ML20217F092

Consequence Evaluation of ANO-2 Efw,Containment Spray & Main Steam & Feedwater Sys Piping

ML20217F092
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/14/1997
From:	Moody J ENTERGY OPERATIONS, INC.
To:
Shared Package
ML20217E904	List: 2CAN099706, Forwards Results of Pilot Plant Application Study Performed at Ano,Unit 2 for Review.Prompt Staff Review Is Requested. Formal Request for NRC Approval Will Be Made Following Submittal of Svc Water Sys Risk Evaluation in Dec 1997 ML20217E921 ML20217E929 ML20217E938 ML20217E950 ML20217E967 ML20217E987 ML20217F007 ML20217F029 ML20217F092
References
NSD-018, NSD-18, NUDOCS 9710070368
Download: ML20217F092 (159)

Text

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Page1 Calculation No. NSD-018 O

a,'j ORIGINAL:

PAGE 1 of/55PAGES Rev.1:

PAGE 1 of PAGES Rev. 2:

PAGE I of PAGES Rev. 3:

PAGE 1 of PAGES QA RECORD 7 IMS NO.

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NO W.O./P.O. NO.

9475 YANKEE NUCLEAR SERVICES DIVISION CALCULATION / ANALYSIS FOR TITLE _C9mtgugnce Evaluation of ANO-2 EFW. Containment Sorav. and Main Steam &

Eeedwater system Pining 4

PLANT Arkansas Nuclear 1 - Unit 2 (ANO-2)

CYCLE N/A CALCULATION NUMBER NSD-018 PREPARED BY REVIEWED BY APPROVED BY SUPE.RSEDES

, /DATE

,/l) ATE

/DATE CALC /REV NO.

fl Yffyf

.f NlA O'"#

REVISION 1 REVISION 2

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REVISION 3 KEYWORDS: ISI PRA. Risk Bajed. Risk Informed. ASME Section XI. FMEA. Consecuenge Analysis. Pining A(.)

9710070368 970930 -

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ADOCK 05000368 PDR ;.

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T bie or c e=te#ts 1.0 OBJECTIVE AND SCOPE 3

1 2.0 METHOD OF SOLUTION 4

2.1 SummaryofEPRIMethodology 4

2.2 Quantitative Basis 8

3.0 INPUTS AND ASSUMPTIONS 14 3.1 IPE Review 14 3.2 SafetyFunctions 15 3.3 Plant Level Assumptions 15 4.0 ANALYSIS 22 4.1 Configurations & Pipe Runs 22 4

4.2 Spatial Arrangement and Walkdown 29 4.3 Initiating Events 39 4.4 MitigatingCapability 41 4.5 Containment & Combinations 43 5.0 RESULTS 49 O

' 5.1 Main Steam 49 5.2 MainFeedwater 50 1

5.3 EmergencyFecdwater 50 q

5.4 Containment Spray 51 4

6.0 CONCLUSION

S & RECOMMENDATIONS 71

7.0 REFERENCES

73 Appendix A Consequence Analysis Results (75 pages)

Systems Results are Presented in Alphabetical Order O

4 Page 3 Calculation No. NSD-018 1.0. Objective and Scope This analysis documents the implementation of the Electric Power Research Institute (EPRI) risk-informed inservice inspection (RISI) consequence evaluation at the Arkansas Nuclear 1 - Unit 2

_ (ANO-2) nuclear power plant. The objectives of the EPRI RISI evaluation process are to identify risk significant piping, define the elements that are to be inspected within this risk significant piping, and identify appropriate inspection methods. As part of determining the risk significance of -

piping, the consequence evaluation focuses on the impact of a pipe failure. In the consequence -

evaluation, probabilistic safety assessment (PSA) techniques and insights are used to determine consequence categories as described in Reference 1.

i The primary objective of the analysis presented here is to categorize the consequence (s) of pipe failures for the ANO-2 Emergency Feedwater (EFW), Containment Spray (BS or CSS), Main Steam (MS), and Main Feedwater (FW or MFW) systems within the analysis scope.

The scope of piping covered by this analysis is summarized below:

EFW - the main flow path from the condensate storage tanks (CST 2T-41 A & B) to the steam generators located inside the containment building. Connected piping, I % inch in diameter or

. greater, out to the first isolation valve is also included; CSS.- the main flow path from refueling water tank (RWT 2T3) and containment sumps to e

the containment spray discharge isolation check valves inside containment. Test return &

LPSI pipe connections to the first valve and common piping to the HPSI and LPSI pump suction is included.

MS - the main flow path from the steam generators to the MSIVs and MSIV bypass isolation valves located outside containment. Connected piping consisting of safety valves, steam dump.

to atmosphere, and steam supply to EFW turbine are included.

FW - the main flow path from the first outside containment isolation valve to the steam e

generators is included, c

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Calculation No. NSD-018

-2.0 Method of Solution The consequence evaluation is conducted assuming pipe failure (loss of pressure boundary-integrity) A pipe failure can occur at almost any time either causing an initiating event or disabling the corresponding system or train during standby, periodic testing, or a real accident demand The same failure can also impact the availability of other mitigating systems. These consequence scenarios are analyzed per Reference 1.

i 2.1 Summary of EPRI Methodology i

l As described in Section 3 of Reference 1, in the consequence evaluation, a pipe failure (loss of pressure boundary integrity) is analyzed with respect to impact on plant operation. Both direct and indirect impacts are considered:

Direct - the failure results in a diversion of flow and a loss of the corresponding train / system or an initiating event. If flow diversion or isolation of a pipe failure can cause loss of a train or i

system function, this is assumed to be the case, This is conservative because pipe failure is always assumed large enough to either disable the system or lead to isolation of a train or l

system.

O V

e Indirect - the failure results in depletion of a tank and loss of system (s) supplied by the tank, and/or spatially impacts other train / system (s) due to spray, flooding, etc. Since it takes time for flooding and draining impacts to occur, detection and isolation capabilities are an important consideration in assessing these impacts The spatial location and impacts of j

propagation are assessed for each assumed pipe failure, A consequence category is assigned based upon the above impacts including the isolability or j

' failure to isolate the break, and the number of available mitigating (unaffected backup) trains.

e Four consequence categories are used: High, Medium, Low, and None. The "High" category represents events with a significant impact on plant safety, while the " Low" category represents

[

events with a minor impact on plant safety, I

- Consequences are categorized in different importance categories, by applying a send quantitativo approach based on the logic structure of the plant IPE. The logic structures specifically exanuned i

in this process are:

- the event tree and system models

[

e' the critical failure combinations, and the success paths

!O i

1.-

~

Page5 Calculation No. NSD-018 The critical failure combinations and the acceptable success paths are analyzed for each safety g

function in order to determine the level of plant protection and importance of different mitigating functions.

The basic consequence ranking philosophy, used in this analysis, can be summarized as:

"High" Rank: Pressure boundary failures resulting in events which are important contributors to the plant risk or pressure boundary failures which significantly degrade the plant's mitigating ability.

" Low" Rank: Pressure boundary failures resulting in anticipated operational events or pressure boundary failures which do not significantly impact the plant's mitigating ability.

" Medium" rank is included to accommodate failure events which do not obviously belong to the "High" or " Low" rank.

The ana'ysis is conducted slightly different depending on whether or not pipe failure causes an initiating event. The following provides examples to explain these differences and the general methodology:

1. Initiating Event - A pipe failure causes a LOCA without failing any other system or train.

This is a direct impact and for this example there are no indirect impacts. When the pipe failure causes an initiating event, Table 2-1 or Table 2-3 is used to determine the consequence g

category. Since the described event causes an initiating event with no impacts on mitigating trains, Table 2-1 applies. A medium LOCA (M) in Table 2-1 leads to a "High" consequence.

2. No Initiating Event - The pipe failure does not cause an initiating event. In this case, Table 2-2 is used to determine the consequence category. The total impact is assumed to include the train containing the pipe failure and a spatial impact on two other systems due to draining the tank and flooding. Further it is assumed that there are two unaffected backup trains available for mitigating the event, unavailability of the system containing the pipe failure requires a plant shutdown witl% 1 day (short AOT in Table 2-2), and the system is required to mitigate design basis cstegory W accidents in Table 2-2. With 2 unaffected backup trains, the consequence category is " Low" in Table 2-2.

3. Combination Event - The pipe failure causes both an initiating event and impacts mitigative systems, therefore, Table 2 3 applies. It is assumed there are three unaffected backup trains available to mitigate the event. Based on Table 2-3 the consequence category is " Low" unless the consequence category for the initiating event in Table 2-1 is higher. Ifit is further assumed the initiating event is a medium LOCA, then using Table 2-1, the final consequence category becomes "High."

The above provides an example of how the importance of pipe failure is analyzed. In example 1, the initiating event is considered and using the results of the IPE, a consequence category is determined. In example 2, mitigating system impacts are assessed and, based on the number of mitigative trains available and the likelihood of system demand during an applicable exposure

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time, a consequence category is determined. For example 3, the combination impacts are considered and, again, mitigative capabilities are determined and the initiating event impact are determined using the results of the IPE.

The above examples and their reference to Tables 2-1,2, and 3 determined pipe failure importance relative to core damage. Pipe failure must also be assessed for impacts on containment performance and their potential for unisolated LOCAs outside containment. Tables 2-2 and 2-3 are also used to extend the analysis to assess containment performance. The scope of systems in this analysis does not include piping connected to the reactor coolant pressure boundary with i

respect to potential LOCAs outside containment. However, Table 2-4 is included for completeness to show how such piping would be independently analyzed.

The following provides additional explanations of the methodology and the tables used in the analysis and discussed above.

I Table 2-1: This table has been revised from Reference I to be ANO 2 specific, based on conditional core damage probability for each initiating event type. This table provides the minimum consequence category when pipe failure causes one of the plant specific initiating events. If additional impacts occur to mitigating systems due to the pipe failure, Table 2 3 must also be used. Table 2-1 also includes potential LOCAs in the containment for piping beyond the first reactor coolant isolation valve (See Table 2-4 for potential LOCAs outside containment).

Table 2-2: This table is used when pipe failure does not cause an initiating event, but affects plant mitigating functions; it has also been revised from Reference 1 to be ANO-2 specific. Assigning consequence categories when the mitigating ability of the plant s affected depends on the i

4

' following attributes:

l. Frequency of pipe challenge, which determines how often the mitigating function of th'e system / train is called upon. This corresponds to the frequency of plant initiating events (i.e.,

not pipe failure frequency) that require the system / train operation.

2[ Number of unaffected backup systems / trains, which determines how many unaffected systems or trains are available to perform the same mitigating function. The availability of multiple trains makes the effect of the loss of systems / trains less significant. Mitigative systerrishould be evaluated for each plant safety function (e.g., reactivity control, RCS inventory, decay heat removal). When considering the consequences, given an isolation failure, the number of trains must also include isolation.

3. Exposure time determines the downtime for the failed systems / trains, or the time the

- synems/ trains would be unavailable before the plant is required to be shutdown, or the time required to repair the break. In this analysis, it is always assumed that the time to repair is greater than the allowed outage time (AOT). Exposure time is a function of the test interval,

-- the detection time, and AOT. AOTs are plant-specific and, usually, short for important safety components. The key attributes in determining the exposure time are the system states when 4

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P:ge 7 Calculation No. NSD-018 the pipe failure is expected to occur (standby, test, or real demand), and time required for g

break detection (means available to detect the diversion of flow).

Four different exposure times are considered:

"All Year," which applies to standby systems am! parts of systems where the run of piping is not " tested" or is not exposed to the loading condition ofinterest during a year.

i l

"Between Tests" applies to standby systems, which are regularly tested (monthly or quarterly). It is assumed that for those systems the actual exposure time is equal to the test interval (1 to 3 months), because, if a degraded condition is present, it will be discovered during the test.

"Long AOT" exposure time applies to operating or standby systems where pipe failure will be detected within a short time. fler the occurrence, and the plant will shutdown if the failure is not recovered (i.e., repaired) during the AOT. The exposure time is, therefore, equal to the AOT plus detection time. A "long AOT" exposure time is I week.

"Short AOT" exposure time applies to the same systems as the "Long AOT," the exposure time is less than or equal to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Table 2-2 also incorporates guidance for assessing containment performance. If there is a g

containment barrier available, the consequence category determined in the table for core damage W

is retained. If there is no barrier or failure of the only available barrier is used in determining the consequence category for core damage, some margin in the consequence category must be present to retain the consequence determined for core damage. If there is no margin, the consequence category is increased as shown in the table.

Table 2-3: This table is used when the impact of pipe failure results in both an initiating event, as well as other direct impacts, and/or indirect impacts, such as loss of mitigative system (s). It is used in combination with Table 2-1 in that the higher consequence category is always selected.

The number of unaffected backup systems / trains available to perform the mitigating functions is determined. The availability ofmultiple backup trains could make the effect of the loss of systems / trains less significant. Systems should be evaluated for each plant safety function (e.g.,

reactivity control, RCS inventory, decay heat removal). When considering the consequences, given an isolation failure, the number of backup trains must also include isolation.

Table 2-3 also incorporates guidance for assessing containment performance. If there is a containment barrier available, the consequence category determmed in the table for core damage is retained. If there is no barrier or failure of the only available barrier is used in detennining the consequence category for core damage, some margin in the consequence category must be present to retain the consequence determined for core damage. If there is no margin, the consequence category is increased as shown in the table.

9

Page 8 Calculation No. NSD-018 Figure 2-1 further summarizes the methodology and application of the tables described above.

- The figure shows the affects of successful and unsuccessful isolation of a pipe failure. When evaluating the impacts ofisolation failure, this failure can be equivalent to an available train depending on detection, time available, and physical crpability (i.e., MOV or trip pump). In the example shown, the reliability ofisolation is assumed to be worth "I train." If pipe failure causes an initiating event (IE), only this portion of Figure 2-1 is utilized. Given an initiating event, and an assumed exposure time of"All Year," the accident dem snd case is enveloping. If no initiating event is caused by the pipe failure, the " accident deman !" configuration is analyzed when applicable, becauw it envelopes the exposure time for t ne " normal" and " testing" configurations.

Table 2-4: All piping connected to the reactor coolant pressure boundary and beyond the first isolation valve are evaluated as potential unisolated LOCAs outside containment using this table.

Piping inside the containment and between the first reactor coolant pressure boundary isolation valve and the containment wall is evaluated in Table 2-1 as a potential / isolable LOCA.

4 2.2 Quantitative Basis The ANO-2 IPE, supplemented with design basis information, is used to define the quantitative basis for applying the EPRI procedure to the consequence evaluation at ANO-2. Figure 3-1 summarizes ANO.2 success criteria for different safety functions.

The following values for conditional core damage probability (CCDP) assuming a pipe failure are utilized by the EPRI methodology to assign consequence categories:

Low CCDP s IE-6 Medium lE-6 < CCDP s IE-4 High CCDP > IE-4 4

1

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Page 9 Calculation No. NSD-018 Table 21 Consequence Category Assignment for ANO 2 Pipe Failures Resulting in Initiating Events initiating Event IEF CDF CCDP Consequence (2)

T1 - Turbine trip 7.6E 01 2.3E 06 3.0E-06 low-medium T2 - Loss of PCS 2.5E-01 9.0E-07 3.6E-06 medium-low T3 LOSP 5.8E-02 1.7E-06 2.9E-05 medium T4 - Excessive FW 9.4E-04 1.9E-09 2.0E-06 low-medium T5 - Steam / Feed break 1.1E 03 1.1 E-09 1.0E-06 medium (3)

T6 - Reactor Trip 2.0E+00 6.0E-06 3.0E 06 low-medium T7 -less of SW 5.5E-03 2.1 E-06 3.8E-04 high T8 - Less of SW P4A 7.4E-02 2.1 E-07 2.8E-06 medium-low T9 -less of SW P4B 7.4 E-02 2.0E 07 2.7E-06 medium-low T10 - Loss of DC D01 3.9E-04 9.8E 06 2.5E-02 high Tl1 - Loss of DC D0' 3.9E-04 1.1 E-06 2.8E-03 high T12 - Loss of AC A3 3.9E-04 3.2E-06 8.2E-03 high T13 - Loss of AC A4 3.9E-04 5.8E-08 1.5E-04 high-medium Tl4 - Loss of AC B5 1.0E-03 1.9E-07 1.9E-04 high-medium TIS - Loss of AC B6 1.0E-03 1.2E-07 1.2E-04 high-medium S - Small LOCA 5.0E 03 1.7E 06 3.4E-04 high-medium M - Medium LOCA 1.0E-03 1.7E-06 1.7E-03 high A - Large LOCA 1.0E-04 1.4E 06 1.4E-02 high R-SGTR 9.8E-03 9.5E-08 9.7E-06 medium Potential / Isolable LOCA (1)

(1)

(1) low-medium ISLOCA (1)

(1)

(1) high (1) Piping connected to reactor coolant pressure boundary is not included in the analysis scope; included for completeness. Consequence depends on isolation failure likelihood and other conditions. Also, see Table 2-4, (2) When CCDP is close to a lower consequence, a range is shown. He first consequence shown in the range is assumed in the analysis. In the case of transients (TI, T4, and T6), a low consequence is assumed in the analysis. The IPE is judged to be causervative (e.g., additional credit for AFW and hunun actions) relative to other initiators (e.g., note T5 CCDP is lower) and the CCDP nlue is close to the iE-6 threshold. Other initiators that are marginal could be evaluated further with the IPE to determine whether a more realistic CCDP is possible.

(3) Steam & Feedwater breaks although marginally low are considered a severe plant challenge (e.g., high energy lines) and assumed to be medium consequence.

Initiating event frequency (IEF) is from IPE Table 3.3-6 (page 3.3-23) and core damage frequency (CDF) is from IPE Table 3.5.4-7A (page 3.5-59).

He above events can be assigned to design basis categories as in Reference 1 (Table 3.2) by considering the IPE initiating event frequency (IEF) in the above table.

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i Page 10 Calculatica No. NSD-018 l

T Table 2-2 Guidelines for Assigning Consequence Categories to Pipe Failures Resulting in Loss of J

System (s)ffrain(s) Without an Initiating Event Affected Systems Number of Unaffected Backup Trains Frequency of Exposure Time Challenge to Challenge 0

0.5 1.0 1.5 2.0 2.5 3.0 23.5 L

Anticipated Betmen tests (13 month)

[

L L

llMl!

L L

L (DB Cat II) long AOT(I week)

Shon AOT(s I day)

L L

L L

I) h Infrequent Between tests (13 month)

L L

L b

(DB Cat III)

Long AOT(1 nek) b

]

j L

L L

L Shon AOT(s 3 days)

Mi!

L L

L L

L L

L L

Allyear Unexpected Between tests (13 month)

L L

L L

a (DB Cat IV)

Long AOT(1 week)

1. My L

L L

L L

Shon AOT(s 3 da31)

L L

L L

L L

H

= High Consequence Category Medium Consequence Category M m L

=

Low Consequence Category Containment Performance - If there is no containment barrier and the consequence category is determined by e diagonal shaded y

box, the consequence category is increased.

- Medium becomes High t@$

O - Low becomes Medium m

b

Page11 Calculation No. NSD-018 Table 2-3 Guidelines for Assigning Consequence Categories to Combinations of Consequence g

impacts (Initiating Event and Mitigating Train (sySymem(s) Impact)

Combination ofInitiating Event &

Consequence Category Mitigating Ability AITeas Less than 2 unaf.ected backmp trains available for 3%iM{EDIDMN#Q%

vr.; WMO f;. P

.r.

..,s At least 2, but less than 3 unaffected backup trains

(orIE chtEgory fromTable 2 hip available for mitigation lifhis,hst)$

LOW At least 3 unaffected backup trains available for (or IE category from Table 2-1, mitigation ifhigher)

No mitigating ability affected IE category from Table 2-1 O

Note: Mitigating systems always correspond to the analyzed initiating event.

Containment Performance - If there is no containment barrier and a minimum number of unaffected backup trains, the consequence category is increased as follows:

2 unaffected backup trains and no containment barrier: " Medium" becomes "High." If the number of unaffected trains is between 2 and 3, " Medium" is retained.

3 unafrected backup trains and no containment barrier: " Low" becomes " Medium." If the number of unaffected trains is greater than 3, " Low" is retained.

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Page 12 Calculation No. NSD-018 Table 2-4 Guidelines for Assigning Consequence Categories to Pipe Failures Resulting in Increased Potential for an Unisolated LOCA Outside of Contairant Protection Against LOCA Consequence Category Outside Containment 1 active' I

2 1 Passive khk(Q;[ hikEilDEy[hhES 2 Active hthiMe&MEDIdM$jpje*h *l A

1 Active,1 Pat,sive ggjg;

??ti.p 1

2 Passive LOW l

More than 2 NONE

1. An Active Protection is presented by a valve which needs to close on demand.

2. A Passive Protection is presented by a valve which needs to remain closed.

t l

i

+

O 1

l

Page 13 Calculation No. NSD-018 Figure 2-1 Summary of Methodology Showing Effects ofIsolation Anilable Mitigating Trains Needed FromIPE Pipe geenm;o, no,=1 Ya y"

3 - > Low Segment -->

Anticable

-+

(operating er

• • " IE Y"

1,oi,uon i Table 2-3

> 2 O Med II Fails N'85'tia St=b)

<1 --> IIigh No No No I **i" 2 --> Iow I

• Table 2-3

-> 1 --> Med Ter%

<1 - > lligh

Table 2-1 v

Y" Yes l "'> l w Acadent Img er Slut Aoi T8124 I'*'"i "

a/

Expoewe Tavie

Iligh Jo o

I===

1 --> Low

-?

• <1 --> IIigh insignificant risk because direct initiate: is

--+unlikely, exposwe time is small and im will be on leak and/or controlled shutdoun

+

T Ya T

Ya w 93 t Table 2-2

<1 -> High a train i

1 --> Low

• Table 2-2 gin y,,,

g Expmure Tune 2 - > Low tsotation Table 2-2

> 1 --> Med (1) example assmnes IE leads to hw sm~rm in Table 2-1;

<1 --> High a

y, thus, Table 2-3 is used for combination impacts case.

I **,*

(2) probability of a real system challenge (acendent demand) is g ag assumed to be less than IE-2/yr (DB Cat IV)

> Table 2-2 g

9 9

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P:ge 14 Calculation No. NSD-018 J-O 3,0 inputs and Assumptions.

i in addition to Reference 1, numerous plant specific documents are reviewed (see Section 7 p

references); the following are key inputs to this analysis:

ANO 2 IPE (Reference 2) is used to assess importance and unavailability of systems, trains,

- accident initiators, and accident sequence types. The IPE also contains information on systems operation, dependencies, and spatial consequences (e.g., internal flooding initiators).

The ANO-2 P& ids, Isometrics, and Plant Design Drawings (References 3, 4, and 5) are i-utilized to identify piping locations.

ANO-2 Design Basis Documents (References 6 through 9),

ANO-2 Internal Flooding Study (Reference 10) 3.1 IPE Review The ANO-2 IPE (Reference 2) is used to evaluate the importance ofinitiating events, systems,

' and spatial locations affected by potential pipe leaks and/or failures.

Core damage frequency depicted in the ANO-2 IPE is approximately 3,4E-5/yr Table 2-1 shows the contribution of accident initiator types as well as conditional core damage probability (CCDP) which provides an indication ofmitigation capability for each initiator, The following summarizes the review results:

1

• = LOCAs outside containment, internal floods, and ATWS sequences are screened from the IPE as contributing less than IE-6/yr, i

Loss ofDC bus 2D01 or 2D02 are important. These events prevent fast transfer of AC power, cause blackout at one bus, loss of main feedwater, and once-through cooling is unavailable (ECCS vent valves unavailable). This is combined with' failure of the unaffected EFW train and/or operator failur, to recover AC power to cause core damage.

Loss of AC bus 2A3 or 2A4 are important These events result in blackout at one bus and o

loss of main feedwater. This is combined with operator failures to realign affected DC to

. another AC bus and/or control EFW flow with realignments or local actions.

IPE Table 3.5.4-3 summarizes the importance ofoperator actions and equipment. Operator O important. Batteries, EFW train A, and diesel generators are impo

Page 15 Calculation No. NSD-018 3.2 Safety Functions Each critical safety function is considered when determining the number of available mitigating trains in the consequence evaluation. Figures 3-1 A & B summarize the ANO-2 IPE (Reference

2) success criteria as a simplified diagram. Reactivity control and pressure boundary integrity functions are not shown in the figure, but are discussed below. The following summarizes how these functions and others are treated in the consequence evaluation:

Reactivity Control - this function is not explicitly included in the consequence evaluatiou.

Although this function is required immediately upon demand to protect the core, a pipe failure is judged more likely to cause a reactor trip than to prevent a reactor protection system success (this function is fail safe, deenergize to actuate). Also, it is judged unlikely that a pipe failure would immediately impact actuation of turbine trip, safety injection, or EFW. The most likely scenario could be an independent failure of RPS (unavailability on the order of IE-5; a medium consequence without other mitigating capability) and failure of safety injection or EFW due to the piping failure. Since such failures due to pipe failure are likely to lead to " Medium" or higher consequences due to impact on other safety functions, the reactivity control function is not explicitly evaluated.

RCS/ Core Heat Removal & Inventory Control - these functions are included in the simplified success diagram as shown in Figures 3-1 A & B. For transients, the steam generators with feedwater or emergency feedwater or auxiliary feedwater can provide the heat removal g

function. Inventory control is assumed not to be a primary concern unless there i2 a challenged and stuck open pressurier safety valve or a seal LOCA (RCS integrity function).

If the steam generators can not provide the necessary heat reraoval, the HPSI system in combination with pressurizer vent paths can provide heat removal and inventory control (once through cooling). For this success path, transfer to containment sump recirculation and heat removal with containment spray is required. As shown in Figure 3-1B, the success criteria changes for LOCAs since inventory control becomes the primary concern. A stuck open pressurizer safety or a seal LOCA (RCS integrity function failure) is assumed to be a i

medium LOCA as modeled in the IPE.

Containment Performance - To maintain the consequence category determined from the above functions, at least one containment barrier must te available or there must be margin in the number of available mitigating trains as described in Section 2. Otherwise, the consequence category is adjusted accordingly.

Table 3-1 summarizes key functions, systems, and pump trains shown in Figures 3-1 A and B.

The table also explains the backups trains assumed in the analysis.

3.3 Plant Level Assumptions Engineeringjudgments are included and discussed throughout the analysis; the following are considered to be key plant level assumptions and judgments:

l l

Page 16 Calculation No. NSD-018 f

l. - Pipe failure can occur at anytime; three configurations are defined as shown in Table 4-1, These are normal (operating or stadby), test, and accident demand. This table also

-l summarizes judgments and assumptions regarding which configurations are most important.

If pipe failure does not cause a direct initiating event, it is assumed that pipe failure occurs i

during the accident demand configuration, if applicable. This assumes pipe failure occurs j

during the most conservative exposure time and accounts for the higher stress placed on the operators with resultant delay in operator response.

2. Pipe failures in moderate energy lines (<200*F and <275 psig) are assumed to be large. This analysis goes beyond the design basis by evaluating the consequences of unisolated large breaks (i.e., flooding) even though they are considered less likely in moderate energy lines.

l Smaller breaks would allow more time for the flooding impacts to occur. Most studies would consider such events almost incredible.

3. Draining one CST (about 200,000 gallons each) into the auxiliary building can not flood the l

LPSI, HPSI, and containment spray pumps. The equalized flood level is less than 8 feet above floc r El 317 which is below the elevation of ventilation openings into these flood i

protected rooms. However, EFW suction would transfer to service water on low pressure.

l Thus, for EFW breaks downstream of the crosstic isolation MOVs (2CV-0789-1 and 0795 2), it is possible that all ECCS on El 317 could be flooded if service water is not isolated or tripped or the ventilation openings closed. The ventilation openings are closed on a safety

- injection signal or by the operators in response to flooding. Because there are numerous

(

indications and time for the operators to prevent such events, they are considered to be very l

unlikely in this analysis.

4 j

4. Main steam line breaks outside the containment building (Room 2155) are acknowledged as j

having the potential to propagate into the fuel handling area (Room 2151), as well as impact -

both EFW steam supply lines. These are considered conservative assumptions since such an extremely severe event is considered unlikely. On the other hand propagation into the spent l

fuel pool area is not assumed to affect safe shutdown equipment.

l S. ANO-2 analyses (Reference 17) concludes that an EFW steam line break during normal operation will not cause a direct plant trip. However, based on more recent analyses, this is judged to be marginal; it is assumed that pipe failure will cause a plant trip initiating event.

Piping failure in normally pressurized piping up to 2CV-0340 are assumed to occur during the normal standby configuration (i.e., it is assumed that pipe degradation is just as likely to j

reveal itsdfin standby as during a demand). Also, it is assumed that environmental impacts -

[

are minor relative to safety equipment at El 335 (Room 2040) if the break is successfully i

detected and isolated. This is judged to be a reasonable assumption given the size of the areas -

l and the location and qualification of key components.

6.' For main feedwater line breaks postulated outside containment, it is assumed that EFW supply valves in the north piping penetration room (2081) and MCC 2B52 at the far end of the corridor in Room 2040 are affected. EFW and ECCS equipment are in protected rooms and assumed not to be affected. The turbine EFW steam supply isolation valve in Room 2040 j-O i 9<et ct 4 8 at a a - >i ano i

- a te r nctien cen cc reilv te i iti te ntw ^).

b o

I

Page 17 Calculation No. NSD-018

7. EFW piping breaks inside the containment have the potential to empty at least a portion of a g

CST. Emptying a CST into the containment building is assumed not to impact reactisity control if once through cooling is required for successful heat removal and inventory makeup (i.e., recirculation with CST in containment). Also, continued flooding of the containment with service water is assumed to be unlikely and is not analyzed (i.e., EFW transfer to service water).

8. Unisolated EFW pipe failures are conservatively assumed to cause flow diversion and failure of the affected EFW tra:as. This isjudged particularly conservative for the lines downstream of 2EFW-7A & D and 8A & B because this assumption fails all EFW.

9. The valve arrangement in Room 2084 and the failure of fire doors into Room 2073 are assumed to preclude flooding of the ECCS valves in Room 2084. Some of the HPSI valves appear to be close to the floor (i.e., I to 2 feet above El 360), but their motor operators are a few feet higher. Spray from EFW lines above could impact some valves, but there are a number of HPSI supply valves and the containment spray valves are separated such that there should always be a discharge path for these systems. Also, flooding to a level of 3 to 5 feet in a room is assumed to fail the door and drain the room (doors open out of rooms toward Room 2073),

10. MCCs at El 354 (Room 2073) and El 335 (Room 2040) are assumed to fail if water accumulates to a height of 6 inches at the MCCs. At El 354, there is a large grated opening to El 335 on the west end of the building. Thus, it is assumed that breaks in this analysis scope can not accumulate 6 inches at this location. It takes a significant time to flood to a g

level of 6 inches at El 335, but it is assumed that failure to isolate results in MCC failure.

W l1. This analysis assumes that filling of an EFW pump room (CST or service water as the source) will not cause gross structural failure of the room or door. The watenight doors are very heavy and open into the rooms.

12. The IPE internal flooding study identifies impacts in rooms from cable terminal points. Sin e most junction boxes, terminal boxes, etc. noted during the walkdown arc at least a few feet off the floor, these impacts are ignored in the analysis. Also, junction boxes appeared to be tight and sealed, therefore, even if water reached them, an electrical fault appeared unlikely.

13. Draining the RWT into the east or west ECCS Room (2007 or 2014) will flood the room where the flood initiated and propagate to the general access area (2006/2011) through ventilation penetrations, but will not flood the other ECCS room. If the flood is initiated in the access area (2006/2011), flood levels could reach the ECCS room ventilation penetrations; it is assumed all ECCS could be flooded and all equipment failed. Even if a more detailed evaluation of room areas showed this to be untrue, loss of RWT would still fail recirculation function. Therefore, this conservatism is not evaluated funher.

14. No credit is allowed for isolation of ECCS Room ventilation penetrations. Isalation could prevent flood propagation into or out of the ECCS rooms. These ventilation openings auto close on a safety injection signal and annunciator response procedures for room flooding direct operators to close these penetrations. Since an ECCS room or the general access area can hold approximately 50% of the RWT, the importance of this assumption is not judged to g'

be high (see next assumption)

Page 18 Calculation No. NSD-018

(

15. Draining approximately 50% of the RWT outside the containment is assumed to fail the containment sump recirculation function (i.e., insufficient NPSH).

16. Suction piping from the CST (EF%) and RWT (CSS)is assumed to fail during an accident demand. This is conservative because the demand stress may not be significantly different than the standby condition.

17. Unisolated flow diversion due to CSS pipe (main flow path) failure is assumed to lead to insufficient containment sump level and failure of containment sump recirculation.

18. MCCs 2B52 impacts are assumed to occur whether isolation occurs or not for RWT suction (20 inch pipe) and feedw.ter line breaks this is conservative.

19. Except for the containment sump piping upstream of 2CV-5647 and 5648, piping is assumed to fail during the RWT injection phase (i.e., if the pipe did not fait during injection it is assumed unlikely to fail during recirculation). Also, transfer to recirculation after the RWT is emptied and subsequent failure to isolate the containment sump on the train with the pipe failure is considered unlikely and neglected. The EOPs require local verification of ECCS rooms drain valves and water tight doors closure upon receipt of RAS pre-trip (alarm at 40%

RWT level).

20. CSS welds inside the containment sump and the piping sleeve are conservatively combined with the consequence of piping outside containment in the same line.

21. Steam generator tube integrity is not assumed to be lost during main steam and feedwater

(]

transients or pipe breaks.

22. The IPEEE (external hazards analysis) assessment neglects (1) the potential impacts of relay chatter from relays with unknown capacity (possible optimism, although this is scheduled to be resolved), (2) an improvement if the seismic capacity of EDG tanks is increased, and (3) a detailed review of fire scenarios (not provided in the IPEEE). These are not judged to significantly impact the analysis results.

O)

L

Page 19 Calculation No. NSD-018 9

Table 31 Assumed System & Train Backup System / function / train Trains Explanation MRV (gate B02) 1 Given no MSIV isolation or loss of PCS initiator, main feedwater is treated as at least I train.

SDBCS/Cond 0

Recovery with steam dump bypass control and condensate has not been credited in the analysis.

ERV (gate Q001) 1.5 Common cause is assumed to be dominated by 4 trains of steam generator supply paths.

ERV (gate Q005) SLB 1.5 Same as above Motor ERV 1

The pump trams are assumed to dominate unavailability. There are multiple injection paths to steam generators and they can be locally opened. Normally open suction to CST and auto switchover to senice water is reliable.

Turbine ERV 0.5 he pump traa. are assumed to dominate unavailability, nere are multiple injection paths to steam generators and they can be locally opened. Normally open suction to CST and auto switchover to senice water is reliable.

ARV 0.5 Highly dependent on operator actions & CST is required.

OPER 1

The "Once Through Cooling" path depends on OPER-2 (SE-3) and can be assumed to be I train as long as there is a success path available in Figure 31 A.

HPSI (gate 11001) 1 OPER assumed to dominate.

~

HPSI A 1

Pump train dominates with multiple injection paths.

HPSIB 1

Pump train dominates with multiple injection paths.

HPSIC Requires operator action.

Pzr vent (gate R001) 1 Redundant series MOVs.

Recire (gate H003) 1 OPER assumed to dominate.

Recare A 1

Sump MOV must open and other MOVs close.

Recire B 1

Sump MOV must open and other MOVs close.

Contamment Spray 1

OPER assumed to dommate.

(cate Y001)

Containment Spray A 1

Pump and discharge MOV dominate.

Containment Spray B 1

Pump and discharge MOV dominate.

Integrity (gate Q01 A)

This is a check on the conditional probability of a transient induced LOCA. Unavailability is based on gate QO28=1 LPSI (gate LOOL)

Not used in anai3 sis.

LPSIA Pump and discharge MOV dominate. Not used in anaissis.

LPSIB Pump and discharge MOV dominate. Not used in anahsis.

SDC (gate LOO 2)

Not used in analysis.

SIT (gate C0001)

Not used in analysis.

SDBCS (gate P300)

Not used in analysis.

9

.. =.

Page 20 Calculation No. NSD-018 O

Figure 3-1 A Simplified Success Criteria for Transient

()

~

MFWot s.

W SDBCS/Cond Transient -

A Success E

HPSI N ECCS HPSl *N CSS *N

)

oPER

--.)

HPSIT 9

LToP HPSIT C SS *B"

_g Wnis Recirc HPSl*C" O - The above simplified diagram applies to a transient with the power conversion system (PCS) d initially available. The containment cooling function is not shown for the once through cooling function because most of CSS piping is required to support recirculation function. Containment cooling is credited as a train for breaks that can be isolated, allowing HPSI and LPSI success.

'i X_)

Page 21 Calculation No. NSD-018 Figure 3-1B Simplified Success Criteria for LOCAs g

Main Feedwater HPSl *N Wtor HPSl *N CSS *#

N 9

Rectre EFW

~+

HPSl *B*

CloCA 9

gygg,,,

Turtdne N

EFW H PSl *B*

CSS *B"

_)

Recirc AFW H PSl *C" 9

(1)OPER Y

SDBCS ECCS s*

~

w nte OPER SDC s

Recowry LTOP

+

w nts (1) If main feedwater or EFW or AFW is successful, the operators can depressurize with steam generators and remove sufficient heat to preclude the need for recirculation and containment heat removal. The containn.ent cooling function is not shown because most of CSS piping is required to support recirculation function and medium LOCA is g

asssumed (SLOCA success path is not used in the analysis).

HPSl *A" LPSl'A" HPSl'A' CSS *A" g

4.OCA HPSl *B"

. Success LLOCA LPSI *B" CSS *B" 9

HPSI *B" (1)

Recirc HPSI"C" sr (1) LPSI is only required for Large LOCAs (LLOCA) and SITS success is not shown (assumed to be more reliable than LPSI). The containment cooling function is not shown because most of CCS piping is required to support recirculation function.

Containment cooling is credited as a train for breaks that can be isolated, allowing HPSI and LPSI success.

O

Page 22 Calculation No. NSD 018 O

r 4.0 Analysis l

4.1 Configurations & Pipe Runs An important input to the consequence evaluation is the system configuration under which piping -

is assumed to fail. The following system configurations are used in the evaluation. For these configurations, the plant is assumed to be at-power.

1. Normal (operating or standby)-

2. Test (periodic testing applies)

3. Demand (real demand due to plant trip or accident) i.

The configuration can influence piping loads, piping degradation mechanisms, the probability of failure (demand vs time dependent exposure), and the probability of detecting and isolating the failure prior to significant propagation and/or impacts, it is assumed that pipe failure occurs i'

during an accident demand if the pipe failure does not cause an initiating event. This is conservative in that it increases exposure time and reduces human reliability in response to a pipe failure in comparison to the ' Normal" and " Test" configurations. This is explained further in Section 2 'and Figure 2-1. Table 4-1 documents judgments made in the consequence evaluation relative to applying the above configurations.

The following summarizes how piping runs and configurations are identified:

1. The system P&ID, isometrics, and plant design drawings (References 3,4 and 5) are reviewed to determine the location of analyzed piping within the plant and associated piping connections (i.e., CST, RWT, and reactor coolant system).. Connections to the reactor coolant' system (i.e., main feedwater and main steam systems) or normal operating systems are considered as having a high potential for causing an initiating event as well as spatial l

impacts. Tank connections can present a significant flood source as well as directly impact i

safety functions.

T

_ 2. The IPE, including the internal flooding study (References 2 and 10), is reviewed to determine the importance of spatial locations (i.e., location of critical equipment),

propagation paths between plant locations, as well as detection & isolation capabilities.

3. Based on the above, the system piping is divided into piping runs based on spatial location -

l

' and an initialjudgment as to initiating event potential and the consequences if an unisolated

. pipe failure occurs. In addition, Table 4-1 is used to determine the applicable configurations.

Location designators in the IPE internal flooding study are used in this analysis. Generally, a t

- new piping consequence ID is defined for each location or an additional consequence ID is defined when'the consequences differ within a location (i.e., isolation capability changes). In

O

.** vivi ce a

10ceti vivisi-er**

iectie -*

consequences do not change.

i

i Page 23 Calculation No. NSD-018 The results are provided in Appendix A and developed throughout this analysis.

Qther Modes of Operation The consequence evaluation is an assessment assuming the plant is at-power. Generally, the at-power plant configuration is assumed to present the greatest risk for piping since the : plant requires immediate responte to control reactivity, heat removal, and inventory control; the plant is critical, at higher pressure, and temperature in comparison to shutdown operation. The potential importance of piping during plant shutdown is evaluated here to establish confidence that no gross misjudgment is made in the consequence assignment. This evaluation concluded that LPSI piping categorized as " Low" during power operation should be categorind as

" Medium" due to shutdown consequence considerations.

Pipe segments that are already a "High" consequence from the evaluation at-power need not be evaluated for shutdown. Those that are aheady " Medium" require confidence that High would not occur due to shutdown configurations. However, a " Low" consequence for power operation requires more confidence that a High would not occur and some confidence that a Medium consequence would not occur. Taking this into account, a review & comparison of system consequence results for power operation versus potential consequence during shutdown operation is conducted. Table 4-3 documents this review. This evaluation concluded that LPSI operaticn in the shutdown cooling (SDC) mode needs further analysis. A fhrther review of LPSI is provided below.

Other observations about shutdown operation considered in this review include the following:

During shutdown EFW, HPSI, and LPSI are not automatic and require manual actuation.

EFW is automatic until cold shutdown (Mode 5, <200*F) and au ECCS actuation is no longer automatic when RCS is <361 psia in Mode 4 (2102.010, Rev 30 " Plant Cooldown").

However, Entergy's outage management philosophy, outage risk management guidelines, and procedures provide assurance that loss of SDC will be dotected and mitigated (e.g.,

2203.29, Rev 9 " Loss of Shutdown Cooling).

Unavailability of mitigating trains is higher due to planned raaintenance during outages.

However, guidelines and procedures assure sufficient reduridancy and account for higher risk configurations (e.g., mid-loop) which requires extra redundancy and/or contir.gencies (e.g.,

2R12 Shutdown Operations Protection Plan, May 8,199D.

For the majority ofpiping, the exposure time associated with operation in a shutdown con 6guration is on the order of 0.1/yr. Also, the operating conditions are much less severe than during power operation. The frequency of being in a more risk significant configuration could be even lower depending on the system and function being evaluated. Operation of LPSI in the shutdown cooling (SDC) mode of operation is an important exception.

For the majority of standby piping, the frequency of challenging important mitigating systems g

is judged to be on the same order of magnitude or lower. Operation of LPSI in the shutdown cooling (SDC) mode ofoperation is an important exception.

Page 24 Calculation No. NSD 018 p

The reacte is shutdown, depressurized, and decay heat is lower than for at power operation.

d The reactivity control function is not a concem because the rods are inserted. Re-criticality during shutdown is unlikely and not judged to effect the present ranking. The inventory makeup (safety injection) is considered the most important function during shutdown, given a class I or 2 pipe break occurs during shutdown causing loss of SDC.

During shutdown, the reactor coolant system and connected piping are not pressurized nor at high temperatures, as during power operation. Piping failures are not as likely (e.g., initiating events) and the at power ant. lysis foi these systems is assumed to envelope shetdown l

conditions. Since the LPSI system is aligned to the reactor coolant system in ti.a SDC mode I

of operation during most of the outage versus being isolated from the reactor in standby during power operation, this system is evaluated further below, Decay heat is lower during shutdown such that the time for recovery of shutdown cooling or i

e

)

inventory makeup is usually longer. Thus, even though equipment may require manual actuation and may also be in rnaintenance, there is time for recovery. LOCAs (considered less likely due to reduced pressure and temperature) would exhibit much less severe environmental conditions (e.g., hot or warm water versus steam) until deay heat starts to heatup reactor aner loss of SDC.

That portion of LPSI that is in standby during power operation and operatea in the SDC mode during an outage 11. Judged to present the most important configuration change requiring further evalur.tlon. Loss of SDC is an important initiating event during shutdown and the potential for an n unisolated LOCA in the LPSI system must also be considered.

U LPSI pipe segments that are challenged during power operation due to an independent

" Demand" are in the "High ' or " Medium" consequence category. Those that are " Medium" can be detected and liolated which would also be the case during shutdown. Thus, the focus is on piping not challenged as part of the LPSI function. If a "High" consequence should result from this review, other " Medium" consequences determined for the LPSI function during operation would have to be evaluated further. The following summarizes the review of LPSI pipe segments relative to power operation:

SDC suction piping upstream of 2CW5084 is already "High" due to a LLOCA during power o

operation. This can be assumed to envelope shutdo,vn risk for the reasons stated above, SDC suction piping downstream of 2C%5084 and upstream of 2C%5086 inside o

containment is a " Medium" consequence duiing power operation because passive failure of the normally closed 2CV-5084 is necessary to challenge piping. Failure of this piping during SDC is assessed bdow by considering two types of scenarios. The first one is associated with initial alignment of SDC because this is when pipe failure would most likely occur due to the demand challenge. The second condders the case where the plant is in cold shutdown and depressurized, pipe rupture is assummi less likely at this point given the successful demand.

1. The real demand occurs when the operators align SDC (RCS pressure <275 psia and g

temperature <245'F) pLr s'ep 8.15 of the plant cooldown procedure (2102.010, Plant Q

Cooldown, Rev 30). During this important evolution, operators are alerted to ensure proper alignment and inventory per the procedure. Thus, during the initial aligrunent and for some

\\\\

4

_ _J

Page 25 Calculation No. NSD 018 time thereafler it can be assumed operators are prepared and alerted to this important conf,guration change. Also, steam generators are still available or recoverable since they are g

being used until the plant is aligned to SDC (assuming 2C%5084 is isolated quick enough).

Although reactor conditions are still relatively severe in comparison to cold shutdown, the operators are alert during this evolution and the steam generators are available (assuming isolation). Thus, for the case where operators successfully isolate the break early, a CCDP of about IE-4 or less for failure to recover a steam generator or inventory makeup is reasonable. For the case where 2CW5084 falls to close (either due to equipment of humm),

the reactor could drain to the invert of the hot and cold leg r,oules. The loss of shutdown cooiing procedure (2203.029 " Loss of Shutdown Cooling" Rev 9) identifies entry conditions, including alarms, and directs the operatort to stop the SDC pump & Isolate SDC at step 4, if RCS level is decreasing rapidly. The procedure exits to lower mode functional recovery (2202.011 " Lower Mode Functional Recovery" Rev 0) for both SDC isolation success (step 4.D) and failure (step 4.0). This procedure repeats steps to secure and isolate SDC,,ss well as other attempts to locate and isolate inventory loss. It also provides steps for restoring level and/or heat removal depending on the configuration. Assuming the operators have a socond chance with regard to providing inventory makeup after failing to isolate (e.g., before boil off and core damage), a CCDP on the order of IE-4 or less is reasonable.

2. If pipe failure occurs later in the outage when the reactor is in cold shutdown (<200'F sad depressurized), it is possible that steam generators are not available or the RCS is vented or open (vessel head is of!). Also, the operators may not be as alert if the configuration is deemed to be steady state (e.g., the alignment has been successful for some time, the reactor is cold, and decay heat is lower). Ifit is assumed steam generators are not available, and SDC g

is lost due to the break, inventory makeup is the primary concern (e.g., makeup must at least satisfy decay heat boil off). Still, isolation can provide the operators significant time especially if the refueling cavity is full. For the case where the operators are at mid loop, they should again be alert due to the importance of this configuration, but isolation is almost irrelevant because level is already near the invert of the reacter nozzles. Thus, for the mid-loop configuration, there is some increased level of alertness by thc operators where as when the refuel cavity is full there is more time to detect and isolate. Procedures require redundant inventory makeup during mid loop (2R12 Shutdown Operations Protection Plan, May 8, 1887). A CCDP of IE-4 or lower is reasonable for a number of reasons. The likelihood of pipe failure after the initial demand and during cold conditions is smaller. The exposure time for the more risk significant configurations is lower and there is planned alertness and backup equipment available during these higher risk configurations. The operators have to fail to provide makeup or the equipment must fail.

Pipe breaks on the suction side envelope breaks on the discharge where there is a check valve to isolate the reactor Still discharge breaks could pump down reactor inventory until detected and isolated or pump cavitation occurs.

SDC suction piping down stream of 2CV-5086 inside containment is a " Low" consequence o

during power operation because 2 passive valve failures of the normally closed 2CV-5084 and 50S6 are necessary to challenge piping. Failure of this piping during SDC isjudged to be a " Medium" consequence. The rationalis the same as the previous segment except there are 2 redundant valves for isolation; the human is assumed to dominate isolation failure, i

Page 26 Calculation No. NSD-018 b]

SDC suction piping down stream of 2CV 5086 and upstream of 2CV 5038 outside

/

e containment is a "hiedium" consequence during power operation because of the potential consequences of a LOCA outside contrinment with containment bypass. Failure of this piping during SDC is considered a "hiedium" consequence for similar reasons described above. The LOCA emironmental conditions (failure of 2 hf 0Vs to close or human error) outside containment during shutdown arejudged to be much less severe than the power operation case with regard to potential impact on mitigating systems. The fact that water is being lost outside containment is still a concern. Still, failure to close 2 redundant hiOVs is considered a "hiedium" comequence.

SDC suction piping down stream of 2CV-5038 outside containment is a " Low" consequence during power operation because there are three normally closed valves. Failure of this piping during SDC is considered a "hiedium" consequence for similar reasons described above.

Piping downstream of manual valves 2SI-4A and 4D and upstream of manual valves 2SI 5A and SD is also only used during SDC. It is a " Low" consequence during power operation.

l Thes.: lines provide redundant paths through the two heat exchangers. Thus, isolation of a break in one of these lines would allow SDC recovery with the other heat exchanger path.

The lines evaluated above envelope, but a "hiedium" consequence is still assigned for this piping.

Piping downstream of 2SI-SA and SD and upstream of 2CV-5093 is also " Low" during power operation because this piping is used for SDC and not the LPSI function. A failure

' q here would lead to loss of SDC because the piping is common to both trains. A "hiedium" Q

consequence is assigned based on the above.

In summary, most LPSI piping is already in the "High" or "hiedium" category based on power operation. The SDC pipe segments not challenged as part of the LPSI function arejudged to have a "hiedium" consequence. Some piping which is considcred " Low" for power operation is "hiedium" due to SDC considerations. A more detailed risk assessment of shutdown configurations would be needed to support a " Low" consequence for the piping.

Extemal Events The consequence evaluation is an assessment utilizing design basis information and the plant PRA for internal initiating events. Pipe breaks cause the same initiating events in the PRA and their frequencies in the present evaluation is higher than the frequency of fire and seismic events.

Ilowever, these low frequency events beyond the design basis have potential common cause effects that could possibly effect the importance of piping. Because of this, the importance of piping during external events beyond the design basis is assessed here to establish confidence that no gross misjudgment is made in consequence assignment. This evaluation concluded that the steam driven EFW pump train categorized as " Low" could be categorized as "hiedium" due to external hazards, but this is considered marginal and no change in consequence assignment has been made. All other piping consequences bound external events.

(

P:ge 27 Calculation !!o. NSD 018 Pipe segments that are already a "fligh" consequence from the evaluation need not be evaluated for extemal events. Those that are already "hiediurn" require confidence that fligh would not occur due to external events. liowever, a " Low" consequence for power operation requires more confidence that a liigh would not occur and confidence that a hiedium consequence would not occur. Taking this into account, a review & comparison of system consequence results versus potential consequence during extemal events is conducted.

The following observations can be made, in general, for all external initiators:

For piping which is assumed to cause an initiating event in the present analysis (RCS, connections to RCS, and operating systems), external initiating events should not have an impact on pipe importance. The frequency of the initiator is already 1.0 in the present analysis. The frequency of the exterral event causing a pipe failure is low and the probability of an external event simultaneous with the pipe break is also low.

Based on the above, it is expected that piping in mitigating systems that respond on

" Demand" to extemal initiating event challenges are more likely to be effected. The frequency of challenge and impacts on redundant rnitigating functions due to the external initiator are considered.

i

(

The ANO IPEEE is reviewed; the results are summarized for each hazard below. The following sunanarizes the review for each of the major hazards (seismic, fire, and other):

I O

Seismic Challenges Except for the emergency diesel fuel tank A & B (T 57A & B), other stmetures, systems, and components in the seismic safe shutdown list screened at the 0.3g IlCLPF (high confidence low probability of failure). Some relays with unknown capacity are not resolved and are not evaluated in this review. The calculated HCLPF for the two tanks is 0.2g. It can be concluded that seismic loss of offsite power (HCLPF < 0.2g) and seismic failure of the tanks would result in an imponant accident scenario (station blackout with recovery unlikely).

l The potential effects of seismic initiating events on consequence ranking is assessed by l

considering the l' equency of challenging plant mitigating systems and the potential impact on the r

existing consequence category. The following summarizes this assessment:

(

Piping in the analysis scope will have a capacity much greater than the 0.3g screening value l

and is not considered likely to fail during a seismic event.

hiost class 1 piping is already assumed to cause an initiating event in this analysis. The frequency of an canhquake induced pipe failure in these systems is less than assumed in the present analysis. Also, the likelihood of a simultaneous seismic event during or after a pipe break is low.

Reactivity control is unlikely to be effected by seismic events because loss of offsite power o

(usually the seismic limiting component with any consequence) will de-energize and drop control rods. The earthquake is more likely to cause a scram rather than prevent it. A very g

large earthquake could cause mechanical failure of the core and/or prevent rods from

Calculation No. NSD 018 O

entering the core, liowever, such a low probability event would likely impact most functions due to equipment failures, causing core damage. The importance of the piping becomes irrelevant at this point and it is a low probability event.

With regard to mitigation, the most likely scenario would be loss of offsite power due to the st Ismic event. The seismic capacity of offsite power has been found to be lirniting, both with respect to seismic capacity and its impact on the plant; it causes the unavailability of feedwater, main condenser, and all equipment dependent on normal AC power. It also cha!!enges emergency diesels (usually less reliable than the numerous trains of mitigating systems tney support). Based on a typical fragility for LOSP (Reference 13), a llCLPF of about 0.lg is assumed. This fragility when combined with the seismic hazards developed for the ANO site (References 14 and 15) indicate the unconditional frequency of a seismically induced LOSP is less than IE-4/yr. Since the analysis includes initiating event challenges on the order of 1.0 for EIM and led for ECCS systems, the seismic challenge isjudged to be enveloped by the present analysis. Note that IE-4 alone provides the basis for a " Medium" CCDP. Table 4-4 further summarizes postulated sebmic scenarios with both frequency of challenge and backup trains.

With regard to the impact on mitigation backup trains, Table 4-4 summarizes a review of

~

how seicmic events may influence consequence ranking. Based on this review, the steam driven EFW may be marginally " Low" or on the lower end of the " Medium" consequerice range. Some steam EFW piping is " Low" in the present analysis. These scismic findings are not judged significant enough to influence this " Low" ranking. Also, ECCS systems (CSS, LPSI, and IIPSI) may be marginally " Low" based on a seismic challenge.110 wever, this does not impact consequence assignment since the piping is already " Medium" and "High" in the present analysis.

Fire Challenges - The total estimated core damage frequency due to intemal fires is 3.5E 5/yr in the ANO IPEEE. Fires in the turbine building (50%), cable spreading room (17%), diesel corridor (17%), intake structure (8%), control room (5%), and auxiliary building extension (3%)

dominate risk. The IPEEE report did not provide sufficient information on the dominant scenarios regarding which systems failed, what the initiating event is, and which mitigating systems are available. Typically, important fire scenarios are those that impact support systems (e g., because of their common cause effect) and/or multiple mitigating systems. Similar to seismic events, fires usually do not impact reactivity control nor cause LOCAs unless it is due to a stuck open relief valve.

Similar to the seismic analysis, the frequency of mitigating system challenges from fires is judged to be less than assumed in the present analysis. For example, fires causing loss of feedwater and challenging EFW will be less than the 1.0/yr used in the analysis. However, the overall impact the fire has on mitigating systems is important. Table 4 5 provides an example to demonstrate how the consequences may be influenced by fire initiating events. The format is similar to seismic in that loss of offsite power is assumed to be an important challenge because it makes feedwater and the main condenser unavailable (AFW is also assumed unavailable). Note that fires are not assumed to cause a LOCA (pipe break) which is a possibility for seismic. Challenging ECCS and

Page 39 Calculation No. NSD-018 contairunent spray piping depends on a fire causing a LOCA condition (stuck open relief valve or failure of all EFW) which is considered in Table 4 5.

W It is concluded that EFW could have a " Medium" importance based os fires. Ifor ver, the s

CCDP isjudged to be on the lower end of the " Medium" rance and FFW cowquence rankings are not changed. IIPSI and CSS are alsoj;dged to be in the "Mediura" categoy, but these systems are already in the " Medium" and "fligh" category.

Other Challenges - these hazards are screened in the ANO IPEEL and are assumed not to influence ranking. The frequency of challenging mitigating systenu due to these other external challenges is comparable or less than considered in the seismic and fire analysis above. Also, the likelihood ofimpacting mitigating systems is less. The discussion of seismic and fire is assumed to envelope.

Based on a review of the ANO 2 external event information, the RISI results are not expected to change significantly.

O O

1

Page 30 Calculation No. NSD-018 4.2 Spatial Arrangement and Walkdown 4.2.1 Spatial Arrangement The location of piphs, the propagation paths from that location, the spatial impacts from the pipe failure, and propagation (i.e., sprays, flooding) are necessary to assess direct impacts (i.e.,

initiating event potential) and indirect impacts (i.e., flooding) in the consequence analysis. System P&lDs, Isometric drawings, and the IPE internal flooding study are key inputs in assessing these impacts for each system. A plant specific walkdown is conducted to confirm these spatial impacts.

Figuras 5 1 through 5 4 provide simplified system diagrams and summarizes the location of main steam, main feedwater, emergency feedwater, and containment spray piping within the analysis scope. Plant locations, as defined in the IPE Internal flooding study, are used in the analysis.

These locations are summarized in Table 4 2 and described below relative to propagation, l-detection (only spatial detection; system detection mechanisms are discussed later for each system), and potentialimpactsf Containment Main steam, main feedwater, emergency feedwater, and containment spray pip

• g is located m

inside the containment, however, flooding la contained and there are no success path equipment O ie at ai i4 **

• i - nt. o ti i i4

<ai n'i i 4 ai a e t i i Fr S

and containment sump level.

(blilldt Condensate storage tanks (CST) and EFW suction piping from the tanks are located in the yard -

- and outside the auxiliary and turbine buildings. There is no spatial detection assumed in the analysis for this piping and there la no impact other than loss of the CST. The refueling water tank (RWT) and containment spray piping from the tank is located in the yard and outside the auxiliary and turbine buildings. There is no spatial detection assumed in the analysis for this piping and there is no impact other than loss of the RWT, Room 2155 - Steam Pine Area at El 404 OtAB 2155-Al Main steam piping penetrates containment at El 436-3 (above the refbeling area at El 404 in auxiliary building) and turns north to the steam pipe area where it drops down several feet into the main steam block valves (2C%1010-1 and 1060 2) According to the high energy pipe break analysis (Reference 7 page 3.6-9), no safety related equipment or structures are affected by steam line breaks. However, pipe breaks are not postulated is;cm the containment structure and the main steam block valves based on design. After a plant walkdown and review of adjacent rooms, it isjudged unlikely that steam line breaks would impact safety equipment. Propagation is through doors onto the roof of an adjoining building, through the steam line pipe chase toward

~ the turbine building, and a stairway into the turbine auxiliary building. For more severe pipe breaks, the building siding would likely be pushed out providing further veating of the event. It is possible for the more severe events to vent into the spent fuel pool area (Room 2151-A).

L

Page 31 Calculation No. NSD 018 Ilowever, this area is very large and propagation to safety equipment mostly at lower elevations g

isjudged unlikely.

The main steam supply to emergency feedwater pump turbine driver (isolation MOV 2CV-1000-I and 1050 2, and the check valves are located at about El 420 to 440 where the two lines combine as one)is routed through a vertical shaft near the new fuel storage area and drops from El 418-4 to 350-3 (Reference 7 page 3.615). The pipe mns through the fuel pool cooling and purification pump area (RAD 2040-JJ) to the emergency feedwater pump room (2024 U) A break in this line will not require safety systems actuation since blowdown is within the makeup of the rnain feedwater pumps (Reference 17) Piping breaks in the spent fuel pool area are judged to have minor inipacts based on the size of the area and lack of safety equipment in this area. The detection and impact of EFW steam line breaks is discussed below for Room 2040.

The main steam supply to the atmospheric dump valves is also located at RAD 2155 A at about El 425 to 440 and pipe failure does not affect safety related equipment (Reference 7 page 3.6-16). The detection of small pipina breaks that do not cause a plant trip would be similar to EFW breaks.

Etactor Auxiliary Buildinn Elevations 386. 372. & 368 Piping within the scope of this analysis is neither located here nor can it propagate to these i

elevations. The control room and critical electrical equipment is located at these elevations. The emergency diesel generators are located at El 369 with surrounding rooms at El 374-6 and 372.

A water tight door is provided for access between EDO rooms and the corridor entrance to the north room. There is a 5 inch curb at the south room corridor entrance. Each EDG room has an intm; ion alarm and float type switches that alarm in the control room.

i o

Reactor Auxiliary Buildinn Elevations 354. 335. and 317 Most of the piping within the analysis scope is located at these elevations. Propagation from elevation 354 to elevation 335 is easily accomplished by grating on the west end of the building corridor (Room 2073). The auxiliary building elevator and east stairway 2001 (2149-D) also provide propagation paths. Propagation from elevation 335 to elevation 317 is through east staltway 2001 (2149 D). Specific rooms are described below in greater detail.

Electrical Eauipment Room at El 354 (2076 HID Piping in the scope of this analysis is neither located here nor caa it propagate to this room.

Access to this room is from the turbine building.

Room 2081 - North Pininn Penetration Room at El 354 and 335 fRAB 2081 HID In this analysis, Room 2081 includes Room 2048 which is the designated room for El 335. Both cf the main feedwater lines enter the containment through the north piping penetration room which consist of two levels connected by a spiral staircase from floor elevation 335. Valves 2CV-1024-1 and 1074-1 are located in this area at about El 359. The second isolation valve in each feedwater line (2CV-1023-2 and 1073 2) is located outside the reactor auxiliary building. The design basis break in this room is a break at the flued head penetration. Plant modifications have been made to prevent failure of safety related stmetures and equipment associated with the

Page 32 Calculation No. NSD 018 O

electrical penetration and equipment rooms (Reference 7 page 3.610). Piping failures in this analysis are also not a::sumed to cause stmetural failure. Propagation is down through the spiral staircase and grating to elevation 335. There is a door with no latch (a requirement of high energy line break analysis) to a large corridor (RAB 2040 JJ). Also, there is a door at elevation 354 into a stairway which is tight and opens into the room. Continued propagation and detection at El 317 is the same as described below for Room 2040.

Two ERV header supply lines to steam generator B (one from each EFW train) are also located in the north piping penetration room. Ileader hiOVs and check valves are located in this room above elevation 354. Test return valve 2CV-0798 is located about 5 feet above El 335.

Propagation and detection would be the same as described for main feedwater.

ERV is the most important potential system impact. It is assumed main feedwater line breaks would impact the EFW discharge hiOVs located in this room (ERV supply to steam generator B failure) due to the high energy line break environment (i.e., pipe whip and/or jet impingement).

Otherwise, the valves are located high enough off the floor to preclude impacts due to flooding.

Room 2084 - Unper South Pininn Penetration Room at El 360 (RAB 2084 DD)

In this analysis, Room 2084 includes adjoining rooms that cormect to Room 2084 discussed l

below. Two ERY header supplies to steam generator A (one from each ERV train) are located in this room.11eader hiOVs and check valves are located in this room at about El 365. Both containment spray discharge paths are in this room where they penetrate the containment O

building (containment spray discharge hiOVs are located at about El 362).

Propagation would be out the doors into the corridor (Room 2073) at El 354. Propagation from elevation 354 to elevation 335 (Room 2040)is easily accomplished by grating on the west end of the building corridor (Room 2073). The auxiliary building elevator and east stairway 2001 (2149 B) also provide propagation paths. Continued propagation and detection at El 317 is the same as described below for Room 2040.

Other important valves located in this room include normally closed HPSI header supplies and normally closed LPSI supplies to the RCS hot and cold legs. The motor operators are judged to be high enough off the floor to preclude impacts due to flooding.

Room 2055 - Lower South Pipine Penetration Room at El 335 (RAB 2055-JD In this analysis, Room 2055 includes connected Room 2031. ERV suction piping from the Unit 1 CST passes through this area. ERV discharge piping to steam generator A, including normally closed (fail closed) test return valve 2CV-0714 1, is located in this room. Containment spray discharge piping also passes through this room. Propagation is through a door into Room 2040 at El 335. Continued propagation and detection at El 317 is the same as described below for Room 2040.

Other important valves located in this room include normally open IIPSI train A & B supply to the cold legs and the LPSI locked open supply from the heat exchangers and locked open low

Page 33 Calculation No. NSD-018 pressure injection supply. The motor operators arejudged to be high enough off the floor to g

preclude impacts due to flooding and the valves are in their normal safe position (open).

Room 2073 - General Access Area at El 354 (RAB 2073-DD)

In this analysis, Room 2073 includes several connected smaller rooms. There is no piping, within the scope of this analysis, located in this room. However, propagation into this room must be considered with respect to system impacts as discussed above. Propagation to elevation 335 (Roon. 2040)is casily accomplished by grating on the west end of the building corridor. The auxiliary building elevator, floor drains, and east stairway 2001 (2149 B) also provide propagation paths. Continued propagation and detection at El 317 is the same as described below for Room 2040.

The most important component in this room is htCC 2B62 which contains breakers for key train B valves. These valves include noanally closed containment spray train B supply (2CV-5613 2),

normally closed train B containment sump accirculation (2CV-5650-2), normally closed HPSI hot leg 2 supply (2CV 5102-2), one of four normally closed HPSI train B cold leg supplies (2CV-5076-2), normally open HPSI train B orifice bypass (2CV 5104 2) and one of two normally closed LPSI train B cold leg supplies (2CV-2077 2). Also, train B of CVCS, shutdown cooling, and diesel room ventilation are powered from this hfCC.

ERV line breaks in Rooms 2084 are unlikely to cause a flood high enough to fail hfCC 2B62.

ERV flow is sufficiently low (<1000 gpm), the floor area is large, there are several floor drains, g

the hiCC is not in direct line with a pipe failure, and it takes at least 6 inches of water to fail the w

hiCC, which is highly unlikely due to the easy propagation to El 335 through the grating at the west end of the corridor.

The containment spray piping is larger than the ERV piping located in Room 2084; the flow rate is larger (>2000 gpm) than ERV Still, the large floor arem and propagation paths at El 354 are adequate to preclude a 6 inch buildup of water needed to impact the hiCC. The door opens out of Room 2084, thus, limited water can collect before gross failure of the door.

There are service water valves located in this room, but their motor operators are more than a foot off the floor where again flooding is not expected to reach.

Room 2040 - General Access Area at El 335 (RAB 2040-m In this analysis, Room 2040 includes several connected rooms, including tank room 2054 which contains RWT suction piping and hiOVs to containment spray. The following analysis scope piping is located in Room 2040:

Steam to the turbine driven ERV pump, including normally closed 2CV-0340 and 2SV-0205.

o These valves are behind a wall and protected from feedwater line breaks that propagate from Room 2081.

ERV pump discharge piping to the south and north penetration rooms, o

ERV common suction piping from the Unit 1 CST.

o

Page 34 Calculation No. NSD 018

(~')

Containment spray suction piping from RWT, including nomially open valves 2CV-56301 e

V and 2CV 5631-2. These valves are located several feet above the floor in tank room 2054 and can not be flooded. Some of the piping is also located outside the tank room in the

corridor, Propagation from room 2040 is into stairwell 2001 (RAB 2149 B) and down to elevation 317 (RAB 2006 LL and 2011 L). Detection is provided by the auxiliary building sump (El 317) high level alarm (annunciator 2K15)in the control room " AUX BLDO SUhiP LEVEL HIGH" (Reference 11). Corrective actions for flooding include ensuring that ESF pump rooms are isolated. ERY pump rooms are protected from flooding as described below (Rooms 2024 and 2025).

The most important component in this room is hiCC 2B52 which contains breakers for key valves. These valves include normally closed containment spray supply train A (2CV 5612-1),

normally closed train A containment sump recirculation (2CV 5649-1), normally closed HPSI hot leg 1 supply (2CV 5101-1), two of four normally closed HPSI train A cold leg supplies (2CV-50351 and 2CV-5075-1), normally open HPSI pump B & C recirc (2CV-51281 & 2CV.

5127-1), normally open HPSI train A orifice bypass (2CV 5103 1), and one of two normally l

closed LPSI train A cold leg supplies (2CV 2037-1). Also, train A of CVCS, shutdown cooling, and diesel room ventilation are affected by this MCC.

There is no steam line break detection for the ERV steam line. There is remote pressure g) indication in the control room, but no alarm. The pipe runs near the fuel pool cooling and s

purification pumps to the emergency feedwater pump room (2024 JJ). Based on Reference 17, a break in this line is not expected to cause enough of a pressure drop to result in a main steam isolation signa! Gd518) or reactor trip because blowdown is with;n the makeup of the main feedwater pumps. However, this isjudged marginal and the analysis assumes that a plant trip does occur. Detection of ERV steam line breaks is based on the following (assumes the realistic case of no plant trip):

Recognition of steam leak by operations based on control room indications and noise. A core operating limit supervisory system (COLSS) high power alarm is expected. A power reduction would be required to clear the alarm. A controlled shutdown would be initiated in light of standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe.

Assuming that the operators have not identified or isolated the leak, upo.1 reactor shutdown to RCS hot shutdown conditions, RCS overcooling symptoms would begin to manifest. In response to this overcooling, EOPs would be utilized and the steam supply isolation valve (s) closed. If the break is unisolable, feedwater to the affected steam generator would be isolated and the generator allowed to blowdown and depressurize.

The ERV steam leak could impact spent fuel pool cooling first because ofits close proxirnity to the pumps which are not environmentally qualified. However, it takes a significant amount of T time for the spent fuel pool to heat up and this impact is considered low importance due to time IO available for recovery and the multiple makeup sources. There ar'c other non safety components

Page 35 Calculation No. NSD 018 at El 335 that could affect plant operation, including the charging pumps. Ilowever, they are g!

located at the other end of the floor and are unlikely to be immediately affected by an ERV steam line break. Safety related MCC 2B52 (qualified for elevated temperature, pressure, and steam em.:onment) is also at the other end of the floor. Given the size of this room and the relative location of equipment, a controlled plant shutdown is more likely for ERY steam leaks. Failure to detect and perforrn a controlled shutdown could eventually lead to a reactor trip due to emironmental impacts on equipment. The analysis assumes a reactor trip occurs and then, credits isolation before long term impact occurs to the MCC and other equipment.

l For a main feedwater line break in Room 2081, MCC 2B52 is assumed to fail because of l

potentially large, hot steam and water propagation into the room. Valves located a few feet above the floor are not assumed to be affected.

EFW line breaks in Rooms 2081,2084,2055, and 2040 are unlikely to flood MCC 2B52 causing its failure. ERV flow is relatively low (<1000 gpm), the floor area is large, the MCC is not in direct line with a pipe failure, and it takes at least 6 inches of water to fail the MCC (propagation will occur through a stairway and floor drains to El 317). Given the size of the areas, including the intermediate auxiliary building elevation 326, and propagation to El 317, it is unlikely that the CST could actually fail the MCC (e.g., 6 inches of water at El 335). Still, the analysis assumes failure of the MCC ifisolation fails or a door to the stairway is not opened.

l l

Containment spray suction piping from the RWT is larger with larger flow rates (>2000 gpm and

>15,000 gpm if a double ended rupture is assumed) than ERV piping. In addition, this piping is closer to 2B52. It is assumed containment spray suction piping in Room 2040 is severe enough to splash and fail MCC 2B52, Room 2024 - Turbine ERV Pumn (RAB 2024-m ERV steam, suction, and discharge piping associated with the turbine driven pump is located in this room. Also, common suction piping with the mm or driven pump is located in this room.

ERV pump rooms are at El 329 with ac.ess from El 335 through open stairs. The open stair stvts about 8 inches above El 335 such that most floods will not reach the EFW pump room doors. Each room has a water tight door (opens into room), an intrusion alarm in the control room, and a float type level switch with an alarm in the control room (Reference 11).

The IPE internal flooding study indicates turbine driven ERV tcom (page 6-8) contains c:, ole terminal end points that impact both trains ofEFW, including its recovery from the cor. trol room.

This is identified as MOV 2CV 0707 which is normally open and now is deactivated such that it will not isolate the normal CST suction path. Floods in this room (i.e., not isolated in time) are assumed to fail the turbine driven pump. Since the door is very heavy, opens into the room, and the room is water tight, any leakage out of the room is expected to be within floor drainage capability and have no impact on equipment outside the room.

O

l Page 36 Calculation No. NSD 018 3

Room 2025 - Motor EFW Pumo (RAB 2025 JJ) -

Suction and discharge piping associated with the motor driven pump is located in this room.

Also, the common suction piping to both EFW r". :rs passes through Room 2025.

EFW pump rooms are at El 329 with access from El 335 through open stairs. The open stair i

starts about 8 inches above El 335 such that most f!oods will not reach the EFW pump room i

j doors. Each room has a water tight door (opens into room), an intrusion alarm in the control 1

j room, and a float type level switch with an alarm in the control room (Reference 11).

]

Floods in this room (i.e., not isolated in time) are assumed to fall the motor driven pump. Since

~

the door is very heavy, opens into the room, and the room is water tight, any leakage out of the i

j room is expected to be within floor drainage capability and have no impact outside.

Rooms 2006 & 2011 - General Access & Tendon Access at El 317 (RAB 2006.LL & 2011.LL}

In this analysis, all rooms at El 317 except the ECCS rooms discussed below are included as Room 2006 and/or 2011. With regard to the analysis scope, only the containment spray piping is located outside the ECCS rooms at this elevation. RWT suction piping to containment spray j

train B passes through Rooms 2002 and 2006. Also, the containment spray test return piping, Ancluding valves 2SI 5A & SB, are in Room 2011 & 2012. However, piping breaks above El 2

335 will propagate to these rooms. Detection is provided by the RAB sump level (Reference 11),

i There is potential service water and shutdown cooling impacts in this area, however, HPSI, i

containment spray, and EFW are not affected.

~

l In order to impact HPSI, containment spray, and LPSI, a very large flood must accumulate in l

these rooms as described below for Rooms 2014,2007, and 2010.

[

Rooms 2014. 2007. & 2010 - ECCS A. B. & C. RespectiveW at El 317.

With regard to analysis scope piping, only containment spray piping is located here, specifically in Rooms 2014 and 2007. Also, RWT suction piping to CSS pump 2P35B is routed thro agh j

Room 2006. In this analysis, Room 2013 is included with 2014, Room 2009 is included with 2007, and 2006 includes Rooms 2011 & 2012, as well as several pump rooms and the stairway.

j IfRooms 2006 & 2011 flood up to about El 328, HPS! "C" room (2010) will be flooded, unless 3

the ventilation openings are isolated (safety injection signal or by operators in Reference 11).

l Then, if 2006, 2011, and 2010 flood to about El 329, ECCS rooms "A" (2014) and "B" (2007) will be flooded. Flood propagation into the ECCS rooms is through ventilation openings.

4 I

4 0

4

,-=,-n.me,.-vn-er--

-c.e 4.-v,w+

v-vv..m.w.ww,w-v-w - y r, e mm.

,a.-see-s

-%.+.-e.-v.

-r----r~ww.ve--ew,m--

,,y,.

--w %+-we-v.

av., r e-r-,-iv-,-----rs+---.--w

Pcge 37 Calculation No. NSD 018 The following summarizes the areas and propagation paths at El 317 based on the IPE internal flooding study; Rcom Description fl Propagation between 2006/2011 3

RAD 2006 LL General Access 3316 El 317 RAD 2011 LL Tendon Gallery 240 El 317 RAD 2010 LL IIPSI C 486 about El 328 through ventilation opening RAD 2007 LL, East IIPSI 2610 nbout El 329 through ventilation opening RAB 2014 LL West HPSI 2610 about El 329 through ventilation op ening Each train of ECCS (HPSI, LPSI, containment spray, and SDC heat exchanger) is in a separate water tight room called the East and West Rooms (2007 and 2014). IIPSI C (2010) is in a separate water tight room on El 317 called the Center Room. Each room has conductance type level detectors that alarm in the control room (Reference 11).

The combined area ofRooms 2006 and 2011 is >3500 R and a CST (about 200,000 ga'lons) 2 would not reach El 325. Thus, it is assumed that a CST can not flood the ECCS rooms. In addition, the combined volume of a CST and a typical main condenser hot well (approximately l

60,000 gallons)is assumed not to reach El 325.

Draining the RWT (about 500,000 gallons)into Room 2007 or 2014 is investigated. To fdl one cf these rooms up to the ventilation openings requires about 234,000 ga'lons (12 A

• 2610 ft' '

h 7.48 gallons /ft'). To flood Rooms 2006/2011 up to El 328 where HPSI C could be affected requires an additional 287,000 gallons (11 ft

• 3500 fl' ' 7.48 gallons /ft'). Therefore, it is assumed that draining the RWST can not flood more than one containment spray room (2014 or j

2007), ifinitiated within one of these rooms.

)

DrWning the RWT into Rooms 2006,2011, and 2010 up to El 329 where Rooms 2007 & 2014 could be affected requires about 359,000 gallons (12 ft

• 4000 ft'

• 7.48 gallonsM'). Assuming that 3 feet of water is required in Rooms 2007 and 2014 to fail electrical equipment, an additional 116,000 gallons are required (3 fl

• 5200 fl' ' 7.48 gallons /ft'). Without a more detailed analysis of floor areas and/or elevations at which HPSI, LPSI, and CSS will be affected, it is concluded that failure to isolate RWT uoods into the general access area will fail all ECCS, For example, the floor area presented in the IPE for the tendon gallery area appears to neglect some floor area; flooding the ECCS may not be possible. However, draining 50% of the RWT into this area will fail recirculation anyway, Therefore, these conservatism's are not evaluated further.

Also, failure to isolate the RWT is assumed to drain 50% of the RWT outside containment which is then assumed to fail the containment sump recirculuion function due to inadequate NPSH.

Since an ECCS room (train A and B) or the general access area could contain 50% of the RWT, the capability of ECCS room ventilation isolation preventing loss of ECCS is not credited in the

analysis, g

Page 38 Calculation No. NSD 018

(]

Iurbine Auxiliary Bui]Iina Rooms Q223 KK. 2225 WW. 2050. J l

V Common CST suction piping is touted through these areas on its way to Room 2025. Also, Rooms 2055 and 2081 could potentially propagate to the turbine auxiliary building. There is no safety equipment in these locations and the more likely propagation is into the turbine building.

No trstial impacts are assumed in this area except possibly the power conversion system (PCS).

Potential impacts on the PCS are not evaluated because arrangement drawings indicate the turbine building area is very large, precluding flooding impacts on PCS.

4.2.2 Walkdown On November 19 and 20,1996, a walkdown was performed at ANO 2 to assess potential spatial interactions associated with splashing, spraying, and flooding, including propagation paths. The following individuals participated in the walkdown and meetings at ANO 2:

Rick Fougerousse (ANO ISI)

Tim Rush (ANO PRA Group)

Randy Smith (ANO Consult 0nt)

Jim Moody (YAEC Consultant)

Pat O'Regan (YAEC) g) The plant was in an unexpected outage and radiological controls would not allow ac south piping penetration rooms (Rooms 2084 and 2050) and El 317 (Rooms 2006,2011,2014, t"

2007, and 2010). However, this is not judged to have an impact on the analysis since spatial questions were answered for these areas during the visit. The focus of the walkdown was in those areas where analysis scope piping exists and their propagation paths and impacts. The following summarizes the walkdown observations:

Main steam piping area (Room 2155) was investigated where main steam and EFW steam lines were observed along with the main steam isolation valves and EFW steam isolation and check valves. Although unlikely, it is possible for certain large main steam line breaks to impact both steam lines supplying EFW. The main steam lines are near the common wall with the refueling area (Room 2151), thus, it is considered possible that a very large steam break could damage and/or vent through this siding. There also is siding and doors that open out to an adjoining building roof and stairway (turbine auxiliary building).

Fuel handling and spent fuel pool area (Room 2151) was walked down. The EFW steam o

piping was observed coming vertically down from the steam piping area and into a pipe chase which comes out at elevation 335 (Room 2040). This is a very large area and it isjudged unlikely that main steam piping break propagation to this area would impact safety equipment which is mostly located at lower elevations. Also, EFW cteam line break is judged unlikely to impact safety equipment.

North Piping Penetration (Room 2081) was walked down. EFW and main feedwater valves o

k were identified in the room. Grating and a spiral stair ensures easy propagation to elevation

page 39 Calculation No. NSD-018 335 where there is a door with its latch removed (required due to high energy line break g

analysis) opening out to Room 2040. A door at elevation 354 opens into the room and 1

provides access to a stairwell and the turbine auxiliary building. It would be diflicult for floods to access Room 2081 from the turbine auxiliary building side Propagation into 2081 from 2040 would not affect any equipment as the EFW and MF valves are above the floor.

Elevation 335 (Room 2040) is a very large area containing general access, corridors, and several large non safety related rooms. Several floor drains were observed. EFW and containment spray piping is located here, including RWT suction MOVs The MOVs are located high off the floor in the tank room, protected from floods. Also, the EFW steam admission valve 2CV-0340 2 and 2SV-0205 is located behind a wall and sufficiently off the floor to be protected. Several rooms connect to this room from elevation 354 (Room 2073) and the piping penetration rooms (Rooms 2055 and 2084) at elevation 335. The most critical component identified in this area is MCC 2B52 which powers several taaln A components.

Although the MCC is not near analysis scope piping, it is at the east stairw:,y entrance (the propagation path to El 317). If six inches of water could be accumulated at El 335 or if a very large pipe break occurred, it is considen ed possible that the MCC could fail, EFW pump rooms (2024 and 2025) at elevation 329 were inspected. The stairs from Room e

2040 down to the EFW pump room entrances are protected from flooding because the stairs start about 8 inches off the floor at elevation 335. Also, the pump rooms have a flood protection door that opens into each room. Piping and valves in each room were identified and confirmed. Also, the rooms were noted to be water tight; any leakage out of the room (assuming the room fills from a pipe break) would be small ar.1 within the capacity of drainage systems. Room flood detectors and floor drains were observed.

Elevation 354 (Room 2073) is a large area containing general access, corridors, and other non safety related rooms. Several floor drains were observed. There is no analysis scopr.

piping located here, but the upper south piping penetration area (Room 2084) will propagate to this room. The most critical component identified in this area is MCC 2B62 which powers several train B components. The MCC is not near analysis scope piping and thes e is easy propagation through grating at the west end of the floor away from the MCC. It appears unlikely that six inches of water could accumulate at El 354.

4.3 Initiating Events There are two types ofinitiating events or demands considered in this analysis:

1. The pipe failure causes a direct initiating event.

2. When the pipe failure does W cause a direct initiating event, an independent demand for the system is assessed as describe)in Section 4.4.

O

Page 40 Calculation No. NSD-018 p

Direct inhininn Event U

To ensure that direct impacts from initiating events and the unavailability of mitigating systems are properly considered (i.e., impact of support systems and other common cause effects), the conditional probability of core damage due to initiating events in the ANO 2 IPE (Reference 2) is assessed. Table 2 1 summarizes consequence categories applied to ANO-2 IPE initiating events when the pipe failure causes such an event. This table is plant specific for ANO 2 and replaces Table 3.1 of Reference 1.

The following summarizes how initiating events apply t'or each piping run and configuration in Table 41:

1. Operating - only the " Normal" configuration is evaluated when the piping is in a normal operating system or the piping is connected to a normally operating system. At ANO 2, pipe failure in the main steam and feedwater systems results in an initiating event or it is assumed to be the case. The other configurations either do not apply or are less likely with similar consequences.

2. Standby & One Banier with Operating Sys0m - in the case of piping beyond the first barrier (1 active or passive valve), initiating events are analyzed, including potential initiators due to fai!. re of the barrier. Also, pipe failure on demand (i.e., from an independent initiator) is analyzed.

3. Standby & Periodic Testing -in the case of piping beyond the secc.kd barrier (2 active and/or s

passive valves), in!tiating events are analyzed, including potemial initiators due to failure of the barriers. Also, pipe failure on demand (i.e., from an independent initiator) is analyzed.

Periodic testing during normal operation is assumed to challenge the piping and reduce exposure time for possible pipe failure during a " demand."

4. Standby & No Periodic Testing - this is the same as the case above except the piping is not periodically tested and therefore, the exposure time is longer (not reduced by testing).

S. Standby & No Accident Demand -in this case, the pipe is not automatically challenged during an accident. The evaluation considers pipe degradation as revealing itself during

" normal standby" and " test" configurations. These are the preferred configurations relative to exposure time for accident demands.

Independent Demand AT ANO-2, if pipe degradation reveals itself during " Normal" or " Test" configurations, detection will occur from the auxiliary building sump alarms or low CST level or low RWT level or from visual inspection. An eventual manual shutdown can be assumed based on technical specifications irisolation and repair of the leak is not quick enough. The exposure time for a real accident demand is lower; if an accident does not occur, human reliability is expected to be high during these configurations. For these reasons, pipe failure is assumed to occur during the p "ituation for the operators. Demand" configuration, if applicable, due to the increa Vs

Page 41 Calculation No. NSD 018 An initiator or controlled shutdown can be assumed for high energy lines connected to the main steam and feedwater systems (Iow steam generator level or pressure) depending on pipe size.

Piping in the auxiliary building will likely lead to manual scram or shutdown ifit occurs during the " Normal" or " Test" configuraticas. With no shutdown (implies isolation success) and no independent initiator, the consequence associated with repair time (i.e., within limiting condition i

of operation) is Low. The " Demand" configuration which assumes pipe failure during an independent accident demand is evaluated for the worst case when it applies.

4,4 Mitigating Capability Mitigating capability is determined in the analysis utilizing the following:

1. After r <aluating the total impact on train / systems (direct and indirect impacts, including ini' ating event, system or train containing the pipe failure, spatial propagation, and draining),

the remaining available mitigating trains (backup trains) from Figure 3-1 are identified.

2. If pipe failure does not cause an initiating event, the frequency of challenging the system (real accident demand) and the exposure time are evaluated. For an EFW train, the allowed outage time (AOT)is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and testing frequency is monthly based on the ANO 2 technical specifications (Reference 12). For a containment spray train, the AOT is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and the pump trains are tested quarterly. The frequency of challenging standby systems used in Table 2-2 when pipe segment failure does not cause an initiating event is described further below.

3. The ability to isolate a break is evaluated and credited, if feasible.

4. When evaluat'ng the consequences from "no isolation"(either not possible or failure to isolate), the prabability ofisolation failure is assessed. Based upon the likelihood of detection and the time ava'!able for the operator response, usually an equivalent backup train is assumed in the analysis.

The consequence evaluation addresses the potential of both successfulisolation and unsuccessful isolation of the break. The reliability of detection and isolation depends on plant configuration, redundancy, and whether human actions are required. Ifisolation is successful, the impact includes the direct impact associated with the initiating event and the applicable train or system containing the pipe failure, and limited spatial considerations. Ifisolation fails, indirect impacts are considered, however, the probability ofisolation failure is assessed. Detection and isolation capabilities at ANO-2 are summarized below:

High energy lines (HEL) such as the main steam and feedwater lines have automatic o

redundant instrumentation for break detection. Low steam generator level will lead to a reactor trip as will overcooling events that impact RCS conditions. A low steam generator pressure signal will isolate main steam and feedwater lines as well as trip the main feedwater h

pumps. The EFW steam supply will not likely cause an initiating event, but there is pressure

Page 42 Calculation No. NSD-018 and flow indication in the control room and a leak in piping directly connected to main steam or feedwater line willimpact power production.

s There is detection capability and procedural guidance for the operators given moderate energy line events in the auxiliary building where the greatest potential for impacts can occur.

The auxiliary building sump alarm, ECCS pump room flood alarms, and EFW pump roorn flood alarms (Reference 11) provide indications of ficoding. Low CST level alanns &

indications (EFW) and low RWT alarms & indications (containment spray) also alert the operators. EFW Pump discharge pressure indication and annunciators (>l350 psig and

<1000 psig) provide indications for EFW pump discharge piping (Reference 8). Also, each of the 4 EFW headers have flow indications and annunciators (>325 gpm and <240 gpm). Each containment spray header has a low flow annunciator in the control room (<2000 gpm with pump running and CSAS). Also the header levels during standby are monitored and annunciated at both high and low level setpoints (79% and 12.5%, respectively).

An assessment of operator response before significant impacts occur is included in determining the available mitigating trains in the analysis (Appendix A documents this for each system and run of piping within the system).

When pipe failure does not cause an initiating event, the independent accident demand initiator assumed in the analysis for EFW and containment spray, both standby systems, is as follows:

l

(~T Ue For EFW, loss of power conversion system (PCS, T2) is chosen rather than loss of DC or AC (TIO through TIS) because it presents the most likely challenge. The loss of DC or AC initiator has a much lower frequency of challenge (<lE 3/yr). Althcugh they can impact one train of EFW, MF and AFW are not guaranteed to fail and th'ese lower frequency events are judged to have similar impacts as developed for loss of PCS.

For containment spray, a medium LOCA (M)is chosen. As shown in Figure 3-1B, the medium LOCA initiator reduces mitigating capability to the two trains of containment spray.

For this reason, a medium LOCA challenge is assumed.

As described in Section 2, the combination of all impacts is assessed. If an initiating event occurs, Tables 2 1 and 2-3 are utilized to determine the consequence category, otherwise, Table 2 2 is used.

The following summarizes additional system inputs to the analysis:

The auxiliary feedwater pump (2P75) is located in the turbine building (El 325 below the main feedwater pumps) and can discharge into the main feedwater pumps discharge header or into the EFW lines downstream of the EFW pumps. This is a manual operator action, but controls and indications are available in the control room. When isolation failure occurs, AFW is not credited (human dependency, CST will be pumped down, and EFW transfers to service water).

p

Page 43 Calculation No. NSD-018 ERV suction transfer to service water requires both an EFAS (emergency feedwater g

actuation signal) and ERV low suction pressure (<5 psig).

Each ERY pump is designed to provide >485 gpm at a discharge pressure of>l200 psig when steam generator pressure is >800 psia.

Normal EFW st etion is from the CST through 2C%0707 (located in the turbine building).

Overload heaters have been removed from normally open 2CV-0707 to prevent spurious operation of the valve.

The main steam isolation sig.tal (MSIS if either steam generator pressure decreases to 751 psla) isolates main steam and feedwater. It also removes EFAS allowing EFW discharge paths to close. Once the plant protection system (PPS) has determined the affected steam generator, EFAS to unafrected steam generator retums. The unaffected steam generator is the one that has a 90 psia higher pressure. If the pressure in both generators increases to

>751 psia then the EFW valves will cycle on steam generator level only.

Each containment spray pump is designed to provide 2200 gpm at a discharge head of approximately 525 feet. Break flow for the discharge side of the CSS pumps ahead of flow restricting orifices (2FO 5625/5626) at pump runout flow is 3200 gpm. Break flow from the RWT through a 20 h.ch diameter suction pipe is greater than 15,000 gpm assuming a double ended break.

g There is containment spray discharge pressure and flow indication in the control room for each train.

Containment spray is initiated by a containment spray actuation signal (CSAS - containment High High pressure of 23.3 psia). Containment spray suction transfers to the containment sump on a recirculation action signal (RAS - low RWT level, 6% level).

4.5 Containment & Combinations As described in Section 2, containment performance is considered in determining the final consequence category. A cor uinment barrier is required or the consequence evaluation must l

show margin. The results are provided in Appendix A and summarized in Section 5.

1 l

O

page 44 Calculation No. NSD 018 O

Table 41 Type of Pipe Versus Applicable Plant Configurations Type of System /

Applicable Configuratio Comments piping Normal Test Demand

1. Operating or Standby X

Normal - ually an initiating event (IE). Also, directly connected to unisolated. TCA considered for pipe beyond the operating system first automa e (active) RCS isolation valve.

Test - condition does not apply.

Demand - applies, but IE cnvelopes unless significant loads are identified.

2. Standby vnd one X

X Normal potential IE due to passive failure of passhe barrier from valve.

operating system Test does not apply.

Demand - applies

3. Standby and periodic X

X X

Normal applies, but leakage in a standby pipe testing (two or more without operating loads is likely to be small with passive barriers from detection & isolation reliability high'.

operating.ystem)

Test - applies, but detection and isolation reliability high as with " Normal" and piping challenge reduces demand exposure time.

Demand applies, but periodic testing reduces likelihood of pipe failure unless significant loads' identified.

4. Standby and no X

X Normal same as above

(

periodic testing (two or Test - does not apply, more passive barrierr Demand applies from operating system)

5. Standby and no X

X Normal-same as above accident demand Test - piping is challenged by periodic testing during normal operation.

Demand - dacs not apply.

1. EFW and containment spray systems are maintained full to preclude water harnmer loads (elevation of normal open suction from CST and RWT). EFW discharge connections to main feedwater are monitored once per shift for high temperature which indicates back leakage of main feedwater into EFW, EFW steam has several steam traps to prevent over speed and excessive loads; to ensure proper trap operation, operators drain various points periodically. Also, the steam bypass valve (2SV-0205-

2) opens before the main isolation valve (2CV 0340-2) to minimize over speeding of the turbine.

2. EFW system leakage would reduce CST level and containment spray system leakage would reduce RWT level with indication and alarms available in the control room. Also, containment spray header (not in scope) low level alarms in the control room will alert operators to leakage if there is leakage past system check valve (s). Auxiliary building sump level, ECCS pump room flood level, and EFW pump room Good level alarms are available in the contml room to provide additional detection capability.

O

Page 45 Calculation No. NSD 018 Table 4 2 Pipe Location & Break Propagation for MS, FW, EFW, & BS laation Description Propagation Path Containment Containment Building None 2155 A Steam Pipe Area (El 404)

Outside through doors and siding, main steam pipe chase toward turbine Bldg, stairway through door, and fuel handling area if siding is failed (large MS break).

2151 A Fuel handling (El 386)

Throughout the elevation and into stairways.

2073 DD General Access (El354)

Other non safety related rooms at El 354, grating at west end of corridor down to 2040 (tank room) provides easy propagation. Also, cast stairway, elevator, and floor drains to 2040 and El 317.

2040 JJ General Access (El 335)

Other non safety related rooms at El 335, through east stairwell and floor drains to El 317 (2011 & 2006).

2024 JJ Tr.rbin, EFW (El 335)

Watertight room, otherwise to 2040.

2025 JJ Motor E 'V (El 335)

Watertight room, otherwise to 2040.

2 0S1 1111 wrth Piph g Penetration (El 335 &

2040 354; 2034 DD Upper South Piping Penetration (El 2073 360) 205LJJ Lower South Piping Penetation (El 2040 335)

Outside Yard and pipeway outside Bldgs No propagation to Auxiliary Bldg and safety equipment.

l 2223 KK Pipeway, Equip Access (TB El 335) 2225, no propagation to Auxiliary Bldg and i

safety equipment.

2225 WW Regen Waste Pump & Tank Area 2223, no propagation to Auxiliary Bldg and (TB El 335) safety equipment.

2050 Pipeway in Turbine Blds (TB El Turbine Bldg no propagation to Auxiliary Bldg l

335) and safety equipment.

2011 LL Tendon Gallery Access (El 317) 2006 first and then 2010 at >11 ft, then 2014 &

2007 at >12 ft (ventilation openings if open).

I 2006 LL General Access Area (El317) 2011 first and then 2010 at >l1 ft, then 2014 &

2007 at >l2 ft (ventilation openings if open).

2014 LL ECCS "A" 2006 and 2011 at >l2 feet of water and ventilation openings not isolated.

2007 LL ECCS "B" 2006 and 2011 at >l2 feet of water and ventilation openings not isolated.

2010-LL IIPCS "C" 2006 and 2011 at >l1 feet of water and ventilation openings not isolated.

O l

Calculation No. N Table 4-3 Review & Companson of Power & Shutdo vn Operations System Power Operation Shutdown Operation RCS LOCAs result in 'lligh" wu+a Much less severe qu4mg conditions and alreadv "IIigh" for maior pepmg.

HPSI

" Medium" consequence for major piping He f.up wcy ofchallenging HPSI during shutdown isjudged to be similar to or less than beyond first RCS isolation valve required to power vpudm. He system is assm.gJ to require manual imtsaten and portions of the support cold leg injection & recirculation system are more likely to be in maintenance. Still, a w.uGu4m ofchallenge f.up.cncy and a backup train (decay heat. time, ec..yu.ma) is judged to provide a "Med-:um" consequence.

c LPSI "IIigh"and " Medium" consequence for his system is normally in standby during power vpu4=, but it is vyu% most of the major piping beyond first RCS isolation outage and it's failure is an initimeing cwnt. This systern requires further analysis valve required to support cold leg injection iu osMzing the LPSI functon durmg power qm.wna is alreadv"Medmm" and "High."

CVCS

" Medium"and " Low"wome ma for His system may also be operatmg durmg shutdown and could impact !...whny. Howtver, major piping beyond first RCS isolation the operatmg condi: ions are much less sewre, prping is smaller, and the system is not vahe(further from RCS is low) required for mitiganon. Pontr operation is bounding.

CSS "High"and "Medmm"conscquences for De ;mpuiww ofcontainment heat removal and sprays during shutdown is significantly

^

majorpiping reduced. Tygncally, this function is not even modeled in shutdown risk assessments. Power operation is boundmg.

MS

" Medium" for the large main steam lines Main steam is not usually avadable nor Qu.dui upon for q, 4m or mitigation during and " Low"umsec ma for the smaller cold shutdown. Power vyw4;cni is bum 4;.g.

e steam drrven EFWline FW

" Medium"due to loss of feuwater.

Main feedwater depends on steam, is not vym.bg during shutdown, and is not ye.ded upon for mitigation. Por;er operation is bum. Jing.

EFW

" Medium"and " Low" consequence Motor driwn EFW could be vpu dug during the imtsal cooldown phase before significant

&ymdirg on impact maintenance starts and when the steam generators are...;Ifu'c (AFW is rnore likely to be used). Later, the f.mp.c.-.cy of challenging EFW during shutdown is similar to or less than power vru.Wai (steam may not be available). The system requires manual imtianon and pucuvio of the system are more likely to be in maintenanz If RCS is intact with a steam generator available, there is more time to recour EFW, AFW, <=ir==te, or some other extemal source. If RCS is not intact (e.g, vessel head is off), EFW is not relevant to mitigation. Power vem4;vs is bv J;..g.

w

Page 47 Calculation No. NSD-018 Tabic 4-4 Seismic - Possible Scenarios & Impacts on Mitigating Systems System Fiquswy of Challenge Backup Trains CCDP Conclusion Scenario Frequency EFW Seismicloss ofoffsite power with 2

<I E-4 2: Once through cooling and 1 EFW train. One

~1E4 (Iow) s wigucy dieseltrains available EFW train is anu iul to fail on demand.

Seismic loss ofoffsite power with

<I E-5 1: Once through coolirs Loss ofe:I ElTV -loss of

~1E4 (Iow) non-seismic failure of I e.wigu.cy diesel support to motor drhrn EFW and then diesci train failure ofsteam driven on demmi is anm.d Seismic station blackout

<1E-5 0: The turbine driven EFW could delay core May not be <1E4. Steam damage until DC power disdesw nu.ukg DC driven EFW could bein the a

pourtis available and no LOCA.

Iow-Med um range HPSI Seismicloss ofoffsite power with 2

<1 E-4 2-Transient induced LOCA probability or failure

~1E4 (Iow) ciussey desel trains available of EFW (irdudirg desel) p.m.s a backup train.

(no LOCA)

HPSI prowdes a backup train. I HPSI train assumed to failon demand.

Seismic LOCA with 2 cr.s ocy

<1E-4 1: HPSI train. I HPSI train.mm.mi to fail on

~1E4 (Iow) s diesel trams available (assume demand.

LOSP)

Seismic LOCA with non-seismic

<1 E-5 0: less ofdesel support to one train and then May not be <1E4. HPCI could failure ofI eiusewy deseltrain failuru ofsecond train on demmi is amm.ui.

bein thelow-Medmm range (assume LOSP)

Seismic blackout & LOCA

<l E-5 0: HPCI L.Jc.sg with no AC power NA LPSI See HPSI above, LPSI is needed for a large LOCA (fswomcy is <1E-5)

CSS See HPSI above, CSS shares, with LPSI and HPSL the RWT & containment sump suction which is iwuL ui for LOCAs e

O O

O l

catenfation No. N l'

i Table 4-5 Fire - Possible Scenanos & impacts on Mitigatin t Systems System Fmm.rcy of Challenge Backup Trains CCDP Conclusion Scenano Frequency l

EFW loss ofoffsite power with 2

<!E-2 2-Once through cooling and 1 EFW train. One

~1E4 (Low), but motor dnven e.~gecy diesel trains available assumed EFW train is Am=~i to faH on 4*n=nri EFW cmid be Medmm Ioss ofoffsite power with I

<1E-3 1: Once through cooling. loss ofall EFW-loss of May not be <1E4. EFW couki m.m3 cy diesel train available

.um ui diesel support to motor driven EFW and then be Medium.

failure ofsteam driven on demand is um.mi.

Station blackout

<1 E-4 0: Although the turbine driven EFW cooki delay May not bc <1E4. Steam 2mm.oi core damage until DC M isassuming DC driven EFW could bein the poweris available and no LOCA.

Iow-Medium range HPSI Loss ofoffsite powerwith 2 s1E-2 2-Transient induced LOCA probability or failure

~1E4 (Iow) w~3esy diesel trains available assumed of EFW (;.Mg diesel) y.

6 a backup train.

HPSI prcvides a backup train. I HPSI train Amo..~i to fail on demand.

loss ofoffsite powerwith I

<!E-3 1: Transient induced LOCA probabihty or fashre May not be <!E4. HPSI trams w~smsy diesel train assum:d of EFW (includmg dicsci) p s a backup train.

probably Medmm Loss of HPSI -loss ofdiesel support to one train and other train Amm.J to fail on demand.

Station blackout -

<l E-4 0:IIPCIirrelevant with no AC power NA

.mo..mi LPSI LPSI is needed for a large LOCA which is not 6k u: Ukely for fire initiators (see HPSI)

CSS See HPSI above, CSS shares, with LPSI and HPSI, the RWT & containment sump suction whidi is required for LOCAs

Page 49 i

Calculation No. NSD 018 O s.o a..uit.

l This section summarizes the results of the consequence evaluations described in the previous section and in attached Appendix A. The following is provided for each system analyzed, as i

appropriate:

{.

• System function Key system level assumptions (see also Section 3.3) i Simplified diagram with table denoting piping and locations i

e Summary of tesults with conclusions and recommendations, as appropriate i

1

~

l 5.1 Main Steam j

The function of the power conversion system (PCS - feedwater and main steam) is to produce i

electric power from the steam coming from the steam generators, condense the steam into water,

}

e,nd return the heated feedwater to the steam generators. The function of the main steam system is to cany steam from the steam generators to the main turbine or condenser. In addition, main steam provides over pressure protection, can provide heat removal during plant transients, is j-required to support feedwater and EFW pump operation, and the system pressure boundary is required to satisfy the containment function.

Figure 5 1 provides a simpli6ed diagram of main steam (MS) with a table that denotes the piping

}

line numbers included in the analysis as well as their locations. The turbine EFW steam supply piping is included in the main steam analysis. Table 5 1 summarizes the consequence analysis 4

results in Appendix A. The following further summarizes these results:

Main steam piping, except bypass lines, has a " Medium" consequence due to the conditional core damage frequency in the IPE for steam line breaks (see Table 2 1). Piping inside l-containment is marginally " Low" based on the IPE (e.g., additional analysis mayjustify a i

" Low" consequence). Piping outside containment is some what remote from success path i

= equipment and the area is easily vented to the outdoors. This was con 6rmed during a plant j.

walkdown. Thus, it is assumed the main steam line will not create spatial impacts, except for j

the turbine EFW steam supply.

}-

The main steam bypass piping has a " Low" consequence because the piping is small and o

unlikely to cause an initiating event.

EFW steam piping has a " Low" consequence because the pip *mg is small and is assumed -

o 4

unlikely to cause a direct initiating event although this is assumed. This piping is also assumed to bejust as likely to fall in ' standby as during a demand. The location of sensitive 4

electrical equipment is mostly remote from this piping and is not assumed to be affected L

unless there is a failure by the operators to detect and isolate the break.

4

?

r l

..v,--,w,--,-

1. .,.,~m

.,m

,-,i-.r.-,.-w---,v,._

..e.,,w,.-n.r

,c,-,mr

-v w e n,-w m

-e,,..-.-,,-,-

e.,..-y,--

...,v-w-.-.,,w--,

Pcce 50 Calculation No. NSD 018 5.2 hiain Feedwater The function of the power conversion system (PCS - feedwater and main steam) is to proAce electric power from the steam coming from the steam generator, condense the steam into water, and retum the heated feedwater to the steam generator. The function of the feedwater system is to provide a dependable supply of heated feedwater to the steam generator. In additEn, the system provides isolation of the steam generators during main steam and feedwater line breaks, and a pressure boundary is required to satisfy the containment function.

Figure 5 2 provides a simplified diagram of main feedwater (FW) with a table that denotes the piping line numbers included in the analysis as well as their locations. Table 5 2 summarizes the consequence analysis results in Appendix A. The following further summarizes these results:

hiain feedwater piping has a "hiedium" consequence due to the conditional core damage fregaency in the IPE for feedwater line breaks (see Table 2-1). The analysis assumes that breaks outside containment will effect EFW supply valves to steam generator B (in the same room as the main feedwater pipe break) and hiCC 2B52 at the east end of Room 2040 (effects train A dischstge valves in HPSI, CSS, and LPSI systems).

5.3 Emergency Feedwater The function of emergency feedwater (EFW) is to provide a safety grade backup water source of feedwater to the steam generators when needed to meet cooling requirements during accident conditions.

Figure 5 3 provides a simplified diagram of emergency feedwater (EFW) with a table tha'.

denotes the piping line numbers included in the analysis as well as their locations. Steam supply piping to the turbine EFW pump is included in the main steam analysis. Table 5-3 summarizes the consequence analysis results in Appendix A. The " Systems Irnpact" and "Dackup Trains" columns in Table 5 3 provide results for both isolation success cnd isolation failure cases, when appropriate. The isolation success case is presented first with "m" separating the isolation failure case second. Also,"Once Through B" refers to availability of the train B discharge valves for once through cooling (both trains of pumps are available). Like wise, "Once Through A" refers to spatial impacts on hiCC 2B52 which effects train A once through cooling discharge valves.

The following further summarizes the results in Table 5-3:

l l

Generally, a " Low" consequence occurs when both trains ofEFW pumps and at least 2 l

discharge paths to at least one steam generator can sunive the isolation success case. Also, I

the motor driven pump train must survive the isolation success case. The turbine driven pump is credited as % train versus the motor driven pump a full train based on assumed reliability and availability. Thus, when breaks occur in the turbine pump train, a less reliable train, there is more margin with mitii

. capability versus a break in the more reliable motor driven pump train. AFW is not...ated when isolation failure occurs (human dependency assumed, h

Page$1 Calculation No. NSD 018

('

pumping CST out, and transferring to senice water), but once through cooling is allowed.

\\

Flow diversion is assumed for the train that is not isolated.

A " Medium" consequence occurs when the motor driven EFW pump train is lost either due to isolation success or when isolation capability is unreliable The turbine driven EFW pump, AFW, and once through cooling do not proside enough backup trains in the analysis. Flow diversion is assumed for the train that is not isolated which with additional analysis may be conservative for some of the piping.

A " Low" consequence is obtained for nonnally aligned CST piping located outside the auxiliary building (EF\\WC 10) and the normally isolated Unit 1 CST piping (EFW-C-111 5,4 Containment Spray The function cf containment spray system (CSS) is to spray borated water into the primary containment in the event of a loss of coolant or main steam line break accidents. The system also introduces Sodium Ilydroxide (NaOll) to reduce iodine concentrations and prosides containment sump recirculatlon and heat removal.

Figure 5-4 provides a simplified diagram of containment spray (CSS) with a table that denotes the piping line numbers included in the analysis as wc!! as their locations. Common RWT and containment sump suction piping to the IIPSI and LPSI pumps is included in this analysis. Table g

5-4 summarizes the consequence analysis results in Appendix A. The following further summarizes these results:

Decause there are 2 trains of CSS and containment sump recirculation and one of these trains is usually disabled in the analysis (i.e., the assumed pipe failure), one backup train is the most that can be developed in the analysis. Thus, except for pipe failures inside containment which do not fail ECCS or the CSS hat removal function, it is difficult to develop a " Low" consequence for this system. CSS-C-14A & B r e " Low" because this piping is inside containment; RWT is not potentially diverted outside containment, CSS C-16,17A & 17B are " Low" "cause the piping is small, unlikely to divert a significant portion of RWT, and is isolable de the recirculation phase without effecting HPSI and LPSI and containment cooling.

When pipe breaks can not be isolated and insufIicient RWT inventory makes it to containment sump for recirculation, or failure of pipe in one train has spatial impacts on the other train regardless ofisolation success, a "High" consequence results (CSS C-01,02 and 03D), One backup train in combination with containment bypass is also a "High" consequence (CSS-C-06A and 06D).

A " Medium" consequence results when one of the ECCS trains can succeed (i.e., isolation success) and isolation failure can be credited, pV

Page 52 Calculation No. NSD-018 Figure 5-1 A Main Steam (MS)

Inside Containment l 2CV-lO40-1 MS-049A Room 2155

,_j _

2CV-1010-1 l

MS-C-02A ToSO *A" - {#"""]

gG MS-C-01A :

MS-M3A

[

Roon2155 " 2CV-1000-1 MM MS-C-07 l

Room 2040 P xun 2010 i EM e,N.

Room 2024 v

t

!l! MS-C-o4A 2NS-39A Room 2155 l

g f MSCGtB^

p-2P7A 2CV-1050-2 Room 2155 2CV4340-2 Th

~

~1 W-03B yds-9B

\\

Room 2155

,a

._.._ J u

^

2CV-1060 hD5 l

-~

Room 2155 l-Room 2151 ToBO *B"

>g i

a u + -u w w

pipe %

l.

Room 2155 MS-C-OlB MSC09B Room 2155

~

2CV-1090-2 Note that ADV piping (not shown) is included in MS-C-02A and 02B. Also, bypass piping (2SV-0205) around 2CV-0340-2 is not shown.

_. _ _ ~ _ _ _ _ _ _ _ _ _ _. _

m-

[

Page 53 p

Calculation NG NSD-018 Figure 5-1B Main Steam (MS) Piping location & Consequences I

Main Steam and EFW Steam Pipina 14 cations (1)

Pipe Descriptica Consequence location l

2 EBB 1 MS from Steam Generator 2E 24A to 2CV-1010-1 OlA-C='aie 2C%1010-1 is in 2155 02A' 21$5 A 2 EBB 2 MS from Steam Generator 2E-24D to 2CV-1060-2 OlB Contamment i

2C%1060-2 is in 2155 02B 2155 A i

2 EBB-6 from 2 EBB 1 to 2CV-1000-1 (EFW)

-03A 2155 A I

2C%1000-1 is in 2155 2 EBB-8 from 2 EBB 1 to 2CW1001 and 2MS 3005 (steam dump) 02A 2155-A 2 EBB-7 from 2 EBB 2 to 2CV-1050-2 (EFW) 03B 2155 A 2C%1050 2 is in 2155 2 EBB 9 from 2 EBB 2 to 2CW1051 (steam dump) 02B 2155 A 2 EBB 16 MSIV bypass to 2C%1040 09A 2155 A-2 EBB-17 MSIV bypass to 2CW1090 09B 2155-A 2EBC-1 from 2C%l000-1 to 2P7A 04A,05 2155-A 2MS-39A is in 2155 05 2151 A 2MS-39B is in 2155 05 pipe chase Stop valve 2C%0340 & 2SV 0205 in 2040 06,07 2040-JJ Turbine & remaining valves in 2024 08 2024 JJ b

2EBC-2 from 2C%1050-2 to 2MS-39B (2EBC-1) 04B 2155-A D

2MS-39B is in 2155

. All steam dump and safety valve piping and valves are in 2155. Single EFW steam line leaves 2155 to supply turbine driven pump in 2024.

i O

1

Page 54 Calculation No. NSD-018 Figure 5-2 Main Feedwater (FW) g

}

FW-C-01 A A

~

l

\\

I

> To S/G *A" I

bl 2CV 1023-2 2CV 10241 2FVd5A FW-C-03A From EFW (l

Figure 5-3C I N 2EFW-9A l FW-C-02B q

I FW-C-01 B hA

]

> To S/G *B" 2CV 1073-2 2CV-10"41 2FW-5B FW C-038 L From EFW l

Figure 5-3C 2EFW 98 Main Feedwater Piping Locations Pipe Description Consequence location 2DBB-1 from 2CV-1024-1 to Steam Generator 2E-24A OlA,02A Contamment 2CV-1024-1 in 2081 03A 2081-HH 2DBB-2 from 2CV-1074 1 to Steam Generator 2E-24B OlB,02B Contamment 2CV-1074-1 in 2081 03B 2081-HH 2DBD-1 from 2CV-1023-2 to 2CV-1024-1 not in scope 2081-1H1 (1) 2DBD-2 from 2CV-1073 2 to 2CV-10741 not in scope 2081-HH (1) 2DBB-3 EFW to Steam Generator 2E-24A Figure 5-3C 2DBB-4 EFW to Steam Generator 2E-24B Figure 5-3C (1) Main feedwater analysis scope is from 2CV-1024-1 and 2CV-1074-1 to the steam generators. 2CV-1023-2 and 1073-2 are located outside 2081 in the turbine building and this piping is not in ecope.

O

s O

U Calculation No. NSD Figure 5-3 A Emergency Feedwater (EFW) Suction 4

EFWC11 Room 2025 2CS4I6 Outsik E

j r

Room 2055 CST 2E.FW-2B Room 2040 t

7' g

SW T41B 2CS44Cf

/2CM45 l

2CV Sl&1 IH)R 1 4.

_J-I 2CS-817 l

f EFWCOSB I

l Room 2025 EFWC09B i

Startup & B/

Room 2025 2EFW-23 m2 D Demm M To AFW i

2EFW4706 4

2CT-5 b

h, l j

,yy, N

N N

l><3-2Cu7 9-i

,c i

2EFW-16 2EFW-801 2EFW-1 2EFW-812 EFW&l0 M*

CST 2CT-41 Outsule

-C>C

>4-Room 2223

~

2T41D 2CT-40 Room 2225 Room 2050 EFW-C-09A 2CV-0795-2 Room 2024

~Jn i

W C-08A Room 2024 2P7A 1

2 2A Sw

[

2CV-0711-2 IIDR 2 i

i l

1 x

SUS Page 56 Calculation No. NSD-018 Figure 5-3B Emergency Feedwater (EFW) Pump Discharge 1

g 2EFW-4B MDP EFWC05B 4

2P7B Room 2MO 2CV-1El U

E Room 2081 Room 2025 Room 20$$

From AFw N

2EFW-5A 2EFW.$1 1P 2CV-714 -

2CV-1075-1

~

dL 2EFW-10B' g

Room 2025 V_V Room 2024 f

JkJk 2EFW-29 1P 2EFW-11A Fmn W N

JL2EFW-5B 4

g i

t i 2EFW-4A EFW-C-05A 2CV-1026-2 2 A Room 2040 2EFW-OA+-

/

Room 2081 EFWMr.

Room 2055 Room 2024 Room 2084 1

2CV-107&2

+.-

I a

Page 57 Calculation No. NSD-018 Figure 5-3C Emergency Feedwater (EFW) Discharge to Main Feedwater & SGs J

Inside Containment I

t Room 2084 ;

EFWC 03B i

Q) - Rom 2084 ;

2EFW-9A 4

N' N

[

N To SO 'A' 2CV-1025-1 2CV 1038-2 2EFW 7B a..

.... - L yza

< 12A r-.

. _ _ _.f Room 20 B4 203':

2 K, EFW C 01 A 2CV h026-2 2CV 10371 2EFW 7A 4

J j

2P7A -

l Room 2081 ;

EFWC 03D :

Room 2081 [

9 I

pj y

[

9B l To SO 'B' 2CV 1075-1 2CV-1036-2

'8B

- J '-

j EFW-C-(2B EFW-C-12B

.: Room 20B1 iEFW C-04C,,-...--

a f)toom 208 EFW-C-03C EFW-C41B J,

Room 208L i,

IN r,

2CV-1076-2 2CV 10391 2EFN'-8A a

i Inside Containment

\\-

Page 58 Calculation No. NSD-018 Figure 5-3D EFW Suction Piping and Applicable Consequence & Location h

EFW Suction Piping (Figure 5 3A)

Pipe lDesenption Consequence laation 2HCD-195 from CST 2T-41 A & B to 2EFW-16 (2HBD-91) 10 Outside 2CV-0707 is in pipeway (room 2050) 10 2223 KK 2EFW 16 is in EFW room (2025) 10 2225 WW 2CT-5,40 and 41 a e out near the CSTs 10 2050 09B 2025 JJ 2HCD 258 from 2HCD 195 out near the CSTs to normally closed 2CT 113 10 Outside j

(Unit 1) i 2HBD-91 from 2HCD-195 (2EFW-16) & 2EFW-0706 to 2EFW 801 09B 2025-JJ (2HBC-85) 10 2050 l

2EFW-16 and 801 is in EFW room (2025) 2EFW 0706 is in pipeway (room 2050) 2HBD-883 from 2HBD-91 to 2EFW-23 ( south wall to AFW pump 2P75) 09B 2025 H 2HBC-85 from 2EFW-801 to 2P7B & includes common suction crosstie 08B,09B 2025-JJ 08A,09A 2024-JJ 2HCC-282 E n CST T 41B to 2HBC-85 11 Outside Check valves 2CS-844 and 845 are in EFW room (2025) 1I 2055 JJ 2CS-816 and 817 are out near the Unit 1 CSTs 11 2040-JJ 09B,11 2025-U 2HBC-86 from 2HBC-85 to 2P7A & includes SW connection 08A 2024-11 0

Page 59 Calculation No. NSD 018 Figure 5-3E EFW Pump Discharge Piping and Applicable Consequence & Lccation EFW Pump Discharge Piping (Figure 5 3B)

Pipe Description Consequence Location 2DBC-1 from 2P7B to 2CV-1038 2 (through 2CV-10251) 06B,07 2025-JJ 2CV-1038 and 1025 are located in 2084 07 2024 JJ 2EFW-5A & 6 tre in 2025 05B 2040 JJ 2CV-0714 (test return)is in 2055 05B 2055-JJ includes piping between 2EFW-SA & SB (Consequence 07)

(See Below) 2084-DD 2DBC-3 from 2DBC-1 to 2CV 1036-2 (through 2CV 1075-1) 05B 2040-JJ 2CV-1036 and 1075 arelocated in 2081 (See Below) 2081-HH 2CV-0798 (test retum)is in 2081 2DBC-2 from 2P7A to 2CV 10391 (through 2CV-1076-2) 06A 2024-JJ 2CV-103? and 1076 are located in 2081 05A 2040-JJ 2EFW-5B is in 2024 (See Below) 2081-I&l 2EFW-)1B to 2DBC-3 in 2081 2DBC-4 from 2DBC-2 to 2CV-1037-1 (through 2CV-1026-2) 05A 2040 JJ 2CV-1037 and 1026 are located in 2084 05A 2055 JJ 2EFW-ll A to 2DBC-1 is in 2055 (See Below) 2084-DD 2DBC-7 2P7A minimum bypass from 2DBC-2 to 2EFW-10A 05A 2081-HH 2DBC-8 2P7B minimum bypass from 2DBC-1 to 2EFW-10B OSB 2055-DD 4

2DBC-12 from 2DBC-1 to 2EFW-31 (AFW supply) 06B 2025 JJ p

2DBC-13 from 2DBC 2 to 2EFW-29 (AFW supply) 06A 2024-JJ V

EFW Discharge Piping to Main Feedwater & SGs (Figure 5-3C)

Pipe Description Consequence laation 2DBC-1 from 2P7B (between 2CV-1025 and 2CV-1038) 04B 2084 2DBC-3 from 2DBC-1 (between 2CV 1075 and 2CV-1036) 04D 2081 2DBC-2 from 2P7A (between 2CV-1076 and 2CV-1039) 04C 2081 2DBC-4 from 2DBC-2 (between 2CV-1026 and 2CV-1037) 04A 2084 2DBB-3 from 2CV-1037-1 and 2CV-1038 2 to Steam Generator 2E-24A OlA,12A Contamment 02A,03A,03B 2084-DD 2DBB-4 from 2CV-1039-1 and 2CV-1036-2 to Steam Generator 2E-24B OlB,12B Cnntenment 02B,03C,03D 2081-HH Ov

Page 60 Calculation No. NSD-018 Figure 5-4A Containment Spray System (CSS) Suction Re mg CSS-C-03A R

1 R

T3 4

2BS-IA 2A 3A

~1

@M CSS-C-01 I Roo M

a6A m 2040 2P35A Outside hrludes Suction to

_j i 2CV-5649-1 2P60A M 2P19A(IIPSI) A---

[@

2P89C

~

2CV-4 50-2 l

charging g a 2CV 5647-1 CSSC-16 2BS-6 pmnp Room 2014 Outside N

2 2P66 CSS-C-o6B d

Room 2007 N

2CV 5648-2 CSS-C-16 2CV-5650-2 Room 2040 Cvd==-:=t 3r'O CSS-C-04B Sump A

IncludesStrtion to--

E 0

2P60B (1 PSI)&

Room 2040 2Ps9B(HPSI) 22V-5631r2 2BS-1B a

n

~

x

~

2BS-2B 2BS-3B s j

CSS M 3B CSS-C-05 CSS-C-04B Room 2040 Room 2006 Room 2007 s

2P35B g

G

f]

f)

Pa, v

V Calculation No. NSD Figure 5-4B Containment Spray System (CSS) Discharge CSS-C-15A CSS &l0A 2BS-1 Room 2007 2SI-SA RWTA Room 2014

~

WbW 2BS-44A r~-"~ M E

I CSS-C-11 A CSS-C-12 CSS &13A JE35A CSS-C-14A Room 2055 Ream 2084{

Room 2084 r

-==

T2W7A xn20 k h }yo 3

Spray l-h ie

,b,5A iu CSS-C-09A 2CV-5612-1:

Room 2014 CSS-C-ORA

- jl ll

~

2P3IA i'

Room 2014 JL N

mis rl*

CSS-C-17A l 2SA-fSA 2BS-17A 2CV-5673-1 Room 2084 m

CSS-C-15B Room 2007 CSS-C-10B 2SI-5B RWT&

2BS-12B Room 2007 N

> W_.

-N-IEC1 header I

2BS-44B r 6=g gm i il i

r-CSS-CM 2E35B g$_,t CSS &12B, CSm 3B' CSS &l4B Room 2055 Room 20841 Room 2084:

j 7

N-1 lg Room 2007 ig Spray

,i

_, _,,,,,j,,

I

~N.

u k

IBS4B CSS-C-09B 2CV-5613-2 SB

' Room 2007 CSS COBB 2P3IB Room 2007

!l II j

N mia r1*

L B

2BS-173

. CV-5672-1 Room 2084

Page 62 Calculation No. NSD-018 Figure 5-4C Containment Spray System (CSS) Piping By Consequence & Location g

l Containment Spray Piping Pipe Description Consequence Location 2HCB 24 Common RWT suction to 2CV-5630-1 and 56312 01 Outside 2CV-5630-1 and 5631-2 are at El 348 in tank room 2054 02 2040 2HCB-7 Common RWT suction to SFPP and charging pumps 16 Outside 2040 2HCB 26 RWT suction A from 2CV-5630-1 to check valve 2BS-1 A and 03A 2040 from 2BS 2A to pump 2P35A 04A 2014 2HCB 27 RWT suction B from 2CV-56312 to check valve 2BS-1B and 03B 2040 from 2BS 2B to pump 2P358 05 2006 04B 2007 2HCB15 Contamment sump suction A to 2BS-1 A and 2BS-2A 06A Sump Includes suction to 2P60A and 2P89A 2014 2HCB-13 Contamment sump suction B to 2BS-1B end 2BS-2B 06B Sump Includes suction to 2P60B and 2P89B 2007 2GCB 10 Pump 2P35A discharge to heat exchanger 2E35A 07A 2014 2GCB-35 Pump 2P35A min flow to 2BS-17A 08A 2014 2DCB-11 Pump 2P35A min flow from 2BS 17A to 2CV-56731 08A 2014 2GCB16 Pump 2P35A discharge from heat exchanger 2E35A to 2CV5612-09A 2014 1 and test retum manual valve 2SI 5A (flow element is in 2014) 10A 2014 2SI-5A is in Room 2011/2012 11A 2055 2CV-5612-1 is at El 362 in Room 2084 12A 2084 2GCB-11 Pump 2P35B discharge to heat exchanger 2E35B 07B 2007 2GCB-34 Pump 2P35B min flow to 2BS-17B 08B 2007 2GBC-69 NAOH supply to pump 2P35B ISB 2007 2GBC ~,0 NAOH supply to pump 2P35 A 15A 2014 2DCB-13 Pump 2P35B min flow from 2BS-17B to 2CV-5672 1 08B 2007 2GCB-17 Pump 2P35B discharge fr >m heat exchanger 2E35B to 2CV5613 2 09B 2007 and test retum manual valve 2SI 5B (Oow element is in 2007) 10B 2007 2SI-5B is in Room 2011/2012 11B 2055 2CV-5613-2 is at El 362 in Room 2084 12B 2084 2HCB-20 2P35A discharge downstream of 2CV-5612-1 to contamment 13A 2084 penetration 2HCB-21 2P35B discharge downstream of 2CV-5613-2 to contamment 13B 2084 penetration 2HCB 3 2P35A discharge downstream of 2CV-5612-1 inside containment 14A Containment 2HCB-4 2P35B discharge downstream of 2CV-5613-2 inside containment 14B Containment 2HCB-93 Service air connection to train A 17A 2084 2HCB-94 Service air connection to train B 17B 2084 9

g

,7 pg

()

V Calculation No. NSD-UT3

' Table 5-1 Consequence Analysis Summary - Main Steam & EFW Steam Piping ID I

16.,;.

Spatial Configuration trutsstor Isolation

$ a. i,W Backup Ccessanmers Egosure Table Rank 3

Imation Traim Time Used MS-C-01 A MS from SO"A" C -.-~.;

Cp.6.s T5 No PCS & EFW NA MSIV outside NA 2-1 MEDIUM meam due to T5 MS-C418 MS from SO "el" Conte _.-.;

Operstmg TS No PCS& EFW NA MSIV outside NA 2-I MEDIUM Wenm due to T5 MS-C42A MS from SO "A" 2ISS Operstmg TS No PCS & EFW

>2 (EFW Passive bemer NA 2-3 MEDIUM steam due to T5.

"D", AFW, inside EFW "A"due to Once se whip.

T. -J.)

MS-C-02B MS from SO "B" 2155 Operstmg TS No PCS & EFW

>2 (EFW Passive bamer NA 2-3 MEDIUM s* cam due to T5.

"B", AFW, imide EFW "A"due to Once se whip.

TheJ.)

MS-C-03A EFW er= "A" 2155 St Ay T6 No partselloes of 3 (PCS, Pan. eve bemer NA 2-3 IDW Unisolable FCS& EFW EFW, AFW, inside meam Once Thw.J.)

MS-C-03 B EFW mesm "B" 21?S St ai 16 No partiallms of 3 (PCS, Passive bemer NA 2-3 LOW Unisolable PCS& EIW EFW, AFW, inside steam Once T';, J.)

MS-C-04A EFW - --. "A" 2155 St ay T6 2CV-1000 partial loss of 3 (PCS, 2CV-1000 w/

NA 2-3 WW Isolable EFW steam EFW,AFW, Passive barrier Once M

t.wJ.)

MSC04B EFW steam "B" 2155 St -4 T6 2CV-1050 partsal loss J 3 (PCS, 2CV-1050 w/

NA 2-3 WW 7

Isolable EFW mesm EFW, AFW, Passive barrier Once inside T1 rough)

MSC05 EFW - 4 above 2155,2151,

Stia, T6 2CV-1000 EFW steam 3 (PCS, 2CV-1000 &

NA 2-3 WW El354 pipe chase and 1050 EFW "B",

1050 w/ Paw we AFW,Once barrier inside

v. - J.)

MS-C-06 EFW a u to 2040 Sway-T6 2CV-1000 ETW eam g 3 (PCS, Unaffected NA 2-3 WW 2CV-0340 and 1050 EFW steam.

EFW "D",

AFW, PCS &

AFW, Once train A ofonce Through)g thnngh cooling (isolation, EFW "B",

once tfrough "B")

Page 64 Calculation No. NSD-018 Table 5-1 Consequence Analysis Summary - Main Steam & EFW Steam Piping ID 16 W.

Spatial Configursuon Imtiator isolation Symem Ergects Backup Contammera Egenure Tatde Rank tecation Trains Tirne Used MSC47 EFW meam from 2040 Dernand No(12 (CV-1000 PCS(T2)&

>2 (ETW UnmHected Between test 2-2 LOW 2CV4340 chaIW.)

and 10$0 EFW meam g "B", AFW, a 2CW PCS(F21EFW Once 0340 mesm, ATW A T1 sough g onceGuangh A) isolation, EFW T A ence Through In MSC48 EFW Steam in 2024 Dema.d No(T2 2CV-1000 FCS(T2) A

>2(E.A Unasected Detween test 2-2 1DW turbe room challenge) and 1050 EFW steam "B", AFW, or2C%

Once 0340 Through)

MS-C 09A MSIV t,,-

2153 Standby No(T2 No FCS (T2) A

>2 (EFW, Faserve bemer ImgAOT 2-2 1DW challenge) partialloss of AFW,Once inside EFW mesm throt@)

MSC49D MSIV tr3 pens 2135 Standby

. challenge) partialloss of ATW,Once inside No(T2 No PCS(T2) A

>2 (EFW, Passm bemer Img AOT 2-2 IDW EFW meam

$wough) e O

O

CalculationNo N Table 5-2 Cm-- +- -- + Adris Summary - Main Feedwater ID Destnphen Spatial Con 6guration Inemoor leoishan Systemimpace Bacitup Traum Cesamummen Egesme TsNe Rmuk Ims6am Teme used FW-C 01 A MF to SO"A" Contasunas Operahng T3 No FCS(TS) A NA Unasected NA 2-1 MEDIUM downeemmeof EFW to 80 "A" 2FW-SA eme tot 3 FW 441B MF to SO "B" Conessament Operahng T3

~Jo FCS (TS) A NA Umm8scend NA 2-1 MEDIUM dommereen of EFW to SO "B"

' 2FW-3B due tot 3 FW-C 02A MF lo SO "A" Centeenment Operateg TS (l) 2FW-3A A FCS(T3)

NA 2CV-1024 NA 2-3 MEDIUM upeream of 2FW-2CV-1024 m

3A FW C 02B MF to SO "B" Censasunant Operseng T3 (1) 2FW-38 A FCS(TS)

NA-2CV-1974 NA 2-1.

MEDIUM upstressa of 2FW.

2CV-1974 eunids 3B FW C 03A MF h SO "A" 2081 Opershng T3(1) 2FW-3A A FCS(TSA Train 2(t.rw A AFW 2FW-3Ainside NA 2-3 MEDIUM e

2CV-1024 A ECCS to 80 "A" and disdnarge omhus Train B Once M

dad =ese vehus)

FW-C438 MF to 80 "B" 2081 Operahng T3(1) 2FW-3B &

PCS(T3L Train 2 rrw A AFW 2FW-3B inside oA 2-3 MEDIUM t

eusside 2CV-1974 A ECCS to SO"A"and dia:Amrge omhus Train B Omoe n sh disd=rse

,=hus)

(1) Breaks upstream of check valve 2FW-5A and 5B could be classified as T2 or T6 initiating events, but the conseq jence results are not affected-

Page 66 Calculation No. NSD-018 Table 5-3 C-.,_.

Analysis Survenary-Emergerry Feedwster i

ID D-Winn Spatial Config sratson Imtistw isolation System Impacts Backup Trains Contasunere Exposure Table Rar*

toce6en (note 1)

(note 1)

Twne Used EfW-C41A EFW to SO A Contamrners Demand Assumed 2EFW-9A PCS(T2L EFW 2(EFW A AFW 2EFW-7A A 7D between 2-2 MEPIUM Inside Containment T2 irmide a to SO "A" to SO "D",Once outside test l

MOVs g

T1woogh g l

eutside PCs,EFW, AFW indation & Once

)

Through) i EFW G IB EFWIoSOB Corsamment Demand Assumed 2E1W-98 FCS(T2A EFW 2 (EFW & AFW 2EFW-EA & SB between 2-2 MEDIUM Inside Containment T2 inside A to SO "B" to SO "A",Once cuiside test

)

MOVs g

T1 rough a l

outside PCS, EFW, AN isolation & Once i

"Drough)

EFW-C-02A EFWto SO A 2084 Demand Assumed 2FFW-9A PCS(T2k EFW 2(EFW A AFW 2EFW-9A between 2-2 MEDIUM Outside T2 Faide A to50"A" to 50 "B", Once inside test Coresinment MOVs g

Through g outside PCS, EFW, isolation & Once AFW,Once Through B)

Threugh A EFW C.42B EFW to SO B 2031 Demand Assumed 2EFW-98 FCS(T2A EFW 2(EFW A AFW 2EFW-98 between 2-2 MEDIUM Outside T2 imide &

to 50 "B" to SO "A", Once umide test Containmers MOVs g

Through g outside PCS, EFW, isolation & Once AN,Ona Through B)

Threach A EFWQ3A EFW to SO A 2084 Demand Assumed 2CV-1026 PCS(T2A EFW 3 (EFW, AFW, Unafrected between 2-2 IDW between 2CV 1037 T2 er 1037 A to SO "A" Once T1 rough g test and 2EFW-7A g

isolation, EFW D PCS, EFW A.

A Once11 rough AN. Once B)

Through A EFWG3B EFW to SO A 2084 Demand Assumed 2CV-1025 PCS (T2A ElW 2.3 (EFW, AFW, Unaffeded between 2-2 WW bc*meen 2CV-1038 T2 er l038 Dio SO"A" OnceThrough g test and 2EFW-7B g

isolatson, EFW A PCs, EFW D, A Onm Through AFW.Once B)

Through A EFW-C-03C EfWtoSOB 203I Demard!

Assumed 2CV-1076 PCS(T2L EFW 3 (EFW. AFW, Unaffected between 2-2 WW betwem 2Cbs039 T2 erIO3*

A to SO "D" Once Through g test and 2EFW-8A g

isolation, EFW B PCS,EFW A, A Once Thmugh AFW,Once B)

Through A e

O O

p kJ

'/

Calculation No. NSD-UT8 Table 3-3 C-p.a Analysis Summary-Emergency Feedwater ID Descriptnen Sv aia*

Configuraten Indsator Isnietson System impacts Backup Trams Cornemmers Expomre Table Rank Igon (mwe I)

(nnte 1)

Time Used EFW4-03D EFW to SO B Y,dI Demand Assumed 2CV-1073 FCS (T2), EFW 2 3 (EFW, AFW, Unaffected between 2-2 IJ)W between 2CV-1036 T2 or1036 B to 50 "B" 0%ce Through g test and 2EFW-8B g

isolatm EFW A 3

FCS, EFW B.

A Once Through AfW Once B) 11rou,) A EFW-C-04A EFW to SO A 2084 Demand Assumed 2CV-1026 PCS (F2A EfW 3 (EFW. AFW, UnaRected between 2-2 LOW between 2CV-1026 T2 A to 50 "A" Once Through g test and 1037 g

isolation EFW D l

PCS, EFW A.

A Once Through l

AFW,Once B) 1hrough A EJW-C 04D EFW to SO A 2084 Demand Assumed 2CV-1923 FCS (T2), EFW 2.5 (EFW, AFW, Unaffected between 2-2 LOW be* ween 2CV-1025 T2 B to 50 "A" Once Through g test an(1032 g

isolation EFW A PCS, EFW B,

& Once Through AF%,Once B)

T1eough A EFW-C-04C EFW to SO D 2081 Demand Assumed 2CV-1076 PCS (F2), EFW 3 (EFW. AFW, Unaffected between 2-2 IJ)W between 2CV-1076 T2 A to 50 "B" Once Through g test and 1039 g

isolation. EFW B PCS, EFW A.

A Once Through AFW, Once B)

Tiecogh A EFW-C44D EFW to SO B 2081 Demars!

Assumed 2CV-1073 PCS (F2A EFW 2.5 (EFW, AFW, UnaRected betw en 2-2 LOW Inwcen 2CV-1073 T2 B to SO "D*

Once Through g test and 1036 g

isolation. EFW A PCS, EFW B, A Once Through AFW, Once B)

Through A EFWE.-OSA EFW A to sos 20t4 De nand Asmsmed 2r7A trip PCS(12A EFW 2.3 (EFW B, Unaficcted betwee t 2-2 LOW Outside Pump 2081 T2 A suction A_g AfW, Once test Rooma 2055 MOVa PCS, EFW A, Through g 2040 AfW Once isolation EFW D Through A

& Once Through B)

EFW-C-05 B EFW D to SOe 20J4 Demand Assuned 2P7B trip PCS (F2A EFW 1(EFW A AFW, Unaffected between 2-2 MEDitAf OM Purnp 2031 T2

& suction Dg

• Once Through g test nooms 2035 MOVs PCS,Eiw D.

isolation. EFW A 2040 AFW,Once

& Once Through Through A B)

EFWC44A EFW A in Pump 2024 Demand Assumed 2P7A trip PCS(T2A EFW 2.5 (EFW B, Urmfrected between 2-2 1DW Room T2 or room A

AFW, Once test flanding Through)

Page 68 Calculation No. NSD-018

' Table 5-3 Consequence Annivuis Summary-Fanergency Feedwater ID Descryuon Sparts!

Conrigurittoon inniator Isolation System lnymets Backup Trust Contanimert Exposure Table Rank laication (cote 1)

(note 1)

Tu'ne Used EFW-C460 EFW H in rump 2023 Demand Assumed 2r/Dirip PCS(T2A EFW 2(EFW A, AFW, UnaNected between 2-2 MEDIUM P_com T2 er rearn D

Once Through) test flood' g m

EFW-C47 Between 2EFW-3A 2024 Deriand Asmmed Yes (pipe PCS(T2L EFW I (Once Through)

UnaNected ally ar 22 IDW and SB 2025 T1 and diattenge due to challenge additional requires ercreenies raitures locally (wxpected oper.eig EST g valves) l chsflenge)

EFWD48A EFW ASectionin 2024 Demand Assumed 2CV-0793 PCS(T2A EFW 2.3(EF W B.

UnaNeced teween 2-2 IDW Pump Room T2 and 0711 A

AIW,Once test and SWS 1hrough)

EF# C08B EFW D Suction ira 2025 Demand Asomed 2CV4789 PCS(T21 EFW 2 (EP# A, AFW, UnaNeck4 between 2-2 MEDIUM Pump Room T2 and 0716 B

Once11 rough) test and SWS TFWC09A Common CST Pye 2024 Demand Assumed 2CV-0707 PCS (T2 A E.FW 2.5 (EFW H, Unsfected between 2-2 LDW in EFW A Pump T2 locaffy ag!

A AFW,Once test Room SWS Through)

EFW-C49B Ceimon CST Pipe 2023 Demand Assumed 2Cv4707 PCS(T2k EFW 2(EFW A, AFW, Unageoed between 2-2 MEDIUM in EFW D Pump T2 nocally d D

Oncelhrough) tem Room _

SWS e

jl EFW-C-IS Common CS1 Pipe Outside Denrmd Assumed NA PCS(T2) 3 (EIW. AFW, Unaficceed between 2-2 1DW Octside 2223

""2 Once Through) sent 2223 20$0 EFW O!!

Unitl CST Piping Outside Dem ui Assumed NA PCS(T2X EFW 2(EFW A AFW, UnaNected a:tyear 22 IDW upstrenin ofchect 2035 T2 A Unit B

Once Through) valves 844 A 843 2040 1 CST 2025 cha!!enge

{

(expected Eequency or etm' lente)

EFW ol2A EFW to SO "A" Certainment Standby TS No PCS(T3) A NA UnaNected NA 2-1 MEDIUM

.'- -. -. of EFW to So "A"

^

2EFW-9A due to T5 EFW&l2B EFWto80*B" Contamment Standby T3 No PCS(TS) A NA UnaNected NA 2-1 MEDIUM ewnstream of EFW to SG "B" 2EFW-99 he to T5 Note 1: Successful isolation result is shown first and then isolation failure case separated by "of' when applicable. "Once Through B" refers to once through cooling mode ofinventory control and heat removal with train B discharge valves available (both pump trains are available but the A train discharge ulves are failed). Similarly,"Once Through A" refers to train A discharge valves.

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Calculation No. NS4

'lable 5-4 Consequence Analysis Summary - Containment Spray ID Deseng4 sos Spatial Configuration hutistor Isolation Symem impacts Beaup Trams Contauunne Exposure Table Rank Imention Tune Unni CSS 441 Common RWI outside

.W Assumed M No CSS. HPSI,11S1 0

Unaffected between 2-2 HIG11 suction outside test CSS-C42 Common RWT 2040 Demand Assumed M No CSS. H"il,11SI O

Unaffected between 2-2 HIGH suction inside test CSS-C43A RWT suction A in 2040 Demand Assumed M 2CV-5630 ECCS A g all I(CCCSD g Unaffected between 2-2 MEDIUM 2040 ECCS isolation) test CSSC438 RWT suction B in 2040 Demand Assumed M 2CV-%31 n!! ECCS & CSS 0

UnafTected between 2 -2 d!'ill 2040 test CSS C 04A RWT suction A in 2014 Demard Asrumed M 2CV-5630 ECCS Ag all I(ECCS B g Unaffected between 2-2 MEDIUM 2014 ECCS isolation) tem CSSC 048 RWT suction B in 2007 Demand Assumed M 2CV-5631 ECCS B g all I(ECCS Ag Unaffected between 2-2 MEDIUM 2007 ECCS isolation) tem CSS-C45 RWT suction B in 2006 Demand Assumed M 2CV-563I Ef <.4 B g all I(ECCS Ag UnafTected between 2-2 MEDIUM 2006 ECCS isolation) test CSS-C46A Sung suctson A in 2014 Demand Aesumed M 2CV-%47 ECCS Agall I(ECCS B g Bypass ifisol allyear 2-2 111G!!

2014 ECCS isoletum) fails CSS & O6B Sur ip suction B in 2007 Demand Assumed M 2CV-5648 ECCS B g all I(ECCS Ag Bypass afIsol all year 2-2 IIIGH 2007 ECCS isolation) fails CSS &07A 2P35A discharge to 2034 Demand Assumed M tnp puup ECCS A g all I(ECCS B g Unaffected belmeen 2-2 MEDIUM 2DSA A 2CV-ECCS isolation) test

$630 CSS & o7B 2P358 discharge to 2007 Demand Assumed M trip pung ECCS B g all I(ECCS A g UnafTected betwee 2-2 MEDIUM 2D5B A 2CV-ECCS isolatim) test

% 31 CSSCOSA 2P35A nuniflow 2014 Demand Assumed M trip pump CSS A I(CSSB)

UneSected between 2-2 MEDIUM

& 2CV-test 56O CSS-C 08B 2P358 mini flow

.2007 Demand Assumed M trip pung CSS B 1(CSS A)

Una0ected feween 2-2 LIEDIUM

& 2CV-test 5631 i

CSS &O9A Downstream of 2014 Demand Assumed M trip pump ECCS A g nu I(ECCS B g Unaffected between 2-2 MEDIUM 2DSAin 20I4

&2CV-ECCS isolation) tet

% 30 CSS-C-09B D - - cf 2007 Demand AssureA M trip pung ECCS B g all I(ECCS Ag Unaffecsed feween 2-2 MEDIUM 2DSBin 2007 A 2CV-ECCS isolation) tem St',31 CSScl0A 2P35Atestreturn 20I4 Deinend Assumed M trip pump ECCS Agall 1(ECCS B g Unaflected between 2-2 MEDIUM in 2011 A2CV.

ECCS isolation) test 5630 CSS-C-10B 2P35B test return 2007 Demand Assumed M inp pung ECCS B g all I(ECCS Ag UnalIncned between 2-2 MEDIUM in 2011 A 2CV-ECCS isolation) test 5631 i

PagC 70 Calculation No. NSD-018 Table 5-4 Conwic Anahsis Summary-Containment Spray ID L Mian Spatial Config=.irstum Imtiator isolation System byacts BackupTraers l Corsammers Entware isNe Ranit 1 mention Time timed CSS-C-1I A D

.a -a of 2055 Demand Asmsmed M anp purry ECCS A ce att I (ECCS B g UnafTeded tetween 2-2 MEDIUM 2E35Am:20$$

A2CV-ECCS isolation) test

$630 CSS &llB IL.a.- of 2055 Demand Assurned M tnp g,mmp ECCS B g en I{ECCSA g Unst!aded between 2-2 MEDIUM 2E35D in 2055

&2CV-ECCS isolation) test

$611 CSS &l2A U@n of 2CV-2084 Demand Assumed M tnp purg ECCS Ag all I(ECCS B g Unafrected between 2-2 MEDIUM

$612 in 2084

& 2CV-ECCS isolation) test

$630 CSS &l2B Upstream of 2CV-2084 Demand Assumed M tnp png ECCS B g an I(ECCS Ag Unaffected between 2-2 MEDIUM

$613 in 2084

&2CV.

ECCS isolution) test 5631 CSS & l3A IL.a,- of 2084 Demand Assurned M tnp purry CSS A g all 1:(CSS Bg 2BS-SA uwide an year 2-2 MEDIUM 2CV-5612 in 2084

&2CV.

ECCS isolation) 5612 CSS & l38 C a e of 2014 Demand Assumed M tnp pump CS? B g all 1:(CSS Ag 2BS-3B eside all year 2-2 MEDIUM 2CV-5613 in 2084 A 2CV-ECCS isolation) 5613 CSS &l4A IL.4,- ef Corsainment Demand AssurrM M trip purg ecme 2

2CV-5612 and an year 2-2 IDW 2CV-5612 in a2CV-closalsynnern Centairenent 5612 cuiside CSS &l4B C_.a.-

of Cornaarnent Derasand Assumed M tnp pump none 2

2CV-M13 and an year 2-2 IDW 2CV-5613 in

& 2CV-closed system Conaminment 5613 outside CSS &l5A NAOH to Tram A 2014 Demand Assumed M tnppump ECCS A 1: ECCS B UrmEccted be* ween 2-2 MEDIUM

&2CV-test 5630 CSS &l5B NAOli to Train B 2007 Demand Assume =" M tnp purry ECCSB 1: ECCS A Unaf!' cted between 2-2 MEDIUM e

& 2CV-test 5'31 CSS & l6 RW A soSFTP A Outside Demand Assumed M No None AII Unsgected a5 year 2-2 IDW chartma 2040 CSS &l7A

..L mir 2084 Demand Assumed M enp pump CSS A 2: ECCS, CSS 2BS-SA inside a!Iyear 2-2 IDW connection to Trein a 2CV-B & Care A

%I2 Cooling CSSCI7B Sem mer 2084 Demand Assumed M inp runp CSSB 2: ECCS, CSS 2BS-5B irside all year 2-2 IDW annection to Train a 2CV-A & Core B

56 3 Coolir g 9

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Page 71 Calculation No. NSD-018 g

U 6.0 Conclusions & Recommendations Conditional core damage probability (CCDP) for certain initiating events is marginally in the

" Medium" consequence category range (see Table 2-1). Specifically, turbine and reactor trip (Tl and T6) nave minor impacts on mitigating systems and their CCDP is greater than other less benign initiators such as main steam line break (TS). Conservatism in the model and quantification is likely the cause of these differences which is not unusual in PRAs when the initiators are not significant contributors to risk. In this study, T1 and T6 are assumed to be in the " Low" consequence range; future more realistic analyses will result in CCDPs in the " Low" rather than " Medium" consequence range. The following consequence ids in this analysis scope could be affected by other initiators:

MS-C-01 A & IB could be " Low" since CCDP for TS is at IE-6.

FW-C-01 A, OlB,02A & 02B and EFW-C-12A & 12B could be " Low" since CCDP for T5 is at 1E-6.

The EPRI methodology presently requires that an independent piping demand be considered if pipe break during normal plant operation does not cause an initiating event. As a result, suction piping from the CST (EFW) and RWT (CSS) is assumed to fail during an accident demand. This is conservative because the demand stress may not be significantly different than the standby Q

condition. One objective of this reference plant analysis is to identify such potential conservatism V

(as well as potential optimism) for future methodology updates. Ifit is concluded that leaks are as likely to be detected during standby as during a demand for piping connected to atmospheric tar /cs, the following consequence ids in this analysis scope could be effected:

EFW-C-08B and 09B could be a " Low" consequence rather than " Medium" (some piping that connects to the pump may still have to remain Medium).

CSS-C-01, 02, 3 A,3B and portions of 4 A & 4B could be reduced from a "High" or

" Medium" consequence, but this also depends on other methodology interpretations or changes to Table 2-2. If a medium LOCA is assumed during a short AOT, this frequency is certainly low enough to be considered a " Medium" consequence, but Table 2-2 requires that a "High" consequ nce be assigned with no backup trains available. This is done to ensure defense-in-depth; a basis for why detection and a controlled shutdown within a short exposure time period represents an equisalent level of defense-in-depth would have to be

. developed.

Note that RWT suction piping downstream of check valves 2BS-l A and IB must consider demand loads from a containment sump recirculation actuation. Thus, the demand assumption should be retained here.

Several " Low" and " Medium" consequence analysis results depend on successful operator actions to identify the broken pipe and isolate it before additional impacts occur. It may be o) appropriate to utilize the training simulator and/or operator interviews to discuss s

(

scenarios and confirm that the analysis is not too optimistic. The following are examples to consider:

P:ge 72 Calculation No. NSD-018 EFW steam line break in Room 2040 during normal power operation - a change in power is expected to occur and there is pressure indication on this line, but not an annunciator. The analysis assumes a high likelihood ofisolation (2CV-1010 ar.d 1050) before significant damage to equipment in Room 2040.

Loss of power conversion system initiating event and EFW Pump 2P-7B discharge pipe breaks on demand in Room 2040 - there is EFW flow, and RAB sump level annunciators in l

the control room. The pump can be tripped and suction MOV may need to be closed to prevent gravity draining the CST. The time it takes to isolate and initiate other recovery actions would be ofinterest.

Medium LOCA initiating event and containment spray pump discharge piping ruptures on demand - there is CSS flow, and ECCS room flood annunciators in the control room. The i

pump can be tripped and the suction MOV (2CV-5630 or 5631) probably needs to be closed to prevent gravity draining the RWT. The time it takes to isolate this event would be of interest. Also, when RAS occurs, observing the operators isolate or prevent the containment sump from draining into the ECCS room is important.

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Page 73 Calculation No. NSD-018 7.0 References

1. EPRI TR-106706, Work Order 3230, Interim Report, June 1996 " Risk Informed Inservice Inspection Evaluation Procedure" prepared by Electric Power Research Institute, Yankee j

Atomic Electric Company, and Sartrex Corporation.

2. - ANO Probabilistic Risk Assessment (PRA), Ir.dividual Plant Examination (IPE) Submittal, Report No. 94-R-2005-01, Rev 0

3. ANO-2 Piping and Instrument Diagrams M-2202, Sheet 1, Rev 45, " Main Steam" M-2202, Sheet 2, Rev 63, " Main Steam" M-2202, Sheet 3, Rev 12, " Auxiliary Steam" M 2202, Sheet 4, Rev 16, " Lube Oil, Lube Oil Cooling Electro / Hydraulic Controls & Main Steam" M 2204, Sheet 1, Rev 89, " Condensate & Feedwater" M-2204, Sheet 2, Rev 68, " Condensate & Feedwater" M-2204, Sheet 3, Rev 39, " Condensate & Feedwater" M-2204, Sheet 4, Rev 55, " Emergency Feedwater" M-2204, Sheet 5, Rev 8, " Condenser Vacuum" M-2206, Sheet 1, Rev 122, " Steam Generator Secondary System" 3

M-2206, Sheet 2, Rev 21, " Steam Generator Secondary System" i

M-2236, Sheet 1, Rev 77," Containment Spray System" i-

_ M-2232, Sheet I, Rev 103, " Safety Injection System" M-2212, Sheet 4, Rev 21, "Make-up Water Demineralization System" M-204, SH. 5, rev 12, " Emergency Feedwater Storage" l

4. ANO-2 Isometric Drawings:

2DBB-2-1, Sheet 1, Rev 13, "Large Pipe Isometric Main Feedwater Supply to Steam Generator 2E-24B From 2CV-1074-1" i

2DBB-1-1, Sheet 1, Rev 10, "Large Pipe Isometric From Main Feedwater Supply to Steam Generator 2E-24A" 2DBB-3-1, SH 1, Rev 21, "Large Pipe Isometric Emergency Feedwater Supply from 2CV-f' 1037 & 2CV-1038 to Line 2DBB-1-24" 2DBB-3-1, SH 2, Rev 2, "Large Pipe Isometric Emergency Feedwater Supply from 2CV-1037 & 2CV-1038 to Line 2DBB-1-24" 2DBB-4-1, Rev 23, "Large Pipe Isometric Emergency Feedwater Supply from 2CV-1036 &

2CV-1039 to Line 2DBB-2-2" 2DBC-1-1, Sheet 1, Rev 20, "Large Pipe Isometric Emergency Feedwater Pump 2P-7B Discharge to Steam Generator 2E-24A" 2DBC-1-1, Sheet 2, Rev 1, "Large Pipe Isometric Emergency Feedwater Pump 2P-7B i

Discharge to Steam Generator 2E-24A" l

2DBC-1-2, Sheet 1, Rev 21, "Large Pipe Isometric Emergency Feedwater Pump 2P-7B 1

Discharge to Steam Generator 2E-24B"

Page 74 Calculation No. NSD-018 2DBC-2-1, Sheet 1, Rev 14, "Large Pipe Isometric Emergency Feedwater Pump 2P-7A Discharge to Steam Generator 2E 24A" 2DBC-2-2, Sheet 1, Rev 18, "Large Pipe Isometric 2P-7A Emergency Feedwater Pump Discharge Piping to 2E-24A Steam Generator" 2DBC-3-1, Sheet 1, Rev 14, "Large Pipe Isometric Emergency Feedwater Pump 2P-7B Discharge to Steam Generator 2E-24B" 2DBC-4-1, Sheet 1, Rev 13, "Large Pipe Isometric Emergency Feedwater Pump 2P-7A Discharge to Steam Generator 2E-24A" 2DBC-4-1, Sheet 2, Rev 2, "Large Pipe Isometric Emergency Feedwater Pump 2P-7A Discharge to Steam Generator 2E-24A" 2DBC-7-1, Sheet 1, Rev 7, " Small Pipe Isometric Emergency Feedwater Pump 2P-7A Minimum Bypass" 2DBC-8-1, Sheet 1, Rev 4, " Small Pipe Isometric Emergency Feedwater Pump 2P-7B Minimum Bypass" 2DBC-12-1, Sheet 1, Rev 2, "Large Pipe Isometric Auxiliary Feedwater Pump (2P75) Check Valve Test Connection" 2DBC-13-1, Sheet 1, Rev 3, "Large Pipe Isometric Auxiliary Feedwater Pump (2P75) Check Valve Test Connection" 2DBD-34-1, Sheet 1, Rev 2, " Large Pipe Isometric Auxiliary Feedwater Discharge Pump 2P75 2DBD-34-2, Sheet 1, Rev 1, " Small 4pe Isometric Auxiliary Feedwater Pump 2P75 Connections 2 EBB-1-1, Rev 20, Large Pipe Isometric Main Steam From Steam Generator 2E-24A to g

Containment Penetration 2P-1" 2 EBB-2-1, Rev 14, Large Pipe Isometric Main Steam From Steam Generator 2E-24B to Containment Penetration 2P-2" 2 EBB-1-2, Sheet 1, Rev 10, Large Pipe Isometric Main Steam Header From Penetration 2P-I to MSIV 2CV-1010-1" 2 EBB-2-2, Sheet 1, Rev 9, Large Pipe Isometric Main Steam Header #2 From Penetration 2P-2 to MSIV 2CV-1060-?"

2 EBB 8-1, Sheet 1, Rev 9, L:ge Pipe Isometric Main Steam Dump to Atmosphere THRU 2CV-1001" 2 EBB-9-1, Sheet 1, Rev 9, Large Pipe Isometric Main Steam Dump to Atmosphere THRU 2CV-1051" 2 EBB-7-1, Sheet 1, Rev 11, Large Pipe Isometric Emergency Feedwater Pump Steam Supply to 2CV-1060-2" 2 EBB-6-1, Sheet 1, Rev 12, Large Pipe Isometric Main Steam Supply to 2CV-1000-1" 2 EBB-16-1, Sheet 1, Rev 13, "Small Pipe Isometric Main Stearr Bypass For 2CV-1010-1" 2 EBB-17-1, Sheet 1, Rev 8, "Small Pipe Isometric Main Steam Bypass For 2CV-1060-2" 2EBC-1-1, Sheet 1, Rev 24, Large Pipe Isometric Main Steam Supply to Emergency Feedwater Pump Turbine Driver 2K-3 From Main Steam Header #1" 2EBC-1-2, Sheet 1, Rev 33, Large Pipe Isometric Main Steam Supply to Emergency Feedwater Pump Turb Driver From Main Steam Header #1" 2EBC-1-2, Sheet 2, Rev 2, Large Pipe Isometric Main Steam Supply to Emergency Feedwater Pump Turb Driver From Main Steam Header #1"

Page 75 Calculation No, NSD 018 g3 2EBC-2 1, Sheet 1, Rev 13, Large Pipe Isometric Main Steam Header #2 Supply to

U Emergency Feedwater Pump Turbine Driver 2K-3" 2HBD 91-1, Sheet 1, Rev 14, "Large Pipe Isometric Emergency Feedwater Pumps 2P-7A&B Inlet From Main Condenser" 2HBD 91-2, Rev 4, " Isometric - Turbine Aux, Bic'3. Condensate System" 2HBD-883-1, Rev 0, "Large Pipe Isometric Auxiliary Feedwater Pump (2P75) Suctian" 2HCC-282-1, Sheet 1, Rev 1, "Large Pipe Isometric Emergency Feedwater From T-41B to 2P-7A & B" 2HCC-282-2, Sheet 1, Rev 1, "Large Pipe Isometric From Condensate Storage Tanks T-4IB to Emergency Feedwater Pumps 2P-7A & 2P-7B" 1-2HCC-282-3, Sheet 1, Rev 1, "Large Pipe Isometric Condensate Storage Tanks T-41B l

Supply to Emergency Feedwater Pumps 2P-7A & B" 2HCC-282 3, Sheet 2, Rev 0, "Large Pipe Isometric Condensate Storage Tanks T-41B Supply to Emergency Feedwater Pumps 2P-7A & B" 2H%282-4, Sheet 1, Rev 1,"Large Pipe Isometric Condensate Storage Tanks T-41B Supply to Emergency Feedwater Pumps 2P-7A & B" 2HCC-282-5, Sheet 1, Rev 1, "Large Pipe Isometric Condensate Storage Tanks T-4IB i

Supply to Emergency Feedwater Pumps 2P-7A & 7B" 2HCC-282-6, Sheet 1, Rev 2, "Large Pipe Isometric From Condensate Storage Tanks T-41B l

to Emergency Feedwater Pump 2P-7A & B" j

2HCD-195-1, Rev 7, " Isometric - Yard Area Plant Make-up" 2HCD-195-2, Rev 9, " Isometric - Turbine Aux. Bldg. Plant Make-up" 2HCD-258-1, Rev 7, " isometric.."

4 2DCB-11-1, Sheet 1, Rev 8, "Small Pipe Isometric Minimum Flow Line From 2GCB-35 to j

2DCB-2" i

2DCD-13-1, Sheet 1, Rev 8, "Small Pipe Isometric Containment Spray Pump 2P-35B 3

Minimum Flow Line to Refueling Water Tank 2T-3" 2GCB-10-1, Sheet 1, Rev 13, "Large Pipe Isometric From Containment Spray Pump 2P-35A to Shutdown Cooling Heat Exchanger 2E-35A" 2GCB-10-1, Sheet 2, Rev 0, "Large Pipe Isometric From Containment Spray Pump 2P-35A' to Shutdown Cooling Heat Exchanger 2E-35A" 2GCB-11-1, Sheet 1, Rev 15, "Large Pipe Isometric Containment Spray Pump 2P-35B to -

SI utdown Cooling Heat Exchanger 2E-35B" 2GCB-io-i, Sheet 1, Rev 10, "Large Pipe Isometric Containment Spray Discharge From Shutdown Cooling Heat Exchanger 2E-35A" 2GCB-16-1, Sheet 2, Rev 77, "Large Pipe Isometric Containment Spray Dischar;e From Shutdown Cooling Heat Exchanger 2E-35A" 2GCB-17-1, Sheet 1, Rev 13, "Large Pipe Isometric Discharge Header From Shutdown Cooling Heat Exchanger 2E-35B"

- 2GCB-17-1, Sheet 2, Rev 0, "Large Pipe Isometric Discharge Header From Shutdown Cooling Heat Exchanger 2E-35B"

_ 2GCB-34-1, Sheet 1, Rev 2, "Small Pipe Isometric Containment Spray Pump 2P-35B Minimum Flow Line to 2FO-5627" 2GCB-35-1, Sheet 1, Rev 4, "Small Pipe Isometric Containment Spray Puap 2P-35A l

Minimum Flow Line to 2FO-5624"

Page 76 i

Calculation No. NSD-018 i

2HCB-13-1, Sheet 1, Rev 15,"Large Pipe Isometric From Containment Sump to g

Containment Spray Pump 2P-35B Inlet" 2HCB-13-1, Sheet 2, Rev N, "Large Pipe Isometric From Containment Sump to Containment Spray Pump 2P-35B Inlet" 2HCB 13 2, Sheet 1, Rev 4, "Large Pipe Isometric Containment Sump to Containment Spray Pump 2P-35B" 2HCB-15-1, Sheet 1, Rev 14, "Large Pipe Isometric From Containment Sump to Contaimnent Spray Pump 2P-35A" 2HCB-15-1, Sheet 2, Rev N, "Large Pipe Isometric From Containment Sump to Containment Spray Pump 2P-35A" 2HCB-15-2, Sheet 1, Rev 6, "Large Pipe Isometric From Containment Sump to Containment Spray Pumps" 2HCB-24-1, Sheet 1, Rev 5, "Large Pipe Isometric Refueling Water Tank 2T-3 to Containment Spray Pumps" 2HCB-24-2, Sheet 1, Rev 6, "Large Pipe Isometric Refueling Water Tank 2T-3 to Containment Spray Pumps" 2HCB-26-1, Sheet 1, Rev 15, "Large Pipe Isometric Containment Spray Pump 2P-35A Supply" 2HCB-27-1, Sheet 1, Rev 12,"Large Pipe Isometric Containment Spray Pump 2P-35B Supply From Control Valve 2CV-5631-2" 2HCB-27-1, Sheet 2, Rev 0, "Large Pipe Isometric Containment Spray Pump 2P-35B Supply From Control Valve 2CV-5631-2" 2HCB-20-1, Sheet 1, Rev 6, "Large Pipe Isometric Supply From Valve 2CV 5612-1 te h

Flued Head 2Pl7 2HCD-20-2, Sheet 1, Rev 4, "Large Pipe Isometric Building Spray Return From 2FI-5690 2HCD-21-1, Sheet 1, Rev 6, "Large Pipe Isometric Containment Spray From Valve 2CV-5613-2 to Containment Penetration 2P-23 2HCB-21-2, Sheet 1, Rev 5, "Large Pipe Isometric 2FI-5693 Return to Line 2HCB-21 2HCB-3-1, Sheet 1, Rev 16, "Large Pipe Isometric Containment Spray Header From Containment Penetration 2P-17 2HCB-3-1, Sheet 2, Rev 3, "Large Pipe Isometric Containment Spray Header From Containment Per.etration 2P-17 2HCB-3-1, Sheet 3, Rev 2, "Large Pipe Isometric Containment Spray Header From Containment Penetration 2P-17 2HCB-4-1, Sheet 1, Rev 8, "Large Pipe Isometric Containment Spray Header From Containment Penetration 2P-23 5, ANO-2 Plant Design Drawings:

M-2045, Rev 43 " AREA 24 Containment Auxiliary BLDG Plan EL 335 to 354" M-2038, Rev 37 " AREA 23 Containment Auxiliary BLDG Plan EL 354" M-2033, Rev 46 " AREA 23 Containment Auxiliary BLDG Plan EL 354 to 368" M-2044, Rev 31 " AREA 24 Containment AUX Building Plan EL 354 to 372" M-2070, Rev 12 " Condensate Storage tank & Reactor Makeup Tank Plan & Sections" M-2056, Rev 24 " AREA 25 Containment Building Plan EL 357 to 376-6" g

M-2055, Rev 27 " AREA 25 Containment Building Plan EL 376-6 to 40L6"

Page 77 Calculation No. NSD-018-

) (l M 2054, Rev 21 " AREA 25 Containment Building Plan EL 405-6 to 426-6" V

M-2040 SHT 4, Rev 13 " AREA 23 Turbine Auxiliary BLDG Section U23-U23" M 2040 SHT 3, Rev 13 " AREA 23 Turbine Auxiliary Building Section G23-G23" M-2040 SHT 5, Rev 13 " AREA 23 Turbine Auxiliary BLDG Miscellaneous Sections" M-2040 SHT 6, Rev 12 " AREA 23 Turbine Auxiliary BLDG Section E23 E23" M 2845, Rev 12 "Small Piping AREA 24 Containment Auxiliary BLDG Plan El 335 to 354" M-2838, Rev 11 "Small Piping AREA 23 Turbine Auxiliary BLDG Plan El 354"

6. ANO Fire Hazards Analysis, Rev 3, Controlled Set #16

7. ANO Unit 2 FSAR, Amendment 13, Portions of Sections 3.6.4, Chapter 10, and Chapter 15

'4

8. ANO Unit 2 System Training Manuals:

Steam Generators & Main Steam System, STM 2-15 Rev 3 i

Main Feedwater System, STM 2-19, Rev 2 Emergency Feedwater and Auxiliary Feedwater Systems, STM 2-19-2, Rev 1 Containment Spray System, STM 2-08, Rev 1

9. Design Configuration Documentation Project:

l ANO-2 Emergency Feedwater System, ULD-2-SYS-12, Revision 0 ANO-2 Feedwater and Steam Generator Blowdown Sysiems, ULD-2-SYS-13, Revision 0 ANO-2 Main Steam System ULD, ULD-2-SYS-21, Revision 0 i

ANO-2 Containment Spray System, ULD-2-SYS-05, Revision 0 1

10. ANO-2 Internal Flooding Study (ANO-2 Calculation No. 89-E-0048-35, Rev 0)

11. ANO-2 Control Room Indications and Annunciators i

Procedure 2203.012W, page 2 of14, Rev 11, Annunciator 2K15, A-1, AUX BLDG SUMP i

LEVEL HIGH.

Procedure 2203,012L, page 77 and 78 of 100, Rev 27, Annunciator 2K12, H-8, ESF ROOM (S) LEVEL HI.

Procedure 2203.012L, page 79 of 100, Rev 27, Annunciator 2K12, J-8, TURBINE BLDG SUMP STA 1 LEVEL HI.

Procedure 2203.012L, page 90 of 100, Rev 27, Annunciator 2K12, J-9, TURBINE BLDG 4'

SUMP STA 2 LEVEL HI.

Procedure 2203.012L, page 80 of 100, Rev 27, Annunciator 2K12, K-8, A/B SPRAY HDR LVL HI/LO.

i Procedure 2203.012L, page 89 of 100, Rev 27, Annunciator 2K12, H-9, EFWP ROOM (S)

LEVEL HI.

Procedure 2203.012L, page 90 of 100, Rev 27, Annunciator 2K12, J-9, TURBINE BLDG SUMP STA 2 LEVEL HI.'

4

' Procedure 2203.012F, page 62 of 64, Rev 26,- Annunciator 2K06, A-9, RWT LEVEL LO LO PRETRIP.

' Q Procedure 2203.012F, page 63 of 64, Rev 26, Annunciator 2K06, B-9, RWT LEVEL LO.

b

Page 78 Calculation No. NSD-018 Procedure 2203.012K, page 58 of 120, Rev 26, Annunciator 2K11, J-6, CST 2T41 A/B g

LEVEL LO.

Procedure 2203.012!, page 28 of 76, Rev 26, Annunciator 2K10, A-3, T41B LEVEL LO LO.

Procedure 2203.012J, page 29 of 76, Rev 26, Annunciator 2K10, B-3, T41B LEVEL LO.

Procedure 2203.012J, page 66 of 76, Rev 26, Annunciator 2K10, A-7, CNTMT TEMP / HUMIDITY Hl.

Procedure 2203.012J, page 67 of 76, Rev 26, Annunciator 2K10, B-7, CNTMT SUMP LEVEL HI.

Procedure 2203.012E, page 8 of 69, Rev 24, Annunciator 2K05, D-1, SPRAY HDR FLOW Hl.

Procedure 2203.012E, page 9 of 69, Rev 24, Annunciator 2K05, E-1, SPRAY HDR FLOW LO.

Procedure 2203.012F, page 8 of 64, Rev 26, Annunciator 2K06, D-1, SPRAY HDR FLOW Hl.

Procedure 2203.012F, page 9 of 64, Rev 26, Annunciator 2K06, E-1, SPRAY HDR FLOW LO.

Procedure 2203.012G, pages 54 of 59, Rev 20, Annunciator 2K07, E-9,2P7B SUCT PRESS HI/LO.

Procedure 2203.012G, pages 55 of 59, Rev 20, Annunciator 2K07, F-9,2P7B DISCH PRESS HI/LO.

Procedure 2203.012G, pages 56 of 59, Rev 20, Annunciator 2K07, G-9,2P7B TO A S/G FLOW HI/LO.

Procedure 2203.012G, pages 57 of 59, Rev 20, Annunciator 2K07, H-9,2P7B TO B S/G FLOW HI/LO.

Procedure 2203.012C, pages 83 of 137, Rev 19, Annunciator 2K03, C-9, PUMP SUCT PRESS LO.

12. ANO-2 Technical Specifications 3/4.7.1.2 Emergency Feedwater System (page 3/4 7-5, Amendment 136, and 7-6, Amendment 50) 3/4.6.2.1 Containment Spray System (page 3/4 6-7, Amendment 94)

13. North Atlantic Energy Services Corp. " Individual Plant Examination External Events" Report for Seabrook Station, Response to Generic Letter 88-20, Supplement 4, September 1992.

14. EPRI NP-6395-D, April 1989,"Probabilistic Seismic Hazard Evaluations at Nuclear Plant Sites in the Central and Eastern United States: Resolution of the Charleston Earthquake Issue" Prepared by Risk Engineering, Inc., Yankee Atomic Electric Company, and Woodward-Clyde Consultants.

15. NUREG-1488, " Revised Livermore Seismic Hazard Estimates for 69 Nuclear Power Plant Sites East of the Rocky Mountains" Final Report, April 1994.

h

i i

Page 79 Calculation No. NSD-018

16. Summary Report ofIndividual Plant Examination ofExternal Events (IPEEE) for Severe i

Accident Vulnerabilities for Arkansas Nuclear One, Unit 2, May 1996.

17. ANO-2 Calculation 96 E-0022-01,"ANO 2 Steam Generator Pressure Drop Due to an EFW Steam Supply Line Break," April,1996 i

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Calculation No. NSD.018 i

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Appendix A

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I Consequence Analysis Results f

l (Listed by System in Alphabetical Order) l 3

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PAGE C1

CALC, NO, NSD 018 13 Aug-97 FMECA Consequence Informatiot Report Consequence ID: CSS C01 Consequence

Description:

Degradation of Common RWT suedon outside auxiliary building during an independent demand (line 21lCD 24 outside)

Break Size Large Isolability of Break: No ISO Comments: Unisolable.

Spatial : 'fects: local Effected location: Outside Spatial Effects Comments: The common RWT suedon piping outside the auxiliary building (near the RWT) can not propagate to the auxillary building and impact safety equipment.

Initleting Event: N Initiating Ever.1ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping. This is conservative since pipe break during normal standby may be just as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

less of System: SM 3 System IPE ID:

CSS,llPSI, LPSI System Recovery: Joss of RWT(flow diversion) results in common cause failure of all ECCS.

14ss of Traln: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is *1Dgh' based on Table 2 2 (unexpected frequency of challenge, between test exposure, and no backup trains). No impact on containment isolation.

Consequence Category: 111G11 O

Consequence nank:

O i

l t

(

l l

l

\\

O 1

1

PAGE 80 CALC.

NO.

NSD 018 O

>> ^ e>

rusci ce Se2 e eer rer iie nener

~

Consequence ID: CSS C-02 Consequence

Description:

Degradadon of Common RWT suction upstream of 2CV.5630 & $6311n auxillary building during an independent demand (line 211CB 24 in auxillary building)

Break Size:

Large isolability of Break: No ISO Comments: Unisolable.

Spatial Effects: Propagadon Effected lacelion: Room 2040 Spatial ElTects Comments: 'Ihe common RWT suedon piping will likely fall MCC 2B52 in the corridor at El 335 (Room 2040) and propagate to El 317 (Rooms 2006 & 2011) through floor drains and the east stairway. Also, El 317 will fill up and propagate into the ECCS rooms (2007,2010, & 2014). Detecdon is provided by auxillary building sump high level alarm and the ECCS room flood slarms in the control room, but this is irrelevant since the break is unisolable.

Initiating Event: N Initiating Event ID: N/A Inndating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping. 'This is conservative since pipe break during normal standby may be just as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

lesso System: SM 3 System IPEID:

CSS, HPSI, LPSI r

System Recovery: Loss of RWT (flow diversion) results in common cause failure of all ECCS.

d less of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is High' based on Table 2 2 (unexpected frequency of challenge, between test exposme, and no btdup trains). No impact on containment isoladon.

Consequence Category: HIGil O

Consequence Rank:

O 1

0 2

PAGE B3 CALC.

NO.

NSD 018 13 Aug 97 FMECA Consequence Information Report h

Consequence ID: CSS-C 03A Consequence

Description:

Degradation of RWT suction A downstream of 2CW5630 in Room 2040 during an independeni demand (line 213CD 26 in Room 2040)

Ilreak Stre:

Large isolability ofIlreak Yes 150 Comments: 2C%56301 can te closed itom the control room. Detection is t'ased on auaillary building sump high level alarm and CSS low flow alarm if the break is large enough. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagadon 12fected lacation: Room 2040 Spatial Effects Comments: RWT suedon piping will likely fall MCC 2B52 in the corridor at El 335 (Room 2040) and propagate to El 317 (Rooms 2006 & 2011) through floor drains and the cast staltway. MCC 2B52 contains breakers for normally closed CSS valves 2CW

$6121 and 56491 (containment sump recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007,2010, & 2014) falling all ECCS, Detection is provided by auxillary building sump high level and ECCS toom flood alarms in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M)initiatur is assumed to challenge this piping. his is conservative since pipe break during normal standby may te just as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

Loss of System: SM 3 System IPE ID:

CSS,IIPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS either due to flow diversion or insufficient RWT inventory in the containment sump to support recirculation.

Loss of Traln: 'IM3 Train ID:

CSS A,ilPS! A.LPSI A Train Reconry: Tsolation :uccess leads to loss of ECCS train A.

Consequence Comment: Consequence is ' Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and 1 backup train. ECCS train D). ne failure to isolate case is a ' Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence nank:

O l

l 3

PAGE 9d CALC.

N0, NSD 018 O

>> ^ e>

r u c c i c e se2 e ee i rerf iie n eneri Consequence ID: CSS-C-0311 Consequence Decription: Degradation of R%T suction B downstream of 2C%5631 in Room 2040 during an independent demand (line 2HCB 27 in Room 2040)

Break Sleet Large Isolability of Break Yes ISO Comn nts: 2C%56312 can be closed from the contral room. Detection is based on auxillary building sump high level alann and CSS low flow alarm if the break is large enough. A low RWTlevel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected Location: Room 2040 Spatial Effects Comments: RWT suction piping will likely fall MCC 2B52 in the corridor at El 335 (Room 2040) and propagate to El 317 (Rooms 2006 & 2011) through floor drains and the east staltway, MCC 2B52 contains breakers for normally closed CSS valves 2C%

$6121 and $6491 (containment sump recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007,2010, & 2014) falling all ECCS, Detection is provided by auxiliary building sump high level and ECCS room flood alanns in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping. This is conservative since pipe break during normal s;andby may be just as likely (i.e.,

demand stress of RWT head is not significantly different during dernand).

O LossofSystem: SM 3 System IPE ID:

CSS, HPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS either due to flow diversion or insufficient RWT inventory in the containment sump to support recirculation. Isolation success also leads to loss of both CSS trains due to assumed impact on MCC 2B52 before isolation. Normally closed 2C%5612 1 can not fully open for train A success dae to flood impact on its breaker in

MCC2B52, Loss of Train: TM 2 Train ID:

HPSI B,ISSI B Train Recovery: Isolation success leads to loss of ECCS train B and both tralns of CSS as shown above.

Consequence Comment: Consequence is 'High" based on Table 2 2 (unexpected frequency o, challenge, between test exposure, and no backup train). No impact on containtnent isolation.

Consequence Category: HIGH O

Consequene. Rank:

O O

4

PAGE AT

CALC, NO.

NSD 018 13-Aug 97 FMECA - Consequence Information Report h

Consequence ID: CSS-C-OtA Consequence Desulption: Degradation of Suction A downtream of 2CV 5630 & 2CV 5649 in Room 2014 during an independent demand (lines 211CB 26 and 2ilCD 15 downstream of 2CV-5649 in Room 2014) fireak Stres Large Isolability of Break Yes ISO Comments: 2CV 56301 can be closed from the control room (break is assumed to cecur during RWT injection phase). Detection is based on Room 2014 flood alarm, aualliary building sump high level alarm, and CSS low flow alarm if the break is large enough. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected location: Room 2014 Spatial Effects Comments: RWT suction piping will likely flood ECCS train A in Room 2014 before isolation.

Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not flood Room 2007 (ECCS train B).

Ilowever, failure to isolate can be assumed to result in loss of sufficient R%T inventory to fall containment sump recirculation. Detection is provided by ECCS room flood and sualliary building sump high level alarms in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping. 'Ihis is conservative since pipe break during normal standby may be just as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

Loss of System: SM-3 System IPE ID:

CSS,IIPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS either due to flow diversion or insufficient R%T inventory la the containment sump to support recirculation.

Loss of Traln: TM 3 Train ID:

CSS A,llPSI A.LPSI A Train Recovery: Isolation success leads to loss of ECCS train A.

Consequence Comment: Consequerwe is ' Medium" based on Table 2 2 (unexpected frequency of ciudienge, between test exposure, and I backup train - ECCS train B). The failure to isolate case is a " Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM C

Consequence Rank:

O O

5

PAGE 1%

CALC, NO, NSD 018 O

> >.Au..,>

r u c c i. c e S 2... 1 rer m.iie. n ege<<

Consequence ID: CSS-C-04B Consequence

Description:

Degradation of Suedon B downstream of 2CW5631 & 2CV.5650 in Room 2007 during an independent demand (linec 2HCB 27 and 211CB 13 downstream of 2CW

$650in Roorn 2007)

Break Size Large Isolability of Break Yes ISO Comments: 2C%5631 2 can be closed from the control.oom (break is assumed to occur during RWT injection phase). Detecdon is based on Room 2007 flood alarm, auxiliary building sump high level alarm, and CSS low flow stann if the break is Ivge enough. A low RWT level alann will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected lecation: Room 2007 Spatial Effects Commentst RWT suction piping will likely flood ECCS trtJn B in Room 2007 before isolation.

Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not flood Room 2014 (ECCS train A).

Ilowever, failure to isolate can be assumed to result in loss of sufficient R%T inventory to fall containment sump recirculation. Detecdon is provided by ECCS room flood and aualliary building sump,high level alarms in the control room.

Initiating Event: N Init!aling Event ID: N/A Initiating Event Recovery: A medium LOCA (M) inidator !s assumed to challenge this piping. *Ihis is

/]

conservative since pipe break during normal standby may be just as likely (i.e.,

b demand stress of RWT head is not significandy different during demand).

Loss of System: SM 3 System IPE ID:

CSS, HPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS either due to flow diversion or insuffic!:nt R%T inventory in the containment sump to support recirculadon.

Loss of Train: TM 3 Train ID:

CSS B, HPSI B, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B.

Consequence Comment: Consequence is

• Medium" based on Table 2-2 (unexpecied frequency of challenge, between test exposure, and 1 backup train ECCS train A). 'Ihe failure to isolate case is a

• Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

0 t

O 6

PAGE 87

CALC, NO, NSD 018 13 Aug 97 FMECA Consequence Infortnation Report h

Consequence ID: CSS-C-05 Coasequence

Description:

Degradation of RWT suction 11 downstream of 2CV 5631 in Roorn 2006 during an indeperd.nt demand (line 211CD 27 in Room 2006)

Break Sizes Large Isolability of Break: Yes ISO Comments: 2C%5631 2 can be closed from the control room. Detection is based on auxiliary building sump high level alarm and CSS low flow alarm if the break is large enough. A low RWT ievel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation rffected Iecation: Room 2006 Spatial ' Effects Comments: Failure to isolate is assumed to propagate into ECCS Rooms 2007,2010, & 2014 through ventilation openings even if they do isolate automatically on an SI signal.

Also, failure to isolate can be assumed to result in loss of sufficient RWTinventory to fr.il containment sump recirculation. Detection is provided by auxiliary building sump high level alarm in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping. This is conservative since pipe break during normal standby may be just as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

Loss of System: SM 3 System IPE ID:

CSS. IIPSI, IJ'SI System Recovery: Isolation failure is assumed to fall all ECCS either due to flow diversion, flooding, or insufficient RWT inventory in the containment sump to support secirculation.

Loss of Train: TM 3 Train ID:

CSS D,IIPSI D, LPSI B Train Recovery: Isolation success leads to loss of ECCS train D.

Consequence Comment: Consequence is

• Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train. ECCS train A). *Ihe failure to isolate case is a " Medium" based on I backup train (isolation). No impact on containment isolation.

Ccnsequence Category: MEDIUM O

Consequence nank:

O O

7

PAGE BB LALC.

NO.

NSD 018 O

> > ^

r a c c ^ c e ea e e >=rer - tie = " ener*

Consequence ID: CSS-C-06A Consequence

Description:

Degradation of Containment sump suclion A upstream of 2CV.5649 during an independent demand (line 2}iCB.15 from containment sump to 2CV 5649)

Break Sizes Large Isolability of Break Yes ISO f'9mments: 2CV 5647 1 can be closed from the control roorn. Detection is based on Room 2014 flood alarm and containment sump level.

Spatial Effects: Propagation Effected lacation: Room 2014 Spatial Effects Comments: Containment sump suction piping will likely f.ood ECCS train A in Room 2014 before isolation. Fallure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings and draining the sump into the auxillary building.

Detection is provided by Room 2014 flood and auxiliary building sump high level alarms in the control room.

Initiating Event: N Inlllating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: SM 3 System IPE ID:

CSS. HPSI, LPSI System Recovery: Isolation failure case is assumed to lead to loss of containment sump (common cause failure of i

ECCS recirculation).

O Loss of Trata: TM 3 Train ID:

CSS A.HPSI A,LPSI A t

. \\ ] Train Recovery: Isole. ion success leads toloss of ECCS train A recirculation.

Consequence Comment: Consequence is

• Medium

• based on Table 2-2 (unexpected frequency of challenge, all year exposure, and I backup train. ECCS train B) 'Ihe failure to isolate case is a

• Medium

• based on 1 backup train (isolation). 'Ihe consequence is upgraded to *High*

because piping failure together with failure to isolate (2CV 5647 1, MOV failure to close) can result in cor.tainment bypass.

Consequence Category: HIGli O

Con.equence Rank:

O O

S

PAGE m

CALC, N O.

NSD 018 13 Aug 97 FMECA Consequence Information Report Consequence ID: CSS C 06D Consequence

Description:

Degradadon of Containment sump suction B upstream of 2CV 5650 during an independent demand (line 211CD 13 from containmeat sump to 2CV 5650)

Ilreak Stre:

Large Isolability of Break: Yes ISO Comments: 2CV 5648 2 can be closed from the control room. Detection is based on Room 2007 flood alarm and contalnment sump level.

Spatial Effcets: Propagadon Effected 14 cation: Room 2007 Spatial Effects Comments: Containment sump suction piping willlikely flood ECCS train B in Room 2007 before isolation. Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings and draining the sump into the auxiliary building.

Detecdon 15 provided by Room 2007 flood and auxiliary building sump high level alarms in the control room.

Initiating Event: N Initiating Event ID: N/A initiating Event Recovery: A medium LOCA (ht)inillator is assumed to challenge this piping.

less of System Shi3 System IPE ID:

CSS,llPSI, LPSI System Recovery: Isolation failure case is assumed to lead to loss of containment sump (common cause failure of ECCS recirculation).

Less of Train: Thi 3 TraloID:

CSS B,IIPSI D, LPSI B Train Recovery: 1 solation success leads to loss of ECCS train B recirculation.

{

Consequence Comment: Consequence is *htedium* basco on Table 2-2 (unexpected frequency of challenge, all year exposure, and I backup train. ECCS train A). The failure to isolate case is a

'hiedium" based on I backup train (isoladon).1he consequence is upgraded to *lligh" because piping failure together with failure to isolate (2CV 5648 2, h10V failure to close) can result in containment bypass.

Consequ nce Category: lilGil O

Consequence Rank:

O O

9

PAGE'10

CALC, NO, NSD 018 13 Aug 97 FMECA ConsequenceInformation Report Consequence ID: CSS C-07A Consequence

Description:

Degradation of Pump 2P35A discharge to heat exchanger 2E35A during an independent demand (line 20CB 10)

Break Size Large Isolabulty of Breakt Yes ISO Commentri Tripping the pump and closing suction MOV 2CV 5630 may be required to prevent gravity draining through pump 2P35A from the RWT (break is assumed to occur during RWT injection phase). Detection is based on Room 2014 flood alarm, auxilla.y building sump high level alarm, and CSS low flow alarm if the break is large enough. A low R%T level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected Location: Room 2014 4

Spatial Effects Comments: Flooding is assumed to affect train A ECCS in Room 2014 before isolation can occur, Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through vendladon openings, but the RWT can not flood 2007 (ECCS train B). However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fall

]

containtnent sump recirculadon. Detection is provided by ECCS room flood and auxiliary building sump high level alarms in the control room.

4 Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: SM 3 System IPE ID:

CSS, HPSI, LPSI System Recovery: Isoladon failure is assumed to fall all ECCS due to insufficient R%T inventory in the containment sump to support recirculation.

Loss of Train: TM 3 Train ID:

CSS A.HPSI A.LPSI A Train Recovery: Isoladon success leads to loss of ECCS train A due to flooding in the room before isolation.

Consequence Comment: Consequence is

• Medium" based on Table 2 2 (unexpected frequency of cha!!enge, between test exposure, and I backup train - ECCS train B). 'lhe failure to isolate case is a " Medium

• consequence based on I backup train (isoladon).

Consequence Category: MEDIUM O

Consequence Rank:

O O

10

PAGE %

C ALC.

NO.

NSD 016 13-Aug 97 FMECA Consequence Inforruation Report h

Consequence ID: CSS-C-07Il Consequence

Description:

Degradation of Pump 2F35Il discharge w heat exchanger 2E35D during an independent demand (line 2GCD l1)

Ilreak Sizes Large isotability of Dreaki Yes ISO Comments: Tripping the pump and closing suction MOV 2CV 5631 may be required to prevent gravity drairJng through pump 2P35D from the RWT (break is assumed to occur during R%T injection phase). Detection is based on Room 2007 flood alarm, aualliary building sump high level alarm, and CSS low flow alarm if the break is large enough. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected locaJon: Room 2007 Spatial Effects Comments: Flooding is assumed to affect train A ECCS in Room 2007 before isolation can occur. Failure to isols'e is assumed to prepagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not flood 2014 (ECCS train A). Ilowever, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fall containment sump recirculation. Detection is provided by ECCS room flood and auxiliary building sump high level alarms in the control room.

initiating Event: N Initiating Event ID: t4/A initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

less of System: SM 3 System IPE ID:

CSS, HPSI,1151 System Recovery: Isolation failure is assumed to fail all ECCS due to insufficient R%T inventory in containment sump to support recirculation.

Loss of Train: TM 3 Train ID:

CSS D, HPSI D LPS si Train Recovery: Isolation success leads to loss of ECCS train D due to flooding in the room before ist '. don.

Consequence Comment: Consequence is ' Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train ECCS train A). "The failure to isolate case is a " Medium" consequence based on I backup train (isolation).

Consequence Category: MEDIUM O

Consequence nanki O

O 11

PAGE CALC.

N O.

NSD 018 O

13 Aug 97 FMECA ConsequenceInformation Report Consequence ID: CSS-C 08A Consequence

Description:

Degradadon of Pump 2P35A mini flow in Room 2014 during an independent demand (line 2GCB 35 and line 2DCB ll upstream of 2CW5673 in Room 2014)

Break Size Large isolability of Break Yes ISO Comments: Trippio the pump and closing suction MOV 2CW5630 is not assumed necessary to allow successful injection of the RWT into the containment (this is only a 2 inch pipe). If needed, it is assumed this train would be operated and not isolated during the RWT injection phase. Also,

)

CSS could be isolated locally by closing 2BS 2A in Room 2014 which would allow operation of l

HPSI A and LPSI A without further leakage into the room. Detection is based on Room 2014 l

flood alarm and auxiliary building sump high level alarm.

Spatial Effects: Propagation Effected Location: Room 2014 Spatial Effects Commentst Flooding is assumed to affect train A ECCS in Room 2014 if not isolated. Another opportunity to recognize the need for isolation is assumed to occur during recirculation actuadon. Failure to isolate during the second opportunity by closing 2C%5647 or 2CW5649 (may be flooded) is assumed to fall the recirculation phase of inventory control and heat removal. Failure to holate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings. Detection is provided by ECCS toom flood and auxiliary building sump high level alarms in the control room.

Initleting Event: N Initlating Event ID: N/A h

Initlatlng Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

.w of System: SM 3 System IPE ID:

CSS, HPSI, LPSI 7..n Recovery: Isolation failure case (2 failures)is assumed to lead to loss of containment sump (common cause failure of ECCS recirculation).

Loss of Trala: TM 3 Train ID:

CSS A,llPSI A LPSI A Train Recovery: Isolation success leads to loss of only CSS train A. Failure to isolate before recirculation (I failure)is assumed to lead to failure of ECCS train A due to flooding in the room.

Consequence Comment: Consequence is ' Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and 1 backup trains CSS B in recirculation). The failure to isolate cases are hw" consequence based on 2 backup trains (isolation and ECCS B or 21solations).

Consequence Category: MEDIUM O

Coosequence aank:

O OG 12

PAGE %

CALC, NO, NSD 018 13 Aug 97 FMECI ConsequenceInformation Report hl Consequence ID: CSS-C-08B Consequence

Description:

Degradation of Pump 2P35B mini flow in Room 2007 during an independent demand (line 2GCB-34 and line 2DCD 13 upstream of 2CV 5672 in Room 2007)

Break Stre Large Isolability of Break Yes ISO Comments: Tripping the pump and closing suedon MOV 2C%5631 is not assumed necessary to allow succetsfulinjection of the RWTinto the containment (this is only a 2 inch pipe). If needed, it is assumed this train would be operated and not isolated during the RWTinjection phase. Also, CSS could be isolated locally by closing 2BS 2B in Room 2007 which would allow operation of IIPSI B and IJ'SI B without further leakage into the room. Detection is based on Room 2007 flood alarm and auaillary building sump high level alarin.

Spatial Effects: Propagadon Effected Location: Room 2007 Spatial Effects Comments: Flooding is assumed to affect train 11 ECCS in Room 2007 if not isolated. Another opportunity to recognize the need for isolation is assumed to occur during recirculation actuation. Failure to isolate during the second opportunity by closing 2CW5M8 or 2CW5650 (may be flooded) is assumed to fall the recirculation phase of inventory control and heat removal. Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings. Detection is provided by ECCS room flood and auxiliary building sump high level alarms in th control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

14ss of System: SM 3 System IPE ID:

CSS,!! PSI, LPSI l

System Recovery: Isolation failure case (2 failures)is assumed to lead to loss of containment sump (common I

cause failure of ECCS recirculation).

Loss of Train: TM 3 Train ID:

CSS B,IIPSI B, LPSI B I

Train Recovery: Isolation success leads to loss of only CSS train B. Failure to isolate before recirculation (I failure)is assumed to lead to failure of ECCS train B due to flooding in the room.

Conseqaence Comment: Consequence is " Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup trains CSS A in recirculathn), The failure to isolate cases are 'lew" consequence based on 2 backup trains (isolation and ECCS A or 2 isolations),

Consequence Category: MEDIUM O

Consequence Rank:

O O

13

PAGE 94 ut C.

N O.

NSD 018 O

13 Aug 97 FMECAIConseqiience Inforination Report Consequence ID: CSS-C-09A Consequence

Description:

Degradadon of Pump 2P35A discharge downsucam of heat enchanger 2E35A in Room 2014 during an independent demand (line 2GCD.16 in Room 20l4) lireak Size Large Isolability of fireak Yes ISO Comments: Tripping the pump and closing suction MOV 2CV 5630 may be required to prevent gravity draining through pump 2P35 A fem the RWT(break is assumed to occur during RWT injection phase). Detecdon is based on koom 2014 flood alarm, auxiliary building sump high level alarm, and CSS low now alarm it the break la large enough and upstrearn of flow eternent. A low R%T level alarm will also occur, t>ut it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effuted Location: Room 2014 Spatial Effects Comments: Flooding is assumed to affect train A ECCS in Room 2014 before isolation can occur, Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not nood 2007 (ECCS train B). However, failure to isolate can be assumed to result in loss of sufGelent RWT inventory to fall containment sump recirculation. Detection is provided by ECCS room Dood and auxillary building sump high level alarms in the control room.

Initiating Event: N Initiating Event ID: N/A initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

O Loss of System: SM 3 System IPEID:

CSS HPSI,LPSI V

Systen. Recovery: Isolation failure is assumed to fall all ECCS due to insuf0clent RWT inventory in the containment sump to support recirculation.

Imss of Train: TM 3 Train ID:

CSS A.HPSI A,LPSI A Train Recovery: 1 solation success leads to loss of ECCS train A due to fleoding in the room before isoladon.

Consequence Comment: Consequence is ' Medium' based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train - ECCS train B). The failure to isolate case is a ' Medium" consequence based on I backup train (isolation).

Consequence Category: MEDIUM O

Consequence Rank:

O 14

PAGE 96

.aLC.

NO, NSD 018 13 Aug 97 FMECA ConsequenceInformation Report h

Consequence ID: CSS-C 09D Consequence

Description:

Degradation of Pump 2P35B discharge downstream of heat exchanger 2E353 in Room 2007 during an independent demand (line 2GCB 17 in Room 2007)

Break Sl:4 Imge Isolability of Break: Yes ISO Comments: Tripping the pump and closing suction MOV 2CV.5631 rnay be required to prevent gravity i

draining through pump 2P3511 from the RWT (brt ak is assumed to occur duing RWT injecdon phase). Detecdon is based on Room 2007 flood alarm, auxiliary building sump high level alarm, and CSS low flow alarm if the break is large enough and upstream of flow element. A low RWT level alarm will also occur, but it could be associsted with the assumed LOCA condition.

Spatial Effects: Propagation Effected Location: Room 2007 Spatial Effects Comments: Flooding is assumed to affect train B ECCS in Room 2007 before isoladon can occur. Failure to holate is assumed to propass'e into Rooms 2006 & 2011 through vendlation openings, but the R%T can not flood 2014 (ECCS t'aln A). liowever, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fall containment sump recirculadon. Detection is provided by ECCS room flood and auxiliary building sump high level alanns in the control room.

Initladng Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M)inidator is assurrd to challenge this pip!ng, i

14ss of System: SM 3 System IPE ID:

CSS,IIPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient RWT inventory in the containtnent sump to support recirculadon.

Loss of Traln: TM 3 Train ID:

CSS B,!! PSI B LPSI B Train Recovery: Isolation success leads to loss of ECCS train B due to flooding in the room before isolation.

Consequence Comment: Consequence is ' Medium

• based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train ECCS train A). *Ihe failure to isolate case is a ' Medium" consequence based on 1 backup train (isolation).

Consequence Category: MEDIUM O

Conxquence Rank:

O O

15

PAGE %

CALC, NO, NSD 018 O

>> ^ - >

racci coa ea eace >Dror-iio neveri

=

Ceaseqwace ID: CSS-C.10A Consegwace

Description:

Degriuiadon of Pump 2P35A discharge test retum upstream of 2SI 5 A in Room 2014 during an independent demand (line 20CB.16 in Room 2014)

Break Sise Large Isolabuity of Break: Yes ISO Comuments: Tripping the pump and closing suction tiOV 2CV.5630 may be required to prevent gravity draining through pump 2P35A from the RWT (break is assumed to occur during RWT injection I hase). Detecdon is based on auxiliary building sump lugh level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed IDCA condklon.

Spatial Effects: Propagation Effected 14 cation: Room 2014 Spetlal Effects Comewats: Failure to Isolate is aswmed to propagate into Rooms 2006 & 2011 through vendlation openings even if they do isolate automatically on a SI signal. Also, failure to isolate can be assumed to result in loss of sumclent RWT inventory to fall containment sump recirculadon. Detection is provided by ECCS toom arut auxiliary

- building sump high level s' arm in the control room, initiath.g Event: N 1rlanating Event ID: N/A lattisting Event Recovery: A medium LOCA (M) inidator is assumed to chalte.nge this piping.

less ofSystem: SM 3 System IPEID:

CSS, HPSI, LPSI System Recovery: Isoladon failure is assumed to fail all ECCS due to insumclent RWTinventory in the containment semp to support recirculation.

Imss of Trala 'I43 TraleID:

CSS A,HPSI A,LPSI A Trale Recovery: Isolation success leads to loss of ECCS train A.

Conseqwace Comnws.t Consequence is ' Medium

• based on Table 2 2 (unexpected frequency o challenge, r

between test exposure, and I backup train ECCS train B). *Ilw failure to islate case is a

• Medium" consequence based on 1 backup train (isolation).

Consequence Category: MEDIUM O

Consequence Rank O

O 16

PAGE 97 CALC.

NO.

N S D-018 13 Aug 97 FMECA Consequence Information Reporf Consequence ID: CSS-C 10ll Consequence

Description:

Degradadon of Pump 2P35B discharge test return up,tream of 2SI 511 in Roorn 2007 during an independent demand (line 2GCit.17 in Room 2007) 11reak Sise Large Isolability of Ilreaki Yes ISO Comments: Tripping the pump and closing suction MOV 2CV 5631 may be required to prevent gravity draining through pum' T3511 from the R%T (break is assumed to occur during RWT injecdon phase). Detection is based on auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be assoelated with the assumed LOCA condidon.

Spatial Effects: Propagation Effected Locadon: Room 2007 Spatial Effetis Comments: Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings even if they do isolate automatically on a Si signal. Also, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fall containment sump recirculadon. Detection is provided by ECCS room and auxiliary building sump high level alarm in the control room.

Initiating Event: N Initlating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) Initiator is assumed to challenge this piping.

Imss rTSystem: SM 3 System IPE ID:

CSS,!! PSI, LPSI l

System Recovery: Isolation failure is assumed to fail all ECCS due to insufficient R%T inventory in the containment sump to support recirculation.

less of Train: TM 3 Train ID:

CSS B,llPS! II, LPSI B 1

Train Recovery: Isoladon success leads to loss of ECCS train B.

Consequence Comment: Consequence is ' Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train. ECCS train A). The failure to isolate case is a

• Medium" consequence based on I backup train (isolation).

Consequence Category: MEDIUM O

Cons,.quence Rank O

a 0

17

PAGE %

CALC, NO, NSD 016 O

>> ^ S e>

vueci ce seeue cei rep-iieaitenePi Consec,uenee ID: CSS C 11 A Consequence

Description:

Degradadon of Pump 2P35A discharge downstrearn oflie4t exchanger 2E35A in Room 20$5 during an lidependent demand (line 20CB.16 in Room 2055)

Break Stes:

Large Isolability of Break Yes ISO Commeats: Tripping the pump and closing suction MOV 2CV.5630 may be requised to prevent gravity dralning thro':gh pump 2P35A from the RWT (break is assumed to occur during R%Tltdection phase). Detecdon is based on auxiliary building sump high leul alarm. A low RWTlevel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected location: Room 2055 Spatla: Effects Comments: There are no impacts in Room 20$5, but propagation is into Room 2040 where MCC 21152 is located. Isolation failure is assumed to affect this MCC. Room 2040 propagates to El 317 (Rooms 2006 & 2011) through Door drains and the east staltway MCC 2B52 contains breakers for nonnally closed CSS valves 2CV 56121 and 56491 (containment sump recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007,2010, & 2014) falling all ECCS.

Detection is provided by auxiliary building sump high level and ECCS room flood alarms in the control room.

Initiating Event: N Initiating Esent ID: N/A O-Initiating Event Recovery: A medium LOCA (M)inidator is assumed to challenge this piping.

Loss of System: SM 3 System IPE ID:

CSS. HPSI, LPSI Syrtem Recovery: Isolation failure is assumed to fall all ECCS due to !nsufficient RWTinventory in the containment sump to support recirculation.

less of Train: TM 3 Train ID:

CSS A,IIPSI A,LPSI A Train Recovery: Isolation success leads to loss of ECCS train A.

Consequence Comment: Consequence is

• Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and 1 backup train. ECCS train B). The failure to isolate case is a

• Medium" based on 1 backup train lisolation). No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

O 18

P AG E (Y)

CALC, NO, NSD0%

$3 Aug 97 FMECA Consequence Infornation Report h

Consequence ID: CSS C 1ID Coruequence

Description:

Degradation of Pump 2P35B discharge downstream of heat exchanger 2E35B in Room 2055 during an inde,4nder? f.cmand (line 2GCB 17 in Room 2055) lireak Size Large Laolabutty of Break Yes ISO Comments: Tripping the pump and closing suedon MO" 2CW6631 may be required to prevent gravity draining through pump 2P35B from the RM : break is suumed to occur during RWT injection phase). Detecdon is based on auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condidon.

Spatial Effects: Propagation Effected Location: Room 2055 Spatial Effects Comments: nere are no impacts in Room 2055, but propagation is into Room 2040 where MCC 2B52 is located. Isolation failure is assumed to affect this MCC. Roem 2040 propagates to El 317 (Roorns 2006 & 201l) through floor drains and the east stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CW56121 and 56491 (containtnent sump recisculation A). If unisolated. El 317 will fill up and propagate into the ECCS rooms (2007,2010, a 2014) falling all ECCS.

Detection is provided by auxiliary building sump high tevel and ECCS toom flood alarms in the control room.

Initiating Event: N Initiattug Event ID: N/A Initiating Event Recovery: A medium LOCA (M)inidatoris assumed to challenge this piping.

Loss of System: SM 3 System IPElu:

CSS,itPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient PWTinventory in the containment sump to support recirculadon. Isolation success cousu lead to loss of both CSS trains due to impact on MCC 2B52 before isolation, but containment cooling provides a backup train.

Loss of Train TM 3 Train ID:

CSS B,llPSI B, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B and potentially both trains of CSS as described above, but containment cooling backs up CSS.

Coracquence Comment: Consequence is " Medium" based on Table 2 2 (unexpected f;auency ot challenge, between test exposure, and I backup train), he failure to isolate case is a

• Medium" based on 1 backup traln (isolation). No impact on containraent isolation.

Consequence Category: MEDIUM O

Consequence Rank O

O 19

P AGE ico C ALC, NO, NSD 018 e

! O a^

v u n c i c e sea e ee iDrct - ae > n eneri Consequence ID: CSS.C 12A Consequence

Description:

Degradation of Pump 2P35A discharge upstream of 2CVd612 in Room 2084 during an independent dernead (l'ne 2GCD 16 in Rooni 2084)

Break Slae Large Isolatility of Break: Yes 150 Comments: Tripping the pump and closing suction MOV 2CV.5630 may be required to prevent gravity draining through pump 2P35A from the R%T (break is assumed to occur durirg R%T injection phase). Detecdon is based on auxiliary building sump high level alarm. A low R%Tlevel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagadon Effected Location: Room 2084 Spatial Effects Comments: In Room 2084, the potential exists for spray impacts on HPSI and LPSI discharge valves, it is assumed there is sufficient separadon between trains as with the CSS valves in this room. Propagation is into Room 2073 (EL 354) where MCC 2B62 is located, but flooding of the MCC is judged unlikely. From Room 2073 propagadon condrues easily to El 335 (Room 2040) through floor grating and the east stairway.

Propagation into Room 2040 where MCC 2B52 is located in the corridor. Isolation failure is assumed to affect this MCC. Room 2040 propagates to El 317 (Rooms 2006 & 2011) through floor drains and east staltway. MCC 2B52 contains breakers for normally closed CSS valves 2CV.56121 and 56491 (enatainment sump secuculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CV.

q 5613 2 and $6501 (containment sump recirculadon B). If unisolated, El 317 will

,g fill up and propagste into the ECCS rooms (2007,2010, & 2014) falling all ECCS, Detection is provided by auxiliary building sump high level and ECCS room flood alarme in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: SM 3 System IPE ID:

CSS HPSI,LPS!

System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient RWT inventory in the containment sump to support recirculadon.

Loss of Train: TM 3 Train ID:

CSS A HPSI A,LPSI A Train Recovery: Isolation success leads to loss of ECCS train A.

Consequence Comment: Consequence is " Medium

• based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train). '!he failure to isolate case is a ' Medium

• based on 1 backup train (isolation). No impact en containment isolation.

Consequen e Category: MEDIUM O

Consequence nank:

O O

PAGE 101

CALC, NO, NSD 018 13 Aug 97 FMECA - Consequence Information Report h

Consequence ID: CSS-C 1211 Consequence

Description:

Degradation of Pump 2P35D discharge upstream of 2CV-5613 in Room 2084 during an independent demand (line 2GCB 17 in Room 2084)

Break Fizes Large Isolability of Break: Yes ISO Comments: Tripping the pump and closing suction MOV 2CV 5631 may be required to prevent gravity draining through pump 2P3511 from the RWT (break is assumed to occur during R%T injection phase). Detection is based on auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effec'.ed Iecation: Room 2084 Spatial Effcets Comments: In Room 2084, the potential exists for spray impacts on HPSI and LPSI discharge valves. It is assumed there is sufficient separation between trains as with the CSS valves in this room. Propagation is into Room 2073 (EL 354) where MCC 2B62 is located, but flooding of the MCC is judged unlikely. From Room 2073 propagation continues easily to El 335 (Room 2040) through floor graung and the east stal way.

Propagation into Room 2040 where MCC 2D52 is located in the corridor. Isolation falle la assumed to affect this MCC. Room 2040 propagates to El 317 (Rooms j

2006 & 201I) through floor drains and cast stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV 56121 and 56491 (containment sump recirculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CV-5613 2 and 56501 (containment sump recirculation B). If unisolated, El 317 will 3

fill up and propagate into the ECCS rooms (2007,2010, & 2014) falling all ECCS.

t Detection is provided by auxiliary building sump high level and ECCS room flood alarms in 'he control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System SM 3 System IPE ID:

CSS, HPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient RWTinventory in the containment sump to support recirculation.

less of Traln: TM 3 Trsin ID:

CSS B. HPSI D, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B.

Consequence Comment: Consequence is " Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and 1 backup train). The failure to isolate case is a ' Medium" based ou 1 backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence nank:

O O

21

P AGE 10R.

CALC.

NO. NbMb 13 Aug 97 FMECA ConSequenceInformation Report Consequence ID: CSS C 13A Consequence

Description:

Degradation of Pump 2P35A discharge downstrearn of 2CW5612 in Roorn 2084 during an independent demand (line 2HCB 20)

Break Sleet Large Isotahllity of Break: Yes ISO Comments: Trip pump 2P35A or close MOV 2C%$612 (break is assumed to occur during R%T Injection l

phase). Detection is based on auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effecta: Propagation Effected location: Room 2084 Spatial Effecta Comments: In Room 2084, the potential exists for spray impacts on HPSI and LPSI discharge valves. it is assumed there is sufficient separation between trains as with the CSS valves in this room. Propagation is into Room 2073 (EL 354) where MCC 2B62 is located, but flooding of the MCC is judged unlikely. From Room 2073 propagation continues easily to El 335 (Rcom 2040) throut.h floot grating and the east stalrway.

Propagation into Room 2040 where MCC 2B52 is located in the corridor, Isolation failure is assurr.ed to affect this MCC. Room 2040 propagates to El 317 (Rooms 2006 & 2011) through floor draln. and east staltway. MCC 2B52 conta8ns breakers for normally closed CSS valves 2C%56121 and 56491 (containment sump recirculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CW

$613 2 and $6501 (containment sump recirculation B). If unisolated, El 317 will O

fill up and propagate into the ECCS :uoms (2007,2010, & 2014) falling all ECCS.

Detection is provided by auxilbry building sump high level and ECCS room flood alarms in the control room.

Initiating Event: N Initiating Event ID: N/A initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: SM 3 System IPE ID:

CSS,liPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient RWTinventory in the containment sump to support recirculation.

less of Traln: TM 1 Train ID:

CSS A Train Recovery: Isolation success leads to loss of CCS train A, but containment coo!ir.g provides backup.

Consequence Comment: Consequence is 'Medlum" based on Table 2 2 (unexpected frequency of challenge, all year exposure, and I backup train for failure to isolate). The successful isolation case is a " law' ccuscquence with two backup trains counting containment cooling. 2BS 5A provides containment isolation inside containment.

Consequence Category: MEDIUM O

Consequence nank:

D O

n

PAGE 163

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report g

Consequence ID: CSS-C 13B Consequence Descripdon: Degradadon of Pump 2P3511 discharge downstream of 2CV 5613 in Room 2084 during an independent demand (line 211CD-21) lireak Site Large Isolabulty of Break Yes ISO Comments: Trip pump 2P35B or close MOV 2CV.5613 (break is assumed to occur during RWT injection phase). Detecdon is based on auxiliary building sump high level alarm. A low R%T level alarm will also occur, but it could be associated with the assumed thCA condidon.

Spalla! Effects: Propagation Effected Location: Room 2084 Spatial Effects Comments: In Room 2084, the potential exists for spray impacts on liPSI and LPSI discharge valves, it is assumed there is sufficient separation between trains as with the CSS valves in this room. Propagadon is into Room 2073 (EL 354) where MCC 2B62 is located, but flooding of the MCC is judged unlikely. From Room 2073 propagation condnues easily to El 335 (Room 2040) through floor graung and the east stairway.

Propagadon into Room 2040 where MCC 2B52 is located in the corridar. Isoladon failure la assumed to affect this MCC. Room 2040 propagates to El 317 (Rooms 2006 & 2011) through floor drains and east. stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV.5612-1 and 56491 (containment sump recirculation A). MCC 2B62 contams breakers for normally closed CSS valves 2CV.

5613 2 and 56501 (containment sump recirculation B). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007,2010, & 2014) falling all ECCS.

Detection is provided by auxiliary building sump high level and ECCS room flood alarms in the control room.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recotery: A medium LOCA (M)lcitiatv is assumed to challenge this piping.

Loss of System: SM 3 System IPEID:

CSS,IIPSI, LPSI System Recovery: Isolation failure is assumed to fall all ECCS due to insufficient R%T inventory in the containment sump to support recirculation.

Loss of Train: TM 1 Traln ID:

CSS B Train Recovery: Isolation success leads to loss of CCS train B, but containment cooling provides backup.

Consequence Comment: Consequence is

• Medium" based on Table 2 2 (unexpected frequency of challer:ge, all year exposure, and I backup train for failure to isolate). *Ihe successful isolation case is a

• low

• consequence with two backup trains counting containment cooling. 2BS 5B provides containment isolation inside containment.

Consequence Category: MEDIUM O

Consequence Rank:

O O

23

1 PAGE104 CALC.

NO.

NS0 018 13 Aug 97 I'MECA Consequence Information Report l

Conwqoence ID: CSS-C 14A Consequence

Description:

Degradation of Pump 2P35A discharge downstream of 2C%5612 inside Containment during an independent demand (line 2HCB 3 upstreans of 2BS 5A) lireak Size Large Isolability of Break Yes ISO Comments: Trip puinp 2P35A or close MOV 2CW5612, but this is not necessary to prevent additional impacts since the R%T is being pumped to the containment (ths pipe break affects spray effectiveneas, but not the heat removal fuction). Not easy to detect except containment pressure may not reduced as fast as expected and trmin B is still avallat,le.

Spallat Effects: Containment Effected Location: Containment Building Spatial Effects Comments: Equipment inside containment is qualified for this event.

-Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M)IrJtlator la assumed to challenge this piping.

Loss of System: N System IPEID:

N/A System Recovery: N/A Loss ot' Train: N Train ID:

N/A Train Recovery: Loss of CSS train A occurs only if the train is isolated by the operators. 'Ihe train is still O

onsequence Comment: Consequence is Low" based on Table 2 2 (unexpected frequency of challenge, all year capable of performing its constainment heat ternoval function.

C exposure, and 2 backup trains. CSS A & B and ECCS A & B). 2C%5612 and closed system outside provide containment isolation.

Consequence Category: Low O

Consequence nanki O

O 24 I

o

PAGE lO5 C ALC.

NO.

NSD 018 13 Aug.97 FMECA - Consequence Information Report h

Consequence ID: CSS-C 14D Consequence

Description:

Degradation of Pump 2p35D discharge downstrearn of 2CV 5613 inside Containment during an independent demand (line 211CB-4 upstream of 2BS 5D)

Break Size Large Isolability of Break: Yes ISO Comments: Trip pump 2p35D or close MOV 2CV 5613, but this is not necessary to prevent additional Impacts since the RWTis being pumped to the containment (the pipe break affects spray effectivenus, but not the heat ternoval fuction). Not easy to detect except containment pressure i

may not reduced as fast as expected and train A is still available.

Spatial Effects: Containment Effected Location: Containtnent Building Spatial Effects CommeMs: Equipment inside containment is qualified for this event.

Initiating Event: N Initiating EventID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: N System IPE ID N/A System Recovery: N/A less of Traln: N Train ID:

N/A Train Recovery: less of CSS train B occurs only if the train is isolated by the operators. The train is still capable of performing its constainment heat removal function.

Consequence Comment: Consequence is ' low" based on Table 2 2 (unexpected frequency of challenge, all year exposure, and 2 backup trains - CSS A & B and ECCS A & B) 2CV 5613 and closed system outside provide containment isolation.

Consequence Category: Low O

Consequence nank:

O O

25

PAGE 106 C ALC.

NO.

NSD*018

O

.AuS,'

rusci co SeoRe c.1 rer-iioR ae, ort Consequesne ID: CSS C 15A Consequence

Description:

Degradation of NAOH !1ne to Train A (line 20BC.70) during an independent l

demand Break Slee Large laolability of Break Yes 1

ISO Comuments: Tripping the pump and closing suction MOV 2CV.5630 may be required to prevent gravity draining through pump 2P3$A from the RWT (break is assumed to occur during RWT injection phase). Detect'en is based on Room 2014 flood alarm and auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected i.ocation: Room 2014 Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding of ECCS train A in Room 2014 is assumed only ifisolation falls. Also, flow diversion impacts are not assumed.

Failure to isolate is not assumed to propagate imo Rooms 2006 & 2011 during injection phase due to break slie. Detection is provided by ECCS room flood and auxiliary building sump high level alarms in the control room. Loss of train A must be assumed during the recirculation phase due to isolation, otherwise, the containment sump would be empded into the ECCS room.

Initiatlag Event: N laitiating Event ID: N/A taltiatlag Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

i l

Loss of System: N Systeam IPEID:

N/A Systeen Recovery: Less of all ECCS during recirculation phase is possible if the containment sump was pumped to the auxillery building. *Ihis is judged to be equivalent to 2 isolation failures (2 bokup trains),

less of Trala: TM 3 Train ID:

CSS A, HPSI A, LPSI A Train Recovery: Isolation of ECCS train during recirculation is required. No credit is allowed for local isolation of CSS, thus, allowing recovery of HPSI and LPSI.

I Consequence Comment: Consequence is ' Medium" based on Table 2 2 (unexpected frequency of challenge, between test exposure, and I backup train. ECCS B), Containnwnt isolation is unaffected.

Consequence Category: MEDIUM O

Co equene. Rank:

O O

1 26 F

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-w

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---m--,

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PAGE

\\Cri C A!. C.

NO.

NSD 018 13.Aug 97 FMECA Consequence Information Report h

ConsequenceID: CSS-C 15B Consequence Descripdon: Degradadon of NAOli line to Train B (line 2GBC 69) during an independent demand Break Stre:

Large Isolability of Break Yes ISO Comments: Tripping the pump and closing suedon MOV 2CV 5631 may be required to prevent gravity draining through pump 2P35B from the R%T (breal. is assumed to occur during RwT injection phase). Detecdon is based on Room 2007 flood alarm and auxiliary bellding sump high level alarm. A low RWT level rJarm will also occur, but it could be associated with the assumed LOCA condidon.

Spatial Effects: Propagadon Effected location: Room 2007 Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding of ECCS train B in Room 2007 is assumed only if isolation falls. Also, flow diversion impacts are not assurned.

Fallure to isolate is not assumed to propagate into Rooms 2006 & 2011 during injecdon phase due to break size. Detecdon is provided by ECCS toom flood and auxillary building sump high level alarms in the control room. imss of train B must be assumed during the recirculation phase due to isolation, otherwise, the containment sump would be emptied into the ECCS room.

Initiating Event: N Initiating Etent ID: N/A Initiating Event Recovery: A medium LOCA (M)inidator is assumed to challenge this piping.

Loss of System: N System IPE ID:

N/A System Recovery: lass of all ECCS during recirculation phase is possible if the containment sump was pumped to the auxiliary building. This is judged to be equivalent to 2 isolation failures (2 backup trains).

Loss of Traln: TM 3 Train ID:

CSS B, HPSI B, LPSI B Train Recovery: Isoladon of ECCS train during recirculadon is required. No credit is allowed for local isolation of CSS, thus, allowing recovery of l{ PSI and LPSI.

Consequence Comment: Consequence is

• Medium" based on Table 2 2 (unexpected frecuency of challenge, between test exposure, and I backup train - ECCS A). Conta'm. ant isolation is unaffected.

Consequence Category: MEDIUM O

Consequence aank:

O O

27 l

l

PAGE 106 C ALC.

NO.

NSD 018 O !> ^ 97 aisc^ - co eeuec ce r rormotie nenert Corri oiwnee ID: CSS-C-16 Consequet ce

Description:

Degradation of RWT suction to SFPP and cht.rging (line 2HBC-7) during an independen: demed Break Size:

large Isolability of Break: No ISO Coraments: Unisolable, Spatial E;Tects: Propagation Effected IAcatioe: Outside Spatial Eftwis Comments: This piping is located both outside near the RWT and in Room 2040. Propagation from Room 2040 is down to El 317 (Rooms 2006 & 2011) through floor drains and east stairway, Detection is provided by auxili.ry building sump high level alarm, but thir is irrelevant since the break is unisolable. 'Ihis line is judged to small (3 inch i

diameter) to divert enough of the RWT to cause flow divenion or loss of ECCS.

Initiating Event: N Initiating Event ID: N/A Initiatinr, Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: N System IPE ID:

N/A System Recovery: Pipe blze is assumed to staall to cause flow diversion or lost of ECCS, Loss of Train: N Train ID:

N/A Tralr. Recovery: N/A Consequence Comment: Consequence is *Iow" based on Table 2-2 (unexpected frequency of challenge, all year exposure, and 2 backup trains - CSS A & B and ECCS A & B). Containment isolation is unaffected.

Consequence Category: LOW D

Consequence Rank:

D 28

P AGE \\ 09 C ALC, NO-N 13 Aug 97 FMECA - Conseygence Information Report Consequence ID: CSS-C-17A Consequence

Description:

Degradation of service air connection to Train A (line 211CB-93) during an independent demand Break Size:

Large Isolability of Break: Yes ISO Comments: Trip pump 2P35A or close MOV 2CV 5612 (break is a.ssumed to occur during RWT injection phase). Detection is based on auxiliary building sump high level alarm. A low RWTlevel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected Location: Room 2084 mg Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding ofimpact is not assumed. Also, T

flow disersion impacts are not assumed. Detection is provided by auxiliary building suhip high level alarms in the control room. Loss of train CSS A must be assumed during the recirculation phase due to isolation, otherwise, the containment sump

{

would be emptied into the auxiliary building.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: N System IPE ID:

1VA System Recovery: Loss of all ECCS during recirculation phace is possible if the containment sump was putaped to the auxiliary building. This is judged to be equivalent to 2 isolation failures (2 backup trains).

Loss of Train: T Train ID:

CSS A Train Recov". y: Isolation of CSS train during recirculation is required (2CV-5612). This allows HPSI A &

LPSI A success. Also, containment cooling system can replace CSS A.

Consequence Comment: Conscquence is bw" based on Table 2 2 (unexpected frequency of challenge, all year exposure, and 2 backup trains; HPSI, LPSI, CSS.B. and containment cooling). 2BS-5A provides containment isolation inside containment Consequutce Category: low O

Consequence Rank:

O O

29

PAGE \\l0 C ALC, NO.

NSD 018 O

> > ^ *>

racc^ - co se9 e ee r rer-etiea nevert Consequence ID: CSS-C 17B Consequence

Description:

Der.adation of service air connection to Train B (line 2HCB-94) during an INependent demand Break Size:

Large Isolability of Break: Yes 150 Commentr: Trip pump 2P35B or close MOV 2CV 5613 (break k assumed to occur during RWT injection phase). Detection is based on auxiliary building sump high level alarm. A low RWT level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propsgation Effected Location: Room 2084 Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding of impact is not assumed. Also, flow diversion impacts are not assumed. Detection is provided by auxiliary building sump high level alarms in the contro'. room. less of train CSS B must be assumed during the recirculatioa phase due to isolation, otherwise, the cantainment sump would be emptied into the auxiliary building.

Initiating Event: N Initiating Event ID: N/A Init8ating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

1ess of System: N System IFE ID N/A System Recovery: Loss of sh ECCS during recirculation phase is possibie if the containment sump was pumped to the auxiliary building. This is judged to be equivalent to 2 isolation failures (2 backup lpQ trains).

Loss of Traln: T Train ID:

CSS B Train Recovery: Isolation of CSS train during rt. circulation is required (2CV 5613). This allows HPSI B &

LPSI B success. Also, containment cooling system can replace CSS B.

Consequence Ccmment: Consequence is " Low" based on Table 2-2 (unexpected frequency of challenge, W year exposure, and 2 backup trains; HPSI, LPSI, CCS A, and containment cooling). 2BS 5B provides containment isolation inside containment.

Consequence Category: LOW C

Consequence Rank:

O OV so

PAGE Ill

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report h

Consequence ID: EFW-C-01 A Consequence

Description:

Degradation of EFW flow to steam generator 2E-24A inside containment d. iring an independent demand (line 2DDB 3 between containment penetration and check valve 2EFW 9A)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CW10251 or 1038 2 ar d 2CV-1026 2 or 10371 can be closed by the operator to prevent dumping part of the CST into containment. Detection is based on flow indication from EFW i

pumps, with a continued lowering of steam generator level (i.e., faulted steam generator). Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm). Eventually, containment sump level would provide indication of lost steam generator inventory due to EFW water not reaching the steam generator.

Spatial Effects: Containment Effected Location: Containment Building Spatial Effects Comments: None. Equipment located within the containment is qualified.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from steam generator by 2EFW 9A. A loss of PCS (T2) initiator is assumed to challenge this piping.

Loss of System: SDM 2 System IPE ID:

PCS, EFW System Recovery: PCS loss is as;umed to be the initiator. Pipe degradation causes loss of EFW flow to steam generator "A*. Isolation failure is assumed to cause flow diversion frorn both EFW trains.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Low" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,3 backup train;- EFW, AFW, and once through cooling). For the isolation failure case, the consequence is "hhilum" with 2 backup trains (isolation failure and once through cooling). 2EFW 7A & 7B provide containment isolation outside the containment building, thus, the consequence remains unchanged.

Consequence Category: MEDIUM O

Consequence Rank:

C O

31

P A G E l ic'L CALC.

NO.

N 3 y-01b

- 13 Aug-97 FMECA - Consequence Information Report Consequence ID: EFW.C 01B Consequence

Description:

Degradation of EFW ibw to steam generator 2E-24B inside containment during an independent demand (line 2DBB 4 between containment penetration and check valve 2EFW 9B)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV 10751 or 1036 2 and 2CV-1076-2 or 10391 can be closed by the operator to prevent dumping part of the CSTinto containment. Detection is based on flow indication from EFW pumps, with a continu-d lowering of steam generator level (i.e., faulted steam generator). Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm). Eventually, containment sump level would provide indication of lost steam generator inventory due to EFW water not reaching the steam generator.

Spalla! Effects: Containment ENected Location: Containment Building SpaPal Effects Comments: None. Equipment located within the containment is qualified.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal oper:'.tlon is unlikely since this piping is isolated from steam generator by 2EFW 9B, A loss of PCS (T2) initiator is assumed to challenge this piping.

LossofSystem: SDM-2 System IPEID:

PCS, EFW System Recovery: PCS loss is assumed 'o be the initiator. Fpe degradation causes loss of EFW flow to steam enerator "B", Isolation failure is assumed to cause flow diversion from both EFW trains.

Loss of Trala: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Low" based on Table 2-2 (anticipated frequency of challenge, t.etween test exposurr. time,3 backup trains - EFW, A9P/, and once through cooling). For the isolation failure case, the consequence is " Medium" with 2 backup trains (isolation failure and once through cooling). 2EFW-8A & 8B provide containment isolation outside the containment building, thus, the consequence remains unchanged.

Consequence Category: MEDIUM O

Consequence Rank:

O m

PAGE \\O GALC.

NO.

NSD 018 13 Aug-97 FMECA - Consequence Information Report h

Consequense ID: EFW-C-02A Consequence

Description:

Degradation of EFW flow to steam generator 2E-24 A outside containment d~

e.a independent demand (line 2DBB 3 downstream of check valves 2EFW 7,. d)

Break Size:

Large Isolablity of Break: Yes ISO Comments: 2C%l0251 or 1038-2 and 2C%l026-2 or 10371 can be closed by the operator. Detection is based on flow indication from EFW pumps, with a continued lowering of steam generator level (i.e., faulted steam generator). Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm). Also, propagation to auxiliary building sump and its high level alarm provides further detection capability.

Spatial E.Tects: Propagation Effected location: Room 2084 Spatial Effects Comments: Propagation through a door is into Room 2073 and then through floor grating to elevation 335 (Room 2M0). Also, the east stairway and elevator shaft provide propagation paths, here are floor drains in Rooms 2084,2073, and 2NO. Because of the case of drainage from Room 2073, n, impacts are assumed. It is assumed that sufficient water can not accumulate in Room 2084 to fail all ECCS supply valves.

From Room 2040, pmpagation is into the east stairway (door) and down to El 317

-(Rooms 2006 and 2011). %e auxiliary building sump at El 317 has a high level a! ann in the control room. it is assumed for the unisolated case, that enough water accum;lates at El 335 (Room 2NO) to fail MCC 2B52. EFW at El 335 (Rooms 2024

& 2025) and ECCS at El 317 (Rooms 2007, 2010 & 2014) are protected by watertight doors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Fai:ure to isolate and then failure again to isolate after ElT! transfer to service water is considered unlikely, Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during ns mal operation is unlikely since this piping is isolated '. rom the steam generstor by 2EFN 9A. A loss of PCS (T2)initiater is assumed to challenge this piping.

Loss of System: SDM-5 System IPEID:

PCS, EFW, CSS, HPSI, IPSI System Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW flow to steam generator "A". Isolation failure is assumed to cause flow diversion from both EFW trains and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Ims of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is "Iow" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is

• Medium" with 2 backup trains (isolation failure and train B of once through cooling supply valves). 2EFW-9A provides automatic containtnent isolation inside the containment building, thus, the consequence remains unchanged.

Consequence Category: MEDIUM O

Ccasequence aank:

O g

33 l

3 PAGE le

CALC, NO, N SD-018 O

i3 Aug-97 FMEcA - consequence Inrormation Report Consequence ID: EFW-C-02B 1

l-Consequence

Description:

Degradadon of EFW flow to steam pnerator 2E-24B outside containment during an independent demand (line 2DBB-4 downstream of check valves 2EN-8A & B)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV-1075-1 or 1036-2 and 2CV 1076 2 or 1039 1 can be closed 1 y the operator. Detection is based on flow indication from EFW pumps, with a continued loweing of steam generator level (i.e., fauhed steam generator). Each of the 4 EFW discharge linu has flow indication and acnunciation (>325 or 400 gpm and <240 gpm). Also, propagation to auxiliary building sump and its high level alarm provides funher detection capability.

Spatial Effects: Propagation Effected Location: Room 2081 Spatial Effects Comments: Propagation through a door is into Room 2040 and th.:n into the east stairway (door) and down to El 317 (Rooms 2006 and 201l). There are floor drains in Rooms 2081 and 2040. The auxiliary building sump at El 317 has a high 1: vel alarm in the control room. It is assumed for the unisolated case, that enough water accumulates at El 335 (2040) to fail MCC 2B52. There are no flooding impacts in Room 2081.

EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 &

2014) are protected by watertight doors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

[

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam pnerator by 2EFW-9B. A loss o' PCS (T2) initiator is assumed to challenge this piping.

LossofSystem: SDM 5 System IPEID:

PCS, EFW, CSS, HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator, Pipe degradation causes loss of EFW flow to steam generator "B". Isolation failure is assumed to cause flow diversion from both EFW trains and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is "Imw" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is " Medium" with 2 backup trains (isolation failure and train B of once through cooling supply valves). 2EFW 9B provides automatic containtnent isolation inside the containment building, thus, the consequence remains unchanged.

Conrequence Category: MEDIUM O

Consequence Rank:

O 10.

U 34 m

PAGE i16

CALC, NO.

N S D 018 13-Aug-97 FMECA - Consequence Information Report Consequence ID: EFW-C-03A Consequence

Description:

Degradation of EFW Pump 2P7A flow to steam generator 2E-24A during an independent demand (line 2DBB-3 between 2CW10371 and check valve 2EFW-7A)

Break Size:

Large Isolability of Break: Yes ISO Comm mts: 2CW1026-2 or 1037-1 can be closed by the operator. Propagation to auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow indication from EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm).

Spatial Efftets: Propagation Effected Location: Room 2084 Spatial Effects Comments: Propagation through a door is into Room 2073 and then through floor grating to elevation 335 (Room 2N0). Also, the east stairway and elevator shaft provide propagation paths. nere are floor drains in Rooms 2084, 2073, and 2NO. Because of the case of drainage from Room 2073, no impacts are assumed. It is assumed that wfficient water can not accumulate in Room 2084 to fail all ECCS supply valves.

From Room 2040, propagation is into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). De auxiliary building sump at El 317 has a high level alarm in the control room. It is assumed for the unisolated case, that ervough water i

accumulates at El 335 (Room 2040) to fail MCC 2B52. EFW at El 335 (Rooms 2024

& 2025) and ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors, Emptying the whole CST to El 317 will not flood t!e ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during nonnal operation is unlikely sinu this piping is isolated from the steam generator by 2 check valves. A loss of PCS (T2) initiator is assumed to challenge this piping.

Locs of System: SDM-5 System IPE ID:

PCS, EFW, CSS, HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7A flow to steam generator "A", Isolation failure is assumed to cause flow diversion from EFW pump 2P7A and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment sprsy, LPSI, and HPSI.

Loss of Traln: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is

• Low" based on Table 2 2 (anticipated frequency of challenge, betuxn test exposure time,3 backup trains - EFW, AFW, ard once through cooling). For the isolation failuie case, the consequence is

• Low" with 3 backup trains (isolation failure, EFW B, and train B of once through cooling supply valves). No impact on containment isolation.

Consequence Category: low O

Consequence Rank:

O O

eS

PAGE Ulo CALC.

NO.

NS D-018 13-Aug-97 FMECA - Consequence Information Report ConsequenceID: EFW-C-03B Comaequence

Description:

Degradation of EFW Pump 2P7B flow to steam generator 2E 24A during an independent demand (line 2DBB-3 between 2CW1038-2 and check valve 2EFW.

7B)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV-1025-1 or 1038-2 can be closed by the operator. Propagation to the auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow indication from the EFW pumps. Each of the 4 EIM discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm).

Spatial Effects: Propagation Effected Location: Room 2084 Spatial Effects Comments: Propagation through a door is into Room 2073 and then through floor grating to elevation 335 (Room 2040). Also, the east staltway and elevator shaft provide propagation paths. 'Ihere are floor drains in Rooms 2084,2073, and 2040. Because of the case of drainage from Room 2073, no impacts are assumed. It is assumed that sufficient water can not accumulate in Room 2084 to fall all ECCS supply valves.

From Room 2040, propagation is into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). 'Ihe auxiliary building sump at El 317 has a high level alarm in the control room. It is assumed for the unisolated case, that enough water accumulates at El 335 (Room 2040) to fail MCC 2B52. EFW at El 335 (Rooms 2024 O

& 2025) and ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors. E.nptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event N Initiating EventID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated frorn the steam generator by 2 check valves. A loss of PCS (T2) bitiator is assumed to challenge this piping.

IAss of System: SDM-5 System IPEID:

PCS, EFW, CSS, HPSI, LPSI Systen Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7B flow to steam generator "A". Isolation failure is assumed to cause flow diversion from EFW pump 2P7B and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Ioss of Train: N Train ID:

N/A

Trala Recovery: N/A

C: :: 7 me Comment: Consequence is " Low" based on Table 2 2 (anticipated frequency of challenge, between i

test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is " Low" with 2.5 backup trains (isolation failure, EFW A, and train B of once through cooling supply valves). No impact on containment isohtion.

Conseques ce Category: LOW C

C-r:,_: a Rank:

O

PAGE 0'7

CALC, NO, NSD 018 13-Aug-97 FMECA Consequence Information Report h

Consequence ID: EFW.C-03C Consequence

Description:

Degradation of EFW Pump 2P7A flow to steam generator 2E-24B during an independent demand (line 2DBB-4 between 2CV-1039-1 and check valve 2EFW.

8A)

Break Size:

Large isolability of Break: Yes ISO Comments: 2CV-1076 2 or 10391 can be closed by the operator. Propagation to the auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm).

Spatial Effects: Propagation EffectcE Location: Room 2081 Spatial Effects Comments: Propagation through a door is into Room 2040 and then into the east stairway (door) and down to El 317 (Rooms 2006 and 201I). There tre floor drains in Rooms 2081 and 2040. 'The auxiliary building sump at E! 317 has a high level alarm h the control room, it is assumed for the unisolated case, that enough water accumulates at El 335 (2040) to fail MCC 2B52. There are no flooding impacts in Room 2081.

EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 &

2014) are protected by watertight doors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating EventID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam generator by 2 check valves. A loss of PCS (T2) initiator is assumed to challenge th:s piping.

Loss of System: SDM-5 System IPEID:

PCS, EFW, CSS HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7A flow to steam generator 'B". lsolation failure is assumed to cause flow diversion from EFW pump 2P7A and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Loss of Traln: N Train ID:

N/A

'Irain Recovery: N/A Consequence Comment: Consequence is

• Low" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is "IAw" with 3 backup trains (isolation failure, EFW B, ard train B of once through cooling supply valves). No impact on containment isolation.

Consequence Categoty: low O

Consequence Rank:

O O

37

PAGE M r

N S D.018 C AL C,

NO.-

c 13 Aug 97 FMECA Consequence Information Report I

Consequence ID: EFW C-03D i

Consequence

Description:

Degradation of FF# Pump 2P7B floiv to steam generttor 2E 24B during an independent demand (line 2DBB-4 between 2CW1036-2 and check valve 2EFW.

8B)-

i Break Stae:

Large laolability of Break: Yes j_

ISO Commenta: 2CW1075-1 or 1036-2 can be closed by the operator, Propagation to the auxiliary building -

l sump and its high level alami provides detecuon capability. Further detection is based on flow indication from the EFW pumps, Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm).

S atialEffects: Propagation Effected Location: Room 20Si P

Spatial Effects Comments: Propagation through a door is into Room 2040 and then into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). 'Ihere are floor drains in Rooms 2081 and 2040. *Ihe auxiliary building sump at El 317 has a high level alarm in the -

control room it is assumed for the unisolated case, that enough water accumulates at El 335 (2040) to fall MCC 2B52. There are no flooding impacts in Room 2081.

EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 &

2014) are protected by watertight d6, ors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure esain to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating EventID: N/A laitiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the team generator by 2 check valves. A loss of PCS (T2)inidator is assumed to challenge this piping.

Loss of System: SDM-5 SystemIPEID:

PCS, EFW, CSS. HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7B flow to steam generator "B" Isolation failure is assumed to cause flow diversion from EFW pump 2P7B and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

IAss of Train: N TrainID:

N/A Train Recovery: N/A -

Consequwe Comment: Consequence is " Low" based on Table 2-1 (anticipated frequency of challenge, between -

test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is "Iow" with 2.5. backup trains (isolation failure, EFW A, and train B of or.ce through cooling supply valves). No impact on containment isolation.

Cr-a==-3 Category: LOW.

O Consequence Rank:

O O

PAGE 119

CALC, NO.

NSD 018 13-Aug.97 FMECA - Consequence Information Report h

Consequence ID: EFW-C-04A Consequence

Description:

Degradauon of EFW Pump 2P7A flow to steam generator 2E 24A during an mdependent demand (line 2DBC-4 between 2CV 1026-2 and 2CV 10371)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV 1026 2 can be closed by the operator. Propagation to the auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation

(>325 or 400 gpm and <240 gpm).

Spatial Effects: Propagation Effected Location: Room 2084 Spatial Effects Comments: Propagation through a door is into Room 2073 and then through floor grating to eleution 335 (Room 2040). Also, the east stairway and elevator shaft provide f

propagation paths. *Ihere are floor drains in Rooms 2084,2073, and 2040. Because of the case of drainage from Room 2073, no impacts are assumed, it is assumed that sufficient water can not accumulate in Room 2084 to fail all ECCS supply valves.

From Room 2040, propagation is into th. cast stairway (door) and down to El 317 (Rooms 2006 and 2011). The auxiliary building sump at El 317 has a high level alarm in the control room. It is assumed for the unisolated case, that enough water accumulates at El 335 (Room 2040) to fail MCC 2B52. EFW at El 335 (Rooms 2024

& 2025) and ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N InitiatingEventID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam genuator by 2 check valves. A loss of PCS (T2) initiator is assumed to challenge this piping.

Loss of System: SDM-5 System IPEID:

PCS, EFW, CSS, HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7A flow to steam generator "A". Isolation failure is assumed to cause flow diversion from EFW pump 2P7A and water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Loss of T ; In: N Trata ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is "Imw" bared on Table 2 2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is *1mw" with 3 backup trains (isolation failu:c, EFW B, and train B of oace through cooling supply valves). No impact on containment isolation.

Consequence Category: low O

Consequence Rank:

O O

39

PAGE lad CALC.

NO, NSD 018 OG 3-Aug-97 FMECA - Consequence Information Report l

Consequence ID: EFW-C-04B Consequence

Description:

Degradation of EFW Pump 2P78 flow to steam generator 2E 24A during an independent demand (line 2DBC-1 between 2CV 1025-1 and 2CV-1038 2)

Break Stae: -

Large IsolabL'Ity of Break: Yes I

ISO Conunents: 2CV 1025-1 can be closed by the operator. Propagation to the auxiliary building sump and its high level alarm provides detection capability. Further rietection is based on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation

(>325 or 400 gpm and <240 gpm),

S atialEfrats: Propagation Effected Location: Room 2084 P

j Spatial Effects Comments: Propagation through a door is into Room 2073 and then through floor grating to elevation 335 (Room 2040). Also, the east stairway and elevator shaft provide propagation paths. There are floor drains in Rooms 2084,2073, and 2040. Because of the case of drainage from Room 2073, no impacts are assumed. It is assumed that sufficient water can not accumulate in Room 7A84 to fall all ECCS supply valves.

From Room 2040, propagation is into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). The auxiliary building sump at El 317 has a high level alarm in the control room. It is assumed for the unisolated case, that enough water accumulatu at El 335 (Room 2040) to fall MCC 2B52. EFW at El 335 (Rooms 2024

& 2025) and ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors. Emptying the whole CST to El 317 will not flood the ECCS

(

rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating Event ID: N/A Inidating Event Recovery: Pipe break during normal operation is unlikely since a piping is isolated from the steam generator by 2 check valves. A loss of PCS (T2) initiator is assumed to challenge this piping.

Loss of System: SDM-5 System IPEID:

PCS, EFW, CSS, HPSI, LPSI System Recoven: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EFW pump 2P7B flow to steam generator "A". Isolation failure is assumed to cause flow diversion from EFW pump 2P7B and water accumulation at El 335 which fails MCC 2BS2 affecting train A supply valves for containtnent spray, LPSI, and HPSI.

IAss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is "Iow" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation fiilure case, the consequence is " Low" with 2.5 backup trains (isolation failure, EFW A, and train B of once through cooling supply valves). No impact on containment isolation.

Consequence Category: LOW D

Consequence Rank:

O O

.0

PAGE 13,1 CALC.

NO, NSD MP 13 Aug 97 FMECA - Consequence Information Report h

Consequence ID: EFW-C-04C Consequence

Description:

Degradation of EFW Pump 2P7A (F w to steam generator 2E 24B during an independent demand (iine 2DBC-2 between 2CV-1076 2 and 2CV 1039-1)

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV 1076-2 can be closed by the operator. Propaga'on to the auxiliary building sump and its high level alarm provides detection capability. Further detection is hsed on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation

(>325 or 400 gpm and <240 gpm).

Spatial Effects: Propagation Effected Location: Room 2081 Spatial Effects Comments: Propagation through a door is into Room 2040 and then into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). Here are Door drains in Rooms 2081 and 2040. The auxiliary building sump at El 317 has a high level alarm in the control room. It is assumed for the unisolated case, that enough water accumulates at El 335 (2040) to fail MCC 2B52. There are no flooding impacts in Room 2081.

EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 &

2014) are protected by watertight doors. Emptying the whole CST to El 317 will not l

flood the ECCS rooms. Failure to isown and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam generator by 2 check valves. A loss of PCS (T2) initiator is assumed to challenge this piping.

Loss of System: SDM 5 System IPE ID:

PCS, EFW, CSS, HPSI, LPSI System Recoven: PCS loss is assumed to be the initiator. Pipe degradation causes loss of EPN pump 2P7A flow to steam generator "B". Isolation failure is assumed to cause flow diversion from EFW pump 2P7A and water accumulation at El 335 which fails MCC 2E52 affecting train A supply valves for containment spray, LPSI. and HPSI.

Loss of Train: N Train ID:

N/A Train Recoven: N/A Consequence Comment: Consequence is " Low" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is " Low" with 3 backup trains (isolation failure, EFW B, and train B of once through cooling supply valves). No impact on containment isolation.

Consequence Category: Low O

Consequence Rank:

O O

41

PAGE 19&

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report s

Consequence ID: EFW-C-04D Consequence

Description:

Degradation of EFW Pump 2P7B flow to steam generator 2E-24B during an independent demand (line 2DBC-3 between 2CV 10751 and 2CV-1036 2) l Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV-1075 1 can be closed by the operator. Propagation to the auxiliary building sump and its i

high level alarm provides detection capability, Further d-mtaa is based on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation

(>325 or 400 spm and <240 gpm).

Spatial Effects: Propagation Effected lacation: Room 2081 Spatial Effects Comments: Propagation through a door is into Room 2040 and then into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). There are floor drains in Rooms 2081 and 2040. The auxiliary building sump at El 317 has a high level alarm in the 4-control room. It is assumed for the unisolated case, that enough water accumulates at El 335 (2040) to fall MCC 2B52. 'Ihere are no flooding impactr in Room 2081.

EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 &

2014) are protected by watestight doors. Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW

)

transfer to service water is considered unlikely<

. Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from l

- steam generator by 2 check valves. A loss of PCS (T2) initiator is assumed to j

challenge this piping.

LossofSystem: SDM 5 System IPEID:

PCS, EFW, CSS, HPSI, LPSI l

System Recovery: PCS loss is assumed to be the initiator, Pipe degradation causes loss of EFW pump 2P7B flow to steam generator "B" Isolation failure is assurred to cause flow diversion from EFW pump 2P7B and water accumulation at El 335 which falls MCC 2B52 affecting train A supply -

l valves for containment spray, LPSI, and HPSL Loss of Traln: N Trala IDt N/A l

Train Recovery: N/A Consequence Comment: Consequence is 'Imw" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). For the isolation failure case, the consequence is " Low" with 2.5 backup trains (isolation failure, EFW A, and train B of once through cooling supply valves). No impact on

- containment isolation.

Consequence Category: low D

Co eque.ce Ra.k:

O 4

42 1

PAGE la3

CALC, NO, NSD 018 13-Aug 97 FMECA - Consequence Information Report h

Consequence ID: EFW-C-05A Consequence

Description:

Degradation of EFW Pump 2P7A flow to both steam generators during an independent demand (line 2DBC-2 & 4 outside EFW pump rooms upstream of 2CV-1026-2 & 2CV 1076-2 and min bypass line 2DBC-7)

Break Glze Large Isolability of Break: Yer.

ISO Comments: Pump 2P7A can be tripped, but CST may gravity drain through the punp, therefore, pump suctim MOVs may require isolation. Propagation to the auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow ladication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm ard <240 gpm).

Spatial Effects: Propagation Effected Iecation: Room 2084 Spatial Effects Comments: his piping is located in Rooms 2084,2081,2055, and 2040. Propagation is eventually down to El 317 (Rooms 20% and 2011) via El 335 (Room 2040) for all cases with 2084 first passing through Rcsom 2073. Here are floor drains in all rooms. Because of the case of drainege from Room 2073, no impacts are assumed It is assumed that sufficient water can not accumulate in Room 2084 to fail all EC 3 supply valves. Here are no flooding impacts in Rooms 2081 and 2055. Room 2040 propagates into the east stairway (door) and down to El 317 (Rooms 2006 and 2011). It is assumed for th: unisolated case, that enough water accumulates at El 335 (Room 2040) to fail MCC 2B52. EFW at El 335 (Rooms 2024 & 2025) and ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors.

Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure again to isolate after EFW transfer to service water is considered unlikely.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from steam generators. A loss of PCS (T2) initiator is assumed to challenge this piping.

Loss of System: SDM-4 System IPE ID:

PCS, CSS, HPSI, LPSI System Recovery: PCS loss is assumed to be the initiator. Isolation failure is assumed to cause water accumulation at El 335 which fails MCO 2BS2 affecting train A supply valves for containment spray, LPSI, and HPSL Loss of Traln: T Train ID:

EFW "A' Train Recovery: Pipe degradation causes loss of EFW pump 2P7A flow to both steam generators.

Consequence Comment: Consequence is *Iow" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,2.5 backup trains EFW "B", AFW, and once through cooling). For the isolation failure case, the consequence is "Iow" with 3 backup trains (isolation failure, EFW B, and train B of once through cooling supply valves). No impact on containment isolation.

Consequence Category: low O

Consequence Rank:

0 O

43

PAGE l#/

CALC.

NO, NSD 018 13-Aug 97 FMECA - Consequence Information Report Consequence ID: EFW C-05B Consequence Descripdon: Degradation of EFW Pump 2P7B flow to both steam generators during an independent demand (line 2DBC 1 & 3 outside EFW pump Rooms upstream of 2CV 1025-1 & 2CV 1075-1 and min bypass line 2DBC 8)

Break Size:

Large Isolability of Break: Yes ISO Comments: Pump 2P7B can be tripped, but CST may gravity drain through the pump, therefore, pump suction MOVs may require isolation. Propagation is to the auxiliary building sump and its high level alarm provides detection capability. Further detection is based on flow indication from the EFW pumps. Each of the 4 EFW discharge lines has flow indication and annunciation (>325 or 400 gpm and <240 gpm).

Spatial Effects: Propagation Effected Location: Room 2084 Spatial Effects Comments: This piping is located in Rooms 2084,2081,2055, and 2040. Propagation is eventually down to El 317 (Rooms 2006 and 2011) via El 335 (Room 2040) for all cases with 2084 first passing through Room 2073. There are floor drains in all rwns. Because of the case of drainage from Room 2073, no impacts are assumed. It is assumed that sufficient water can not accumulate in Room 2084 to fail all ECCS supply valves. There are no flooding impacts in Rooms 2081 and 2055. Room 2040 propagates into the east stairway (door) and down to El 317 (Rooms 2006 and

(

2011). It is assumed for the unholated case, that enough water accumulates at El p

335 (Room 2040) to fail MCC 2B52. EFW at El 335 (Rooms 2024 & 2025) and t

ECCS at El 317 (Rooms 2007,2010 & 2014) are protected by watertight doors.

Emptying the whole CST to El 317 will not flood the ECCS rooms. Failure to isolate and then failure agam to isolate after EFW transfer to service water is considered unlikely.

[

Initiating Event: N Initiating EventID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from steam generators. A loss of PCS (T2) initiator is assumed to challenge this piping.

Iass of System: SDM-4 System IPE ID:

PCS, CSS HPSI,LPSI System Recovery: PCS loss is assumed to be the initiator. Isolation failure is assumed to cause water accumulation at El 335 which fails MCC 2B52 affecting train A supply valves for containment spray, LPSI, and HPSI.

Loss of Train: T Train ID:

EFW "B" Train Recovery: Pipe degradation causes loss of EFW pump 2P7B flow to both steam generators.

Consequence Comment: Consequence is " Medium

• based on Table 2-2 (anticipated frequency of challenge, between test exposure time,2 backup trains - EFW "A", AFW, and once through cooling). For the isolation failure case, the consequence is " Low" with 2.5 backup trains (isolation failure EFW A, and train B of once through cooling supply valves).

No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

O O

.]

PAGE IR6 CALC.

NO.

NSD 018 13-Aug-97 FMECA - Consequence Information Report h

Consequence ID: EFW-C-06A Consequence

Description:

Degradation of EFW Pump 2P7 A flow to both steam generators during an independent demand in Room 2024 (line 2DBC-2 and 2DBC-13 from AFW)

Break Size:

Large Isolability of Break: Yes ISO Comments: Pump 2P7A can be tripped or flooding the room will trip the pump. Bere is flood detection in room 2024 with alarm in the control room. Propagation through the f oor drain to the auxiliary 4

building sump and its high level alarm provides additional detection capability. Failure of the pump due to room flooding and a watertight room provides 'he equivalence of isolation.

Spatial Effects: Propagation Effected Location: Room 2024 Spatial Effects Comments: The turbine driven pump is assumed flooded and unavailable. Propagation is through floor drain to El 317 and any leakage out of the room is assumed to be within floor drainage capability outside.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam generators. A loss of PCS (T2) initiator is assumed to challenge this piping.

Iess of System: S Syttem IPE ID:

PCS System Recovery: PCS loss is assumed to be the initiator.

Loss of Traln: T Train ID:

EFW 'A' Train Recovery: Pipe degradation causes loss of EFW pump 2P7A flow to both steam generators.

Consequence Comment: Consequence is

• Low" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,2.5 backup trains - EFW 'B", AFW, and once through cooling). No impact on containment isolation.

Consequence Category: low O

Consequence Rank:

O O

45

PAGE l b CALC.

NO.

NSD 018 FMECA - Consequence Information Report 13 Aug-97 Consequence ID: EFW C-06B Consequence

Description:

Degradation of EFW Pump 2P7B flow to both steam generators during an l

Independent demand in Room 2025 (line 2DBC 1 and 2DBC 12 from AFW)

Break Slee:

Large Isolability of Break Yes

' ISO Comments: Pump 2P7B can be tripped or flooding the room will trip the pump. *!here is flood detection in room 2025 with alarm in the control room. Propagation through the floor drain to the auxiliary 4

building sump and its high level alarm provides additional detection capability. Failure of the pump due to room floodirig and a watertight room provides the equivalence of isolation.

Spatial Effects: Propagation Effected Locatica: Room 2025 Spatial Effects Comments: The motor driven pump is assumed floded and unavailable. Tropagation is through l

floor drain to El 317 and any leakage out of the room is assumed to be within floor drainage capabil;:y outside.

1 Initiating Event: N Initiating Event ID: N/A-Inithtleg Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam generators. A loss of PCS (T2) initiator is assumed to challenge this piping.

l Ims of System: S System IPEID:

PCS System Recovery: PCS loss is assumed to be the in!tiator.

- Loss of Train: T Train ID:

EFW "B" Train Recovery: Pipe degradation causes loss of EFW pump 2P7B flow to both steam generators.

Consequence Comment: Consequence is " Medium" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,2 backup trains EFW "A", AFW, and once through cooling). No impact on containment isolation.

Consequence Category: MEDIUM O

Ceasequence Rank:

O O

o

PAGE 19,'l C ALC, NO, N S D-018 13-Aug-97 FMECA - Consequence Information Report Consequence ID: EFW-C-07 Consequence

Description:

Degradation of EFW Pump flow to both steam generators durity an independent demand of piping between 2EFW.5A and SB (line 2DBC-1)

Break Size:

Large Isolability of Break: Yes ISO Commes.ts: Pump can be tripped or its suction MOVs may be closed to isolate the break. In order to challenge this piping, manual valves 2EFW 5A and 55 must be opened locally, thus, detection would be almost immediate from the demand. 'Ihere is flood detection in room 2024 and 2025 with alarm in the control room. Propagation through the floor drain to the analiary building sump and its high level alarm provides additional detection capability. Failure to isolate could overpressurize the room and propagate to Room 2040.

Spatial Effects: Propagation Effected Location: Room 2024 Spatial Effects Comments: This pipe is located in both rooms 2024 and 2025. Depending on which room the pipe break occurs in, the pump is assumed flooded and unavailable. Propagation is through the floor drain to El 317 and failure to isolate ' vill result in propagation to Room 2040 with subsequent impact on MCC 2BS2. Room 2MO propagates to El 317 (Rooms 2006 and 2011) through the east stairway. All propagation is into the auxiliary building sump and its high level alarm provides detection.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Pipe break during normal operation is unlikely since this piping is isolated from the steam generators. A loss of PCS (T2)init'ator is assumed to challenge this piping.

Loss of System: SM 2 System IPEID:

PCS, EFW System Recove:7: PCS loss is assumed to be the initiator. Also, to challenge this piping one EFW pump train as well as multiple SG discharge paths on the other train would have to fail. 'Ihen, AFW would also have to fail. This is a very unlikely event. Failure to isolate impacts are even less likely since the pipe is challenged by local operator action. Given, the unlikely demand for this pipe -

and its failure, all EFW is assumed to be lost.

Loss of Tralm N Train ID:

N/A Train Recovery: Isolation failure can overpressurize Room 2024 or 2025, and flood Room 2NO affecting MCC 2B52 (train A ECCS supply valves), but this is extremely unlikely.

Consequence Comment: Consequence is hw" based on Table 2-2 (unanticipated frequency of challenge, all year exposure time,1 backup train - once through cooling). Unanticipated frequency in this case has a value of 2 backup trains (multiple failures to challenge this piping).

Consequence Category: low O

Consequence Rank:

O O

47 l

~

l PAGE la%

CALC, NO, NSD 018 AV 13 Aug 97 FMECA - Consequer.ce Information Report Consequence ID:- EFW-C-08A unsequence

Description:

Degradation of EFW Pump 2P7A suction during an independent demand (lme 2HBC-86 downstream of 2CV-07112 and line 2HBC 85 downstream of 2CV-0795-2)

Break Size:

Large Isolability of Break: Yes ISO Comments: Depending on the pipe break location and size, low suction pressure could isolate the CST (2CV-0795-2) and open the service water supply (2CV-0711 2) to pump 2P7A. Otherwise, flooding the room could disable these MOVs before the low pressure transfer to service water. Given transfer to service water, operators would need to isolate service water supply to 2P7A. Flood detection in the room alarms in the control room. The room is also watertight, except for a floor drain to the auxiliary building sump, which also has a high level alarm in the control room.

Spatial Effects: Propagation Effected Location: Room 2024 Spatial Effects Comments: The turbine driven pump is assumed fP.oded and unavailable. Propagation is through a floor drain to El 317 and any leakage out of the room is assumed to be within the floor drainage capability outside.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A loss of PCS (T2) initiator is assumed to challenge this piping. This may be conservative since pipe break during normal standby may be just as likely (i.e.,

Q demand stress of CST head is not signifi:antly different during demand).

Loss of System: S SystemIPEID:

PCS System Recovery: PCS loss is assumed to be the initiator Failure to isolate service water (assuming auto transfer success) could eventually flood all ECCS at El 317. I: is assumed service water would be isolated before such consequences occur (propagation through a floor drain and Icakage out of Roora 2024 would take significant time to flood ECCS).

Loss of Train: T Train ID:

EFW "A" Train Recovery: Pipe degradation causes loss of EFW pump 2P7A suction.

Consequence Comment: Consequence is " Low" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,2.5 backup trains - EFW "B", AFW, and once through cooi.ng). No impact on containment isolation.

Consequence Category: LOW D

Consequence Rank:

O o

PAGE I a c)

CALC, NO, NSD 018 13 Aug-9' FMECA - Consequence Information Report h

Consequence ID: EFW-C-08B Consequence

Description:

Degradation of EFW Pump 2P7B suction during an independent demand (line 21!BC-85 downstream of 2CV-07161 and 2CV-0789-1)

Break Size:

Large Isolabulty of Break: Yes ISO Comments: Depending on the pipe break location and size, low suction pressure could isolate the CST (2CV-0789-1) and open the service water supply (2CV-07161) to pump 2P7B. Otherwise, flooding the room could disable these MOVs before the low pressure transfer to service water. Given transfer to service water, operators would need to isolate service water supply to 2P7B, Flood detection in the room alarms in the control room. He room is also watertight, except for a floor drain to the auxiliary building sump, which also has a high level alarm in the control room.

Spatial Effects

• Propagation Effected Location: Room 2025 Spatial Effects Comments: He motor driven pump is assumed flooded and unavailable. Propagation is through a floor drain to El 317 and any leakage out of the room is assumed to be within the floor drainage capability outside.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A loss of PCS (T2) initiator is assumed to challenge this piping. This may be conservative since pipe break during normal standby may bejust as likely (i.e.,

demand stress of CST head is not significantly different during demand).

IAss of System: S System IPE ID:

PCS System Recovery: PCS loss is assumed to be the initiator. Failure to isolate service water (assuming auta transfer success) could eventu ally flood all ECCS at El 317. It is a<sumed service water would be isolated before such consequences occur (propagation through a floor drain and leakage out of Room 2025 would take signficant time to flood ECCS).

Loss of Traln: T Train ID:

EFW "B" Train Recovery: Pipe degradation causes loss of EFW pump 2P7B suction.

Consequence Comment: Consequence is " Medium" based on Table 2-2 (anticipated frequency of challenge, between test exposure time,2 backup trains - EFW "A", AFW, and once through cooling). No impact on containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

O O

49

PAGE GO CALC.

N O.

N S D-018 O

>> ^ g-97 Fusca - consequence rarormation neport ConsequenceID: EFW-C 09A Consequence

Description:

Degradation of common CST suction in EFW Pump 2P7A Room during an independent demand (line 2HBC-85 upstream of 2CV-0795 2 in Room 2024)

Break Size Large Isolability of Break: Yes ISO Comunents: Low suction pressure could isolate CST (2CV-0795 2) and open the serv'cc water supply (2CV-0711 2) to pump 2P7A. The CST could drain through Room 2024 if not isolated. Local isolation of CST at 2CV 0707 in the turbine building or 2CT-5 at the CST is required. Also, failure of 2CV 0795 2 to close and successful opening of 2CV-07112 would require operators to isolate the service water supply to 2P7A. Flood Mlaa in the room alarms in the control room. 'Ihe room is also watertight, except for a floor drain to the auxiliary building sump, which also has a high level alarm in the control room.

Spatial ENects: Propagation ENected Location: Room 2024 Spatial Effects Comments: The turbine driven pump is e.ssumed flooded and unavailable. Propagation is through a floor drain to El 317 and any leakage out of the room is assumed to be within the floor drainage capability outside.

l Initiatlag Event: N Initiating Event ID: N/A Initiating Event Recovery: A loss of PCS (T2)ini'.lator is assumed to challenge this piping. This may be conservative since pire break during normal standby may be just as likely (i.e.,

demand stress of CST head is not significantly different during demand),

V Loss of System: S System PEID:

PCS System Recovery: PCS loss is assumed to br. the initiator. Failure to isolate CST can not flood ECCS at El 317 and failure to isolate sers ice water before flooding ECCS is not considered likely (prepagation through a floor drain and leakage out of Room 2024 would 'ake significant time).

t Loss of Train: T

'Irain ID:

EFW "A" Train Recovery: Flooding is assumed ta cause loss of EFW pump 2P7A before isolation xcurs. Failure of 2CV-0789 to close will fail all EFW, but this valve is included as part of EFW u.

Consequence Comment: Consequence is " law" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,2.5 backup trains - EFW "B", AFW, and once through cooling). No impact on containment isolation.

Consequence Category: Low O

Consequence Rank:

0 t

50 3

PAGE F51 CALC.

NO.

NSD 018 13 Aug-97 FMEC/t - Consequence Information Report h

Consequence ID: EFW-C-09B Consequence

Description:

Degradation of common CST suction in EFW Pump 2P7B Room during an independent demand (suction piping in Room 2025, including line 210C-85 upstream of 2CV-07891,line 2HBD-91,line 2HBD-883,2HCC-282, and 2HCD-19!)

Break Size:

Large Isolability of Break: Yes ISO Comments: Low suction pressure could isolate CST (2CV-0789-1) and open the service water supply (2CV.

0716-1) to pump 2P7B. The CST could drain through Room 2025 if not isolated. Local isolation of CST at 2CV-0707 in the turbine building or 2CT-5 at the CST is required. Also, failure of 2CV-07891 to close and successful opening of 2CV-07161 would require operators to isolate the service water supply to 2P7B. Flood detection in the room ai.vms in the control room. The room is also watertight, except for a floor drain to the auxiliary building sump, which also has a high level alarm in the control room.

Spatial Effects: Propagation Effected Location: Room 2025 Spatial Effects Comments: The motor driven pump is assumed flooded and unavailable. Propagation is through a floor drain to El 317 and any leakage out of the room is assumed to be within the floor drainage capability outside.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A loss of PCS (T2) initiator is assumed to challenge this piping. This may be conservative since pipe break during normal standby may be just as likely (i.e.,

demand stres; of CST head is not significantly different during demand).

Loss of System: S System IPE ID:

PCS System Recovery: PCS loss is assumed to be the initiator. Failura to isolate CST can not flood ECCS at El 317 and failure to isolate service water before flooding ECCS is not considered likely (propagation through a floor drain and leakage out of Room 2024 would take significant time).

Loss of Traln: T Train ID:

EFW "B" Train Recovery: Flooding is assumed to cruse loss of EFW pump 2P7B before isolatioa occu:s. Failure of 2CV-0795 to close will fail all EFW, but this valve is included as part of EFW A.

Consequence Comment: Consequence is " Medium" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,2 backup trains - EFW "A", AFW, and once through cooling)

Consequence Category: MEDIUM O

Consequence Rank:

O O

51

PAGE

\\ 3 Ds

CALC, N O.

NSD 018 13 Aug-97 FMECA - Consequence Information Report Consequence ID: EFW-C-10 Consequence

Description:

Degradation of common CST suction outside auxiliary building during an independent demand (line 2HCD-195 located outside and in Rooms 2223,2225, and 2050, and line 2HCD-258 located outside)

Break Size:

Large Isolability of Break: Yes ISO Comments: Low suction pressure will isolate CST (2CV-0795-2) and open the ser vice water supply (2CV-0711 2) to pump 2P7A. Similarly,2CV-0789-I could closc and 2CV-0716-l open to pump 2P78. Also, MOV 2CV-0707 in the turbine building can be closed for piping dowtistream of this valve and 2CT 5 can be closed locally at the CST. Failure to isolate drains the CST cither outside v. into the turbine auxillary building.

Spatial Effects: Propagation Effected Location: Outside Spatial Effects Comments: This consequence combines several locations (outside, and Rooms 2223,2225, and 2050) because it is very unlikely that propagation from these locations can affect important equipment.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: A loss of PCS (T2) initiator is assumed to challenge this piping. 'nds may be conservative since pipe break during nonnal standby may be just as likely (i.e.,

demand stress of CST head is not significantly different during demand).

(

Loss of System: S System IPEID:

PCS System Recovery: PCS loss is assumed to be the initiator.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is

• Low" based on Table 2 2 (anticipated frequency of challenge, between test exposure time,3 backup trains - EFW, AFW, and once through cooling). No impac' on containment isolation.

Consequence Category: LOW D

Consequence Rank:

0 t

l

['w/

52 i

PAGE G 3

CALC, NO, NSD 018 13 Aug 97 FMECA - Consequence Information Report h

Consequence ID: EFW C Il Consequence

Description:

Suction from Unit I CST T41B (line 2HCC-282 from outside to check valves 2CS-844 and 845)

Break Size:

Large Isolability of Break: Yes ISO Comments: This piping is normally isolated at the CST by 2CS-C15 and 81'/. Also check valves 2CS-844 and 845 prevent flow from the other suction sources. In the unlikely event this path is opened and used, then pipe failure occurs, th operators would have to close the same valves they had just optned.

Spatial Effects: Propagation Effected Location: Outside Spatial Effects Comments: This consequence combines several locations (outside, and Rooms 2055,2040, and 2025) because the piping is normally isolated and unlikely to be challenged. Room 2025 impact is assumed since it floods the motor driven pump.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: The frequency of challenge is assumed to require failure of the normal Unit 2 CST supply combined with a loss of PCS initiator.

Loss of System: S System IPE ID:

PCS System Recoven: PCS loss is assumed to be the initiator in combinadon with normal Unit 2 CST failure. Given that operators succuessfully align Unit 1 CST to cause this event, it is assumed that operators will isolate the event before ECCS is flooded at El 317, Loss of Traln: T Train ID:

EFW "B" Train Recoven: Given alignment to Unit 1 CST,it is assumed that the motor driven pump (Room 2025)is immediately flooded.

Consequence Comment: Consequence is "Iow" based on Table 2-2 (unexpected frequency of challenge, all year exposure and at least 2 backup trains - EFW "A", AFW, and once through cooling). No impact on containment isolation.

Consequence Categon: low O

Consequence nank:

O O

m

PAGE

\\ ?;4 CALC.

NO.

NSD 018 13 Aug 97 FMECA - Consequence Information Report ConsequenceID: EFW-C-12A Consequence

Description:

Degradation of main feedwater flow to steam generator 2E-24A inside containment during normal operation (EFW line 2DBB 3 downstream of 2EFW-9A).

Break Size:

Large Isolability of Break: No ISO Comments: Feedwater isolation and feedwater pump trip will occur on low steam generator pressure. Also, EFW will remain isolated to the faulted steam generator via a differentirJ pressure between the faulted and good steam genierators. However, blowdown of the faulted steam generator can not be isolated.

4 Spatial Effects: Containment Effected 14 cation: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the conta8nment building are qualified for such events.

Initiating Event: 1 Iultiating Event ID: T5 Initiating Event Recov:.cy: No recovery from an unisolabic feedwater line break. This results in an immediate plant trip due to Icw steam generator level.

Loss of System: SDM-2 System IPE ID:

PCS, EFW System Recovery: MSIV isolation, feedwater isolation and pump trips occur on low steam generator pressure, it is possible to recover a condensate pump and makeup to the unfaulted steam generator. EFW A

discharge to the faulted steam generator is isolated and unavailable. However, there is a

(

discharge path from each EFW pump to the unfaulted steam generator.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 2 1. Containment isolation is unaffected.

Conseqtience Category: MEDIUM O

Consequence Rank:

C bv 54

PAGE

\\?E

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report Consequence ID: EFW C 12B Consequence

Description:

Degradation of main feedwater flow to steam generator 2E-24B inside containment during normal operation (EFW line 2DDB 4 downstream of 2EFW 9B).

Break Size:

Large Isolability of Break: No ISO Comments: Feedwater isolation and feedwater pump trip will occur on low steam generator pressure. Also, EFW will remain isolated to the faulted steam generator via a differential pressure between the faulted and good steam generators. However, blowdown of the faulted steam generator can not be isolated.

Spatial Effects: Containment Effected Iecation: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the containment building are qualified for such events.

Initiating Event: I Initiating Event ID: T5 Initiating Event Recovery: No recovery from an unisolable feedwater sine break. This results in an immediate plant trb due to low steam generator level.

Loss of System: SDM 2 System IPEID:

PCS, EFW L ystem Recovery: MSIV isolation, feedwater isolation and pump trips occur on low steam generator pressure. It is possible to recover a condensate pump and makeup to the unfaulted steam generator. EFW discharge to the faulted steam generator is isolated and unavailable. However, there 1. a discharge path from each EFW pump to the unfaulted steam generator.

Loss of Train: N Train ID:

?#A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 21. Containment isolation is unaffected.

Consequence Category: MEDIUM C

Consequence Rank:

O O

SS

PAGE

\\%

GALC.

NO.

NSD 018 13-Aug 97 FMECA - Consequence Information Report Consequence ID: FW-C 01 A Consequence

Description:

Degradation of main feedwater flow to steam generator 2E 24A inside containment during normal operation (line 2DBB 1 between 2FW.5A and steam generator).

Break Size:

Large Isolability of Break: No ISO Comments: Feedwater isolation and feedwater pump trip will occur on low steam generator pressure. Also, EFW will remain isolated to the faulted steam generator via a differential pressure between the faulted and good steam generators. However, blowdown of the faulted steam generator can not be isolated.

Spatial Effects: Containment Effected Location: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the containment building are qualified for such events.

Initiating Event: 1 Int:lating Event ID: T5 Initiating Event Recovery: No recovery from an unisolable feedwater line break. This results in an immediate plant trip due to low steam generator level.

Loss of System: SDM 2 System IPE ID:

PCS. EFW System Recovery: MSIV isolation, feedwater isolation and pump trips occur on low steam generator pressure. It is possible to recover a condensate pump and makeup to the unfaulted steam generator. EFW Im discharge to the faulted steam generator is isolated and unaveJlable. However, there is a discharge path from each EFW pump and AFW to the unfaulted steam generator.

less of Train:,N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 2 1. Containment isolation is unaffected.

Cansequence Category: MEDIUM O

Consequence aank:

O h

b 56

PAGE F5 7

CALC, NO, NSD 018 13-Aug 97 FMECA - Consequence Information Report h

Consequence ID: FW-C-01B Consequence

Description:

Degradation of main feedwater flow to steam generator 2E-24B inside containment during normal operation (line 2DDB-2 between 2FW 5B and steam generator).

Break Size:

Large Isolability of Break: No ISO (.vmc.ents: Feedwater isolation and feedwater pump trip will occur on low steam generator pressure. Also, EFW will remain isolated to the faulted steam generator via a differential pressure between the faulted and good steam generators. However, blowdown of the faulted steam generator can not be isolated.

Spatial Effect. : Containment Effected Location: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the containment building are qualified for such events.

Initiating Event: I Initiating Event ID: TS Initiating Event Recovery: No recovery from an unisolable feedwater line break. 'Ihis results in an immediate plant trip due to low steam generator level.

Loss of System: SDM-2 System IPE ID:

PCS, EFW System Recovery: MSIV isolation, feedwater isolation and pump trips occur on low steam genentor pressure. It is possible to recover a condensate pump and makeup to the unf aulted steam generator. EFW discherge to the faulted steam ger.erator is isolated and unavailable. However, there is a discharge path from each EFW pump and AFW to the unfaulted steam generator, IAss of Traln: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 2 1, Containment isolation is unaffected.

Consequence Category: MEDIUM O

Consequence Rank:

O O

57

~. -.

PAGE 13D

CALC, NO, NSD 018 O

>> ^

e>

r u z c i - ceDSeoDeeee 1 rerm tied aegeri Consequence ID: FN-C-02A Consequence

Description:

Desi dation of main feedwater flow to steam generato. 2E 24A inside containment

& ut stream of 2FW 5A (line 2DBB 1 between containment penetration and 2FW-SA).

Break Size:

Large Isolability of Break Yes ISO Comments: Feedwater isolation and pump trip will occur on low steam generator pressure, but check valve 2FW 5A isolates faulted steam generator and prevents immediate depressurir+n. Operator.

action or emptying of the condenser hotwell will likely provide feedwater pe x 8p.

Spatial Effects: Containment Effected Location: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the containment building are qualified for such events.

Initiating Event: 1 Initiating Event ID: T5 Initiating Event Recovery: No recovery from a feedwater line break. Reactor trip (T6) will occur imrrallately on low steam generator level and 2FW 5A prevents steam generator blowdown and low pressure isolation in the short term.

Loss of System: SDM-2 System IPE ID:

. PCS, EFW J

System Recovery: 1.oss of PCS is assurned due to feedwater pump trip (operator or loss of suction from condenser p) hot well) or eventual MSIV isolation on low steam generator pressure or operator action. It is

(

possible to recover a condensate pump and provide makeup to the unfaulted steam generator, Also, EFW could be isolated from the faulted steam generator before FW isolation occurs.

However, this is recoverable and there is a discharge path from each EFW pump and AFW to the unfaulted steam generator.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 2-1. 2CV 10241 provides containment isolation.

4 Consequence Category: MEDIUM O

Consequence Rank:

O a

58

PAGE G'l

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report h

Consequence ID: FW C-02B Consequence

Description:

Degradation of main feedwater flow to steam generator 2E 24B inside containment

& upstream of 2FW-5B (line 2DBB 2 between containment perstration and 2FW.

5B),

Break Size:

Large Isolability of Break: Yes ISO Comments: Feedwater isolation and pump trip will occur on low steam generator pressure, but check valve l

2FW 5B isolates faulted steam generator and prevents immediate depressurizadon. Operator action or emptying of the condenser hotwell will likely provide feedwater pump trip.

Spatial Effects: Containment Effected 14 cation: Containment Building Spatial Effects Comments: Feedwater line breaks are within the design basis and the necessary safety components located inside the contairenent building are qualified for such events.

l Initiating Event: I Initiating Event ID: TS Initiating Event Recovery: No recovery from a feedwater line break. Reactor trip (T6) will occur immediately l

on low steam generator level and 2FW 5B prevents steam generator blowdown and j

low pressure isolation in the short serm.

l Loss of System: SDM 2 System IPE ID:

PCS, EFW System Recovery: Loss of PCS is assumed due to feedwater pump trip (operator or loss of suction from condenser l

hot well) or eventual MSIV isolation on low steam generator pressure or operator action. It is l

possible to recover a condensate pump and provide makeup to tbc unfaulted steam generator, Also, EFW could be isolated from the faulted steam generate; before FW isolation occurs.

However, this is recoverable and there is a discharge path from esch EFW pump and AFW to the unfaulted steam generator.

Loss of Train: N Train ID:

N/A l

Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 21,2CV 10741 provides containment isolation.

Consequence Category: MEDIUM O

Consequence Rais:

O l

l l

l l

O 59 l

PAGE 14D

CALC, NO.

NSD 018 13 Aug 97 FMECA Consequence Information Report Consequence ID: FW C-03A Consequence

Description:

Degradation of main feedwater flow to steam generator 2E 24A outside 4

containment during normal operation (line 2DBB 1 between 2CV 10241 and containment penetration).

Break Size:

Large Isolabilky of Break: Yes ISO Comments: Feedwater isolation and pump trip will occur on low steam generator pressure, but check valve 2iNASA isolates faulted steam generator and prevents immediate depressurization. Operator action or emptying of the condenser hot well will likely provide feedwater pump trip.

Spatial Effects: Propagation Effected Location: Room 2081 Spatial Effects Commet >: Propagation is into Room 2040, then into the east stairwell and down to El 317 (Rooms 2006,ud 201l) into the auxiliary building sump (high level alarm in control room). EFW at El 335 (Rooms 2024 and 2025) and ECCS at El 317 (Rooms 2007,2010, and 2014) are protected by watertight doors. It is assumed that EFW discharge valves in Room 2081 and MCC 2B52 iri Room 2040 are affected by this high energy pipe break. Even if FW continued unisolated and emptied a CST into the building, ECCS is unaffected at El 317.

Initiating Event: I Initiating Event ID: TS 1

Initleting Event Recovery: No recovery from a feedwater line break. Reactor trip (T6) will occur immediately d

p) on low steam generator level and 2FW 5A prevents steam generator blowdown and y

low pressure isolation in the short term.

LossofSystem: SDM 5 System IPEIDt PCS, EFW, HPSI, CSS, LPSI System Recovery: Loss of PCS is assumed due to feedwater pump trip (operator or loss of suction from condenser hot well) or eventual MSIV isolation on low steam generator pressure or operator action. It is possible to recover a condensate pump and makeup to the unfaulted steam generator. Also.

EFW could be isolated from the faulted steam genera:or or the supply valves in Room 2081 could fall from the harsh environment. However, there is a discharge path from euch EFW pump to the unfaulted steam generator, Failure of MCC 2BS2 in Room 2040 is also assumed to affect train A supply valves in the containment spray, HPSI, and LPSI systems.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Tables 21 and 2 3 (2 backup trains, including EFW and AFW to SG A, FW recovery, and train B of once thmugh cooling supply valves). 2FW-5A provides containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

O 1

V 60

PAGE 14 1

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report h

Consequence ID: FW-C-03B Consequence

Description:

Degradation of main feedwater flow to steam generator 2E-24B outside contMnment during normal operation (line 2DBB 2 between 2CW1074 1 and containment penetration).

Break Size:

Large Isolability cf Break: Yes ISO Comments: Feedwater isolation and pump trip will occur on low steam generator pressure, but check valve 2FW 5B isolates faulted steam generator and prevents immediate depressurization. Operator action or emptying of the condenser hot well will likely provide feedwater pump trip.

Spatial Effects: Propagation Effected Location: Room 2081 Spatial Effects Comments: Propagation is into Room 2040, tr en into the east stairwell and down to El 317 (Rooms 2006 and 2011)into the auxiliary building sump (high level slarm in control room). EFW at El 335 (Rooms 2024 and 2025) and ECCS at El 317 (Rooms 2007,2010, and 2014) are protected by watertight doors. It is assumed that EFW discharge valves in Room 2081 and MCC 2B52 in Room 2040 are affected by this high energy pipe break. Even if FW continued unisolated and emptied a CST into the building, ECCS is unaffected at El 317.

Initiating Event: 1 Initiating Event ID: 75 Initiating Event Recovery: No recovery from a feedwater line break. Reactor trip (T6) will occur immediat:ly on low steam generator level and 2FW 5B prevents steam generator blowdown and low pressure isolation in the short term.

Loss of System: SDM-5 System IPEID:

PCS, EFW, HPSI, CSS, LPSI System Recovery: Ims of PCS is assumed due to feedwater pump trip (operator Or loss of suction from condenser hot well) or eventual MSIV isolation on low steam generator pressure or operator action. It is possible to recover a condensate pump and makeup to the unfaulted steam generator. Also, EFW could be isolated from the faulted steam generator or the supply v.alves in Room 2081 could fail from the harsh environment. Hnwever, there is a discharge path from each EFW pump to the unfaulted steam generator. Failure of MCC 2B52 in Room 2040 is also assumed to affect train A supply valves in the containment spray, HPSI, and LPSI systems.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Tables 2 1 and 2-3 (2 backup trains, including EFW and AFW to SG A, FW recovery, and train B of once through cooling supply valves). 2FW-5B provides containment isolation.

Consequence Category: MEDIUM O

Consequence Rank:

O O

61

PAGE W 9s CALC.

NO.

NSD 018 nU 13 Aug-97 FMECA - Consequence Information Report Consequence ID: MS-C-01 A Consequence

Description:

Degradation of main steam flow from steam generator 2E 24A inside containment during normal operation (line 2 EBB 1 inside containment).

Break Stre:

Large Isolability of Break: No ISO Comments: Blowdown from faulted steam generator is not isolable. Steam line break detection (low steam generator pressure) will isolate MSIVs and feedwater to the faulted steam generator. Also, EFW flow to the faulted steam generator will be isolated and remain isolated via differential pressure between faulted steam generator and good steam generator.

Spatial Effects: Containment Effected Location: Containment Building Spatial Effects Comments: Steam line breaks are within the design basis and the necessary r,afety components located inside containment are qualified for such events.

Initiating Event: 1 Initiating Event ID: T5 Initiating Event Recovery: No recovery from an unisolable steam lir.e break. 'Ihis will result in an immediate plant trip.

Loss of System: SDM 2 SystemIPEID:

PCS, EFW System Recovery: MSIV isolation, feedwater isolation, and feedwater pump trip occur on low steam generator i

pressure. lt is possible to recover a condensate pump and makeup to the unfaulted steam l O generator. EFW discharge to the faulted steam generator is isolated and unavailable. However.

l V there is a discharge path from each EFW pump to the unfaulted steam generator. Also,1 of 2 steam suppl

'hs to the turbine EFW pump is unavailable, but the other steam supply is more relia! ^

• e turbine EFW pump itself. Also, the auxiliary feedwater pump could be used. Loss v. i n dump capability from the faulted steam generator is neglected smce the event essenually provides successful depressurization.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 2 1. Containment isolation is unaffected.

Consequence Category: MEDIUM O

Consequence Rank:

O 1

l l

,a b

e2

PAGE

\\43 CALC.

NO.

NSD 0)8 13-Aug 97 FMECA - Consequence Infortnation Report h

Consequence ID: MS-C-01B l

Consequence

Description:

Degradation of main steam flow from steam generator 2E-24B inside containment l

during normal operation (line 2 EBB-2 inside containment).

Break Size:

Large Isolability of Break: No ISO Comments: Blowdown from faulted steam generator is not isolable. Steam line break detection (low steam i

generator pressure) will isolate MSIVs and feedwater to the faulted steam generator, Also, EFW flow to the faulted steam generator will be isolated and remain isolated via differential pressurt between faulted steam generator and good steam generator.

Spatial Effects: Containment Effected location: Containment Building Spatial Effects Comments: Steam line breaks are within the design basis and the necessary safety components located inside containment are qualified for such events.

Initiating Event: 1 Initiating Event ID: T5 Initiating Event Recovery: No recovery from an unisolable steam line break. 'Ihis will result in an immediate plant trip.

Loss of System: SDM-2 System IPE ID:

PCS,EITV System Recovery: MSIV isolation, feedwater isolation, and feedwater pump trip occur on low steam generator pressure. It is possible to recover a condensate pump and rnakeup to the.mfaulted steam generator EFW discharge to the faulted steam generator is isolated and unavailable. However, there is a discharge path from each EFW pump to the unfaulted steam generator. Also, I of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply is more reliable than the turbine EFW pump itself. Also, the auxiliary fec4 water pump could be used. Loss of the steam dump capability from the faulted steam generator is neglected since the event essentially provides successful depressurization.

Loss of Train: N Train ID:

N/A Train Recovery: N/A Consequence Comment: Consequence is " Medium" based on Table 21. Containment isolation is unaffected.

Consequence Ca'egory: MEDIUM O

Consequence Rank:

C O

e

PAGE W4 C ALC, NO, NSD 018 m(J 13-Aug 97 FMECA - Consequence Information Report i

Consequence ID: hts-C-02A Consequence

Description:

Degradation of main steam flow from' steam generator 2E 24 A outside containment during normal operation (line 2 EBB 1 between penetration 2P l and 2CV1010-1, and conneated lines >4 inch diameter such as 2 EBB 8).

Break Size:

Large Isolability of Break: No ISO Comments: Blowdown from faulted steam generator is not isolable. Steam line break detection (Iow steam generator pressure) will isolate MSIVs and feedwater to the faulted steam generator. Also, EFW flow to the faulted steam generator will be isolated and remain isolated via differential pressure between faulted steam generator and good steam generator.

Spatial Effects: Propagation Effected Location: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a stairway door into the turbine auxiliary building. For a severe main steam line break it is possible to damage and/or push the siding out into the adjecent fuel handling area (Room 2151). However, this 6 a large area and safety equipment is located at lower elevations.

Initiating Event: I Initiating Event ID: T5 Initiating Event Recovery: No recovery from an unisolable steam line break. This will result in an immediate o

plant trip, Loss ofSystem: SDht 2 System IPE ID:

PCS, EFW System Recovery: htSIV isolation, feedwater isolation, and feedwater pump trip occur on low steam generator pressure, it is possible to recover a condensate pump and makeup to the unfaulted steam generator. EFW discharge to the faulted steam generator is isolated and unavailable, However, there is a discharge path from each EFW pump to the unfaulted steam generator. Also, I of 2 stcam supply paths to the turbine EFW pump is unavailable, br.he other steam supply is more reliable than the turbine EFW pump itself. Also, the auxiliary feedwater pump could be used. Loss of the steam dump capability from the faulted steam generator is neglected since the event essentially provides successful depressurization.

Loss of Traln: T Train ID:

EFW "A" Train Recovery: It is possible for large main steam line breaks to affect bott, EFW turbine steam supply liner which are in close proximity and smaller piping.

Consequence Comment: Consequence is "hiedium" based on Tables 21 and 2 3 (>2 backup trains, including motor EFW, AFW, and once through cooling). Passive closed barrier provided by the steam generator is credited for containment isolation.

Consequence Category: hfEDIUM C

Consequer.ce Rank:

O i

V 64

PAGE N6

CALC, NO, NSD 018 13-Aug 97 FMECA - Consequence Information Report h

Consequence ID: MS-C-02B Consequence

Description:

Degradation of main steam flow from steam generator 2E-24B outside containment during normal operation (line 2 EBB-2 between penetration 2P 2 arx! 2CV1060-2, and connected lines >4 inch diameter such as 2 EBB 9).

Break Size Large Isolability of Break: No ISO Comments: Blowdown from faulted steam generator is not isolable. Steam line break detection (low steam generator pressure) will isolate MSIVs and feedwater to the faulted steam generator. Also, EFW flow to the faulted steam gc:erator will be isolated and remain isolated via differential pressure between faulted steam generator and good steam generator.

Spatial Effects: Propagation Effected Location: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a stairway door into the turbine auxiliary building. For a severe main steam line break it is possible to damage and/or push the siding out into the adjacent fuel handling area (Room 2151). Ilowever, this is a large area and safety equipment is located at lower elevations.

IEltlating Event: I Initiating Event ID: TS Initiating Esent Recovery: No recovery from an unisolable steam line break. This will result in an immediate plant trip.

l Loss of System: SDM-2 System IPEID:

PCS, EFW System Recovery: MSIV isolation, feedwater isolation, and feedwater pump trip occur on low steam generator pressure. It is possible to recover a condensate pump and makeup to the unfaulted steam generator. EFW discharge to the faulted steam generator is isolated and unavailable. However, there is a discharge path from each EFW pump to the unfaulted steam generator. Also,1 of 2 I

steam supply paths to the turbine EFW pump is unavailable, but the other steam supply is more reliable than the turbine EFW pump itself. Also, the auxiliary feedwater pump could be used. Loss of the steam dump capability from the faulted steam generator is neglected since the event essentially provides successful depressurization.

Iers of Train: T Train ID:

EFW "A" Train Recovery: it is possible for large main steam line breaks to Lffect both EFW turbine steam supply lines which are in close proximity and smaller piping.

Consequence Comment: Consequence is " Medium" based on Tables 21 and 2-3 (>2 backup trains, including motor EFW, AFW, and once through cooling). Passive closed barrier provided by the steam generator is credited for containment isolation.

Consequence Category: MEDIUM O

Consequence aank:

O 9

65

PAGE l'-l lo

CALC, NO, NSD 018

(~

\\

13-Aug 97 FMECA - Consequence Information Report ConsequenceID: MS-C-03A Consequence

Description:

Degrada lon of EFW steam supply from steam generator 2E-24A during normal operation (line 2 EBB 6 from main steam line 2 EBB 1 to 2CW1000-1).

Break Sizes Large Isolabuity of Break: No ISO Comments: Blowdown from faulted steam generator is not isolable. This line is marginally large enough to cause an automatic plant trip.

Spatial Effects: Propagation Effected Location: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a staltway door into the turbine auxiliary building.

j Initiating Event: I initicting Event ID: T6 Initiating Event Recovery: An automatic plant trip is assumed. Otherwise, detection is expected from a high power alarm and a controlled shutdown is assumed due to standing orders to do so

[

as a result of any unknown or uncontrolled loss of 50 Mwe.

Loss of System: N System IPEID:

N/A System Recovery: N/A IAss of Train: TDM 2 Train ID:

PCS, Turbine EFW a-l Train Recovery: The affected steam generator would be isolated once identified during the controlled shutdewn.

I of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply l

path is rnore reliable than the turbine EFW pump itself.

Consequence Comment: Consequence is ' Low" based on Tables 21 and 2 3 (3 backup trains available, including PCS, EFW, AFW, and once through cooling). Passive closed barrier 4

provided by the steam generator is credited for containment isolation.

Consequence Category: Low O

Consequence aank:

O-i 4

'I V ss i

1

PAGE 1 0

CALC, NO, NSD 018 13 Aug-97 FMECA - Consequence Information Report h

Consequence ID: MS C 03B Consequence

Description:

Degradation of EFW steam supply from steam generator 2MiB during normal operation (line 2 EBB-7 from main steam line 2 EBB 2 to 2CV.1050 2).

)

Break Size:

Large Isolability of Break No ISO Comments: Blowdown from faulted steam generator is not isolable. This line is marginally large enough to cause u automatic plant trip.

Spatial Effects: Propagation Effected Location: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjolaing buildings), down through main steam line chase tcward the turbine building, and through a stairway door into the turbine auxiliary building.

Initiating Event: I Initiating EventID: T6 Initiating Event Recovery: An automatic plant trip is assumed. Otherwise, detection is expected from a high power alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe, Loss of System: N System IPE ID:

N/A System Recovery: N/A Loss of Train: TDM 2 Train ID:

PCS, Turbine EFW Train Recoverp 'Ihe affected steam generator would be isolated once identified during the contic!!ed sh': down.

I of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply path is more reliable than the turbine EFW pump itself.

Consequence Comment: Coasequence is ' Low" based on Tables 21 and 2 3 (3 backup trains available, i

I including PCS, EFW, AFW, and once through cooling). Passive closed barrier i

provided by the steam generator is credited for containment isolation.

Consequence Category: low O

Consequence.nank:

O 1

t O

67

(

PAGE 14b CALC.

NO, NSD 018 13-Aug 97 FMECA Consequence Information Report Consequence ID: MS-C-04A Consequence Desc 1ptioat Isolable degradation of EFW steam supply from steam generator 2E-24A during normal operation (line 2EBC-1 between 2CW1000-1 and check valve 2MS 39A).

- Break S! e:

Large Isolability of Break: Yes ISO Conunents: 2CW10001 can be closed by the operators to isolate this break and check valve 2MS 39A

(

prevents backflow from line "B.* 'Ihis line is marginally large enough to cause an automatic plant trip and there is no automatic isolation of 2CW1000-1.

Spatial Effects: Propagation FRected I4 cation: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a stairway door into the turbine auxiliary building.

Initiating Event: !

Initiating Event ID: T6 Initiating Event Recovery: An sutor.atic plant trip is assumed. Otherwise, detectior is expected from a high

_ power s arm and a controlled dutdown is assumed due to standing orders to do so as a res alt of any unknown or uncontrolled loss of 50 Mwe.

IAss of System: N Systein IPEID:

N/A System Recovery: N/A

- IAes of Train: TD

. Trala ID:

Turbine EFW Trale Recovery: 1 of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply path is more reliable than the turbine EIW pump itself.

I C: 1;-_ _ - = Comment: Consequence is " Low" based on Tables 2 1 and 2 3 (3 backup : rains available, including PCS, EFW, AFW, and once through cooling). 2CV 1000-1 provides containment isolation.

Consequence Category: Low O

Conr,quence Rank:

O 1

PAGE hcl

CALC, NO, NSDO1E 13 Aug 97 FMECA - Consequence Information Report h

Consequence ID: MS-C-04B Consequence

Description:

Isolable degradation of EFW steam supply from steam generato: 2E 24D during normal operation (line 2EBC 2 between 2CW1050-2 and check valve 2MS 39B).

Break Size:

Large Isolability of Dreak: Yes ISO Comments: 2C%1050-2 can be closed by the operators to isolate this break and check valve 2MS 39B prevents backflow from line "A." This line is marginally large enough to cause an automatic plant trip and there is no automatic isolation of 2CV-1050-2.

Spatial Effects: i opagation ElTected 14 cation. Room 2155 Spatial Effects Comruents: Propagation is through access Joors and room siding to outside (roof of adjoining buildings), down throt gh truun steam line el toward the turbine building, and throuth a stairway door into the turbine auu ary bu"fing.

Initiating Event: 1 Initiating Event ID: T6 Initiating Event Recovery: An automa. tic plant trip is assumed. Otherwise, detection is expectui from a high power alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe, Loss of System: N Systeru IPEID:

N/A Syste n Recovery: N/A Loss of Train: TD Train ID:

Turbine EFW Train Recover 7: 1 of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply path is more reliable than the turbine EFW pump itself.

Consequence Comment: Consequence is 'IAw" based on Tables 21 and 2-3 (3 backup trains available, including PCS, EFW, ATW, and once through cooling). 2C%1050-2 provides containment isolation.

Consequence Category: low D

Consequence Rank:

O O

69

PAGE 160

CALC, NO.

NSD 018 r

f 13-Aug 97 FMECA - Consequence Information Report Consequence ID: MS-C-05 Consequence

Description:

Degradation of EFW steam supply from both steam generators during normal operation (line 2EBC 1 from check valves 2MS 39A & B to El 354).

Break Size:

Large Iso! ability of Break: Yes ISO Comments: 2C%10001 and 2C%1u50-2 can be closed by the operators to isolate this break. "Ihis line is marginally trige enough to cause an autorratic plant trip and there is no automatic isolation of 2CW1000-1 and 2CW1050 2.

SpatialEffects: Propagation Effected Location: Room 2155 Spadal Effects Comments: Piping is located in Rrom 2155,2151, and vertical pipe chase to El 354.

Propagation from Room 2155 is through awess doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward 'he turbine building, and through a stairway oor into the turbine auxiliary building.

Propagation from Room 2151 is into a very la ge area and at an elevation away from safe shutdown equipment. It is assumed that dJe to the torturous pathway that breaks in the pipe chase do not easily propags.te into Room 2040 at El 335.

Initiating Event: I Initiating Event ID: T6 Ioltiating Event Recovery: An automatic plant trip is assumed. Otherwise, detection is expected from a high

(

power alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe.

A Loss ofSystem: N System IPE ID:

N/A 53ystem Recovery: N/A Loss of Train: T Train ID:

Turbine EFW Train Recovery: Steam supply to the turbine EFW pump is unavailable.

Consequence Coment: Consequence is ' Low" based on Tables 2 1 and 2 3 (3 backup trains available, including PCS, EFW B, AFW, and once through cooling). Containment isolation is unaffected.

Consequence Categoryt Low O

Consequence aank:

O O

70

PAGE 15(

CALC, NO.

NSD'M8 13 Aug 97 FMECA - Consequence Information Report h

i l

ConsequenceID: MS-C-06 Consequence

Description:

Degradation of EFW steam supply in Room 2040 during normal operation (line 2EBC-1 from El 354 to normally closed 2CV 0340).

Break Size:

Large Isolability of Break: Yes ISO Cornments: 2CV 10001 and 2CV 1050-2 tan be closed by the o;erators to irolate this break. His line is marginally large enough to cause an automatic plant trip and there is no automatic isolation of 2CV 1000-1 and 2CV 1050 2.

Spatial Effects: Propagation Effected Location: Room 2040 Spatial Effects Comments: The fuel pool cooling and purification pumps are in the vicinity of this piping and are likely impacted (Judged to be low consequence due to significant time for recovery and makeup). The most important component, MCC 2B52, is at the other end of the room, it is assumed to fail for the case where operators fail to detect and isolate.

Initiatint Event: I Initiating Event ID: T6 Initiating Event Recovery: An automatic plant.dp is assumed. Otherwise, detection is expected from a high power alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe.

Loss of System: N System IPEID:

N/A System Recovery: N/A Loss of Train: TM-4 Train ID:

Turbine EFW, HPSI A, LPSI A, CSS A Tra:n Recovery: Steam supply to the turbine EFW pump is unavailable. For the failure to detect and isolate case, L is assu:ned MCC 2B52 is affected which contains breakers for key valves. Dese valves include normally closed valves in containment spray train A, HPSI train A cold leg supplies, and LPSI train A.

Consequence Comment: Consequence is ' Low" based on Tables 2-1 and 2-3 (3 backup trains available, including PCS, EFW D AFW, and once through cooling). For the failure to isolate case, the consequence is still " Low" (isolation, EFW B, and once through cooling).

Containment isolation is unaffected.

Consequence Category: low O

Consequence Rank:

O l

l i

O 71

PAGE 10 1 C ALC - NO, NSD Olb n

U 13 Aug 97 FMECA - Consequence Information Report Consequence ID: MS-C-07 Consequence

Description:

Degradation of EFW steam supply on demand in Room 2040 (line 2EBC-1 from normally closed 2CWO340 to Room 2024).

Break Size:

Large Isolability of Break Yes ISO Comments: 2CW1000-1 and 2CW1050-2 can be closed by the operators to isolate this break. Normally closed 2CV 0340 2 can also be reclosed. Since this line is normally in standby and 2CV 0340-2 opens on an EFW demand, pipe break is assumed to occur during a test or accident demand.

Spatial Effects: Propagation Effected Location: Room 2040 Spatial Effects Comments: The fuel pool cooling and purification pumps are in the vicinity of this piping and are likely impacted (Judged to be low consequence due to significant time for recovery and makeup). 'Ihe most important component, MCC 2B52, is at the other end of the room. It is assumed to fall for the case where operators fall to detect and isolate.

Initiating Event: N Initiating Event ID: N/A laitiating Event Recovery: Pipe break during standby is judged less likely then during a pump test demand. An independent loss of PCS (T2)is assumed to challenge piping.

Ioss of System: S System IPE ID:

PCS System Recovery: PCS loss is assumed to be the initiator.

Loss of Train: TM-4 Train ID:

Turbine EFW, HPSI A. LPSI A, CSS A Train Recovery: Steam supply to the turbine EFW pump is unavailable. For the failure to detect and isolate case, it is assumed MCC 2BS2 is affected which contains breakers for key valves. 'Ihese valves include normally closed valves in containment spray train A, HPSI train A cold leg supplies, and LPSI train A.

Consequence Comment: Consequence is " low" based on Table 2 2 (Anticipated challenge, between test exposure, and 2.5 backup trains available, including motor EFW, AFW, and once through cooling). For the failure to isolate case (loss of MCC 2B52), the censequence is also ' low" because there is still 2.5 backup trains with a train of once through cooling, motor EFW, and isoaltion failure. Containment isolation is unaffected.

Consequence Category: Low 0

Consequence Rank:

O OO 72

/

PAGE 153

CALC, NO, NSD 018 13-Aug-97 FMECA - Consequence Information Report h

Consequence ID: MS-C-08 Consegnence

Description:

Degradation of EFW steam supply on demand in Room 2024 (line 2EBC 1 in Room 2024).

Break Size:

Large Isolability of Break: Yes ISO Comments: 2CV-10001 and 2CV.1050 2 can be closed by the operators to isolate this break. Normally closed 2CV-0340-2 can also be reclosed. Since this line is normally in standby and 2CV-0340 2 opens on an EFW demand, pipe break is assumed to occur during a test or accident demand.

Spatial Effects: Propagation Effected Iecation: Room 2024 Spatial Effects Comments: The turbine EFW pump room is watertight (except for floor drain) with heavy doors that open into the room. Steam leakage through penetrations (to Room 2040) and the floor drain (to auxiliary building sump at El 317) is expected, but this is not judged significant enough to impact safety equipment.

Initiating Event: N Initiating Event ID: N/A Iultiating Event Recovery: Pipe break during standby is judged less likely than during a pump test demand. An independent loss of PCS (T2)is assumed to challenge piping.

Loss of System: S System IPEID:

PCS System Recovery: PCS loss is assumed to be the initiator.

Iess of Trala: T Train ID:

Turbine EFW Train Recovery: Steam supply to the turbine EFW pump is unavailable.

Consequence Comment: Consequence is ' Low" based on Table 2-2 (Anticipated challenge, between test exposure, and 2.5 backup trains available, including motor EFW, AFW, and once through cooling). For the failure to isolate case, the consequence is judged to 've similar since Room 2024 contains most of the steam. Containment isolation is unaffected.

Consequence Category: LOW D

Consequence Rank:

O l

O 73

(

PAGE 154

CALC, NO, N SD 018 h

I$ Aug-97 FMECA - Consequence Information Report Consequence ID: MS-C-09A Consequence

Description:

Degradation of MSIV bypass line during normal operation (line 2 EBB.16 from main steam line 2 EBB 1 to 2C%1040-1).

Break Size:

Large Isolability of Break No ISO Comments: Blowdown from faulted steam generator is not isolable. This line is not large enough to cause an autmatic plant trip or MSIV isolation.

Spatial Effects: Propagation Effected IAcation: Room 2155 Spatial Effects Comments: Propagation is through access doors and room siding to outside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a stairway door into the turbine auxiliary building.

3 Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Piping is not large enough to cause an automatic plant trip. Detection is expected from a high power alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe Loss of System: S System IPE ID:

PCS System Recovery: PCS loss is assumed to be the demand.

Imsu of Train: TDM 2 Train ID:

PCS, Turbine EFW f\\

Q Train Recovery; 'Ihe affected steam generator would be isolated once identified during the controlled shutdown.

I of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply path is more reliable than the turbine EFW pump, itself.

Consequence Comment: Consequence is "Iow" based on Tables 2 2 (anticipated challenge, long AOT, abd at a

least 2 backup trains available, including EFW, AFW, and once through cooling).

3 Passive closed barrier provided by the steam generator is credited for containment isolation.

Consequence Category: low D

Consequence aank:

O

(

74 j

l h

PAGE 15 5

CALC, NO.

NSD 018 13-Aug-97 FMECA - Consequence Information Report h-Consequence ID: MS-C 09B Consequence

Description:

Degradation of MSIV bypass line during normal operation (line 2 EBB 17 from main steam line 2 EBB 2 to 2CV 1090-2).

Break Stae:

Large Isolabuity of Break: No ISO Cotaments: Blowdown from faulted steam generator is not isolable. This line is not large enough to cause an automatic plant trip or MSIV isolation.

Spatial Effee.s: Propagation Effected Location: Room 215$

Spatial Effects Comments: Propagation is through access doors and room siding to o"tside (roof of adjoining buildings), down through main steam line chase toward the turbine building, and through a stairway door into the turbine auxiliary building.

Initiating Event: N Initiating Event ID: N/A Initiating Event Recovery: Piping is not large enough to cause an automatic plant trip. Detection is erpected from a high oower alarm and a controlled shutdown is assumed due to standing orders to do so as a result of any unknown or uncontrolled loss of 50 Mwe.

Loss of System: S System IPE ID:

PCS System Recovery: PCS loss is assumed to be the demand.

Loss of Traln: TDM 2 Trr.in ID:

PCS, Turbine EFW Train Recovery: The affected steam generator would be isolated once identified during the controlled shutdown.

1 of 2 steam supply paths to the turbine EFW pump is unavailable, but the other steam supply j

path is more reliable than the turbine EFW pump, itself.

Consequence Comment: Consequence is " low" based on Tables 2 2 (anticipated challenge, long AOT, abd at least 2 backup trains available, including EFW, AFW, and once throup cooling).

Passive closed barrier provided by the steam generator is credited for containment isolation.

Consequence Category: Low O

Consequence aank:

O

\\

1 75

}

g

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