Text

Request for Alternative ANO2-R&R-004, Revision 1, Response to NRC Request for Additional Information
	ML072220160
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/06/2007
From:	Mccann J; Entergy Operations
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	CNRO-2007-00015, CNRO-2007-00028
	Download: ML072220160 (44)
	v • d • e

nteigy Entergy Operations, Inc.

1340 Echelon Parkway Jackson, Mississippi 39213-8298 Tel: 601-368-5758 John F. McCann Director, Nuclear Safety & Licensing CNRO-2007-00028 August 6, 2007 U. S. Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Request for Alternative ANO2-R&R-004, Revision 1 Response to NRC Request for Additional Information Arkansas Nuclear One, Unit 2 Docket No. 50-368 License No. NPF-6

REFERENCE:

Entergy Operations, Inc letter CNRO-2007-00015 to the NRC dated April 17, 2007

Dear Sir or Madam:

Per the referenced letter, Entergy Operations, Inc. (Entergy) submitted Request for Alternative ANO2-R&R-004, Rev. 1, which requested the NRC staff's authorization to implement a risk-informed safety classification (RISC) process for repair/replacement activities in Class 2 and 3 moderate energy systems at Arkansas Nuclear One, Unit 2 (ANO-2). In its review of the request, the NRC staff requested that Entergy provide a test case, or example, that demonstrates the RISC process. Entergy is providing the requested example in the enclosure to this letter to support the staffs review. Following approval of ANO2-R&R-004, Rev. 1, any specific application of this process to a plant system Would be initiated and controlled in accordance with appropriate engineering programs.

In addition to submitting the requested example, Entergy revises the need date for ANO2-R&R-004, Rev. 1 to April 17, 2008. Should you have any questions regarding this submittal, please contact Guy Davant at (601) 368-5756.

This letter contains no commitments.

JFM/GHD/ghd

Enclosure:

Application of Risk-Informed Safety Classification Process for Repair/Replacement Activities in Class 2 and 3 Moderate Energy Systems kL)6ý

CNRO-2007-00028 Page 2 of 2 cc: Mr. J. S. Forbes (ECH)

Mr. 0. Limpias (WPO)

Mr. T. G. Mitchell (ANO)

Dr. Bruce S. Mallett U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 U. S. Nuclear Regulatory Commission Attn: Mr. Alan Wang .

MS O-7D1 Washington, DC 20555-0001 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847

CNRO-2007-00028 bcc: Mr. W. B. Abraham (G-ADM2-LIC)

Mr. C. A. Bottemiller (G-ADM2-LIC)

Mr. W. B. Brice (M-ECH-521)

Mr. J. J. Costedio (K-JAF-H145)

Mr. A. Y. Eng (K-WPO-12C)

Ms. C. D. Faison (K-WPO-12C)

Ms. S. T. Fontenot (W-GSB-318)

Mr. B. S. Ford (M-ECH-521)

Mr. K. W. Hall (M-ECH-36)

Mr. D. E. James (N-GSB-64)

Mr. R. S. Lewis (M-ECH-36)

Mr. D. N. Lorfing (R-GSB-42)

Ms. K. A. Maher (R-GSB-42)

Mr. D. J. Mannai (V-VYP-1 03)

Mr. R. J. Murillo (W-GSB-318)

Mr. D. J. Ropson (K-WPO-11 D)

Ms. K. K. U. Tom ((K-JAF-H716)

Ms. D. S. Waldron (N-GSB-64)

Mr. R. W. Walpole (K-IP-GSB2E)

Echelon Information Management File [54]

ENCLOSURE CNRO-2007-00028 APPLICATION OF RISK-INFORMED SAFETY CLASSIFICATION PROCESS FOR REPAIR/REPLACEMENT ACTIVITIES IN CLASS 2 AND 3 MODERATE ENERGY SYSTEMS

Enclosure to CNRO-2007-00028 Page lof40 APPLICATION OF RISK-INFORMED SAFETY CLASSIFICATION PROCESS FOR REPAIR/REPLACEMENT ACTIVITIES IN CLASS 2 AND 3 MODERATE ENERGY PIPING SYSTEMS I. OVERVIEW This document package contains an example application of the risk-informed safety classification (RISC) process to be applied to repair/replacement activities in Class 2 and 3 moderate energy piping systems. This process was submitted to the NRC staff for approval by Entergy Operations, Inc. (Entergy) as Request for Alternative ANO2-R&R-004, Rev. i via letter CNRO-2007-00015 dated April 17, 2007. The RISC process was developed by EPRI and is founded upon the EPRI risk-informed inservice inspection (RI-ISI) evaluation procedure (EPRI TR-1 06706, Rev B-A).

The NRC granted Arkansas Nuclear One, Unit 2 (ANO-2) approval to implement what, is known as a full-scope RI-ISI program [i.e., Class 1, 2, and some 3 / non-nuclear safety (NNS) piping] using the EPRI RI-ISI procedure.' As such, the vast majority of the information necessary to support the repair/replacement relief request already exists.

The final piece of the process is what is termed "the additional considerations', which consists of a series of questions that supplement the consequence evaluation that was previously developed as part of the RI-ISI application. These additional considerations were addressed by developing draft responses and conducting an interdisciplinary review during a-meeting held on July 12, 2007 at the ANO site.

II. APPLICATION As requested by the NRC, Entergy has developed this example application of the RISC process by applying it to the Containment Spray System (CSS). 2 The CSS evaluation does not credit the Containment Cooling System (CCS), which provides another means of containment heat removal independent of CSS. As such, the consequence rank identified herein is conservative for a numberof segments. However, the rank of high-ranked segments would not change since failure of these segments typically results in a loss of Emergency Core Cooling Systems (ECCS) and/or a containment bypass potential.

Table 1, below, is taken from the RI-ISI evaluation for CSS with one modification being to ID

s CSS-C-17A and -17B, which no longer credit CCS as available backup. 3 Figures 1 and 2, also taken from the RI-ISI evaluation, provide simplified piping diagrams of CSS.

1 The NRC's approval is documented in a letter to ANO-2 dated December 29,1998.

2 Any specific application of this process to a plant system would be initiated and controlled in accordance with appropriate engineering programs.

3 Entergy submitted the ANO-2 RI-ISI application, which included the Consequence Information Reports, to the NRC via letter 2CAN099706 dated September 30, 1997.

Enclosure to CNRO-2007-00028 Page 2 of 40 TABLE 1 CSS Consecluence Assessment Summary

.. ID * ": 'Descripion - - ^ .,. " Configum-tior i Initiator .Ioaion'*.-

a- : ,.,,;*. - Backup Containment ', Tm N t l=:*": ;

Decito -Spatial Cnguain Itaor slton -System. AalbeEpsr TbeUed Rank I -Location. IsP t, Impacts ckp Cnamet Time (Note 1 Trains CSS-C-01 Common RWT Outside Demand Assumed No CSS, HPSI, 0 Unaffected between 2-2 HIGH suction outside M LPSI test CSS-C-02 Common RWT Assumed No CSS, HPSI, Unaffected between 2-2 HIGH suction inside 2040 Demand M LPSI test CSS-C-03A RWT suction A 2040 Demand Assumed 2CV-5630 ECCS A or 1 (ECCS B or Unaffected between 2-2 MEDIUM in 2040 M all ECCS isolation) test CSS-C-03B RWT suction B Assumed 2CV-5631 all ECCS & Unaffected between 2-2 HIGH in 2040 2040 Demand M CSS test CSS-C-04A RWT suction A Assumed 2CV-5630 ECCS A or 1 (ECCS B or Unaffected between 2-2 MEDIUM inscin 2014 Demand M all ECCS isolation) test CSS-C-04B RWT-suction 2007 Demand in 2007 B Assumed M 2CV-5631 ECCS all ECCS B o. 1 (ECCS A or isolation) Unaffected between test 2-2 MEDIUM CSS-C-05 RWT suction B 2006 Demand Assumed 2CV-5631 ECCS B or 1 (ECCS A or Unaffected between 2-2 MEDIUM in 2006 eM all ECCS isolation) test.

CSS-C-06A Sump suction Assumed 2CV-5647 ECCS Ao.r 1 (ECCS B or Bypass if Isol all year 2-2 HIGH A in 2014 M all ECCS isolation) fails CSS-C-06B Sump suction B in 2007 2007 Demand Assumed M

ECCS all ECCS B 2r 1 (ECCS A or isolation) failsif Isol Bypass 2P-35A Assumed Trip pump & ECCS A or 1 (ECCS B or between 2-2 MEDIUM CSS-C-07A discharge to 2014 Demand M 2CV-5630 all ECCS isolation) Unaffected test 2E35A 2P35B Assumed Trip pump & ECCS B or 1 (ECCS A or between CSS-C-07B discharge to 2007 Demand -- Unaffected t2-2 MEDIUM 2E35B M 2CV-5631 all ECCS isolation) test 2P-3A miiAsume Trp pup &between CSS-C-08A 2P-35A mini 2014 Demand Assumed Trip pump & CSS A 1 (CSS B . Unaffected between 2-2 MEDIUM flow M 2CV-5630 test CSS-C-08B 2P35B mini Assumed Trip pump & CSS B 1 (CSS Al) Unaffected between 22 MDU flow 2007 Demand M 2CV-5631 test 22 MDU

Enclosure to CNRO-2007-00028 Page 3 of 40 Spatialpt System AalbeExposure

..ID Description Laon Configuration Initiator liolation .I.mpacts Backup Containment Time i Table Used (Nblet1) Rank Trainsý CSS-C-09A Downstream of Assumed Trip pump & ECCS A or 1 (ECCS B or between 2-2 MEDIUM 2E35A in 2014 2014 Demand M 2CV-5630 all ECCS isolation) Unaffected test CSS-C-09B Downstream of 2007 Demand Assumed Trip pump & ECCS B or 1 (ECCS A or Unaffected between 2-2 MEDIUM 2E35B in 2007 M 2CV-5631 all ECCS isolation) test CSS-C-1 OA 2P-35A test 2011 Demand Assumed Trip pump & ECCS A f 1 (ECCS B or Unaffected between 2-2 MEDIUM return in 2011 M 2CV-5630 all ECCS isolation) test CSS-C-10B 2P35B test 2011 Demand Assumed Trip pump & ECCS B or 1 (ECCS A or between return in 2011 M 2CV-5631 all ECCS isolation) Unaffected test 2-2 MEDIUM CSS-C-11A Downstream of 2055 Demand Assumed Trip pump & - ECCS A or 1 iECCS B or Unaffected between 2-2 MEDIUM 2E35A in 2055 M 2CV-5630 all ECCS isolation) test CSSýC-11B Downstream of 2055 Demand Assumed Trip pump & ECCS B or 1 (ECCS A or between 2-2 MEDIUM 2E35B in 2055 M 2CV-5631 all ECCS isolation) Unaffected test Upstream of CSS-C-12A 2CV-5612 in 2084 Demand Assumed Trip pump & ECCS A or 1 (ECCS B or Unaffected between 2-2 MEDIUM 2084 M 2CV-5630 all ECCS isolation) test CSS-C-12 Upstream U

2CV-5613 of in 2084 Demand Assumed Trip pump & ECCS B or 1 (ECCS A or Unaffected between 2-2 MEDIUM 2 2084 M 2CV-5631 all ECCS isolation) test Downstrea of CSS-C-13A 2CV-5612 in 2084 Demand Assumed Trip pump & CSS A or 1 (CSS B or 2BS-5A all year 2-2 MEDIUM 2 2084 M 2CV-5612 all ECCS isolation) inside CSS-C-13B Downstream 2CV-5613 inof 2084 Demand Assumed Trip pump & CSS B or 1 (CSS A or 2BS-5B all year 2-2 MEDIUM 2 2084 M 2CV-5613 all ECCS isolation) inside Downstream of 2CV-5612 CSS-C-14A 2CV-5612 in Containment Demand Assumed Trip pump & none 2 and closed all year 2-2 LOW.

Containment M 2CV-5612 system outside Downstream of 2CV-5613 CSS-C-14B 2CV-5613 in Containment Demand Assumed Trip pump & none 2 and closed all year 2-2 LOW Containment M 2CV-5613 system outside CSS-C-15A NaOH to Train 2014 Demand Assumed Trip pump & ECCS A 1 ECCS B Unaffected between 2-2 MEDIUM A 2 D M 2CV-5630 E A 1 test

Enclosure to CNRO-2007-00028 Page 4 of 40 Note 1: Tables contained in Yankee Nuclear services Division Calculation No. NSD-018, Rev. 0, August 1997, Consequence Evaluation of ANO-2 EFW, Containment Spray, and Main Steam and FeedwaterSystem Piping, Arkansas Nuclear 1, Unit 2 Note 2: Segments 18A and 18B were not part of the original RI-ISI application (i.e., not within ASME Section Xl scope). Postulated failures of these segments have the same impact as segments 14A and 14B.

Enclosure to CNRO-2007-00028 Page 5 of 40 R e fu elin g " - ------------- C-S-C---- -------------

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.... * ... -2 .... ... . ... ... * .... ... .... . .. " P 35B FIGURE 1 Containment Spray System (CSS) Suction

Enclosure to CNRO-2007-00028 Page 6 of 40 S. . .. ......

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Enclosure to CNRO-2007-00028 Page 7 of 40 III. ADDITIONAL CONSIDERATIONS Piping segments that were determined to be a "Medium", "Low", or "None" consequence category per the consequence evaluation are determined to be high safety significant (HSS) or low safety significant (LSS) by considering the information in Conditions (1) through (10),

below.

Note: Although a large pressure-boundary leak is not always assumed, it was during the RI-ISI evaluations. Also, credit may be taken for plant features and operator actions to the extent these would not be affected by failure of the segment under consideration. If plant features and operator actions are credited, they shall be consistent with those credited in the previous consequence evaluations.

(1) Failure of the pressure-retaining function of the segment will not directly or indirectly (e.g., through spatial effects) fail a basic safety function.

Response

Per Table I above, any segment classified as "Medium"or "Low"will have at least one train unaffected by the postulatedbreak. Perthe glossary,loss of a single train would typically not constitute loss of a basic function.

(2) Failure of the pressure-retaining function of the segment will not prevent the plant from reaching or maintaining safe shutdown conditions; and the pressure-retaining function is not significant to safety during mode changes or shutdown. Assume that the plant would be unable to reach or maintain safe shutdown conditions if a pressure boundary failure results in the need for actions outside of plant procedures or available backup plant mitigative features.

Response

Although the CSS can be used to support shutdown [e.g., as an altemative to Low PressureSafety Injection (LPSI)pumps, the Reactor Water Tank (RWT) provides inventory for filling the refueling canal], the CSS is typically not used to support mode changes or shutdown cooling. Perthe consequence evaluations conducted above, any segment classified as "Medium"or "Low"will have at least one train unaffected by the postulatedbreak. In addition, the consequence evaluation methodology includes an assessment of piping failure during shutdown evolutions.

(3) The pressure-retaining function of the segment is not called out or relied upon in the plant Emergency/Abnormal Operating Procedures (EOPs) or similar guidance as the sole means for successfully performing Operator actions required to mitigate an accident or transient.

Response

While CSS is creditedin the EOPs,per the consequence evaluationsconducted above, any segment classified as "Medium"or "Low" will have at least one train unaffected by the postulated break. As such, these segments (i.e., those categorized as "Medium"or

Enclosure to CNRO-2007-00028 Page 8.of 40 "Low") are not the sole means for successfully performing operatoractions requiredto mitigate an accident or transient.

(4) The pressure-retaining function of the segment is not called out or relied upon in the plant EOPs or similar guidance as the sole means for assuring long-term containment integrity, monitoring of post-accident conditions, or offsite emergency planning activities.

Response

While CSS is credited in the EOPs,per the consequence evaluations conducted above, any segment classifiedas "Medium"or "Low" will have at least one train unaffected by the postulated break. As such, these segments (i.e., those categorized as "Medium"or "Low")are not the sole means for assuringlong-term containment integrity. Additionally, the containment coolers provide an altemate means of containmentcooling and the CSS does not provide a post-accident monitoring function or offsite emergency planning function.

(5) Failure of the pressure-retaining function of the segment will not result in an unintentional release of radioactive material that would result in implementing offsite radiological protective actions.

Response

Failureof the CSS will not cause such events. Rather, the function of the CSS is to respond to such events (e.g., LOCAs). Additionally, per the consequence evaluations conducted above, any segment classified as "Medium"or "Low" will have at least one train unaffected by the postulated break. As such; the design basis function of the CSS will still be fulfilled.

The RISC process shall demonstrate that the defense-in-depth philosophy is maintained.

Defense-in-depth is maintained if:

(6) Reasonable balance is preserved among prevention of core damage, prevention of containment failure or bypass, and mitigation of an offsite release.

Response

This balance is preserved as there'is no change to the design, design basis, or operation of the CSS by this change. The CSS is still required to reliably perform its safety-relatedfunction.

(7) There is no over-reliance on programmatic activities and operator actions to compensate for weaknesses in the plant design.

Response

The consequence evaluation conducted reflects the as-operated/as-designedplant.

This evaluation does not increasethe reliance on programmaticactivities or operator actions. Operatoractions, when credited, are credited consistent with the approved RI-ISI consequence evaluation methodology.

Enclosure to CNRO-2007-00028 Page 9 of 40 (8) System redundancy, independence, and diversity are preserved commensurate with the expected frequency of challenges, consequences of failure of the system, and associated uncertainties in determining these parameters.

Response

System redundancy,independence, and diversity are preserved since there is no change to the design, design basis, or operation of the CSS by this change. The CSS will still be required to reliablyperform its safety-relatedfunction.

(9) Potential for common cause failures is taken into account in the risk analysis categorization.

Response

Yes, "common cause"is a fundamental aspect of the consequence evaluation methodology and, therefore, is taken into account (e.g., see Table 1-2 of ANO2-R&R-004, Rev. 1).

(10) Independence of fission-product barriers is not degraded.

Response

Independence of fission barrieris not degraded since no new dependencies have been created. The CSS is still required to reliablyperform its safety-related function.

If any of the above ten (10) conditions are not true, then HSS shall be assigned. Otherwise, LSS is assigned.

Based upon the above, segments assigned to "Medium" or "Low" consequence rank do not have to be moved into the high consequence rank and can be assigned as "LSS" provided "safety margin" is adequately addressed below.

IV. SAFETY MARGINS As a final step, the RISC process verifies that there are sufficient safety margins to account for uncertainty in the engineering analysis and in the supporting data. Safety margin is incorporated when determining performance characteristics and parameters; e.g., piping segment, system, and plant capability or success criteria. The amount of margin should depend on the uncertainty associated with the performance parameters in question, the availability of alternatives to compensate for adverse performance, and the consequences of failure to meet the performance goals. Sufficient safety margins are maintained by ensuring that safety analysis acceptance criteria in the plant licensing basis are met, or proposed revisions account for analysis and data uncertainty.

Response

Since the safety analysis acceptance criteriain the plant licensing basis are not changed, safety margins remain unchanged and, therefore, acceptable.

Enclosure to CNRO-2007-00028 Page 10 of 40 Based upon all the preceding factors a final RISC for the CSS has been determined. These results are provided in Table 2.

TABLE 2 Final RISC Assiqnments ID Description Spatial Location Rank CSS-C-01 Common RWT suction outside Outside HIGH CSS-C-02 Common RWT suction inside 2040 HIGH CSS-C-03A RWT suction A in 2040 2040 LOW CSS-C-03B RWT suction B in 2040 2040 HIGH CSS-C-04A RWT suction A in 2014 2014* LOW CSS-C-04B RWT suction B in 2007 2007 LOW CSS-C-05 RWT suction B in 2006 2006 LOW CSS-C-06A Sump suction A in 2014 2014 HIGH CSS-C-06B Sump suction B in 2007 2007 HIGH CSS-C-07A 2P-35A discharge to 2E35A 2014 LOW CSS-C-07B 2P35B discharge to 2E35B 2007 LOW CSS-C-08A 2P-35A mini flow 2014 LOW CSS-C-08B 2P35B mini flow 2007 LOW CSS-C-09A Downstream of 2E35A in 2014 2014 LOW CSS-C-09B Downstream of 2E35B in 2007 2007 LOW CSS-C-10A 2P-35A test return in 2011 2011 LOW CSS-C-10B 2P35B test return in>2011 2011 LOW CSS-C-11A Downstream of 2E35A in 2055. 2055 LOW CSS-C-1 1B Downstream of 2E35B in 2055 2055 LOW CSS-C-12A Upstream of 2CV-5612 in 2084 2084 LOW CSS-C-12B Upstream of 2CV-5613 in 2084 2084 LOW CSS-C-13A Downstream of 2CV-5612 in 2084 2084 LOW CSS-C-13B Downstream of 2CV-5613 in 2084 2084 LOW CSS-C-14A Downstream of 2CV-5612 in Containment Containment LOW CSS-C-14B Downstream of 2CV-5613 in Containment Containment LOW CSS-C-15A NaOH to Train A 2014 LOW CSS-C-1 5B NaOH to Train B 2007 LOW CSS-C-1 6 RWT to SFPP & charging Outside 2040 LOW CSS-C-17A Service air connection to Train A 2084 LOW

Enclosure to CNRO-2007-00028 Page 11 of 40 ID Description. Spatial Location Rank CSS-C-17B Service air connection to Train B 2084 LOW CSS-C-1 8A Downstream of 2BS-5A in Containment Containment LOW CSS-C-1 8B Downstream of 2BS-5B in Containment Containment LOW V. CONSEQUENCE INFORMATION REPORTS The Consequence Information Reports, which were developed for the ANO-2 RI-ISI program, summarize the consequence evaluation process. 4 As noted earlier, the CSS evaluation did not credit the Containment Cooling System (CCS). As such, the consequence rank identified herein is conservative for a number of segments. However, the rank for high-ranked segments would not change since failure of these segments typically results in a loss of all ECCS and / or a containment bypass potential.

FMECA - Consequence Information Report CalculationNo. A-PENG.CALC-015. Rev. 00 14-Sep-9 Page A2 of A31 Consequence ID: CSS-C-01 Consequence

Description:

Degrdation of common RWT suction outside auxiliary building during an independent demand (line 2HCB-24 outside)

Break Size: Large Isolability of Break. No ISO Comments: Unisolable.

Spatial Effects: Local Effected Location: Outside Spatial Effects Comments: The common RWT suction piping outside the auxiliary building (near the RWT) can not propagate to the auxiliary building and impact safety equipment' 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 bejust as likely (i.e.,

demand stress of RWT head is not significantly different during demand).

Loss of System: SM-3 System IPE MD: CSS, HPSI, LPSI System Recovery: Loss of RWT (flow diversion) results in common cause failure of all ECCS.

Loss of Train: N Train ID: N/A Train Recovery: N/A Consequence Comment: Consequence is "High" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and no backup trains). No impact on containment isolation.

Consequence Category: HIGH 03 Consequence Rank 0 4 Entergy submitted the ANO-2 RI-ISI application, which included the Consequence Information Reports, to the NRC via letter 2CAN099706 dated September 30, 1997.

Enclosure to CNRO-2007-00028 Page 12 of 40 FMECA - Consequence Information Report Calculat-,n No. A-PENG-CALC-O15. Rev. 00 14-Sep-9 Page A3 of A31 Consequence ID: CSS-C-02 Consequence

Description:

Degradation of common RWT suction upstream of 2CV-5630 & 5631 in auxiliary building during an independent demand (line 2HCB-24 in auxiliary building)

Break Size: Large Isolability of Break: No ISO Comments: Unisolable.

Spatial Effects: Propagatio n Effected Location: Room 2040 Spatial Effects Comments: The common RWT suction piping will likely fail MCC 2B52 in the corridor at El 335 (Room 2040) and propagate to El 317 (Rooms 2006 & 201 1) through floor drains and the east stairway. Also, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014). Detection is provided by auxiliary building sump high level alarm and the ECCS room flood alarms in the control room, but this is irrelevant since the break is unisolable.

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 ED: CSS, -PSI, LPSI System Recovery: Loss of RWT (flow diversion) results in common cause failure of all ECCS.

Loss of Train: N Train ID: N/A Train Recovery: N/A Consequence Comment: Consequence is "High" based on Table 2-2 of RIf 9.18 (unexpected frequency of challenge, between test exposure, and no backup trains). No impact on containment isolation.

Consequence Category: FUGH 13 Consequence Rank 1:1 Consequence Category: HIGH 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 13 of 40 FMECA - Consequence Information Report CalculatonNo. A-PENG*CALC-0)5. Rev. 00 14-Sep-9 Page A4 of A31 Consequence ID: CSS-C-03A Consequence

Description:

Degradation of RWT suction A downstream of 2CV-5630 in Room 2040 during an independent demand (line 2HCB-26 in Room 2040)

Break Size: Large Isolabifity of Break: Yes ISO Comments: 2CV-5630-1 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 level 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 fail 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. MCC 2B52 contains breakers for normally closed CSS valves 2CV.

5612-1 and 5649-1 (containment sump recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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, HPSI, LPSI System Recovery: Isolation failure is assumed to fail all ECCS either due to flow diversion or insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-3 Train El): 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 of Ref. 9.18 (unexpected frequency of challenge, 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 Consequence Rank r' Consequence Category: MEDIUM El Consequence Rank C

Enclosure to CNRO-2007-00028 Page 14 of 40 FMECA - Consequence Information Report CalculaftonNo. A-PENG-CALC-0)5. Rev. 00 14-Sep-9 Page A5 of A31 Consequence ED: CSS-C-03B Consequence

Description:

Degradation of RWT suction B downstream of 2CV-5631 in Room 2040 during an independent demand (line 214CB-27 in Room 2040)

Bre"k Size: Large Isolability of Break: Yes ISO Comments: 2CV-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 RWTIevel alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagatio n Effected Location: Room 2040 Spatial Effects Comments: RWT suction piping will likely fail 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. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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, HPSI LPSI System Recovery: Isolation failure is assumed to fail 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 2CV-5612-1 can not fully open for train A success due to flood impact on its breaker in MCC2B52.

Loss of Train: TM-2 Train ED: HPSI B, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B and both trains of CSS as shown above.

Consequence Comment: Consequence is "High" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and no backup train). No impact on containment isolation.

Consequence Category: FUGH El Consequence Rank E]

Consequence Category: HIGH 0 Consequence Rank C

Enclosure to CNRO-2007-00028 Page 15 of 40 FMECA - Consequence Information Report Calculadon No. A-PENG-CALC-015, Rev. 00 14-Sep-9 Page A6 of A3)

Consequence ID: CSS-C-04A Consequence

Description:

'Degradation of Suction A downstream of 2CV-5630 & 2CV-5649 in Room 2014 during an independent demand (lines 2HCB-26 and 2HCB-15 downstream of 2CV-5649 in Room 2014)

Break Size: Large'. Isolability of Breiak Yes ISO Comments: 2CV-5630-1 can be closed from the control room (break is assumed to occur during RWIT injection phase). Detection is based on Room 2014 flood alarm, auxiliary 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).

However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fail 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: N/A Initiating Event Recovery: A medium LOCA CM) 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 signficantly different during demand).

Loss of System: SM-3. System IPE ID: CSS, -PSI, LPS1 System Recovery: Isolation failure is assumed to fail all ECCS either due to flow diversion or insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and 1 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: lffiDrLJM 13 , Consequence Rank 13 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 16 of 40 FMECA - Consequence Information Report, CalculationNo. A-PENG-CALC-0Z5, Rev. 00 14-Sep-9 Page A7 of A31 Consequence ID: CSS-C-04B Consequence

Description:

Degradation of Suction B downstream of 2CV-5631 & 2CV-5650 in Room 2007 during an independent demand (lines 2HCB-27 and 2HCB-13 downstream of 2CV-5650 in Room 2007)

Break Size: Large Isolability of Break: Yes ISO Comments: 2CV-5631-2 can be closed fi-om the control room (break is assumed to occur during RWT injection phase). Detection is based on Room 2007 flood alarm, auxiliary 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 2007 Spatial Effects Comments: RWT suction piping will likely flood ECCS train 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).

However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fail 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: 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 bejust as likely (i.e.,

demand stress of RWT head is not signficantly different during demand).

Loss of System: SM-3. System WPE ID: CSS, HPSI, LPSI System Recovery: Isolation failure is assumed to fail all ECCS either due to flow diversion or insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and I backup train - ECCS train A). The failure to isolate case is a "Medium" based on 1 backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM 11 Consequence Rank []

Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 17 of 40 FMECA - Consequence Information Report Calklatiwi No. A-PENG-C4LC-O)5. Rev. O0 14-Sep-9 Page A8 of A31 Consequence ID: CSS-C-05 Consequence

Description:

Degradation of RWT suction B downstream of 2CV-5631 in Room 2006 during an independent demand (line 2HCB-27 in Room 2006)

Break Size: Large Isolability of Break: Yes ISO Comments: 2CV-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 level alarm will also occur, but it could be associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected Location: 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 RWT inventory to fail 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 (Mvi) 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, HPS!, LPSI System.Recovery: Isolation failure is assumed to fail all ECCS either due to flow diversion, flooding, or insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-3 Train ED: 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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and I backup train - ECCS train A). The failure to isolate case is a "Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM Consequence Rank 0.

Consequence Category: MEDIUM D Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 18 of 40 FMECA - Consequence Information Report Calculaton No:A-PENG-CALC-01. Rev. 00 I4-Sep-9 Page 'A9 of A31 Consequence ID: CSS-C-06A Consequence

Description:

Degradation of containment sump suction A upstream of 2CV-5649 during an independent demand (line 2HCB-15 from containment sump to 2CV-5649)

Break Size: Large Isolability of Break: Yes ISO Comments: 2CV-5647-1 can be closed from the control room. Detection is based on Room 2014 flood alarm and auxiliary building sump level.

Spatial Effects: Propagation Effected Location: Room 2014 Spatial Effects Comments: Containment sump 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 and draining the sump into the auxiliary building.

Detection is provided by Room 2014 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 (M) initiator is assumed to challenge this piping.

Loss of System: SM-3 System IPE ID: CSS, HPSL LPSI System Recovery: Isolation failure case is assumed to lead to loss of containment sump (common cause failure of ECCS recirculation).

Loss of Train: TM-3 Train ID: CSS A, HPSI A, LPSI A Train Recovery: Isolation success leads to loss of ECCS train A recirculation.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, all year exposure, and .1 backup train - ECCS train B). The failure to isolate case is a "Medium" based on I backup train (isolation). The consequence is upgraded to "High" because piping failure together with failure to isolate (MOV 2CV-5647-1 failure to close) can result in containment bypass (Table 2-4 of Ref. 9.18)

Consequence Category: HIGH 0 . Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 19 of 40 FMECA - Consequence Information Report Calculation No. A-PENG-CALC-O)5, Rev. 00 14-Sep-9 Page AIO of AS)

Consequence EID: CSS-C-06B Consequence

Description:

Degradation of containment sump suction B upstream of 2CV-5650 during an independent demand (line 2HCB-13 from containment sump to 2CV-5650)

Break Size: Large I olability of Break: Yes ISO Comments: 2CV-5648-2 can be closed from the control room. Detection is based on Room 2007 flood alarm and auxiliary building sump level.

Spatial Effects: Propagation. Effected Location: Room 2007 Spatial Effects Comments: Containment sump suction piping will likely 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.

Detection is 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 (M) initiator is assumed to challenge this piping.

Loss of System: SM-3 System IPE ID: CSS, HPSL LPSI System Recovery: Isolation failure case is assumed to lead to loss of containment sump (common cause failure of ECCS recirculation).

Loss of Train: TM-3 ' Train ID: CSS B, -PSI B, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B recirculation.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, all year exposure, and 1 backup train - ECCS train A). The failure to isolate case is a "Medium" based on 1 backup train (isolation). The consequence is upgraded to "High" because piping failure together with failure to isolate (MOV 2CV-5648-2 failure to close) can result in containment bypass (Table 2-4 of Ref. 9.18).

Consequence Category; lUGH 0 Consequence Rank 13 Consequence Category: HIGH 0 Consequence Rank 0

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Consequence ID: CSS-C-07A Consequence

Description:

Degradation of Pump 2P35A discharge to heat exchanger 2E35A during an independent demand (line 2GCB-10)

Break Size: Large Isolability of Break: Yes ISO Comments: Tripping the pump and closing suction MOV 2CV-5630 may be required to prevent gravity draining through pump 2P35A from the RWr (break is assumed to occur during RWT injection phase). Detection is based on Room 2014 flood alarm, auxilhazy 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: 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 flood 2007 (ECCS train B). However, failure to isolate can be assumed to result in loss of sufficient RWT inventosy to fail 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: 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-3 Train ED: CSS A, HPSI A, LPSI A Train Recovery: Isolation 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 of Ref. 9.18 (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 1 backup train (isolation).

Consequence Category: MEDIUM F-1 Consequence'Rank E3 Consequence Category: MEDIIJM 0 Consequence Rank 0

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Description:

Degradation of Pump 2P35B discharge to heat exchanger 2E35B during an independent demand (line 2GCB-11)

Break Size: Large Isolahility of Break: Yes ISO Comments: Tripping the pump and closing suction MOV 2CV-5631 may be required to prevent gravity draining through pump 2P35B from the RWT (break is assumed to occur during RWT injection phase). Detection is based on Room 2007 flood alarm, auxiliary 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 2007 Spatial Effects Comments: Flooding is assumed to affect train A ECCS in Room 2007 before isolation can occur. Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not flood 2014 (ECCS train A). However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fail containment sump-recirculatian. Detection is provided by ECCS room 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 (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 fail all ECCS due to insufficient RWT inventory in containment sump to support recirculation.

Loss of Train: TM-3 Train ID: CSS B, HPSI 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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and 1 backup train - ECCS train A). The failure to isolate case is a "Medium" consequence based on I backup train (isolation).

Consequence Category: MEDIUM Consequence Rank E3 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 22 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CALC-015,S. Rn, 0 14-Sep-9 Page A)3 of A31 Consequence ID: CSS-C-08A Consequence

Description:

Degradation of Pump 2P35A mini flow in Room 2014 during an independent demand (line 2GCB-35 and line 2DCB-11 upstream of 2CV-5673 in Room 2014)

Break Size: Large Isolability of Break: Yes ISO Comments: Tripping the pump and closing suction MOV 2CV-5630 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 HPSI A and LPSI A without further leakage into the room. Detection is based on Room 2014 flood alarm and auxiliary building sump high level alarm.

Spatial Effects: Propagatio n Effected Location: Room 2014 Spatial Effects Comments: Flooding is assumed to affect train A ECCS in Room 2014 if not isolated. Another oppommity to recognize the need for isolation is assumed to occur during recirculation actuation. Failure to isolate during the second opportunity by closing 2CV-5647 or 2CV-5649 (may be flooded) is assumed to fail 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 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, LPSI System Recovery: Isolation failure case (2 failures) is assumed to lead to loss of containment sump (common cause failure of ECCS recirculation).

Loss of Train: TM-3 Train ID: CSS A, HPSI A, LPSI A Train Recovery: Isolation success leads to loss of only CSS train A. Failure to isolate before recirculation (1 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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and I backup trains - CSS B in recirculation). The failure to isolate cases are "Low" consequence based on 2 backup trains (isolation and ECCS B or 2 isolations).

Consequence Category: MEDFJM 11, Consequence Rank 1-1 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 23 of 40 FMECA - Consequence Information Report CalculationNo.A-PENG.CAL. -015, Rev. 00 Page AU4 of AR) 14-Sep-9 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 2DCB-13 upstream of 2CV-'5672 in Room 2007)

Break Size: -Large Isolabitity of Break. Yes ISO Comments: Tripping the pump and closing suction MOV 2CV-5631 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-2B in Room 2007 which would allow operation of HPSI B and LPSI B without further leakage into the room. Detection is based on Room 2007 flood alarm and auxiliary building sump high level alarm.

Spatial Effects: Propagatia n Effected Location: Room 2007 Spatial Effects Comments: Flooding is assumed to affect train B 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 2CV-5648 or 2CV-5650 (may be flooded) is assumed to fail 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 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, LPSI System Recovery: Isolation failure case (2 failures) is assumed to leadto loss of containment sump (common cause failure of ECCS recirculation).

Loss of Train: TM-3 Train ED: CSS B, HPSI B, LPSI B Train Recovery: Isolation success leads to loss of only CSS train B.-Failure to isolate before recirculation (1 failure) is assumed to lead to failure of ECCS train B due to flooding in the room.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18.(uncxpected frequency of challenge, between test exposure, and I backup trains - CSS A in recirculation). The failure to isolate cases are "Low" consequence based on 2 backup trains (isolation and ECCS A or 2 isolations).

Consequence Category: MEDIUM El Consequence Rank IJ Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 24 of 40 FMECA - Consequence Information Report CalculatonNo. A-PENG-CALC-O5. Rev. 00

,4-Sep-9 Page A15 of A3 Consequence ID: CSS-C-09A Consequence

Description:

Degradation of Pump 2P35A discharge downstream of heat exchanger 2E35A in Room 2014 during an independent demand (line 2GCB-16 in Room 2014)

Break Size: Large Isolability of Break: Yes ISO Comments: 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, 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 associated with the assumed LOCA condition.

Spatial Effects: Propagation Effected 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 flood 2007 (ECCS train B). However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fail 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: N/A Initiating Event Recovery: A medium LOCA (Mvi)initiator is assumed to challenge this piping.

Loss of System: SM-3 System IPE ED: CSS, HPSI. LPSI System Recovery: Isolation failure is assumed to fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-3 Train ID: CSS A, HPSI A, LPSI A Train Recovery: Isolation 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 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and lbackup train - ECCS train B). The failure to isolate case is a "Medium" consequence based on I backup train (isolation).

Consequence Category: ME*DIUrM 13 Consequence Rank []

Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 25 of 40 FMECA - Consequence Information Report Calculafion No. A-PENG-CALC-OiS. Rev. 00 14-Sep.9 Page A16 of A31 Consequence ID: CSS-C-09B Consequence

Description:

Degradation of Pump 2P35B discharge downstream of heat exchanger 2E35B in Room 2007 during an independent demand (line 2GCB-17 in Room 2007)

Break Size: 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 2P35B from the RWT (break is assumed to occur during RWT injection phase): Detection 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 associated 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 isolation can occur. Failure to isolate is assumed to propagate into Rooms 2006 & 2011 through ventilation openings, but the RWT can not flood 2014 (ECCS train A). However, failure to isolate can be assumed to result in loss of sufficient RWT inventory to fail 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: 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-3 Train ID: CSS B, HPSI 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 of Ref. 9. 18 (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 1 backup train (isolation),

Consequence Category': hEEDUJM 0 Consequence Rank r13 Consequence Category: MEDIUM 0 Consequence Rank C

Enclosure to CNRO-2007-00028 Page 26 of 40 FMECA - Consequence Information Report Cak,,dadon No.A-PENG-C4LC-O i. Rm. 00 14-Sep-9 Page A]7 of A31 Consequence ID: CSS-C-10A Consequence

Description:

Degradation of Pump 2P35A discharge test return upstream of 2SI-5A in Room 2011 during an independent demand (line 2GCB-16 in Room 2011)

Break Size: Large Isolabitity of Break: Yes ISO Comments: 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 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 Location: Room 2011 Spatial Effects Comments: Failure to isolate is assumed to propagate into Rooms 2007, 2010, & 2014 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 fail 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.

Loss of System: SM-3. System IWE ID: CSS, HPSI, LPSI System Recovery: Isolation failure is assumed to fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (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: MIEDIUM ["]. Consequence Rank 11 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 27 of 40 Calculadon No. A-PENG-CALC-01S, Rv. 00 FMECA - Consequence Information Report 14-Sep-9 Page A18 of A31 Consequence ED:. CSS-C-10B Consequence

Description:

Degradation of Pump 2P35B discharge test return upstream of 2SI-SB in Room 2011 during an independent demand (line 2GCBT17 in Room 2011)

Break Size: 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 2P35B from the RWT (break is assumed to occr 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: Propagatio n Effected Location: Room 2011 Spatial Effects Comments: Failure to isolate is assumed to propagate into Rooms 2007, 2010, & 2014 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 inventry to fail 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 (MI) 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (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 F-1 Consequence Rank r]

Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 28 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CALC-015,Rev. 00 14-Sep-9 Page A19 of A31 Consequence ID: CSS-C-lIA Consequence

Description:

Degradation of Pump 2P35A discharge downstream of heat exchanger 2E35A in Room 2055 during an independent demand (line 2GCB-16 in Room 2055)

Break Size: Large Isolability of Break. Yes ISO Comments: 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 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 Location: Room 2055 Spatial Effects Comments: There 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. Room 2040 propagates to El 317 (Rooms 2006 & 2011) through floor drains and the east stair well. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). If unisolated, El 317 will fill up and.

propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (unexpected frequency of challenge, 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: MEDUJM 'Consequence Rank 11 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 29 of 40 FMECA - Consequence Information Report Calculation No. A-PENG-CALC-O)3, Rev. 00 14-Sep-9 Page A20 of A31 Consequence ED: CSS-C-11B Consequence

Description:

Degradation of Pump 2P35B discharge downstream of heat exchanger 2E35B in Room 2055 during an independent demand (line 2GCB-17 in Room 2055)

Break Size: 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 2P35B from the RWT (break is 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: Propagation Effected Location: Room 2055 Spatial Effects Comments: There arc no impacts in Room 2055, but propagation is into Room 2040 where MCC 2B52 is located. Isolation failure is assumed to be affected by this MCC.

Room 2040 propagates to El 317 (Rooms 2006 & 2011) through floor drains and the east stair well. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment stunp recirculation A). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation. Isolation success also leads to loss of both CSS trains due to the assumed impact on MCC 2B52 before isolation, but containment cooling provides backup train.-

Loss of Train: TM-3 Train El: CSS B, HPSI B, LPSI B Train Recovery: Isolation success leads to loss of ECCS train B and both trains of CSS as described above.

Consequence Comment: Consequence is '!Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and one backup train). The failure to isolate case is a "Medium" based on one backup train (isolation). No impact on containment isolation.

Consequence Category: MIEDIUM 13 Consequence Rank []

Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 30 of 40 FMECA - Consequence Information Report Cakulation No. A-PENG-CAW-0L1, Rev. 00 14-Sep-9 Page A21 of A31 Consequence ID: CSS-C-12A Consequence

Description:

Degradation of Pump 2P35A discharge upstream of 2CV-5612 in Room 2084 during an independent demand (line 2GCB-16 in Room 2084)

Break Size: Large Isolability of Break: Yes ISO Comments: 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 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 Location: Room 2084 Spatial Effects Comments: In Room 2084, the potential exists for spray impacts on -PSI 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 unlikely. From Room 2073 propagation continues 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 stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). MCC 21362 contains breakers for normally closed CSS valves 2CV-5613-2 and 5650-1 (containment sump recirculation B). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train:. TM-3 Train ED: 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 of Ref 9.18 (unexpected frequency of challenge, between test exposure, and 1 backup train). The failure to isolate case is a "Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category: MEDIUM [] Consequence Rank 0 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 31 of 40 FMECA - Consequence Information Report Calycodon No. A-PENG-CALC-01S. Rev. 00 14-Sep-9 Page A22 of A31 Consequence 11): CSS-C-12B Consequence

Description:

Degradation of Pump 2P35B discharge upstream of 2CV-5613 in Room 2084 during an independent demand (line 2GCB-17 in Room 2084)

Break Size: 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 2P35B from the RWT (break is 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: Propagation Effected Location: Room 2084 Spatial Effects Comments:, In Room 2084, the potential exists for spray impacts on RPSI 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 grating and the east stairway.

Propagation is 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 stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CV-5613-2 and 5650-1 (containment sump recirculation B). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

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 of Ref. 9.18 (unexpected frequency of

challenge, between test exposure, and 1 backup train). The failure to isolate case is "Medium" based on I backup train (isolation). No impact on containment isolation.

Consequence Category:, MEDIUM Consequence Rank 0]

Consequence Category: MEDIUM 0 Consequence Rank C

Enclosure to CNRO-2007-00028 Page 32 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CAC-015. Rev. 00 14-Sep-9 Page A23 of A31 Consequence ID: CSS-C-13A Consequence

Description:

Degradation of Pump 2P35A discharge downstream of 2CV-5612 in Room 2084 during an independent demand (line 2HCB-20)

Break Size: Large Isolability of Break: Yes ISO Comments: Trip pump 2P35A or close MOV 2CV-5612 (break is 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: PropagatioOn Effected Location: Room 2084 Spatial Effects Comments: In Room 2084, the potential exists for spray impacts on -PSI 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 grating and the east stairway.

Propagation is 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 stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CV-5613-2 and 5650-1 (containment sump recirculation B). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation. Isolation success also leads to loss of both CSS trains in recirculation due to assumed impact on MCC 2B62 before isolation (discharge MOV 2CV-5613 is assumed to open prior to impact on MCC).

Loss of Train: TM-1 Train ID: CSS A Train Recovery: Isolation success leads to loss of CSS train A, but containment cooling provides backup.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (uneixpcted frequency of challenge, all year exposure, and one backup train (isolation)) for failure to isolate case. The successful isolation case is a "Low" consequence with two backup trains counting containment cooling. 2BS-5A provides containment isolation inside containment.

Consequence Category: MEDIUM III 3 III Consequence Rank 11 Consequence Category: MEDIUM 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 33 of 40 FMECA - Consequence Information Report CalculagionNo. A-PENG-CALC-01, Rev. 00 9 Page A24 of A31 14-SeP Consequence ID: CSS-C-13B Consequence

Description:

Degradation of Pump 2P35B discharge downstream of 2CV-5613 in Room 2084 during an independent demand (line 2HCB-21)

Break Size: Large Isolability of Break: Yes ISO Comments: Trip pump 2P35B or close MOV 2CV-5613 (break is 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: Propagation 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 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 grating and the east stairway.

Propagation is 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 stairway. MCC 2B52 contains breakers for normally closed CSS valves 2CV-5612-1 and 5649-1 (containment sump recirculation A). MCC 2B62 contains breakers for normally closed CSS valves 2CV-5613-2 and 5650-1 (containment sump recirculation B). If unisolated, El 317 will fill up and propagate into the ECCS rooms (2007, 2010, & 2014) failing 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 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 fail all ECCS due to insufficient RWT inventory in the containment sump to support recirculation.

Loss of Train: TM-I Train ID: CSS B Train Recovery: Isolation success leads to loss of CSS train B, but containment cooling provides backup.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, all year exposure, and, I backup train for failure to isolate). The successful isolation case is a "Low" consequence with two backup trains counting containment cooling. 2BS-5B provides containment isolation inside containment Consequence Category: MEDIUM 11 Consequence Rank C

I1 Consequence Category: MEDIUM C Consequence Rank

Enclosure to CNRO-2007-00028 Page 34 of 40 FMECA - Consequence Information Report Cal,-aIdon No A-PENIG-CALC-OIS. Rev. 00 14-Sep-9 Page A25 of A31 Consequence ID: CSS-C-14A Consequence

Description:

Degradation of Pump 2P35A discharge downstream of 2CV-5612 inside containment during an independent demand (line 2HCB-3 upstream of 2BS5-SA)

Break Size: Large Isolability of Break: Yes ISO Comments: Trip pump 2P35A or close MOV 2CV-5612. but this is not necessary to prevent additional impacts since the RWT is being pumped to the containment (the pipe break affects spray effectiveness, but not the heat removal fuction). Not easy to detect except containment pressure may not reduced as fast as expected and train B is still available.

Spatial Effects: Containment Effected Location: Containment Building Spatial Effects Comments: Equipment inside containment is qualified for this event Initiating Event: N Initiating Event ED: N/A Initiating Event Recovery: A medium LOCA (M) initiator is assumed to challenge this piping.

Loss of System: N System IPE ED: N/A System Recovery: N/A Loss of Train: N Train ID: N/A Train Recovery: Loss of CSS train A occurs only if the train is isolated by the operators. The train is still capable of performing its containment heat removal function.

Consequence Comment: Consequence is "Low" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, all year exposure, and 2 backup trains - CSS A & B and ECCS A &B).

2CV-5612 and closed system outside provide containment isolation.

Consequence Category: LOW 01 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 35 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CALC-015, Rev. 00 14-Sep79 Page A26 of A31 Consequence ID: CSS-C-14B Consequence

Description:

Degradation of Pump 2P35B discharge downstream of 2CV-5613 inside containment during an independent demand (line 2HCB-4 upstream of 2BS-5B)

Break Size: Large . Isolability of Break. Yes ISO Comments: Trip pump 2P35B or close MOV 2CV-5613, but this is not necessary to prevent additional impacts since the RWT is being pumped to the containment (the pipe break affects spray effectiveness, but not the heat removal fuction). Not easy to detect exceptcontainment pressure may not reduced as fast as expected and train A is still available.

Spatial 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) initiator is assumed to challenge this piping.

Loss of System: N System WE ID: N/A System Recovery: N/A Loss of Train: N Train ID: N/A Train Recovery: Loss of CSS train B occurs only if the train is isolated by the operators. The train is still ca*able of performing its containment heat removal function.

Consequence Comment: Consequence is "Low" based on Table 2-2 of Ref. 9.18 (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 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 36 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-C4LC-OIS, Rev. 00 14-Sep-9 Page A27 of A31 Consequence ID: CSS-C-15A Consequence

Description:

Degradation of NAOH line to Train A (line 2GCB-70) during an independent demand.

Break Size: Large Isolability of Break: Yes ISO Comments: 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 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: Propagatio n Effected Location: 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 if isolation fails. Also, flow diversion impacts are not assumed.

Failure to isolate is not assumed to propagate into Rooms 2006 & 2011 during injection phase due to break size. 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 emptied into the ECCS room.

Initiating Event:. N Initiating Event ED: 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: Loss 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 Train: TM-3 ' Train ED: 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.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and 1 backup train - ECCS B). Containment isolation is unaffected.

Consequence Category: MEDIUM 13] Consequence Rank 1-1 Consequence Category: MEDIUM C Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 37 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CAL-015, Rev. 00 14-Sep-9 Page A28 of A31 Consequence IOD: CSS-C-15B Consequence

Description:

Degradation of NAOH line to Train B (line 2GCB-69) during an independent demand.

Break Size: 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 2P35B from the RWT (break is assumed to occur during RWT injection phase). Detection is based on Room 2007 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 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 fails. Also, flow diversion impacts are not assumed.

Failure to isolate is not assumed to propagate into Rooms 2006 & 2011 during injection phase due to break size. Detection is'provided by ECCS room flood and auxiliary building sump high level alarms in the control room. Loss 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 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: N/A System Recovery, Loss 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 Train: - TW-3 Train ED: CSS B, HPSI B, LPSI B Train Recovery: Isolation of ECCS train during recirculation is required. No credit is allowed for local isolation of CSS, thus, allowing recovery of -PSI and LPSI.

Consequence Comment: Consequence is "Medium" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, between test exposure, and I backup train - ECCS A). Containment isolation is unaffected.

Consequence Category: MEDIUM 13 Consequence Rank .3 I Consequence Category: MEDIUM 0 Conseriucoce Rank 0

Enclosure to CNRO-2007-00028 Page 38 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CALC-01S. Rev. 00 14-Sep-9 Page A29 of A31 Consequence ID: CSS-C-16 Consequence

Description:

Degradation of RWT suction to SFPP and charging (line 2HCB-7) during an independent demand.

Break Size: Large Isolability of Break: No ISO Comments: Unisolable.

Spatial Effects: Propagation Effected Location: Outside Spatial Effects 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 auxiliary building sump high level alarm, but this is irrelevant since the break is unisolable. This line is judged too small (3 inch diameter) to divert enough of the RWT to cause flow diversion or loss of ECCS.

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: N/A System Recovery: Pipe size is assumed too small to cause flow diversion or loss of ECCS.

Loss of Train: N Train ID: N/A Train Recovery: N/A Consequence Comment: Consequence is '!Low" base on Table 2-2 of Ref 9.18 (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 E) Consequence Rank 03

Enclosure to CNRO-2007-00028 Page 39 of 40 FMAECA - Consequence Information Report CalculationNo. A.PENG-CALC-0O5. Rev. 00 14-Sep-9 Page A30 of A3)

Consequence ID: CSS-C-17A Consequence

Description:

Degradation of service air connection to Train A (line 2HCB-93) during an independent demand.

Break Size: Large Isolability of Break: Yes ISO Comments: Trip pump 2P35A or close MOV 2CV-5612 (break is 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: Propagation Effected Location: Room 2084 Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding impact is not assumed. Also.

flow diversion impacts are not assumed. Detection is provided by auxiliary building sump 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: N/A System Recovery: Loss 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 Train: T Train ID: CSS A Train Recovery: 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: Consequence is "Low" based on Table 2-2 of Ref. 9.18 (unexpected frequency of challenge, all year exposure, and 2 backup trains; -PSL LPSI, CSS B, and containment cooling). 2BS-SA provides containment isolation inside containment Consequence Category: LOW 1"3 Consequence Rank []

Consequence Category: LOW 0 Consequence Rank 0

Enclosure to CNRO-2007-00028 Page 40 of 40 FMECA - Consequence Information Report CalculationNo. A-PENG-CALC-0i5, Rev. 00 14-Sep-9 Page A31 of A31 Consequence ID: CSS-C-17B Consequence

Description:

Degradation of service air connection to Train B (line 2HCB-94) during an independent demand.

Break Size: Large Isolability of Break: Yes ISO Comments: Trip pump 2P35B or close MOV 2CV-5613 (break is 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: Propagatiopn Effected Location: Room 2084 Spatial Effects Comments: Since this is a small line (2 inch diameter), flooding impact is not assumed. Also, flow diversion impacts are not assumed- Detection is provided by auxiliary building sump high level alarms in the control room. Loss of train CSS B 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 WIE ID: N/A System Recovery: Loss 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 Train: T Train ED: CSS B Train Recovery: Isolation of CSS train during recirculation is required (2CV-5613). This allows HPSI B &

LPSI B success. Also, containment cooling system can replace CSS B.

Consequence Comment: Consequence is "Low" based on Table 2-2 of Ret 9.18 (unexpected frequency of challenge, all year exposure, and 2 backup trains; HPSI. LPSI, CSS A, and containment cooling). 2BS-5B provides containment isolation inside containment.

Consequence Category: LOW 0 Consequence Rank 11 Consequence Category: LOW 0 Consequence Rank 0

v t e Letter Sequence Response to RAI
TAC:MD5250, (Open)
Initiation Request Acceptance... Supplement Administration Questions 20 December 2007 Answers 20 February 2008 6 August 2007 Results Approval... Other: ML090480061, ML090930246
MONTHYEAR2008-02-20 [Table View]

CNRO-2007-00015, Request for Alternative ANO2-R&R-004, Revision 1, Response to NRC Request for Additional Information

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