since they only impact the containment ice i condenser. The ice condenser plays no role in the normal operation of the plant and serves only to mitigate the consequences of severe accidents, and could not cause an accident. The postulated accidents which require the ice condenser to function are independent of the condition of the ice condenser.
Thus the changes could not have any effect on accident causal mechanisms, including previously evaluated ones. Similarly, the changes could not create the possibility of a new or different kind of accident from any accident previously evaluated as accident causal mechanisms are unaffected, including thc. creation of new or different ones.
The requested amendments would not involve a significant increase in the consequences of an accident previously evaluated. The peak pressure 4
F .
, c ** 9 reanalysis with reduced ice weight describes the containment pressure, l temperature,.and ice-melt response to the design basis transient. This reanalysis shows that while various parameters are affected-(e.g., peak i pressure is increased), they remain within bounding values and the containment ice condenser would satisfactorily perform its design function in the event of a LOCA, 1 The requested. amendments would not involve any reduction in a margin of safety. Although the ice bed total ice weight is reduced (i.e., 2,099,790 vs.
2,466,420 lbs.), its total. margin (including the 1.1% safety margin)'is main-tained at 11'1% in'the limits requested to be specified in the T.S.'s (i.e.,
2,099,790 lbs. based on a 1,890,000 lbs. analysis assumption, vs. the previous 2,466,420 lbs based on a 2,220,000 lbs. analysis assumption); and similarly for the resultant-and ice basket weights (i.e., 1081 lbs. vs. 1269). While the peak containment design basis accident pressure is increased from the >
current value of approximately 12.4 psig to approximately 14.1 psig, this is still within the maximum allowable value of 14.8 psig specified by T.S.
3/4.6.1.1, and thus its margin of safety is unchanged (although its opera-tional margin is reduced). ,
The requested amendments also correct an error in the amount of the conserva-tive' allowance stated in the T.S.'s Bases Section to account for systematic error in weighing instruments, This change (from 1% to 1.1%) is more conser-vative/ restrictive than the currently specified value, and thus clearly does not involve a significant hazards evaluation. The commission has provided examples of amendments likely to involve no significant hazards considerations (48FR14870). _ One example of this type is (ii), "A change that constitutes an<
additional limitation, restriction, or control not presently included in the Technical Specifications: For example, a more stringent surveillance require-p ment." This example can be applied in this requested change.
In addition, similar changes on other Westinghouse ice condenser plants in the past have been determined not to involve significant hazards considerations.
Conclusions:
Based on the preceding analyses, Duke Power Company concludes that.the re-quested amendments do not involve a significant hazards consideration, t