LIC-13-0146, Exigent License Amendment Request 13-08 Revise Current Licensing Basis of Pipe Break Criteria for High Energy Piping Outside of Containment

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Exigent License Amendment Request 13-08 Revise Current Licensing Basis of Pipe Break Criteria for High Energy Piping Outside of Containment
ML13280A297
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 10/06/2013
From: Cortopassi L
Omaha Public Power District
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
GL-87-11, LIC-13-0146
Download: ML13280A297 (48)
v • d • e


Text

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UiiiiU Omaha Public Power District 444 South trfh Street Mall Omaha, NE 68102-2247 October 6, 2013 LIC-13-0146 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

References:

1. Docket No. 50-285
2. Generic Letter 87-11 , Relaxation in Arbitrary Intermediate Pipe Rupture Requirements, June 19, 1987
3. Branch Technical Position (BTP} MEB 3-1, Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment, Revision 2, June, 1987
4. NRC-72-0007, Letter from Atomic Energy Commission (A. Giambusso) to Omaha Public Power District (J.L. Wilkins), General Information Required for Consideration of the Effects of a Piping System Break Outside the Containment, including errata of January 11 , 1973
5. LIC-73-0006, Letter from Omaha Public Power District (J.L. Wilkins) to U.S.

Atomic Energy Commission (Angelo Giambusso), March 14, 1973

6. LIC-73-0012, Letter from Omaha Public Power District (J.L. Wilkins) to U.S.

Atomic Energy Commission (Angelo Giambusso), May 15, 1973

7. NRC-73-0043, Letter from Atomic Energy Commission (R. C. DeYoung) to Omaha Public Power District (J.L. Wilkins), August 2, 1973
8. NRC-73-0015, Safety Evaluation of the Omaha Public Power District Fort Calhoun Station, Unit No. 1, April 23, 1973

SUBJECT:

Fort Calhoun Station- Exigent License Amendment Request 13-08 Revise Current Licensing Basis of Pipe Break Criteria for High Energy Piping Outside of Containment Pursuant to 10 CFR 50.90 and 10 CFR 50.91(a)(6), the Omaha Public Power District (OPPD) hereby proposes to amend Fort Calhoun Station (FCS), Unit No. 1, Renewed Facility Operating License No. DPR-40 by revising the current licensing basis (CLB) for High Energy Line Breaks (HELBs). The CLB for HELB is defined by the Giambusso letter (Reference 4), as accepted and implemented by OPPD (References 5, 6}, and Generic Letter 87-11 (Reference 2). NRC guidance, provided in Branch Technical Position (BTP} Mechanical Engineering Branch (MEB) 3-1 Revision 2 (Reference 3), exempted specific piping sections from postulated failures if certain criteria were met. MEB 3-1 was communicated to the industry as an enclosure to NRC Generic Letter 87-11 . This License Amendment Request (LAR) proposes to revise the licensing basis for HELB to allow the use of specific sections of MEB 3-1 Revision 2.

Employment with Equal Opportunity

U. S. Nuclear Regulatory Commission LIC-13-0146 Page2 This change is required because use of MEB 3-1 Revision 2 is not explicitly described in the station licensing basis for all high energy lines.

The Enclosure to this letter provides the details and justification for the LAR. Attachment 1 of the Enclosure explains the reason for the exigency. Attachment 2 lists modifications that have been completed as part of HELB reconstitution and any changes that were required to operator manual actions or compensatory measures. Attachment 3 contains USAR page markups.

Attachment 4 contains the revised USAR pages with changes denoted by revision bars in the right margin. Attachment 5 shows the piping sections covered by this LAR.

This LAR has been evaluated in accordance with 10 CFR 50.91(a)(1) using criteria in 10 CFR 50.92(c). OPPD has determined that this LAR involves no significant hazards consideration.

The basis for this determination is included in the Enclosure.

OPPD requests this LAR be processed as an exigent change and approved within 7 days from the date of submittal in order to minimize the impact on plant restart. The license amendment will be implemented upon issuance.

In accordance with 10 CFR 50.91, a copy of this application, with attachments, is being provided to the designated State of Nebraska official.

No commitments to the NRC are contained in this submittal.

If you have any additional questions, or require further information, please contact Mr. Bill R.

Hansher at (402) 533-6894.

I declare under penalty of perjury that the foregoing is true and correct; executed on October 6, 2013.

~ uis P. Cortopassi Site Vice President and CNO LPC/SPQ/mle

Enclosure:

OPPD's Evaluation of the Proposed Change(s) c: S. A. Reynolds, Acting NRC Regional Administrator, Region IV J. M. Sebrosky, NRC Senior Project Manager L. E. Wilkins, NRC Project Manager J. C. Kirkland, NRC Senior Resident Inspector Director of Consumer Health Services, Department of Regulation and Licensure, Nebraska Health and Human Services, State of Nebraska

LIC-13-0146 Enclosure Page 1 OPPD's Evaluation of the Proposed Change(s)

Exigent License Amendment Request 13*08 To Revise Current Licensing Basis of Pipe Break Criteria for High Energy Piping Outside of Containment 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 Significant Hazards Consideration 4.4 Conclusions

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

ATTACHMENTS:

1. Basis for Exigent Circumstances and Request for Approval Under 10 CFR 50.91 (a)(6)
2. Plant Modifications Completed as Part of HELB Reconstitution and Any Changes to Manual Actions of Compensatory Measures
3. USAR Pages - Markup
4. USAR Pages - Revised
5. Piping Sections Covered By this Change

LIC-13-0146 Enclosure Page2 1.0

SUMMARY

DESCRIPTION The Omaha Public Power District (OPPD) hereby requests an exigent amendment to Fort Calhoun Station (FCS), Unit No. 1, Renewed Facility Operating License No. DPR-40. The CLB for HELB is defined by the Giambusso letter (Reference 6.3), as accepted and implemented by OPPD (References 6.4, 6.5), and Generic Letter 87-11 (Reference 6.1 ).

NRC guidance, provided in Branch Technical Position (BTP) Mechanical Engineering Branch (MEB) 3-1 Revision 2 (Reference 6.2), permitted exempting specific piping sections from postulated failures if certain criteria were met. MEB 3-1 was communicated to the industry as an enclosure to NRC Generic Letter 87-11.

Use of MEB 3-1 Revision 2 is not explicitly described in the station licensing basis for all high energy lines. This License Amendment Request (LAR) proposes to revise the licensing basis for HELB to allow the use of specific sections of MEB 3-1 Revision 2.

The changes to USAR Appendix M, for which NRC approval is sought are found in Attachments 3 and 4. Attachment 3 contains the markup of these sections showing new text in double underline and deleted text in strikeout. Attachment 4 contains the revised (i.e., clean) pages showing the text with revision bars in the right margin denoting where changes were made.

2.0 DETAILED DESCRIPTION Use of MEB 3-1 Revision 2 changes the original licensing basis to allow use of a methodology for evaluating the impact of ruptures in high energy lines on safety related systems, structures, and components.

This License Amendment Request proposes to change the licensing basis for HELB to allow the use of specific sections of MEB 3-1 Revision 2. Specifically, OPPD proposes to allow use of the following criteria in Section B of MEB 3-1 Revision 2 for High Energy piping (detailed subsections are discussed later in Table 2):

1. B.1.b: For exclusion of breaks and cracks between the containment wall up to and including the outboard isolation valves (not being used for Class I piping).

o This exclusion eliminates postulated breaks and cracks at the containment penetration for the Chemical Volume Control System (CVCS) Charging and Letdown, and Steam Generator Slowdown lines.

2. B.1.c (2) (b): For exclusion of breaks in Class 2 and Class 3 piping at intermediate locations based on calculated stress.

o This exclusion eliminates postulated breaks at intermediate locations in the CVCS Charging and Letdown, and Main Steam supply lines to the auxiliary feedwater turbine (FW-10).

3. B.1.c (3): For exclusion of breaks in seismically analyzed non-ASME Class piping at intermediate locations based on calculated stress.

o This exclusion eliminates postulated breaks at intermediate locations in the Steam Generator Slowdown lines.

LIC-13-0146 Enclosure Page3

4. B.1.e (2): For exclusion of arbitrary cracks in Class 2, Class 3, and non-safety piping.

o This exclusion eliminates postulated arbitrary cracks in CVCS Charging and Letdown, Steam Generator Slowdown, and Main Steam supply lines to the auxiliary feedwater turbine (FW-10).

5. B.3.c (1): For exclusion of leakage cracks in piping with diameters of 1 inch and smaller.

o This exclusion eliminates postulated cracks in all piping 1 inch and smaller in all high energy lines.

Applicable MEB 3-1 Revision 2 Sections to be Included in New Licensing Basis The criteria that will be adopted as part of the licensing change and the reason for adopting the criteria are provided in Table 2 below.

Table 2* MEB 3-1 Sections that are to be Included in New Licensmg Bas1s Section No. Description of Section Adopted Reason Fluid System Piping in Containment Penetration Areas - Breaks and cracks need not be postulated in those portions of piping from containment wall to and including the inboard or outboard isolation valves provided they meet the requirement of the ASME Code, Section Ill, Subarticle NE-1120 and the following additional design requirements:

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress as calculated by the sum of Eqs. (9) and (1 0) in paragraph NC-8.1 .b.(1 )(d) 3652, ASME Code, Section Ill ... should not exceed 0.8(1.8Sh + SA). The Sh and SA are allowable stresses at maximum (hot) temperature and allowable stress range for thermal expansion, respectively, as defined in Article NC-3600 of the ASME Code, Section Ill.

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress, as calculated by Eq. (9) in NC-3653 under the loadings resulting Provides basis for excluding from a postulated piping failure of fluid system piping beyond these breaks in containment portions of piping should not exceed the lesser of 2.25 Sh and 1.8 Sy. penetration areas for Primary loads include those which are deflection limited by whip penetrations M2 (CVCS to 8.1.b.(1 )(e) restraints. The exceptions permitted in (c) above may also be applied Letdown HX), M3 (CVCS from provided that when the piping between the outboard isolation valve and Charging Pumps), M10 (SGBD the restraint is constructed in accordance with the Power Piping Code from RC-28) and M13 (SGBD ANSI 831 .1 (see ASS 3-1 8 .2.c.(4)), the piping shall either be of from RC-2A).

seamless construction with full radiography of all circumferential welds, or all longitudinal and circumferential welds shall be fully radiographed. NOTE: The MEB 3-1 Sections t-------t---=---------------~-__;:;__:..__ __----1 applicable to Class I piping are (Fluid System Piping in Containment Penetration Areas) Welded not listed since they will not be attachments, for pipe supports or other purposes, to these portions of used.

8.1.b.(2) piping should be avoided except where detailed stress analyses, or tests, are performed to demonstrate compliance to the limits of B.1.b.(1 ).

(Fluid System Piping in Containment Penetration Areas) The number of circumferential and longitudinal piping welds and branch connections should be minimized. Where guard pipes are used, the enclosed portion 8.1.b.(3) of fluid system piping should be seamless construction and without circumferential welds unless specific access provisions are made to permit inservice volumetric examination of the longitudinal and circumferential welds.

(Fluid System Piping in Containment Penetration Areas) The length of B.1.b.(4) these portions of piping should be reduced to the minimum length practical.

LIC-13-0146 Enclosure Page4 Section No. Description of Section Adopted Reason (Fluid System Piping in Containment Penetration Areas) The design of pipe anchors or restraints (e.g., connections to containment penetrations and pipe whip restraints) should not require welding directly to the outer 8.1.b.(5) surface of the piping (e.g., flued integrally forged pipe fittings may be used) except where such welds are 100 percent volumetrically examinable in service and a detailed stress analysis is performed to demonstrate compliance with the limits of B.1.b.(1 ).

(Fluid System Piping in Containment Penetration Areas) Guard pipes provided for these portions of piping in the containment penetration areas should be constructed in accordance with the rules of Class MC, Subsection NE of the ASME Code, Section Ill, where the guard pipe is part of the containment boundary. In addition, the entire guard pipe assembly should be designed to meet the following requirements and tests:

(a) The design pressure and temperature should not be less than the maximum operating pressure and temperature of the enclosed pipe under Provides basis for excluding normal plant conditions.

8 .1.b.(6) breaks in containment (b) The level C stress limits of NE-3220, ASME Code, Section Ill, should penetration areas for not be exceeded under the loadings associated with containment design penetrations M2 (CVCS to pressure and temperature in combination with the safe shutdown Letdown HX), M3 (CVCS from earthquake. Charging Pumps), M10 (SGBD (c) Guard pipe assemblies should be subjected to a single pressure test from RC-28) and M13 (SGBD at a pressure not less than its design pressure. from RC-2A).

(d) Guard pipe assemblies should not prevent the access required to conduct the inservice examination specified in B.1 .b.(7). Inspection ports, if used, should not be located in that portion of the guard pipe through the annulus of dual barrier containment structures.

(Fluid System Piping in Containment Penetration Areas) A 100%

volumetric inservice examination of all pipe welds should be conducted 8.1 .b.(7) during each inspection interval as defined in IWA-2400, ASME Code,Section XI.

(Postulation of Pipe Breaks in Areas Other Than Containment Provides basis for selecting Penetration) . .. breaks in Class 2 or 3 piping (ASME Code, Section Ill) intermediate break locations in B.1.c.(2l(b} CVCS Letdown and Charging should be postulated at intermediate locations selected by one of the following criteria: lines and Main Steam branch lines to FW-10.

Provides basis for selecting At each pipe fitting (e.g., elbow, tee, cross, flange, and nonstandard break locations in ASME Class 3 fitting), welded attachment, and valve. Where the piping contains no Letdown lines downstream from B.1.c.(2)(b)(i) fittings, welded attachments, or valves, at one location at each extreme of the Letdown Heat Exchanger the piping run adjacent to the prospective structure. CH-7 where stress analyses are not performed to exclude breaks.

At each location where stresses calculated2 by the sum of Eqs. (9) and (10) in NC/ND-3653, ASME Code Section Ill, exceed 0.8 times the sum of the stress limits given in NC/ND-3653.

As a result of piping reanalysis due to differences between the design configuration and the as-built configuration, the highest stress locations Provides basis for removing may be shifted; however, the initially determined intermediate break intermediate breaks in ASME B.1.c.(2)(b)(ii) locations may be used unless a redesign of the piping resulting in a Class 2 and 3 lines including change in pipe parameters (diameter, wall thickness, routing) is required, CVCS Charging and Letdown or the dynamic effects from the new (as-built) intermediate break locations lines and Main Steam supply are not mitigated by the original pipe whip restraints and jet shields. lines to FW-1 0.

Footnote 2: For those loads and conditions in which Level A and Level 8 stress limits have been specified in the Design Specification (including the operating basis earthquake).

LIC-13-0146 Enclosure Page 5 Section No. Description of Section Adopted Reason Provides basis for excluding Breaks in seismically analyzed non-ASME Class piping are postulated breaks in seismically analyzed according to the same requirements for ASME Class 2 and 3 piping non-ASME Class piping using above. the rules provided in B.1.c.(2).

Note: Footnote 4 is not included as FCS has not been licensed to the This basis would be required to B.1.c.(3} remove intermediate breaks in Standard Review Plan. As a result, breaks in non-seismic, non-Category seismically qualified non-ASME I piping are postulated using the original licensing basis. Breaks are to be Class piping with the noted postulated based on the most adverse location to safety related systems, structures, and components, including interactions with seismically exception identified in B.1.b.(2)(a). This is used for analyzed piping.

Steam Generator Slowdown piping.

The designer should identify each piping run he has considered to Provides basis for removing postulate the break locations required by B.1 .c. above. In complex intermediate breaks in eves systems such as those containing arrangements of headers and parallel Charging and Letdown lines, B.1.d piping running between headers, the designer should identify and include Steam Generator Slowdown, and all such piping within a designated run in order to postulate the number of Main Steam supply lines to FW-breaks required by these criteria. 10.

With the exception of those portions of piping identified in B.1.b (within Containment Penetrations), leakage cracks should be postulated as Provides basis for removing follows: arbitrary cracks in eves B.1.e(2) Charging and Letdown lines, (2) For ASME Code, Section Ill Class 2 or 3 or nonsafety class (not Steam Generator Slowdown, and ASME Class 1, 2, or 3) piping, at axial locations where the calculated stress 2 by the sum of Eqs. (9) and (10) in NC/ND-3653 exceeds 0.4 times Main Steam supply lines to FW-the sum of the stress limits given in NC/ND-3653. 10.

Provides basis for excluding B.3.c(1} Leakage cracks need not be postulated in 1 inch and smaller piping. cracks in all 1 inch and smaller high energy piping.

Note: Stress evaluation required to support MES 3-1 analysis will use ASME Section Ill 1986 Edition (as referenced in MES 3-1 Revision 2).

High Energy Systems to which MES 3-1 Revision 2 will be Applied The above portions of MES 3-1 Revision 2 will be applied to the following High Energy System piping sections:

  • CVCS Charging o High energy portion of the Charging system from the Charging pump discharge (CH-1A/1 S/1 C) to the containment penetration.
  • CVCS Letdown o High energy portion of the Letdown system piping from the containment penetration to PCV-210.
  • Steam Generator Slowdown o High energy portion of the Steam Generator Slowdown (SGSD) p1p1ng from the containment penetration to the Slowdown Tank FW-7, the Slowdown Tank to the SGSD transfer pumps (FW-34AIS), and from the SGSD transfer pumps to the Raw Water system branch tee.

LIC-13-0146 Enclosure Page6

These piping sections are shown in Attachment 5. The Attachment 5 markups are intended to provide a general representation of the applicable high energy systems. They are not intended to provide the specific boundaries for each system.

USAR Appendix M, Table M-2-1 identifies a 1-1/2-inch diameter Nitrogen System line with a service temperature of 100°F and a design pressure of 275 psig as a high energy line.

However, this line does not meet the requirement of a high energy line. Per USAR Appendix M, and consistent with the original licensing basis provided in the Giambusso Letter of December 1972 (Reference 6.3), a line can be excluded provided that the service temperature is less than 200°F and the design pressure is less than or equal to 275 psig. As this line meets the exclusion criterion provided in the original licensing basis document, it is removed from Table M-2-1.

3.0 TECHNICAL EVALUATION

The original licensing basis for High Energy Line Breaks at Fort Calhoun Station is based on the May 15, 1973 submittal to the NRC with the enclosed attachment, "Postulated High Energy Line Breaks Outside Containment." This submittal was provided in response to the December 14, 1972 AEC letter to OPPD which transmitted the document entitled, "General Information Required for Consideration of the Effects of a Piping System Break Outside of Containment" and the subsequent two pages of Errata that was issued by the AEC on January 11, 1973 as well as the requirements provided in Supplement No. 1 to the Safety Evaluation on April 23, 1973. The safety evaluation was provided following the OPPD NRC submittal of March 14, 1973 with the enclosed attachment, "INITIAL PHASE: Postulated High Energy Line Rupture Outside Containment Program Description. These documents are referred to as the AEC HELB Criteria. A summary of this licensing basis is provided in USAR Appendix M.

Subsequent to the original submittal, NRC GL 87-11 was issued. This eliminated the requirement to postulate arbitrary intermediate pipe ruptures. A reanalysis of the non-safety portions of the Main Steam and Feedwater piping was performed applying the GL 87-11 criteria and resulted in fewer pipe rupture locations. This was previously incorporated into USAR Appendix M and is the Current Licensing Basis.

The application of Generic Letter 87-11 and the identified sections of BTP MEB 3-1 Revision 2 for specific piping systems supplement the current licensing basis and will continue to ensure that the plant can be safely shutdown and be maintained in a safe shutdown condition during a postulated rupture of a high energy piping system outside of containment.

The current licensing basis requires the postulation of ruptures in normally pressurized high energy systems where the service temperature is equal to or greater than 200°F or the design pressure is greater than 275 psig. The systems that are considered normally pressurized are listed in Appendix M of the USAR. In Jetter LIC-73-0012, OPPD provided the final response to the Giambusso Jetter (Reference 6.5}. The list of normally pressurized high energy systems was listed in that letter. The submittal was accepted in AEC correspondence to OPPD in NRC 73-0043 (Reference 6.6). A latter addition for non-safety related auxiliary feedwater system that

L1 C-13-0 146 Enclosure Page 7 could be used for normal plant startup and shutdown expanded the USAR list of normally pressurized systems. This LAR does not change the list of systems classified as high energy.

The current licensing basis requires that breaks be postulated at various locations, including the terminal ends of high energy piping sections including containment penetrations. A break at a terminal end of high energy piping in Room 13, in the area between the containment penetration and the first outboard isolation valve, could create a harsh environment in auxiliary building areas not classified as harsh environmental areas for these pipe failure events, thereby preventing equipment not qualified for harsh conditions from performing their safe shutdown or accident mitigation functions.

Intermediate break locations are to be based on the requirements of the original AEC Letter of December 14, 1972 supplemented by the Errata of January 11 , 1973. For ASME Class 2 or 3 piping, breaks are postulated at intermediate locations as determined based on stress and two additional arbitrary locations selected on a reasonable basis as necessary to provide protection.

For Non-ASME Class piping, intermediate breaks are taken at arbitrary locations that would provide the most adverse impact on safety related structures, systems, and components. In addition, arbitrary critical cracks are to be postulated in high energy systems where the service temperature is greater than or equal to 200°F or the design pressure is greater than 275 psig.

The location of the critical crack is selected as the location with the most adverse impact on safety related structures, systems and components required to place and maintain the plant in a cold shutdown condition.

Later NRC guidance, provided in Branch Technical Position (BTP) Mechanical Engineering Branch (MEB) 3-1, allowed piping from the containment wall to and including the inboard or outboard isolation valve to be exempt from postulated failures if certain criteria were met. It also includes criteria to eliminate arbitrary intermediate breaks and cracks in piping systems based on stress and usage factor considerations. By using the criteria provided in BTP MEB 3-1 ,

postulated breaks and cracks can be determined based on accepted methodologies using stress to provide more probable locations for intermediate breaks and cracks.

It is noted that in BTP MEB 3-1 , a terminal end is defined as the extremities of piping runs that connect to structures, components (e.g., vessels, pumps, valves), or pipe anchors that act as rigid constraints to piping motion and thermal expansion. A branch connection to a main piping run is a terminal end of the branch run, except where the branch run is classified as part of a main run in the stress analysis and is shown to have a significant effect on the main run behavior. In piping runs that are maintained pressurized during normal plant conditions for only a portion of the run (i.e., up to the first normally closed valve), a terminal end of such a run is the piping connection to this closed valve.

This definition is not included as part of the plant's licensing basis provided in the Giambusso Letter. For the purpose of this report, the definition of a terminal end used for the HELB analysis is that provided in ANSI/ANS-58.2-1988 (Reference 6.10). The terminal end is defined as that section of piping originating at a structure or component (such as a vessel or component nozzle or structural piping anchor) that acts as an essentially rigid constraint to the piping thermal expansion. Typically, an anchor assumed for the piping code stress analysis would be a terminal end. The branch connection to the main run is one of the terminal ends of a branch run, except where the special case where the branch run is classified as part of a main run.

Thus, a normally closed valve separating a pressurized section of piping from a non-pressurized

LIC-13-0146 Enclosure PageS section is not considered a terminal end if the valve does not act as a structural anchor that acts as a constraint to the piping thermal expansion.

In 1999, the NRC approved a similar request from Florida Power Corporation for Crystal River Unit 3 (Reference 6.11 ), which updated the design conditions as called out by GL 87-11 and BTP MEB 3-1. The NRC noted that the change reflected the use of the updated guidance and was approved.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.1.1 Regulations The plant design for protection from piping failures outside containment is to ensure that (1) such failures would not cause the loss of needed functions of safety related systems, and (2) the plant could safely shut down and maintain a cold shut down condition in the event of such failures. The review of the methodology change for selecting postulated breaks and cracks in high energy systems is focused on the effects of these failures to impact safety related systems, structures, and components required to place and maintain the plant in a cold shut down condition.

General Design Criteria:

Fort Calhoun Station was licensed for construction prior to May 21, 1971, and at that time committed to the draft General Design Criteria (GDC). The draft GDC are contained in Appendix G (Reference 6.8) of the FCS USAR. The applicability of the design criteria is discussed below.

CRITERION 26 - Protection Systems Fail-Safe Design USAR Appendix G Criterion 26 requires that protection systems shall be designed to fail into a safe state or into a state established as tolerable on a defined basis if conditions such as disconnection of the system, loss of energy, or adverse environments (e.g., extreme heat or cold, fire, steam, or water) are experienced.

This criterion is met as the change provided in this LAR is only a change to the methodology to selection of breaks and cracks outside containment and at the containment penetration. Since the change only removes arbitrary breaks and cracks outside containment and terminal breaks at the containment penetration, no new breaks are created that are not currently included as part of the FCS original design basis. Therefore, no new adverse environments are created as part of this change.

LIC-13-0146 Enclosure Page 9 CRITERION 40 - Missile Protection USAR Appendix G Criterion 40 requires that safety related structures, systems and components be designed to accommodate the dynamic effects of a postulated pipe rupture, including pipe whip dynamic effects, and jet thrust and impingement effects.

The change provided here does not impact the ability of the plant to protect safety related structures, systems, and components from the dynamic effects of a pipe rupture. The change identified here only address a methodology change to the selection criteria for postulated breaks and cracks outside containment and at the containment penetration. Since the change only removes requirements for arbitrary breaks and cracks in high energy lines outside containment, no new breaks or cracks are created that are not part of FCS's original design basis.

Thus, this change does not result in new dynamic effects from pipe rupture that were not included as part of the original plant design basis.

CRITERION 41 - Engineered Safety Features Performance Capability USAR Appendix G Criterion 41 requires that each engineered safety feature provides the required safety function assuming a failure of a single active component.

The change provided here does not impact the single active failure criterion of the plant. The change identified here only address a methodology change to the selection criteria for postulated breaks and cracks outside containment and at the containment penetration. Since the change only removes requirements for arbitrary breaks and cracks in high energy lines outside containment, no new breaks or cracks are created that are not part of FCS's original design basis.

Thus, this change does not result impact the single active failure criteria for engineered safety features.

4.1.2 Design Basis (USAR)

The pertinent aspects of postulated high energy line rupture outside of containment and their effect on essential structures and equipment is presently contained in USAR Appendix M. Following NRC approval of this LAR, the CLB will be revised such that henceforth, the criteria of Branch Technical Position MEB 3-1 Revision 2 will be utilized for the definition of breaks and crack locations for Letdown and Charging Systems, Steam Generator Slowdown System and the Main Steam supply line to the turbine driven Auxiliary Feedwater pump (FW-10}

to ensure that the plant can reach safe shutdown and be maintained in a safe shutdown condition following a postulated high energy pipe rupture outside of containment.

USAR Appendix M (Reference 6.9), describes the results of the analysis that was conducted in response to receipt of the AEC letter sent by A. Giambusso, Deputy Director for Reactor Projects, Directorate of Licensing, in December 1972 to applicants and licensees (Reference 6.3) on the subject of postulated piping

LIC-13-0146 Enclosure Page 10 failures outside containment. The attachment to this letter provided guidance on measures to be taken and information to be submitted regarding the consideration of the effects of a piping system break outside of containment. An errata sheet for the attachment was sent in January 1973 to recipients of the original letters. The OPPD response to the AEC letter and errata consisted on an initial response (Reference 6.4) and a final response (Reference 6.5), which ultimately led to the Safety Evaluation Report for Fort Calhoun being supplemented to include the staff's evaluation of postulated ruptures of a pipe outside containment that contains high energy fluid which was originally addressed in the original SER (Reference 6.6 and 6.7).

USAR Appendix M, Table M-2-1 identifies a 1-1/2-inch diameter Nitrogen System line with a service temperature of 100°F and a design pressure of 275 psig as a high energy line. However, this line does not meet the requirement of a high energy line. Per USAR Appendix M, and consistent with the original licensing basis provided in the Giambusso Letter of December 1972 (Reference 6.3), a line can be excluded provided that the service temperature is less than 2oo*F and the design pressure is less than or equal to 275 psig. As this line meets the exclusion criterion provided in the original licensing basis document, it is removed from Table M-2-1.

USAR Appendix M, Section 2.4 states that the criteria for determining the location of pipe ruptures will be as provided in NRC Generic Letter 87-11 (Reference 6.1). This section is revised to include the additional criteria that are used from BTP MEB 3-1, Revision 2.

USAR Appendix M Section 4.1 identifies the high energy systems other than major high energy systems. This section is revised to note that the line break criteria for other high energy systems are discussed in Section 2.4.

4.1.3 Approved Methodologies

  • NRC Branch Technical Position MEB 3-1, Postulated Rupture Locations in Fluid System Piping Inside and Outside of Containment, Revision 2, dated June 1987 4.2 Precedent Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No. 181 to Facility Operating License No. DPR-72, Florida Power Corporation, Crystal River Unit 3, Docket 50.302, July 27, 1999. Florida Power Corporation used break exclusion rules to remove intermediate breaks using the plant code of record in lieu of ASME Section Ill.

LIC-13-0146 Enclosure Page 11 4.3 Significant Hazards Consideration The Omaha Public Power District (OPPD) has evaluated whether or not a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change to the current licensing basis (CLB) utilizes NRC guidance (viz., Branch Technical Position (BTP) MEB 3-1, Revision 2, "Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment" and NRC Generic Letter 87-11 ("Relaxation in Arbitrary Intermediate Pipe Rupture Requirements") regarding the locations where breaks and cracks in high energy piping systems outside containment are to be postulated.

Allowing the use of NRC Generic Letter 87-11 and select sections of BTP MEB 3-1 as the basis for determining postulated break and crack locations does not result in an increase in either the probability of a high energy line break (HELB) outside containment or the consequences of such a break. The proposed change does not involve any physical changes to the affected high energy systems or components. These systems have previously been modified, as appropriate, to lower the stresses in the piping and to improve the ability to inspect the welds, in accordance with the relevant requirements of NRC Generic Letter 87-11 and BTP MEB 3-1.

Therefore, the proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed change to the current licensing basis (CLB) is a methodology change and does not involve any physical changes to the affected high energy systems or components. No new equipment is being installed nor is any installed equipment being operated in a new or different manner. A HELB outside containment in the affected systems is an accident previously evaluated, as discussed in Section 4.0 of Appendix M to the Fort Calhoun Station, Updated Safety Analysis Report (USAR).

LIC-13-0146 Enclosure Page 12 No new interactions between systems or components are created. No new failure mechanisms of associated systems will exist.

Therefore, the proposed amendment does not create the possibility of a new or different kind of accident from any previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No.

The proposed amendment provides the regulatory basis for changing the CLB to utilize updated NRC guidance regarding the locations where breaks and cracks in high energy piping systems outside containment are to be postulated.

As stated in the Background section of BTP MEB 3-1, Rev. 2:

"... observation of actual piping failures has indicated that they generally occur at high stress and fatigue locations, such as at the terminal ends of a piping system at its connection to the nozzles of a component. The rules of this position are intended to utilize the available piping design information by postulating pipe ruptures at locations having relatively higher potential for failure, such that an adequate and practical/eve/ of protection may be achieved."

By requiring that the affected piping be maintained within the stress limits and other limits of Generic Letter 87-11 and the identified sections of BTP MEB 3-1, adequate levels of protection will be maintained.

Therefore, the proposed amendment does not involve a significant reduction in a margin of safety.

Based on the above, OPPD concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

The proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be

LIC-13-0146 Enclosure Page 13 released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 REFERENCES

6.1 Generic Letter 87-11, Relaxation in Arbitrary Intermediate Pipe Rupture Requirements, June 19, 1987 6.2 Branch Technical Position (BTP) MEB 3-1 , Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment, Revision 2, June, 1987 6.3 NRC-72-0007, Letter from Atomic Energy Commission (A. Giambusso) to Omaha Public Power District (J.L. Wilkins), General Information Required for Consideration of the Effects of a Piping System Break Outside the Containment 6.4 LIC-73-0006, Letter from Omaha Public Power District (J.L. Wilkins) to U.S.

Atomic Energy Commission (Angelo Giambusso), March 14, 1973 6.5 LIC-73-0012, Letter from Omaha Public Power District (J.L. Wilkins) to U.S.

Atomic Energy Commission (Angelo Giambusso), May 15, 1973 6.6 NRC-73-0043, Letter from Atomic Energy Commission (R. C. DeYoung) to Omaha Public Power District (J.L. Wilkins), August 2, 1973 6.7 NRC-73-0015, Safety Evaluation of the Omaha Public Power District Fort Calhoun Station, Unit No. 1, April 23, 1973 6.8 USAR-Appendix G, Rev. 23, "Responses to 70 Criteria" 6.9 USAR Appendix M, Rev. 14, Postulated High Energy Line Rupture Outside the Containment 6.10 ANSI/ANS 58.2-1988, "Design Basis for Protection of Light Water Nuclear Power Plants Against Effects of Postulated Pipe Rupture," American Nuclear Society, 1988 6.11 Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No. 181 to Facility Operating License No. DPR-72, Florida Power Corporation, Crystal River Unit 3, Docket 50-302, July 27, 1999

LIC-13-0146 Enclosure ATTACHMENT 1 Basis for Exigent Circumstances and Request for Approval Under The Requirements of 10CFR50.91 {A){6)

LIC-13-0146 Enclosure Attachment 1 Basis for Exigent Circumstances and Request for Approval under the Requirements of 10CFR50.91 (a)(6)

As required by 10 CFR 50.91 (a)(6)(vi) licensees requesting approval of amendments to the operating license under exigent circumstances must explain the exigency and why the licensee cannot avoid it. Below are the reasons for the unavoidable exigent circumstances for Fort Calhoun Station (FCS), Unit No. 1.

The Reason for the Exigency and Why the Need for the Requested Action Could Not Reasonably Have Been Identified On June 13, 2013, an unevaluated break location in the steam supply to the auxiliary feedwater turbine located in Room 19 of the auxiliary building was identified. The next day, a deficiency was identified with verifying that the Electrical Equipment Qualification (EEQ) Program met all of the criteria for establishing pipe rupture locations in Room 13 of the auxiliary building. These issues are documented in the Fort Calhoun Station Corrective Action Program. The consequence of these issues is that potential breaks or cracks in high-energy piping could result in environmental conditions being more severe than the equipment in Rooms 13 and 19 is analyzed to sustain during all modes of operation. OPPD promptly addressed these issues by installing a number of modifications as described in Attachment 2.

While these physical improvements were in progress, final discovery of the full extent of this condition was proceeding. This involved a significant effort on OPPD's part and many resources to comprehensively research the design and licensing basis for high-energy line break (HELB) and the EEQ program at Fort Calhoun Station. These issues extend back to the early 1970's when the plant was licensed and the effort required an in-depth review of numerous calculations and modifications. Full discovery of the extent of condition and the appropriate means to reconcile the design of the plant with the licensing basis was only recently completed. This is due in part to the complexity of the issue in conjunction with the due diligence involved in reviewing the complete history comprising over forty years of calculations and modifications against NRC requirements.

Upon completion of the discovery process, extent of condition , and the design and licensing basis reviews, it was determined that modifications consistent with applicable regulatory standards are not sufficient to fully resolve the HELB and EEQ issues. The need to focus resources on making physical improvements to the plant while using many of the same resources to research the extent of condition and history of this issue prevented its resolution in a more timely manner. Two parallel success paths were pursued; one was to assess the replaced piping using the Part 9900 Operability Process and then implement Generic Letter 87-11 guidance after plant restart. The second was to request a license amendment. Following recent discussions with the NRC, OPPD has concluded that a license amendment is the only viable success path.

An amendment is necessary so that OPPD can consider the piping, mechanical, and electrical systems associated with high-energy line breaks and the EEQ Program operable. These systems and components are directly associated with heat-up of the reactor coolant system and must be returned to operable status to enable subsequent system lineups and testing to occur.

LIC-13-0146 Enclosure Due to the complex and integrated nature of the activities required to recover from an extended outage, a protracted delay in such a key activity would have a cascading, adverse impact.

LIC-13-0146 Enclosure ATTACHMENT 2 Plant Modifica tions Comple ted as Part of HELB Reconst itution AND Any Changes to Manual Actions or Compen satory Measures

LIC-13-0146 Enclosure Attachment 2 Plant Modifications Completed as Part of HELB Reconstitution AND Any Changes to Manual Actions or Compensatory Measures As part of the HELS reconstitution effort, several plant modifications were completed to address identified weaknesses in station design (each weakness was documented and tracked in a Condition Report). The table below lists the modifications required. Each modification is installed.

No additional operator actions or compensatory measures were added as part of these modifications. No additional actions or compensatory measure have been identified to implement the MES 3-1 sections described in this LAR. No plant features are currently planned to be removed as part of implementing MES 3-1. If future reconstitution efforts identify the need for any additional modifications, operator actions, or compensatory measures, those will be evaluated under 10CFR50.59.

Modification Description Status EC61599 Replaced socket welds with butt welds to permit 100% volumetric Installed examination as required by MES 3-1 between the containment penetration and outboard isolation valves on eves Letdown, Charging, and both Steam Generator Slowdown lines.

EC61935 Installed redundant solenoids on the auxiliary feedwater turbine Installed steam supply valves, YCV-1045A and S, to prevent a single active failure from causing these valves to open coincident with a HELS in Room 19.

Installed a redundant pressure switch (PS923-1) and redundant control room alarm to alert operators to a potential HELS in Room 19.

This provides a redundant trigger to initiate the pre-existing operator action to isolate the FW-10 steam supply line warm-up valves (small bypasses around the steam admission valves, YCV-1045A/S) upon a sensed low pressure in the steam supply line.

EC52662 Installed a new pipe support, FWS-290, on the Steam Generator Installed Slowdown line near FW-1020. This support reduced calculated piping stresses to within threshold levels, eliminating the need to postulate a break.

EC53866 Auto isolation was provided to the SGSD line when a break occurs in Installed room 13. The modification installed temperature switches which would monitor Room 13 and isolate the break at the HCV-1387A/S and HCV -1388A/S valves.

EC53202 FW-10 MS Supply Piping and Supports were modified, the steam Installed supply line guard pipe was sealed in Room 19, drain valves added, and the guard pipe was extended up into room 81 where slots were added to relieve the steam in the event of a line break in room 19.

LIC-13-0146 Enclosure ATTACHMENT 3 Updated Safety Analysis Report (USAR) Markups

Page 1 of 45 II USAR - Append ix M I Append ix M Postula ted High Energy Line Rupture Outside the Contain ment Rev .:t4 Usage Level:

II I Informatio n Change No.:

Reason for Change:

Preparer:

Sponsor:

Issued:

Fort Calhoun Station

USAR Appendix M Information Use Page 2 of 45 Postulated High Energy Line Rupture Rev.-+4 Outside the Containment List of Tables Table M-2-1 -Systems Outside Containment Exceeding 200°F Service Temperature and/or 275 psig Design Pressure ................................................................................................. 7 Table M-2 Portions of Branch Technical Position MEB 3-1 Used ...................................... 9 Table M.3-1 -Parameters Used in Steam Slowdown Calculation .......................................... 15

USAR Appendix M Information Use Page 7 of 45 Postulated High Energy Line Rupture Rev. +4 Outside the Containment Table M-2-1 -Systems Outside Containment Exceeding 200°F Service Temperature and/or 275 psig Design Pressure System Service Design Maximum Temperature, oF Pressure, psig Line Size, in.

Main Steam 550 985 36 Feedwater 438 1335 20 438 985 16 Charging 130 2735 2 1/2 Letdown 550 2485 2 550 650 2 1/2 Auxiliary Steam 365 150 10 Condensate Return 212 10 6 Steam GeReFateF Steam Generator 550 985 5 Slowdown Sampling 600 2485 3/8 Nitrogen 100 2400 1/2

+00 2-7§ +--+fa Hydrogen 100 2400 1/2

USAR Appendix M Information Use Page 8 of 45 Postulated High Energy Line Rupture Rev. -+4 Outside the Containment 2.3 Identification of Essential Structures and Equipment A review was completed identifying the essential structures and equipment outside of the containment which would be required to place and maintain the plant in a cold shutdown condition following a postulated rupture outside the containment of a pipe containing high energy fluid with the simultaneous loss of off-site power. These structures and equipment consist of the following:

1. Control Room
2. Room 81 of the Auxiliary Building
3. Auxiliary Feedwater System
a. Auxiliary Feedwater Panel, Al-179
b. Emergency Feedwater Tank
c. Auxiliary Feedwater Pumps
d. Piping, valves, etc.
4. Cable Spreading Room
5. Switchgear Area
6. Electrical Penetration Area
7. Diesel Generators
8. Regulating and Shutdown Control Element Assemblies
9. Main Steam Isolation Valves
10. Main Steam Safety Valves
11. Safety Injection System
12. Raw Water system
13. Pressurizer Pressure and Level Control
14. Steam Generator Slowdown Isolation Valves 2.4 Revised NRC Line Break Criteria For high energy fluid piping systems the criteria for determining the location of pipe ruptures will be as provided in NRC Generic Letter 87-11. In addition. portions of Branch Technical Position MEB 3-1 Revision 2 dated June 1987. "Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment" which was enclosed with the NRC transmittal of Generic Letter 87-11 is used for determining the location of pipe ruptures for the eves charaing and letdown. main steam supply to AFW pump FW-1 0. and steam generator blowdown systems. The applicable sections of MEB 3-1 are identified in Table M-2-2.

USAR Appendix M Information Use Page 9 of 45 Postulated High Energy Line Rupture Rev.-+4 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description Fluid System Piping in Containment Penetration Areas - Breaks and cracks need not be postulated in those portions of piping from containment wall to and including the inboard or outboard isolation valves provided they meet the requirement of the ASME Code, Section Ill, 8.1.b Subarticle NE-1120 and the following additional design requirements:

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress as calculated by the sum of Eqs. (9) and (1 0) in paragraph NC-3652, ASME Code, Section Ill ... should not exceed 0.8 (1.8Sh + SA).

The Sh and SA are allowable stresses at maximum (hot) temperature and allowable stress range for thermal expansion, respectively, as defined in 8.1.b.(1 )(d) Article NC-3600 of the ASME Code, Section Ill.

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress, as calculated by Eq. (9) in NC-3653 under loadings resulting from a postulated piping failure of fluid system piping beyond these portions of piping should not exceed the lesser of 2.25 Sh and 1.8 Sy. Primary loads include those which are deflection limited by whip restraints. The exceptions permitted in (c) above may also be applied provided that when the piping between the outboard isolation valve and the restraint is constructed in accordance with the Power Piping Code ANSI 831.1 (see ASS 3-1 8 .2.c.(4)), the piping shall either be of seamless construction with full radiography of all circumferential welds, or all longitudinal and 8.1.b.(1)(e) circumferential welds shall be fully radiographed.

(Fluid System Piping in Containment Penetration Areas) Welded attachments, for pipe supports or other purposes, to these portions of piping should be avoided except where detailed stress analyses, or tests, 8.1.b.(2) are performed to demonstrate compliance to the limits of 8.1.b.(1 ).

(Fluid System Piping in Containment Penetration Areas) The number of circumferential and longitudinal piping welds and branch connections should be minimized. Where guard pipes are used, the enclosed portion of fluid system piping should be seamless construction and without circumferential welds unless specific access provisions are made to permit inservice volumetric examination of the longitudinal and 8.1.b.(3) circumferential welds.

(Fluid System Piping in Containment Penetration Areas) The length of these portions of piping should be reduced to the minimum length 8.1.b.(4) practical.

USAR Appendix M Information Use Page 10 of 45 Postulated High Energy Line Rupture Rev. 44 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description (Fluid System Piping in Containment Penetration Areas) The design of pipe anchors or restraints (e.g., connections to containment penetrations and pipe whip restraints) should not require welding directly to the outer surface of the piping (e.g., flued integrally forged pipe fittings may be used) except where such welds are 100 percent volumetrically examinable in service and a detailed stress analysis is performed to B.1.b.(5} demonstrate compliance with the limits of B.1.b.(1 ).

(Fluid System Piping in Containment Penetration Areas) Guard pipes provided for these portions of piping in the containment penetration areas should be constructed in accordance with the rules of Class MC, Subsection NE of the ASME Code, Section Ill, where the guard pipe is part of the containment boundary. In addition, the entire guard pipe assembly should be designed to meet the following requirements and tests:

(a) The design pressure and temperature should not be less than the maximum operating pressure and temperature of the enclosed pipe under normal plant conditions, (b) The level C stress limits of NE-3220, ASME Code Section Ill, should not be exceeded under the loadings associated with containment design pressure and temperature in combination with a SSE.

(c) Guard pipe assemblies should be subjected to a single pressure test at a pressure not less than its design pressure.

(d) Guard pipe assemblies should not prevent the access required to conduct inservice examination specified in B.1.b.(7). Inspection ports, if used, should not be located in that portion of the guard pipe through the B.1.b.(6) annulus of dual barrier containment structures.

(Fluid System Piping in Containment Penetration Areas) A 100%

volumetric inservice examination of all pipe welds should be conducted during each inspection interval as defined in IWA-2400, ASME Code, B.1 .b.(7) Section XI.

(Postulation of Pipe Breaks in Areas Other Than Containment Penetrations) ... breaks in Class 2 or 3 piping (ASME Code, Section Ill) should be postulated at intermediate locations selected by one of the B.1.c.(2)(b) following criteria:

At each pipe fitting (e.g., elbow, tee, cross, flange, and nonstandard fitting), welded attachment, and valve. Where the piping contains no fittings, welded attachments, or valves, at one location at each extreme B.1.c.(2)(b )(i) of the piping run adjacent to the prospective structure.

USAR Appendix M Information Use Page 11 of 45 Postulated High Energy Line Rupture Rev. +4 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description At each location where stresses calculated<:: by the sum of Eqs. (9) and (1 0) in NC/ND-3653, ASME Code Section Ill, exceed 0.8 times the sum of the stress limits given in NC/N0-3653.

As a result of piping reanalysis due to differences between the design configuration and the as-built configuration, the highest stress locations may be shifted; however, the initially determined intermediate break locations may be used unless a redesign of the piping resulting in a change in pipe parameters (diameter, wall thickness, routing) is required, or the dynamic effects from the new (as-built) intermediate berak locations are not mitigated by the original pipe whip restraints and jet shields.

Footnote 2: For those loads and conditions in which Level A and Level B stress limits have been specified in the Design Specification (including B.1 .c.(2)(b )(ii) the operating basis earthquake). .

Breaks in seismically analyzed non-ASME Class piping are postulated to B.1.c.(3) the same requirements for ASME Class 2 and 3 piping above.

The designer should identify each piping run he has considered to postulate the break locations required by B.1.c. above. In complex systems such as those containing arrangements of headers and parallel piping between headers, the designer should identify and include all such piping within a designated run in order to postulate the number of breaks B.1.d required by these criteria.

With the exception of those portions of piping identified in B.1.b (within Containment Penetrations), leakage cracks should be postulated as follows:

For ASME Code, Section Ill Class 2 or 3 or nonsafety class (not ASME Class 1, 2, or 3) piping, at axial locations where the calculated stress by the sum of Eqs. (9) and (1 0) in NC/ND-3653 exceeds 0.4 times the sum B.1.e(2) of the stress limits given in NC/ND-3653.

B.3.c(1) Leakage cracks need not be postulated in 1 inch and smaller piping.

USAR Appendix M Information Use Page 35 of 45 Postulated High Energy Line Rupture Rev . .:t-4 Outside the Containment 3.6.14 Steam Generator Slowdown Isolation Valves Due to postulated high energy line breaks in the steam generator blowdown lines outside Containment in Room 13, temperature switches were installed that isolate the steam generator blowdown valves on a high room temperature signal.

4. HIGH ENERGY SYSTEMS OTHER THAN MAJOR HIGH ENERGY SYSTEMS 4.1 Identification of High Energy Systems Other Than Major High Energy Systems All systems outside the containment whose service temperatures exceed 200°F or whose design pressures exceed 275 psig are considered to be high energy systems.

For the purpose of this investigation, those systems which are not normally pressurized were excluded from consideration. The main steam and feedwater systems have already been identified as the major high energy systems since they are the two systems, because of line sizes, fluid energy levels and plant arrangement, which would have the greatest potential to inhibit a safe shutdown of the plant in the event of the postulated pipe rupture incident (see Section M.3). The other high energy systems, because of smaller line sizes, lower fluid energy and plant arrangement, offer a lower potential for hindering a safe shutdown of the facility in the event of the postulated rupture. These other high energy systems are the following:

1. Charging
2. Letdown
3. Auxiliary steam
4. Condensate return
5. Steam generator blowdown
6. Sampling
7. Nitrogen
8. Hydrogen
9. Auxiliary Feedwater System (Non Safety Class Portion)

A study was performed to determine what modifications were necessary to protect essential structures and equipment from a postulated rupture in one of these systems.

The results of the study, including the effects of the postulated break, are discussed in Section 4.2 below. Line break criteria are discussed in Section 2.4.

LIC-13-0146 Enclosure ATTACHMENT 4 Updated Safety Analysis Report (USAR) Revisions

p age 1 of 4 5 USAR - Appendix M II II Appendix M Postulated High Energy Line Rupture Outside the Containment Rev .:t4 Safety Classification: Usage Level:

I Safety I I Information I

Change No.:

Reason for Change:

Preparer:

Sponsor:

Issued:

Fort Calhoun Station

USAR Appendix M Information Use Page 2 of 45 Postulated High Energy Line Rupture Rev. +4 Outside the Containment List of Tables Table M-2-1 -Systems Outside Containment Exceeding 200°F Service Temperature and/or 275 psig Design Pressure ................................................................................................. 7 Table M-2 Portions of Branch Technical Position MEB 3-1 Used ...................................... 9 Table M.3-1 -Parameters Used in Steam Slowdown Calculation .......................................... 15

USAR Appendix M Information Use Page 7 of 45 Postulated High Energy Line Rupture Rev.-+4 Outside the Containment Table M-2-1 -Systems Outside Containment Exceeding 200°F Service Temperature and/or 275 psig Design Pressure System Service Design Maximum Temperature, oF Pressure, psig Line Size, in.

Main Steam 550 985 36 Feedwater 438 1335 20 438 985 16 Charging 130 2735 2 1/2 Letdown 550 2485 2 550 650 2 1/2 Auxiliary Steam 365 150 10 Condensate Return 212 10 6 Steam Generator 550 985 5 Slowdown Sampling 600 2485 3/8 Nitrogen 100 2400 1/2 Hydrogen 100 2400 1/2

USAR Appendix M Information Use Page 8 of 45 Postulated High Energy Line Rupture Rev.-+4 Outside the Containment 2.3 Identification of Essential Structures and Equipment A review was completed identifying the essential structures and equipment outside of the containment which would be required to place and maintain the plant in a cold shutdown condition following a postulated rupture outside the containment of a pipe containing high energy fluid with the simultaneous loss of off-site power. These structures and equipment consist of the following:

1. Control Room
2. Room 81 of the Auxiliary Building
3. Auxiliary Feedwater System
a. Auxiliary Feedwater Panel, Al-179
b. Emergency Feedwater Tank
c. Auxiliary Feedwater Pumps
d. Piping, valves, etc.
4. Cable Spreading Room
5. Switchgear Area
6. Electrical Penetration Area
7. Diesel Generators
8. Regulating and Shutdown Control Element Assemblies
9. Main Steam Isolation Valves
10. Main Steam Safety Valves
11. Safety Injection System
12. Raw Water system
13. Pressurizer Pressure and Level Control
14. Steam Generator Slowdown Isolation Valves 2.4 Revised NRC Line Break Criteria For high energy fluid piping systems the criteria for determining the location of pipe ruptures will be as provided in NRC Generic Letter 87-11. In addition, portions of Branch Technical Position MEB 3-1 Revision 2 dated June 1987, "Postulated Rupture Locations in Fluid System Piping Inside and Outside Containment" which was enclosed with the NRC transmittal of Generic Letter 87-11 is used for determining the location of pipe ruptures for the eves charging and letdown, main steam supply to AFW pump FW-1 0, and steam generator blowdown systems. The applicable sections of MEB 3-1 are identified in Table M-2-2.

USAR Appendix M Information Use Page 9 of 45 Postulated High Energy Line Rupture Rev.-+4 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description Fluid System Piping in Containment Penetration Areas - Breaks and cracks need not be postulated in those portions of piping from containment wall to and including the inboard or outboard isolation valves provided they meet the requirement of the ASME Code, Section Ill, 8.1.b Subarticle NE-1120 and the following additional design requirements:

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress as calculated by the sum of Eqs. (9) and (1 0) in paragraph NC-3652, ASME Code, Section Ill ... should not exceed 0.8 (1.8Sh + SA).

The Sh and SA are allowable stresses at maximum (hot) temperature and allowable stress range for thermal expansion, respectively, as defined in 8.1.b.(1 )(d) Article NC-3600 of the ASME Code, Section Ill.

(ASME Class 2 Piping in Containment Penetration Areas) The maximum stress, as calculated by Eq. (9) in NC-3653 under loadings resulting from a postulated piping failure of fluid system piping beyond these portions of piping should not exceed the lesser of 2.25 Shand 1.8 Sy. Primary loads include those which are deflection limited by whip restraints. The exceptions permitted in (c) above may also be applied provided that when the piping between the outboard isolation valve and the restraint is constructed in accordance with the Power Piping Code ANSI 831.1 (see ASS 3-1 8.2.c.(4)), the piping shall either be of seamless construction with full radiography of all circumferential welds, or all longitudinal and B.1.b.(1 )(e) circumferential welds shall be fully radiographed.

(Fluid System Piping in Containment Penetration Areas) Welded attachments, for pipe supports or other purposes, to these portions of piping should be avoided except where detailed stress analyses, or tests, 8.1.b.(2) are performed to demonstrate compliance to the limits of 8.1 .b.(1 ).

(Fluid System Piping in Containment Penetration Areas) The number of circumferential and longitudinal piping welds and branch connections should be minimized. Where guard pipes are used, the enclosed portion of fluid system piping should be seamless construction and without circumferential welds unless specific access provisions are made to permit inservice volumetric examination of the longitudinal and 8.1.b.(3) circumferential welds.

(Fluid System Piping in Containment Penetration Areas) The length of these portions of piping should be reduced to the minimum length 8 .1.b.(4) practical.

USAR Appendix M Information Use Page 10 of 45 Postulated High Energy Line Rupture Rev. +4 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description (Fluid System Piping in Containment Penetration Areas) The design of pipe anchors or restraints (e.g., connections to containment penetrations and pipe whip restraints) should not require welding directly to the outer surface of the piping (e.g., flued integrally forged pipe fittings may be used) except where such welds are 100 percent volumetrically examinable in service and a detailed stress analysis is performed to 8.1.b.(5) demonstrate compliance with the limits of 8.1.b.(1 ).

(Fluid System Piping in Containment Penetration Areas) Guard pipes provided for these portions of piping in the containment penetration areas should be constructed in accordance with the rules of Class MC, Subsection NE of the ASME Code, Section Ill, where the guard pipe is part of the containment boundary. In addition, the entire guard pipe assembly should be designed to meet the following requirements and tests:

(a) The design pressure and temperature should not be less than the maximum operating pressure and temperature of the enclosed pipe under normal plant conditions, (b) The level C stress limits of NE-3220, ASME Code Section Ill, should not be exceeded under the loadings associated with containment design pressure and temperature in combination with a SSE.

(c) Guard pipe assemblies should be subjected to a single pressure test at a pressure not less than its design pressure.

(d) Guard pipe assemblies should not prevent the access required to conduct inservice examination specified in B.1.b.(7). Inspection ports, if used, should not be located in that portion of the guard pipe through the B.1.b.(6) annulus of dual barrier containment structures.

(Fluid System Piping in Containment Penetration Areas) A 100%

volumetric inservice examination of all pipe welds should be conducted during each inspection interval as defined in IWA-2400, ASME Code, B.1.b.(7) Section XI.

(Postulation of Pipe Breaks in Areas Other Than Containment Penetrations) ... breaks in Class 2 or 3 piping (ASME Code, Section Ill) should be postulated at intermediate locations selected by one of the B.1.c.(2)(b) following criteria:

At each pipe fitting (e.g., elbow, tee, cross, flange, and nonstandard fitting), welded attachment, and valve. Where the piping contains no fittings, welded attachments, or valves, at one location at each extreme B.1.c.(2)(b)(i) of the piping run adjacent to the prospective structure.

USAR Appendix M Information Use Page 11 of 45 Postulated High Energy Line Rupture Rev. +4 Outside the Containment Table M-2 Portions of Branch Technical Position MEB 3-1 Used Section Description At each location where stresses calculatedz by the sum of Eqs. (9) and (1 0) in NC/ND-3653, ASME Code Section Ill, exceed 0.8 times the sum of the stress limits given in NC/ND-3653.

As a result of piping reanalysis due to differences between the design configuration and the as-built configuration, the highest stress locations may be shifted; however, the initially determined intermediate break locations may be used unless a redesign of the piping resulting in a change in pipe parameters (diameter, wall thickness, routing) is required, or the dynamic effects from the new (as-built) intermediate berak locations are not mitigated by the original pipe whip restraints and jet shields.

Footnote 2: For those loads and conditions in which Level A and Level B stress limits have been specified in the Design Specification (including B.1.c.(2)(b)(ii) the operating basis earthquake).

Breaks in seismically analyzed non-ASME Class piping are postulated to B.1.c.(3) the same requirements for ASME Class 2 and 3 piping above.

The designer should identify each piping run he has considered to postulate the break locations required by B.1.c. above. In complex systems such as those containing arrangements of headers and parallel piping between headers, the designer should identify and include all such piping within a designated run in order to postulate the number of breaks B.1.d required by these criteria.

With the exception of those portions of piping identified in B.1.b (within Containment Penetrations), leakage cracks should be postulated as follows:

For ASME Code, Section Ill Class 2 or 3 or nonsafety class (not ASME Class 1, 2, or 3) piping, at axial locations where the calculated stress by the sum of Eqs. (9) and (1 0) in NC/ND-3653 exceeds 0.4 times the sum B.1.e(2) of the stress limits Qiven in NC/ND-3653.

B.3.c(1) LeakaQe cracks need not be postulated in 1 inch and smaller piping.

USAR Appendix M Information Use Page 35 of 45 Postulated High Energy Line Rupture Rev.+4 Outside the Containment 3.6.14 Steam Generator Slowdown Isolation Valves Due to postulated high energy line breaks in the steam generator blowdown lines outside Containment in Room 13, temperature switches were installed that isolate the steam generator blowdown valves on a high room temperature signal.

4. HIGH ENERGY SYSTEMS OTHER THAN MAJOR HIGH ENERGY SYSTEMS 4.1 Identification of High Energy Systems Other Than Major High Energy Systems All systems outside the containment whose service temperatures exceed 200°F or whose design pressures exceed 275 psig are considered to be high energy systems.

For the purpose of this investigation, those systems which are not normally pressurized were excluded from consideration. The main steam and feedwater systems have already been identified as the major high energy systems since they are the two systems, because of line sizes, fluid energy levels and plant arrangement, which would have the greatest potential to inhibit a safe shutdown of the plant in the event of the postulated pipe rupture incident (see Section M.3). The other high energy systems, because of smaller line sizes, lower fluid energy and plant arrangement, offer a lower potential for hindering a safe shutdown of the facility in the event of the postulated rupture. These other high energy systems are the following:

1. Charging
2. Letdown
3. Auxiliary steam
4. Condensate return
5. Steam generator blowdown
6. Sampling
7. Nitrogen
8. Hydrogen
9. Auxiliary Feedwater System (Non Safety Class Portion)

A study was performed to determine what modifications were necessary to protect essential structures and equipment from a postulated rupture in one of these systems.

The results of the study, including the effects of the postulated break, are discussed in Section 4.2. Line break criteria are discussed in Section 2.4.

LIC-13-0146 Enclosure ATTACHMENT 5 Piping Sections Covered by This Change

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