ML11327A149

Proposed Technical Specifications (TS) and Bases Amendment TS and Bases 3.7.8, Nuclear Service Water System (Nsws)

ML11327A149
Person / Time
Site:	Catawba
Issue date:	11/22/2011
From:	Morris J Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
10 CFR 50.90
Download: ML11327A149 (63)

Text

Duke JAMES R. MORRIS DrEnergy Vice President Duke Energy Catawba Nuclear Station 4800 Concord Road York, SC 29745 803-701-4251 803-701-3221 fax November 22, 2011 10 CFR 50.90 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 Proposed Technical Specifications (TS) and Bases Amendment TS and Bases 3.7.8, Nuclear Service Water System (NSWS)

Pursuant to 10 CFR 50.90, Duke Energy is requesting amendments to the Catawba Facility Operating Licenses and TS. This request is to modify the subject TS and Bases to allow single discharge header operation of the NSWS (Duke Energy designation "RN") for a time period of 14 days. The change, which is being requested on a permanent basis, will facilitate future maintenance of the Unit 2 NSWS discharge headers in the Auxiliary Building. Specifically, the change will allow each of the discharge headers to be removed from service for refurbishment (i.e., cleaning and coating) due to piping degradation from various corrosion mechanisms, including Microbiological Induced Corrosion (MIC), general corrosion, under deposit corrosion, and preferential weld attack. The change will also facilitate future inspections of the refurbished 42-inch NSWS discharge piping on a periodic basis, in conformance with regulatory requirements. These activities will ensure the long-term reliability of the NSWS.

The contents of this amendment request package are as follows: provides the technical and regulatory evaluations associated with the proposed changes. Attachment 2 provides the marked up TS pages showing the proposed changes. Retyped (clean) TS pages will be provided to the NRC immediately prior to issuance of the approved amendments. Attachment 3 provides the marked up TS Bases pages reflecting the proposed changes to the TS. The marked up TS Bases pages are being provided to the NRC for information only. Attachment 4 is a list of NRC commitments being made in this submittal.

Duke Energy is requesting NRC review and approval of this amendment request submittal within one year from the date of submittal in order to support planned activities on the Unit 2 NSWS discharge headers in the Auxiliary Building. The initial activities include cleaning and coating of the affected piping. Future activities will include periodic inspections of the refurbished piping to ensure that it is performing satisfactorily.

www, duke-energy. com

U.S. Nuclear Regulatory Commission Page 2 November 22, 2011 Duke Energy is requesting a 60-day implementation period in conjunction with these amendments. Implementation of these amendments will require changes to the Updated Final Safety Analysis Report (UFSAR). The following UFSAR sections may potentially be impacted: 3.1, "Conformance with General Design Criteria"; 6.6, "Inservice Inspection of Class 2 and 3 Components"; 7.4.2, "Nuclear Service Water System Instrumentation and Control"; 9.2.1, "Nuclear Service Water"; 9.2.5, "Ultimate Heat Sink"; and Table 9.4, "Nuclear Service Water System Failure Analysis". Necessary UFSAR changes will be submitted to the NRC in accordance with 10 CFR 50.71(e).

This amendment request submittal is considered to be a risk-based submittal in accordance with the guidance provided in NRC Regulatory Guide 1.200, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities".

In accordance with Duke Energy administrative procedures and the Quality Assurance Program Topical Report, this amendment request submittal has been previously reviewed and approved by the Catawba Plant Operations Review Committee.

Pursuant to 10 CFR 50.91, a copy of this amendment request submittal is being sent to the appropriate State of South Carolina official.

Inquiries on this matter should be directed to L.J. Rudy at (803) 701-3084.

Very truly yours, James R. Morris LJR/s Attachments

U.S. Nuclear Regulatory Commission Page 3 November 22, 2011 James R. Morris affirms that he is the person who subscribed his name to the foregoing statement, and that all the matters and facts set forth herein are true and correct to the best of his knowledge.

JamV R. Morris, Vice President Subscribed and sworn to me:

1/- D -//

Date Notary Public My commission expires:

R--

j:7' - dý0*,

Date SEAL

• , 0 I,

.'.Vf-\\

U.S. Nuclear Regulatory Commission Page 4 November 22, 2011 xc (with attachments):

V.M. McCree Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 G.A. Hutto, III Senior Resident Inspector (Catawba)

U.S. Nuclear Regulatory Commission Catawba Nuclear Station J.H. Thompson (addressee only)

NRC Project Manager (Catawba)

U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8-G9A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive & Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

ATTACHMENT 1 TECHNICAL AND REGULATORY EVALUATIONS

Subject:

License Amendment Request to Allow Nuclear Service Water System Single Auxiliary Building Discharge Header Operation for a Time Period of 14 Days

1.

DESCRIPTION

2.

PROPOSED CHANGE

3.

BACKGROUND

4.

TECHNICAL EVALUATION

5.

REGULATORY EVALUATION 5.1 Applicable Regulatory Requirements/Criteria 5.2 Precedent 5.3 No Significant Hazards Consideration 5.4 Conclusions

6.

ENVIRONMENTAL CONSIDERATION

7.

REFERENCES Page 1

1.

DESCRIPTION Pursuant to 10 CFR 50.90, Duke Energy is requesting amendments to the Catawba Facility Operating Licenses and TS. This request is to modify the subject TS and Bases to allow single discharge header operation of the NSWS (Duke Energy designation "RN") for a time period of 14 days. The change, which is being requested on a permanent basis, will facilitate future maintenance of the Unit 2 NSWS discharge headers in the Auxiliary Building. Specifically, the change will allow each of the discharge headers to be removed from service for refurbishment (i.e., cleaning and coating) due to piping degradation from various corrosion mechanisms, including Microbiological Induced Corrosion (MIC), general corrosion, under deposit corrosion, and preferential weld attack. The change will also facilitate future inspections of the refurbished 42-inch NSWS discharge piping on a periodic basis, in conformance with regulatory requirements. These activities will ensure the long-term reliability of the NSWS. Page 2

2.

PROPOSED CHANGE The NSWS single discharge header alignment is being proposed to allow the refurbishment of a portion of the large diameter (42-inch) Unit 2 NSWS discharge piping in the Auxiliary Building (up to the wall at column line "QQ"). This alignment will not affect the NSWS return header piping to the Standby Nuclear Service Water Pond (SNSWP) that is buried (downstream of NSWS isolation valves 1 RN58B and 1 RN63A).

Therefore, the discharge flow paths of the Unit 1 and Unit 2 diesel generators are unaffected. The piping addressed by the single discharge header alignment is within the Auxiliary Building. The single discharge header alignment of the NSWS is being proposed to allow a portion of each of the NSWS return headers in the Auxiliary Building to the SNSWP to be removed from service for cleaning, repairs, and coating, and for periodic follow-up inspections. The proposed TS changes will allow for a Completion Time of 14 days while in the single discharge header alignment.

The NSWS Single Discharge Header Alignment The NSWS single discharge header alignment can be described as follows:

1.

Unit 2 must be in Mode 5, 6, or No Mode.

2.

Unit 1 is in Mode 1, 2, 3, or 4.

3.

A portion (Unit 2 side) of the shared NSWS train discharge piping to the SNSWP is isolated, resulting in a TS Condition entry for Unit 1.

4.

NSWS return header crossover valves 1 RN53B and 1 RN54A are open with power removed and therefore will not automatically close (automatic closure is required on a low-low NSWS suction pit level signal or on a transfer to Auxiliary Shutdown Panel operation). This allows the Unit 1 NSWS components on the affected train to discharge through the opposite train's discharge header, which is aligned to the SNSWP.

5.

Both NSWS trains on Unit 1, and the in-service NSWS train on Unit 2, are aligned to discharge to the SNSWP. The normal non-safety related Lake Wylie discharge flow path is isolated since NSWS is aligned (both suction and discharge) to the SNSWP.

6.

The Unit 2 NSWS non-essential header is isolated.

Notes:

1.

The NSWS cannot be aligned in the single discharge header alignment if the system is already in the single supply header alignment, which is described in TS 3.7.8 and its associated Bases. The combination of these two alignments has not been analyzed.

2.

Unit 2 must be in Mode 5, 6, or No Mode, which are "not applicable" modes for the Component Cooling Water (CCW) System (Duke Energy designation "KC") and the Containment Spray System (CSS) (Duke Energy designation "NS"). The NSWS discharge cooling water flow paths for the Unit 2 CCW System and the CSS heat exchangers on the affected train are isolated during NSWS single discharge header alignment. Page 3

3.

While the NSWS is aligned in the single discharge header alignment, Unit 1 is in a TS Condition for the affected NSWS train (i.e., the train that has its normal safety related flow path to the SNSWP isolated).

4.

With the NSWS aligned to the SNSWP, a low-low NSWS suction pit level signal should not occur; however, NSWS discharge header crossover valves 1 RN53B and 1 RN54A must remain open while in the single discharge header alignment. With the crossover valves open, the components on the affected Unit 1 NSWS train can discharge through the operable NSWS train's discharge header, which is aligned to the SNSWP.

5.

No failures (including pipe ruptures) are required to be postulated on the operable Unit 1 NSWS train's equipment or on the shared equipment on the operable NSWS train, since Unit 1 will be in a TS Condition as a result of the inoperable NSWS train.

The proposed Completion Time for the NSWS in this alignment is 14 days. While in this alignment, the NSWS is not required to withstand another single failure or pipe rupture on the in-service train, as described in Section 3.6.2.1.2 of the Catawba UFSAR. A Probabilistic Risk Assessment (PRA) calculation has been performed and has verified that the Completion Time of 14 days is acceptable.

The diagrams that follow show the NSWS single discharge header alignments for NSWS Trains A and B. Page 4

NSWS Single Discharge Header Alignment - Train A Isolated 2B6t HX E12RN229B B Train A Train To To IRN58B Sp-O Note 3 2A NS HX 2RN148A 148 Trai 1 RN55 HX1RN5 9 RN61 1

RN63A Dlosed A

Trai 1i 1RNP19 Aux Yard Bldg 2B KC)->K HX 1 R NP20 l

1 RN54A

-1RN53B Note 2 Note 2 I8 lRNP18 1RN838 1BKC)

`IAK HX

}11RN229B 1B NS HX Isolated 1RN83 CHX)----

UL Non IN, Ess Hdr 1RN52B 1A NS HX) 1RN148A 1RN843B 1RN57A Note4 Note 4 Shared Return to Lake Wylie 4-Notes:

1.

No failures are required to be postulated on Train 1 B equipment or Train B shared equipment, since Unit 1 is in a TS Condition for NSWS Train A.

2.

NSWS return header crossover valves are open with power removed and therefore will not automatically close on NSWS low-low suction pit level or transfer to Auxiliary Shutdown Panel operation.

3.

NSWS return isolation valve to the SNSWP is open (power removed) with NSWS suction aligned to the SNSWP.

4.

Lake Wylie discharge isolation valves are closed.

5.

2A CCW System heat exchanger and 2A CSS heat exchanger are unavailable. Page 5

NSWS Single Discharge Header Alignment - Train B Isolated B Train A Train To To A

A 28 N HX 2RN229B 1RN58B Closed B

Trai 1RN61 2B KC--I HX 1RNP20 IM4 2A NS 2RN1 48A1 U2 Non.L4 Ess HdrV-IRN551 HX1RN59; 1RN63A Sp-O Note 3 A

Trai

• /1RNP19 Aux Yard B~dg 1RN54A

--1RN538 Note 2 Note 2 1 3

-RNP1 8 1RN83 1RN838 1AKC HX) ',

H1

_B KC Ul Non) rXL--I H 11RN229B Ess Hdr 1RN52B 1B NS HX 1ANSHX)-

1RN148A E]

1RN843B 1RN57A Note 4 Isolated Shared Return to Lake Wylie 4-..

Notes:

1.

No failures are required to be postulated on Train 1A equipment or Train A shared equipment, since Unit 1 is in a TS Condition for NSWS Train B.

2.

NSWS return header crossover valves are open with power removed and therefore will not automatically close on NSWS low-low suction pit level or transfer to Auxiliary Shutdown Panel operation.

3.

NSWS return isolation valve to the SNSWP is open (power removed) with NSWS suction aligned to the SNSWP.

4.

Lake Wylie discharge isolation valves are closed.

5.

2B CCW System heat exchanger and 2B CSS heat exchanger are unavailable. Page 6

TS 3.7.8 governs the NSWS. Limiting Condition for Operation (LCO) 3.7.8 requires two NSWS trains to be operable for each unit that is in Mode 1, 2, 3, or 4. With one NSWS train inoperable (Condition A), the train must be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If this is not accomplished (Condition C), the unit must be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Condition B allows for one NSWS supply header to be inoperable for 30 days due to the NSWS being aligned for single supply header operation.

TS 3.7.8 is proposed to be modified by adding new Condition C (existing Condition C is re-lettered as new Condition D), which governs single discharge header operation. New Condition C allows for a 14 day Completion Time while in this alignment. At the end of the 14 day Completion Time, the NSWS must be restored to dual discharge header operation. New Condition C is modified by three notes. Note 1 states that entry into this Condition shall only be allowed for Unit 1 and for pre-planned activities as described in the Bases of this Specification. Note 2 states that Condition A of this LCO must be immediately entered if one or more Unit 1 required NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE. Note 3 states that LCO 3.0.3 must be immediately entered if one or more Unit 1 required NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE. Finally, Surveillance Requirement 3.7.8.2 is revised by modifying the existing Note to state that the surveillance is not required to be met for valves that are maintained in position to support NSWS single supply or discharge header operation. Appropriate corresponding changes have been made to the TS 3.7.8 Bases to reflect these proposed TS changes. Page 7

3.

BACKGROUND The NSWS, including Lake Wylie and the SNSWP, is the ultimate heat sink for various QA Condition 1 heat loads during normal operation, design basis events, and other design events as dictated by Catawba licensing criteria.

During normal operation the NSWS supplies cooling water to various safety related and non-safety related components. During design basis events, the NSWS is required to support Emergency Core Cooling System (ECCS) operation by providing cooling water to various safety related components along with emergency makeup to selected QA Condition 1 systems. The design basis event which imposes the most stringent requirement on the NSWS is the Loss of Coolant Accident (LOCA). In accordance with 10 CFR 50, Appendix A, General Design Criterion (GDC) 2 (Design bases for protection against natural phenomena), Catawba must withstand the effects of a Safe Shutdown Earthquake (SSE) without affecting the ability of the safety systems to shut down the plant. As such, the design basis events are considered after the occurrence of an SSE.

This means that a loss of Lake Wylie and a dual unit Loss of Offsite Power (LOOP) are assumed.

Additional licensing criteria design events include loss of the main control room, fire, and security events. Each of these events imposes specific requirements on the function of the NSWS and each was reviewed with respect to single discharge header operation.

NSWS Description Two bodies of water serve as the ultimate heat sink for the components cooled by the NSWS. Lake Wylie is the normal source of nuclear service water. A single transport line conveys water from a seismic Category 1 intake structure at the bottom of the lake to both the A and B pits of the NSWS pumphouse serving the NSWS pumps in operation. Isolation of each line is assured by two valves in series and fitted with electric motor operators powered from separate power supplies. Should Lake Wylie be lost due to a seismic event in excess of the design of Wylie Dam, the SNSWP, formed by the seismic Category 1 SNSWP Dam, contains sufficient water to bring the station safely to a cold shutdown condition under all normal, transient, and accident conditions. The SNSWP has a seismic Category I intake structure, with two ASME Section III, Class 3 seismic, redundant lines to transport water independently to each pit in the pumphouse.

Each line is secured by a single motor operated valve. Automatically upon loss of Lake Wylie (as detected by NSWS pump pit level instrumentation), Lake Wylie double isolation valves are closed and the SNSWP valves are opened to both pit A and pit B.

Each pit in the seismic Category 1 pumphouse is capable of passing the flow needed for both normal and required accident conditions. Flow spreaders in front of all the intake pipe entrances prevent vortices and flow irregularities while removable lattice screens protect the NSWS pumps from solid objects. Pumps 1A and 2A take suction from pit A and discharge through strainers 1A and 2A, respectively. Pumps 1 B and 2B take suction from pit B and discharge through strainers 1 B and 2B, respectively. The outlet piping of the respective train's strainers then join back together to form the train A and B supply lines to train A and B components in both units. Outside the Auxiliary Building wall, the train A supply line splits, with the 1A supply header entering on the Unit 1 side, and the 2A supply header entering on the Unit 2 side. Likewise, the train B supply line Page 8

splits, with the 1 B supply header entering on the Unit 1 side, and the 2B supply header entering on the Unit 2 side. The supply and return headers are arranged and fitted with isolation valves such that a critical crack in either header can be isolated and will not jeopardize the safety functions of this system or flood out other safety related equipment. The operation of any two pumps on either or both supply lines is sufficient to supply all cooling water requirements for unit startup, cooldown, refueling, and post-accident operation of two units. However, one pump has sufficient capacity to supply all cooling water requirements during normal power operation of both units or during post-accident conditions if the unaffected unit is already in cold shutdown. All pumps (two per unit) are started during the hypothetical combined accident and loss of normal power. In an accident, the safety injection signal automatically starts both pumps on each unit, thus providing complete redundancy. If a diesel generator or a NSWS pump is out of service for an extended period of time (such as when its associated unit is in cold shutdown), then one pump is sufficient to provide adequate cooling water requirements for the operating unit and to maintain the other unit in cold shutdown in the event of a hypothetical combined accident and loss of normal power. The NSWS design basis is for operation under the worst initial conditions of operation. This condition is assumed to be the low probability combination of a LOCA on one unit, a LOOP on both units, extended shutdown of the other unit, loss of the downstream dam, and a prolonged drought and hot weather and its effect on the SNSWP.

Nuclear service water supplied by the NSWS is used in both units to supply essential and non-essential cooling water needs or as an assured source of water for certain safety related systems. Essential components are those necessary for safe shutdown of the units, and are designed with redundancy in order to meet single failure criteria.

Non-essential components are not necessary for safe shutdown of the units, and are not designed with redundancy. Each unit has two trains of essential heat exchangers, designated train A and train B, and one train of non-essential ventilation heat exchangers, supplied from either train A or train B and isolated on an Engineered Safety Features actuation.

There are two main discharge headers, extending the width of the Auxiliary Building, with the 1A and 2A components returning flow to the train A header, and the 1B and 2B components returning flow to the train B header. During normal station operation, when the NSWS pumps are taking suction from Lake Wylie, discharge crossover valves are open, and all heat exchangers in operation discharge through the train A return to Lake Wylie via the Low Pressure Service Water discharge. Automatically upon emergency low pumphouse pit level (as in the loss of Lake Wylie), double isolation valves close on the return line to Lake Wylie, double isolation valves close on the discharge header crossover, and single isolation valves open on each train's return to the SNSWP. This sequence, along with isolation of the non-essential header and the supply header crossover valves, ensures two independent, redundant supplies and returns, satisfying single failure criteria. The non-essential header double isolation valves will only isolate on a Phase B signal (a Phase B signal isolates the non-safety related portions of the CCW System and the NSWS), not on an emergency low pumphouse pit level. An emergency low pumphouse pit level effectively isolates the non-essential header supply by closing the essential supply header crossovers. NSWS piping in each diesel generator building also has discharge isolation valves that are aligned from Lake Wylie discharge to SNSWP discharge on the same signals which cause the Auxiliary Building headers to align to the SNSWP. The discharge lines to the SNSWP split and discharge Page 9

flow to each "finger" of the SNSWP to assure that surface cooling will occur in all areas of the pond. An orifice is installed to create a pressure drop in the shorter of the two discharge lines to divert flow to the longer of the discharge lines and assure surface cooling over the entire SNSWP. Page 10

4.

TECHNICAL EVALUATION Discussion of General Design Criteria (GDC) Requirements The major regulatory requirements that are relevant when considering the concept of the NSWS single discharge header alignment are 10 CFR 50 Appendix A GDC 4 (Environmental and dynamic effects design bases), GDC 5 (Sharing of structures, systems and components), GDC 44 (Cooling water), and GDC 45 (Inspection of cooling water system).

GDC 4 requires the evaluation of postulated pipe ruptures during normal operation and the evaluation that structures, systems and components important to safety can withstand the effects of these breaks. With only one of the two NSWS return headers to the SNSWP in service while in the single discharge header alignment, the NSWS obviously cannot sustain a pipe rupture on the remaining NSWS discharge header to the SNSWP. The PRA calculation that evaluated the NSWS in this alignment for up to 14 days shows that the increase in risk associated with the NSWS being in the single discharge header alignment is minimal and acceptable. Additional details regarding this calculation and its results are described later in this submittal.

GDC 5 requires that structures, systems, and components important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident on one unit and an orderly shutdown and cooldown of the remaining units. With only one of the two NSWS return headers to the SNSWP in service while in the single discharge header alignment, both units discharge through the only remaining in-service header and the NSWS obviously cannot sustain an additional failure. However, PRA analysis of this alignment shows that the increase in risk associated with the NSWS being in the single discharge header alignment for up to 14 days is minimal and acceptable.

Additional details regarding this calculation and its results are described later in this submittal.

GDC 44 requires suitable redundancy in components and features, and suitable interconnections, leak detection, and isolation capabilities to be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available), the system safety function can be accomplished, assuming a single failure. With only one of the two NSWS return headers to the SNSWP in service while in the single discharge header alignment, the NSWS obviously cannot sustain an additional failure. The alignment has the NSWS pre-aligned to the SNSWP, and valves have been positioned with power removed.

These measures have been incorporated into the PRA calculation that evaluated the NSWS in this alignment for up to 14 days, and this calculation shows that the increase in risk associated with the NSWS being in the single discharge header alignment is minimal and acceptable. Additional details regarding this calculation and its results are described later in this submittal.

GDC 45 requires the cooling water system to be designed to permit appropriate periodic inspection of important components, such as heat exchangers and piping, to assure the integrity and capability of the system. The single discharge header alignment will aid in performing inspections, as required by GDC-45, and repairs (if required) to the NSWS Page 11

return header piping in the Auxiliary Building, since the timeframe for inspection and repair is likely to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Periodic inspection of the pipe coating will be necessary to ensure the coating is performing satisfactorily.

Clarification of single failure requirements is included in ANSI/ANS Standards on single failure and for pipe rupture analysis in NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition". These two requirements have been met by Catawba through two separate programs and have been evaluated separately in support of this request. The requirements associated with single failures involve assumption of single failures during a Condition I, Ill, or IV event. The requirements of NUREG-0800 involve analyzing pipe ruptures with the plant in normal operation, then assuming a single active failure that could inhibit the response.

Discussion of ANSI/ANS Standards on Single Failure Two ANSI/ANS documents are applicable to single failure documentation. These are ANSI N658-1976/ANS-51.7, "Single Failure Criteria for PWR Fluid Systems", and a later version, ANSI/ANS-58.9-1981, "Single Failure Criteria for Light Water Reactor Safety-Related Fluid Systems". These were written to clarify the requirements made in 10 CFR 50 Appendix A.

These documents contain the definition of single failure, active failure, and passive failure, and describe the rules for application of single failure criteria. In summary these state:

Single Failure - A single failure refers to a random failure and its consequential effects assumed in addition to an initiating event and its consequential effects for the purpose of safety related fluid system design and analysis.

Active Failure - An active failure is a malfunction, excluding passive failures, of a component that relies on mechanical movement to complete its intended function on demand.

Examples of active failures include the failure of a powered valve or check valve to move to its correct position or the failure of a pump, fan, or diesel generator to start.

Passive Failure - A passive failure is a failure of a component to maintain its structural integrity or the blockage of a process flow path. Blockage of a process flow path could occur, for example, due to the separation of a valve disc from its stem.... The design flow for a passive failure shall be defined by analysis of realistic passive failure mechanisms in the system, considering conditions of operation and possible failure or leakage modes, as appropriate....

3. Rules for Application of the Single Failure Criteria 3.1 The unit shall be designed such that, for any Condition III or IV initiating event, the safety functions of... emergency core and containment heat removal... can be performed, assuming a single failure in addition to the initiating event.

3.4 During the short term, the single failure considered may be limited to an active failure.

3.5 During the long term assuming no prior failure during the short term, the limiting single failure considered can be either active or passive. Page 12

5.6 The design flow for a passive failure shall be defined by analysis of realistic passive failure mechanisms in the system, considering conditions of operation and possible failure or leakage modes, as appropriate.... As an example... a review... may result in the definition of a design leak rate for passive-failure evaluation based on maximum flow through a failed valve packing or pump mechanical seal.

The systems calculation performed in support of this submittal discusses the reliability of the NSWS valves that are significant to the single discharge header alignment (1 RN53B, 1 RN54A, 1 RN58B, and 1 RN63A). Based on the discussion in this calculation, it is concluded that a passive failure of one of these valves is not credible.

The key assumption in the NSWS single discharge header alignment is that Unit 1 is in a TS Condition and that no further NSWS failures (including pipe ruptures) are required to be postulated on Unit 1 equipment or on shared equipment. The basis for this assumption is described in ANSI/ANS-58.9-1981, Section 4.3, which states: "If one train of a redundant safety-related fluid system or its safety-related supporting systems is temporarily rendered inoperable due to short-term maintenance as allowed by the unit technical specifications, a single failure need not be assumed in the other train."

Discussion of NUREG-0800 Pipe Rupture Considerations NUREG-0800 provides requirements that meet 10 CFR 50 Appendix A GDC 4. Section 3.6.1, "Plant Design for Protection Against Postulated Piping Failures in Fluid Systems Outside of Containment", contains guidance on postulating pipe ruptures with respect to single failures. This guidance includes:

"Where the postulated Piping failure is assumed to occur in one of two or more redundant trains of a dual-purpose moderate energy system, i.e., one required to operate during normal plant conditions as well as to shut down the reactor and mitigate the consequences of the piping failure, single failure of components in the other train or trains of that system only, need not be assumed provided the system is designed to seismic Category I standards, is powered from both offsite and onsite sources, and is constructed, operated, and inspected to quality assurance, testing, and inservice inspection standards appropriate for nuclear safety systems. Examples of systems that may, in some plant designs, qualify as dual-purpose essential systems are service water systems, component cooling systems, and residual heat removal systems."

Catawba UFSAR - Licensing Basis Section 3.6 Protection Against Dynamic Effects Associated With the Postulated Rupture of Piping Catawba's position in response to 10 CFR 50 Appendix A GDC 4 and NUREG-0800 Section 3.6.1 BTP ASP 3-1 and Section 3.6.2 BTP MEB 3-1 are documented in this section of the Catawba UFSAR. The following section is applicable with respect to pipe rupture and single failure: Page 13

3.6.2.1.2 General Design Criteria for Postulated Piping Breaks Other Than Reactor Coolant System Consideration is given to the potential for a random single failure of an active component subsequent to the postulated pipe rupture. Where the postulated piping break is assumed to occur in one of two or more redundant trains of a dual-purpose moderate-energy essential system (i.e., one required to operate during normal plant conditions as well as to shut down the reactor and mitigate the consequences of the piping rupture), single failures of components in the other train or trains of that system only are not assumed, provided the system is designed to seismic Category I standards, is powered from both offsite and onsite sources, and is constructed, operated, and inspected to quality assurance, testing, and inservice inspection standards appropriate for nuclear safety systems.

Section 9.2.1 Nuclear Service Water 9.2.1.1 Design Bases

... Sufficient redundancy of piping and components is provided to ensure that cooling is maintained to essential loads at all times.

9.2.1.2.4 Main Discharge Section There are two main discharge headers, extending the width of the Auxiliary Building with channel 1A and 2A components returning flow to the A header, and channel 1 B and 2B components returning flow to the B header. During normal station operation when RN pumps are taking suction from Lake Wylie, discharge crossover valves are open, and all heat exchangers in operation discharge through the channel A return to Lake Wylie via the Low Pressure Service Water discharge. Automatically upon emergency low pumphouse pit level (as in loss of Lake Wylie), double isolation valves close on the return line to Lake Wylie, double isolation valves close on the discharge header crossover, and single isolation valves open on each channel return to the SNSWP. This sequence, along with isolation of the non-essential header and supply header crossover valves ensures two independent, redundant supplies and returns, satisfying the single failure criteria.

9.2.1.3 Safety Evaluation The Nuclear Service Water System is designed to withstand a safe shutdown earthquake and to prevent any single failure from limiting the ability for the engineered safety features to perform their safety functions.

... The RN System is designed to supply the cooling water requirements of a simultaneous LOCA on one unit and cooldown on the other unit assuming a single failure anywhere on the system, loss of offsite power and loss of Lake Wylie. Upon complete channel separation, both units are assured of having a source of water, at least one pump capable of supplying required flow on its associated channel, and at least one essential header to provide cooling water to components served by RN.

Channels A and B are connected together only at six places: five between the RN supply headers and one between the RN discharge headers. Redundant motor Page 14

operated isolation valves are provided on the normally open crossover lines, and manual isolation valves are used on normally closed, rarely used crossover lines.

Table 9-4 Nuclear Service Water System Failure Analysis Component: Main SNSWP return valves 1 RN63A 1 RN58B Malfunction: Failure to open on Loss of Lake Each valve serves one shared train of RN System return to SNSWP, so failure of one valve to open when Lake return valves close results in failure of only one channel in both units. The remaining channel in each unit is sufficient to shut down both units safely.

Comment & Consequence: If a Unit 1 diesel is known to be out of service, these valves are aligned to the Unit 2 diesel of corresponding channel.

Component: Channel A shared return line to SNSWP Malfunction: Rupture or plug Comment & Consequence: Isolate affected return line A and utilize backup train return line B until train A is repaired.

Component: Crossover valves 1 RN53B or 1 RN54A Malfunction: Failure to close on Loss of Lake Comment & Consequence: A and B valves are in series, so failure of either valve will not prevent channel separation when required.

In reference to the NSWS Failure Analysis described in UFSAR Table 9-4, NSWS valves 1 RN63A or 1 RN58B is in the open position per the single discharge header alignment. Also, one shared discharge line will be out of service, and the opposite train will be in service. Finally, the return header crossover valves remain open in this alignment to provide a discharge flow path for the opposite train of Unit 1 NSWS and therefore, closure of these valves to support channel separation is not desired. Channel separation is not required in this configuration since the NSWS is pre-aligned to the SNSWP, which eliminates the possibility of loss of an entire NSWS train during a swapover to the SNSWP.

Catawba Calculation for the Single Failure of the NSWS The most comprehensive Catawba specific evaluation of single failure in the NSWS is contained in this calculation. This calculation elaborates on the NSWS analysis in UFSAR Table 9-4 and considers multiple equipment losses on failures of relays in addition to component failures. This calculation is predominantly a review of active failures and was reviewed with respect to the proposed single discharge header alignment design change.

However, none of the predicted scenarios will be impacted by the single discharge header alignment since Unit 1 will be in a TS Condition and no additional failures are required to be postulated on opposite train equipment. For example, with NSWS Train A in a TS Condition, no failures are required to be postulated on Unit 1 Train B equipment or on Train B shared equipment. This assumption is described in ANSI/ANS-58.9-1981 Section 4.3, which states, "If one train of a redundant safety-related fluid system or its safety-related supporting systems is temporarily rendered inoperable due to short-term maintenance as Page 15

allowed by the unit technical specifications, a single failure need not be assumed in the other train."

Likewise, with Unit 1 in a TS Condition due to the inoperability of one NSWS train, it is assumed that a pipe rupture does not occur on the remaining in-service Unit 1 NSWS train or on shared NSWS piping, as described in UFSAR Section 3.6.2.1.2.

Design Basis Event Response for the NSWS Single Discharge Header Aliqnment The concept of automatically separating trains in the single discharge header alignment cannot apply, as both trains are connected at the point where the NSWS piping splits just after entering the Auxiliary Building and on the NSWS return headers. In the normal existing configuration, the protection provided by separating trains ensures that adequate equipment is operating to perform its design basis functions. This protects against a failure such as a leak or a diversion of flow on one train from affecting the other train. For design basis events, the failures that must be considered are a single active failure or a single passive failure.

Operational and Single Failure Considerations The entry into the NSWS single discharge header alignment will be restricted to periods when Unit 2 is in Mode 5, 6, or No Mode (defueled). This is due to the isolation of the Unit 2 NSWS to the CCW System and the CSS flow paths when the associated NSWS discharge header is taken out of service. When Unit 2 is Mode 5, 6, or No Mode, it is not in the mode of applicability for the CCW System or the CSS. Additionally, it is assumed that Unit 1 is in Mode 1, 2, 3, or 4.

This section addresses the acceptability of the single discharge header alignment in the two operational configurations that need to be considered and applies the indicated events, assuming that a diesel generator and a NSWS pump on the affected train are out of service (these are considered the failures). Diagrams are shown on the pages following the table.

Note that the configuration of each NSWS train prior to and following the event is the same, since no valves are required to reposition. Page 16

Case Initial Condition(s)

Event Single Failure* Comments 1

1. Single Discharge Header Unit 1 LOCA NSWS pump

1. It is assumed that NSWS pump 2A, NSWS Train A out of service LOOP on 2A diesel generator 2A, and CCW 2A are

2. Unit 1 - Mode 1, 2, 3, 4 both units Diesel removed from service for maintenance,

3. Unit 2 - Mode 5, 6, No Mode generator 2A since NSWS Train A return header to SNSWP

4. NSWS suction and discharge (operable (Note 9) is out of service.

train) are aligned to the SNSWP

2. Since NSWS is aligned to SNSWP,

5. Unit 2 side of NSWS Train A shared NSWS return header crossovers are open and return header to SNSWP isolated for return headers are cross-connected.

maintenance

3. NSWS Train 1A is inoperable but available.

6. CCW 2A and CSS 2A out of service and Discharge flow path to SNSWP for NSWS unavailable Train 1A is available through NSWS Train 1B

7. Diesel generator 2A and NSWS pump 2A discharge.

assumed to be unavailable (out of service for maintenance) 2

1. Single Discharge Header Unit 1 LOCA NSWS pump

1. It is assumed that NSWS pump 2B, NSWS Train B out of service LOOP on 2B diesel generator 2B, and CCW 2B are

2. Unit 1 - Mode 1, 2, 3, 4 both units Diesel removed from service for maintenance,

3. Unit 2 - Mode 5, 6, No Mode generator 2B since NSWS Train B return header to SNSWP

4. NSWS suction and discharge (operable (Note 9) is out of service.

train) are aligned to the SNSWP

2. Since NSWS is aligned to.SNSWP,

5. Unit 2 side of NSWS Train B shared NSWS return header crossovers are open and return header to SNSWP isolated for return headers are cross-connected.

maintenance

3. NSWS Train 1B is inoperable but available.

6. CCW 2B and CSS 2B out of service and Discharge flow path to SNSWP for NSWS unavailable Train 1B is available through NSWS Train 1A

7. Diesel generator 2B and NSWS pump 2B discharge.

assumed to be unavailable (out of service for maintenance)

Notes:

1. Entry in the NSWS single discharge header alignment is restricted to Unit 2 being in Mode 5, 6, or No Mode. Unit 1 is assumed to be in Mode 1, 2, 3, or 4. If Unit 1 has to shut down, then the TS for the NSWS, TS 3.7.8, does not apply once Unit 1 enters Mode 5.

2. Performing scheduled, planned, or discretionary maintenance that renders both NSWS pumps inoperable on either train of NSWS (i.e., draining the NSWS pump pit) is prohibited while the NSWS is aligned in the single discharge header alignment.

3. With Unit 1 in a TS Condition on the shared NSWS Train A discharge header, no failures are required to be postulated on NSWS Train 1 B equipment or on Train B shared equipment. NSWS pump 2B and diesel generator 2B are assumed to be shared equipment. Likewise, with Unit 1 in a TS Condition on NSWS Train B, no failures are required to be postulated on NSWS Train 1A equipment or on Train A shared equipment. NSWS pump 2A and diesel generator 2A are assumed to be shared equipment.

4.

In all cases described above, three NSWS pumps are available after the event since Unit 1 is in a TS Condition and no further failures are required to be postulated on remaining NSWS pumps.

5. With NSWS pump 2A or NSWS pump 2B out of service for maintenance, NSWS procedure enclosures allow the operators to close a Unit 2 NSWS supply header crossover (this is done to comply with the NSWS one pump flow balance requirements, Page 17

since the NSWS one pump flow balance does not assume flow to the opposite train NSWS essential headers). Unit 1 supply header crossovers close on a Sp signal. This combination results in the Unit 1 and the Unit 2 supply crossover valves being closed, and therefore the NSWS supply headers have train separation. However, the return header crossovers are unaffected and remain open with power removed. Alternately, the operators may choose another procedure enclosure that does not close a Unit 2 supply crossover with a Unit 2 NSWS pump out of service. In either case (NSWS Unit 2 supply crossovers open or closed), adequate NSWS flow to essential components is maintained.

6. With NSWS pump 2A or NSWS pump 2B out of service for maintenance, NSWS procedure enclosures allow the operators to isolate the Unit 2 NSWS non-essential header (this is done to comply with the NSWS one pump flow balance requirements, since the NSWS one pump flow balance does not assume flow to the NSWS non-essential headers). However, the operators may choose another procedure enclosure that does not isolate the Unit 2 non-essential header with a Unit 2 NSWS pump out of service. To eliminate the possibility of providing NSWS flow to the Unit 2 NSWS non-essential header, the NSWS single discharge header alignment will isolate the Unit 2 non-essential header so that more NSWS flow is available for essential components served by the NSWS. The Unit 1 non-essential header isolates on a Sp signal.

Therefore, there is no NSWS flow to the Unit 1 NSWS non-essential header.

7. There is no NSWS flow to the CSS heat exchangers or Auxiliary Feedwater (AFW) makeup on the shutdown unit (Unit 2), since these are removed from service per procedure and not required in the modes of applicability for this condition.

8. It should be noted that when the NSWS is aligned in the single discharge header alignment that the NSWS return header crossovers will be open with power removed and therefore will not automatically close on a NSWS low-low pit level signal or on a transfer to the Auxiliary Shutdown Panels. This has a benefit of providing a flow path to the Unit 1 NSWS train. This is allowable, since the three remaining NSWS pumps have adequate capacity to supply the remaining cooling water demands of the three essential headers and three diesel generators. This has been demonstrated by the supporting systems calculation.

9. The Unit 2 diesel generator and the NSWS pump on the affected train are out of service (these are considered the failures). Page 18

Case 1. NSWS Single Discharge Header Alignment - Train A Isolated - Configuration Before and After Event

1.

It is assumed that Unit 2 is Mode 5, 6, or No Mode; therefore, there is no Unit 2 TS Condition on the NSWS.

2.

Unit 1 is in Mode 1, 2, 3, or 4.

3.

A portion (Unit 2 side) of the shared NSWS Train A discharge piping to the SNSWP is isolated, resulting in a TS Condition on Unit 1.

4.

The 2A NSWS pump, 2A diesel generator, and 2A CCW System are assumed to be out of service for maintenance and unavailable.

5.

Return header crossover valves 1 RN53B and 1 RN54A are open with power removed and therefore will not automatically close on a NSWS low-low pit level signal or on a transfer to the Auxiliary Shutdown Panels. Unit 1 NSWS Train A components can discharge through the NSWS Train 1 B discharge header, which is aligned to the SNSWP.

6.

No failures are postulated on Train 1 B equipment or on Train B shared equipment, since Unit 1 is in a TS Condition on NSWS Train A.

7.

NSWS Trains 1A, 1B, and 2B are aligned to discharge to the SNSWP. The Lake Wylie discharge flow path is isolated since the NSWS is aligned (suction and discharge) to the SNSWP. Page 19

2B Ný5 HX ZiiX2RN229B B Train A Train To To 1RN58B Sp-O Note 2 2A NS HX 2RN148A U2 Non B

Ess Hdr; Train 1 RN55 2A KG)"

HX S1RN59 RN61 1RN63A Closed A

Train I

1RNP19 Aux Yard Bkdq 2B KC) -- :1 HX 1RNP20 X, 1RN54A I

-1RN53B Note 1 Note 1 IRNP18 1RN838 1B KC){,l I

IA KCHX HX

[i11RN229B 1BNS HX Isolated Piping:

L L*

1RN83iV U1 Non)

]---

Ess Hdr 1RN52B Sp-K 1A NS HX Y--

• 1RN148A 1RN843B 1RN5TA Note 3 Note 3 Shared Return to Lake Wylie 4

Notes:

1.

NSWS return header crossover valves are open with power removed and therefore will not automatically close on a NSWS low-low suction pit level signal or on a transfer to the Auxiliary Shutdown Panels. Therefore, the NSWS return headers remain cross-connected and NSWS Train 1A has a discharge flow path available through the NSWS Train 1 B return to the SNSWP.

2.

NSWS return isolation to the SNSWP is open (power removed) with the NSWS in the single discharge header alignment.

3.

NSWS return isolation valves to Lake Wylie are closed. Page 20

Case 2. NSWS Single Discharge Header Alignment - Train B Isolated - Configuration Before and After Event

1.

It is assumed that Unit 2 is Mode 5, 6, or No Mode; therefore, there is no Unit 2 TS Condition on the NSWS.

2.

Unit 1 is in Mode 1, 2, 3, or 4.

3.

A portion (Unit 2 side) of the shared NSWS Train B discharge piping to the SNSWP is isolated, resulting in a TS Condition on Unit 1.

4.

The 2B NSWS pump, 2B diesel generator, and 2B CCW System are assumed to be out of service for maintenance and unavailable.

5.

Return header crossover valves 1 RN53B and 1 RN54A are open with power removed and therefore will not automatically close on a NSWS low-low pit level signal or on a transfer to the Auxiliary Shutdown Panels. Unit 1 NSWS Train B components can discharge through the NSWS Train 1A discharge header, which is aligned to the SNSWP.

6.

No failures are postulated on Train 1A equipment or on Train A shared equipment, since Unit 1 is in a TS Condition on NSWS Train B.

7.

NSWS Trains 1A, 1B, and 2A are aligned to discharge to the SNSWP. The Lake Wylie discharge flow path is isolated since the NSWS is aligned (suction and discharge) to the SNSWP. Page 21

B Train A Train To To 2Bfo HX 2~1RN58B RRN229B Closed ED-2ANSH 1

.RN63A 2RN148Aj Sp-Note 2 U2 Non~L_

B Ess HdS"V' 1 Trai 1 RN55 2A KC)T\\*

T-A HX VN" Trai 1RN59 1 RN61 1RNP19 Aux Yard 1RN61

\\Rt'9Bd KCI*I

,*BIdql 2B KC HX 1RNP20 1RN54A

-11 RN53B Note 1 H-Note 1 1RN838 1RNP8 1RN8372>

1BCN[

1AKCHX)------

Li NXKC 1

I Ul Non )-

SRN229B ESS Hdr I RN52Bl Sp-K 1 1B NS HX 1A NS HX 1RN148A 4

1RN843B 1RN57A Note3 Note 3 Isolated Piping:

/

Shared Return to Lake Wylie 4.

Notes:

1.

NSWS return header crossover valves are open with power removed and therefore will not automatically close on a NSWS low-low suction pit level signal or on a transfer to the Auxiliary Shutdown Panels. Therefore, the NSWS return headers remain cross-connected and NSWS Train 1 B has a discharge flow path available through the NSWS Train 1A return to the SNSWP.

2.

NSWS return isolation to the SNSWP is open (power removed) with the NSWS in the single discharge header alignment.

3.

NSWS return isolation valves to Lake Wylie are closed.

Attachment I Page 22

Conclusions The justification provided in the supporting systems calculation for the NSWS single discharge header alignment supports operation in this configuration, since Unit 1 will be in a TS Condition and no additional single failures are required to be postulated on Unit 1 or on shared equipment. However, this conclusion required that a PRA study be performed to determine the additional risk associated with operation in this configuration for up to 14 days and to determine if the alignment was acceptable from a PRA perspective.

With only one of the two NSWS return headers to the SNSWP in service while in the single discharge header alignment, the NSWS cannot sustain an additional failure that affects the remaining NSWS discharge header to the SNSWP. This would include a NSWS pipe rupture or a NSWS valve failure that is in the active discharge flow path to the SNSWP. To mitigate this risk, the NSWS single discharge header alignment has the NSWS pre-aligned to the SNSWP, and valves will be positioned with power removed. These measures have been incorporated into the PRA calculation that evaluated this alignment, and this calculation shows that the increase in risk associated with the NSWS being in the single discharge header alignment is minimal and acceptable.

PRA Considerations Duke Energy has used a risk-informed approach to determine the risk significance of changing the NSWS TS Completion Time beyond its current limit of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The acceptance guidelines given in Regulatory Guide (RG) 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications", were used to determine the significance of this change.

The PRA analysis indicated that the risk acceptance criteria found in RG 1.177 for TS changes were met with a proposed Completion Time of 14 days. The PRA model used to perform this risk evaluation took into account previous modifications that allow the station to operate all four NSWS pumps via a single train when a NSWS supply header is removed from service.

Duke Energy initially performed a quality self assessment of the Catawba PRA against RG 1.200, Rev. 1, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities". That assessment indicated that 231 of the 306 Supporting Requirements (SRs) for Rev. 1 were fully met.

In addition, 24 of the SRs were not applicable to Catawba at all, either because the referenced techniques were not used in the PRA or because the SR was not required for Capability Category (CC) I1. Of the remaining open SRs, only a small number were of a technical nature. These are summarized as follows: Page 23

Supporting Category 11 Requirements Resolution Expected Impact on Requirement Application For parameter estimation, GROUP Revise the data This is a refinement to the components according to type (e.g.,

calculation to equipment failure rates.

motor-operated pump, air-operated segregate standby However, since most valve) and according to the and operating components are grouped DA-B1 characteristics of their usage to the component data.

appropriately, the overall exetSegregate aporaey h

vrl extentsupported by data: (a) co nents bimpact will be small and is missintysupored (eg.

datandby, components by not expected to have a mission type (e.g., standby, sriecniint operating), (b) service condition service condition to significant impact on this (e.g., clean vs. untreated water, air) the extent supported application.

by the data.

Based on preliminary evaluations using the EPRI HRA calculator, calibration errors that result in failure of a single channel are expected to fall in the low 103 range. Calibration errors that result in failure of multiple channels are IDENTIFY, through a review of expected to fall in the low procedures and practices, those 10-5 range. Relative to calibration activities that if Enhance the HRA to post-initiator HEPs, HR-A2 performed incorrectly can have an consider the potential equipment random failure adverse impact on the automatic for calibration errors.

rates, and maintenance initiation of standby safety unavailability, calibration equipment.

HEPs are not expected to contribute significantly to overall equipment unavailability. (In fact, recent modeling updates for Oconee support this position.) Therefore, this is not expected to have a significant impact on this application.

Relative to post-initiator IDENTIFY which of those work HEPs, equipment random practices identified above (HR-Al, Identify maintenance failure rates, and HR-A2) involve a mechanism that maintenance unavailability, simultaneously affects equipment in activities that could calibration HEPs are not either different trains of a redundant simultaneously affect expected to contribute HR-A3 system or diverse systems [e.g.,

simultan ect significantly to overall use of cmmon calbrationequipment in either eqimnuavlblty use of common calibration different trains of a equipment unavailability.

equipment by the same crew on the redundant system or Mean values for HEPs were same shift, a maintenance or test diverse systems.

used in the supporting activity that requires realignment of analysis with no significant an entire system (e.g., SLCS)].

impacts to the resulting CDF and LERF values.

PROVIDE an assessment of the Mean values for HEPs were HR-D6 uncertainty in the HEPs. USE Develop mean values used in the supporting mean values when providing point for pre-initiator HEPs.

analysis; therefore, the SR estimates of HEPs.

has been addressed for this I application. Page 24

Supporting Category 11 Requirements Resolution Expected Impact on Requirement Application Characterize the uncertainty in the Mean values for HEPs were estimates of the HEPs, and Develop mean values used in the supporting HR-G9 PROVIDE mean values for use in for post-initiator analysis; therefore, this the quantification of the PRA HEPs.

issue has been addressed results.

for this application.

This item is relevant to Give theexpeted applications that include For each flood area not screened Given the expected ofninternal flood initiators.

out using the requirements under flood areas needed to Whereas the cut sets IF-Bib, IDENTIFY the SSCs located satisfy requirement generated for this in each defined flood area and IF-IF-Ay, additional application include an A2 along flood propagation paths IAaitiol internal flooding event, it that are modeled in the internal equipment will need does not dominate the events PRA model as being dentified and results (see section below required to respond to an initiating discussed in order to entitled "Internal/External event or whose failure would Floods PRA which IF-C2c challenge normal plant operation, requirements of the confirms no significant and are susceptible to flood. For impact from internal each identified SSC, IDENTIFY, for current flooding flooding events).

the purpose of determining its analysis does not Therefore, this item is not susceptibility per IF-C3, its spatial discuss flood expected to have a location in the area and any mithis will have to significant impact on this flooding mitigative features (e.g.,

be corrected to satisfy application. (An update to shielding, flood, or spray capability the requirements of the Catawba internal ratings).

the ASmentsnof.flooding analysis to meet the ASME Standard.

RG 1.200 Rev. 2 is planned for completion in 2011.)

This item is relevant to applications that include internal flood initiators. The The current flooding lone significant internal analysis identifies the flooding event found in the For the SSCs identified in IF-C2c, submergence failure cut sets generated for this IDENTIFY the susceptibility of each height of the application involves the SSC in a flood area to flood-equipment important Auxiliary Shutdown Panel.

induced failure mechanisms.

to accident mitigation, However, this event does INCLUDE failure by submergence but, except for the not dominate the results and spray in the identification Auxiliary Shutdown (see section below entitled IF-C3 process. ASSESS qualitatively the Panel, never "Internal/External Floods impact of flood-induced addresses the impact PRA" which confirms no mechanisms that are not formally of spray. Spray as a significant impact from addressed (e.g., using the failure mechanism internal flooding events).

mechanisms listed under Capability needs to be Therefore, this item is not Category 111 of this requirement),

addressed in the expected to have a by using conservative assumptions.

analysis or a note significant impact on this made explaining why application. (An update to it was omitted.

the Catawba internal flooding analysis to meet RG 1.200 Rev. 2 is planned for completion in 2011.) Page 25

Supporting Category

'1 Requirements Resolution Expected Impact on Requirement Application This item is relevant to applications that include internal flood initiators.

Whereas the cut sets IDENTIFY inter-area propagation generated for this through the normal flow path from application include an one area to another via drain lines; Provide more analysis internal flooding event, it and areas connected via back flow of flood propagation does not dominate the through drain lines involving failed flowresults (see section below check valves, pipe, and cable potential structural entitled "Internal/External IF-C3b penetrations (including cable trays),

failure of doors or Floods PRA" which doors, stairwells, hatchways, and walls due to flooding confirms no significant HVAC ducts. INCLUDE potential loads and the impact from internal for structural failure (e.g., of doors potential for barrier flooding events).

or walls) due to flooding loads and unavailability.

Therefore, this item is not the potential for barrier expected to have a unavailability, including significant impact on this maintenance activities.

application. (An update to the Catawba internal flooding analysis to meet RG 1.200 Rev. 2 is planned for completion in 2011.)

This item is relevant to applications that include internal flood initiators.

Whereas the cut sets generated for this application include an internal flooding event, it INCLUDE, in the quantification, does not dominate the both the direct effects of the flood results (see section below (e.g., loss of cooling from a service entitled "Internal/External IF.E6b water train due to an associated Address potential Floods PRA" which pipe rupture) and indirect effects indirect effects.

confirms no significant such as submergence, jet impact from internal impingement, and pipe whip, as flooding events).

applicable.

Therefore, this item is not expected to have a significant impact on this application. (An update to the Catawba internal flooding analysis to meet RG 1.200 Rev. 2 is planned for completion in 2011.)

This issue affects some small LOCAs. Because the In crediting HFEs that support the Explicitly model RCS small LOCA contribution to accident progression analysis, USE depressurization for Large Early Release LE-thac pliciden p

ressionanays, UE small LOCAs and Frequency (LERF) is small, LE-C6 the applicable requirements of pefrthnomeiaipctwudb paragraph 4.5.5, as appropriate for perform the no material impact would be paragrap 4.ve 5 o

aslofthe approriat f dependency analysis expected. Therefore, this the level of detail of the analysis.

on the HEPs.

item is not expected to have a significant impact on this application. Page 26

The remaining open SRs required enhanced documentation but none was expected to have a significant impact on the PRA results or insights. Based on this assessment, the internal events portion of the Catawba PRA fully satisfies all of the configuration and control requirements for meeting Rev. 1 of RG 1.200.

Per Section 4.2 of RG 1.200, Rev. 2, an assessment is required for permanent plant changes that have an impact on the PRA model but have not been incorporated.

Outstanding changes to be incorporated in future PRA updates are recorded and evaluated per PRA Workplace Procedure XSAA-1 06, "Workplace Procedure for PRA Maintenance, Update and Application". These events are captured and tracked via an in-house PRA database, "PRA Tracker". Based upon criteria set in XSAA-106, plant changes affecting the PRA model are classified as either "high", "medium", or "low" risk.

The resolution of all "high" and "medium" risk items, as well as all applicable "low" risk items, is assessed below:

Tracker Item Risk Description/Evaluation No.

Station modification CD500063 adds new manual valves to the NSWS Discharge Header. The manual valves will normally be locked open. Consider adding these valves to the NSWS model.

0-05-0017 Low These valves were added to both the Loss of NSWS and main fault trees. Adding these valves makes an insignificant contribution to the Loss of NSWS risk as well as to the overall risk results.

C-03-01163 adds NSWS cross connect piping and valves to allow a single NSWS header to supply the cooling water to both trains of the diesel generators. Other miscellaneous changes also to fire hose racks and diesel generator starting air supply C-05-0019 Low piping.

These modifications have been made to the NSWS and are included in the revised fault tree model used to support this analysis.

Install 30-inch crossover NSWS line in Auxiliary Building to allow single header operation (as a replacement for the existing 20-inch crossover). Also, modification CD200358 needs to be reviewed with this package as it also has other NSWS piping C-05-0027 Low changes. Unit 1 modification package is CD100139.

These modifications have been made to the NSWS and are reflected in the revised fault tree model used to support this analysis.

Modifications to the NSWS headers to add crossovers between diesel generators. CD100106 adds crossovers too. Also, CD500062 upgrades NSWS pump strainer discharge piping to support a cross tie to be installed under modification CD500091.

C-06-0004 Low Per the change form evaluation, the modifications are expected to be mostly editorial and will result in an improvement in Core Damage Frequency (CDF); therefore, there are no expected I

I impacts that would alter the results of this analysis. Page 27

Tracker Item Risk Description/Evaluation No.

Add alternate feedwater makeup line to each steam generator (reference letter to NRC dated February 26, 2007).

C-07-0016 Medium The NSWS discharge line does not have any impact on this item; therefore, no impact on this analysis.

Need to isolate the NSWS non-essential headers during single header NSWS flow to allow sufficient flow to essential NSWS components.

Per the change form evaluation, there was no change to the CDF when assessing the impact of this change. In addition, this change is referring to NSWS operation in the single supply header mode which would not be allowed during implementation of single discharge header operations. Therefore, there is no impact to this analysis.

PIP C-06-08437, Implement NSWS single supply header operation. Also, PIPs C-07-02571 and C-08-04845.

Modifications have been made to the NSWS and are reflected C-09-0001 Low in the revised fault tree model used to support this analysis. As stated above, NSWS operation in the single supply header mode will not be allowed during implementation of single discharge header operations. Therefore, there is no impact to this analysis.

Valves 1/2CA-6 have been closed to isolate the auxiliary feedwater condensate storage tank to prevent potential vortexing problems.

0-09-0007 Medium A sensitivity study was performed in the supporting risk calculation and showed the delta risk values are the same regardless of tank availability. Therefore, there is no impact on this analysis.

This modification is part of the ECCS Water Management project. The modification removes the automatic start of the containment spray pumps on high-high containment pressure concurrent with Containment Pressure Control System C-09-0008 Medium permissive and only allows for a manual start of the containment spray pumps.

The NSWS discharge line does not have any impact on this item; therefore, no impact on this analysis.

Incorrect logic discovered in the Cr3a PRA model with respect to instruments associated with NSWS low pit level.

0-10-0001 Low Per the change form evaluation, when modeling this error, the base case did not change in either value or number of cut sets for CDF and LERF. Therefore, no impact on this analysis.

Rev. 2 of RG 1.200 includes external events in the PRA quality assessment and provides a position to the current revision of the ASME/ANS PRA quality standard.

Accordingly, the impact on the submittal results due to external events was assessed.

These included the effects from seismic events, fires, floods, and tornadoes/high winds. Page 28

Seismic PRA The current Catawba seismic PRA model of record was last updated as part of Revision 3 of the PRA model. The current methodology used is the same as that described in detail in the Individual Plant Examination (IPE) submittal and in Section 3 of the Individual Plant Examination for External Events (IPEEE) submittal, both of which have already been reviewed by the NRC.

The current seismic PRA contains the technical elements given in Section 1.2.6 of RG 1.200, Rev. 2 as part of the methodology referenced above. A site-specific seismic hazard analysis was performed for Catawba and is documented in EPRI Report RP1 01-53, "Probabilistic Seismic Hazard Evaluation for Catawba Nuclear Station". This hazard was used to develop the analyses discussed above for the IPE, IPEEE, and current seismic model. Furthermore, Duke Energy has been actively following developments related to GI-199, "Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States". In 2008, Risk Engineering Inc. performed preliminary comparisons of the EPRI 2008 seismic hazards and EPRI 1989 seismic hazards for the Duke Energy plants. Their results indicated no significant impact to Catawba.

A seismic fragility analysis was also performed as part of the seismic PRA development.

Median fragilities were developed for risk-important components and structures, along with their corresponding randomness and uncertainty factors. These values were used in the IPE and IPEEE analyses, as well as in the current seismic PRA model.

The seismic plant response is determined using a fault tree comprised of a combination of several random events from the plant internal events tree in conjunction with events representing the median fragilities of plant equipment and structures. The resulting accident sequences (cut sets) are then evaluated against the plant seismicity curves and the median fragilities using a Monte Carlo analysis which determines the seismically-induced CDF.

Components with median seismic capacities in excess of 2g are screened out of the seismic fault tree model due to their low probability of failure. Likewise, structures are eliminated from consideration when their seismic capacities are in excess of 2.5g.

Among those components and structures screened out were the SNSWP dam, the NSWS pumps, and all qualified piping and valves. Therefore, the NSWS components and piping are considered to be seismically rugged. Since the NSWS components and structures were screened out of the model, a sensitivity study was performed to conservatively bound the impact of having a NSWS discharge line unavailable during a seismic event. The seismic CDF showed only a modest increase using very conservative bounding assumptions. In addition, there were no new failure modes introduced and consideration of the seismic impact is thus not a factor for this assessment.

In accordance with the discussion in this section and the results of the bounding analysis above, Duke Energy considers inclusion of seismic results as insignificant to the overall results. Therefore, it is judged that the analyses assessing the influence of seismic events provide an acceptable evaluation of the contribution of the seismic risk for the requested Completion Time of 14 days. Page 29

Internal Fire PRA The current Catawba fire PRA model analysis and methodology used in the model of record is the same analysis and methodology as described in the IPE submittal, Section 4 and Appendix B of the IPEEE submittal, and as discussed in the Supplemental IPEEE Fire Analysis Report (letter from Duke Power Company to NRC, "Supplemental IPEEE Report", McGuire Nuclear Station and Catawba Nuclear Station, dated July 30, 1996),

all of which have already been reviewed by the NRC.

The plant-specific fire PRA analysis consists of four steps, each of which is described below:

The Catawba site and plant areas were analyzed to determine critical fire areas and possible scenarios for the possibility of a fire causing one or more of a predetermined set of initiating events. Screening criteria were defined for those fire areas excluded from the fire analysis.

If there was a potential for an initiating event to be caused by a fire in an area, then the area was analyzed for the possibility of a fire causing other events which would impact the ability to shut down the plant. These were identified by reviewing the impact on the internal events analysis models.

Each area was examined with an event tree fire model to quantify fire damage probabilities. The event tree related fire initiation, detection, suppression, and propagation probabilities to equipment damage states.

Fire sequences were derived and quantified based on the fire damage probabilities and the additional failures necessary for a sequence to lead to a core melt. The additional failures were quantified by the models used in the internal events analysis.

The major changes to the current fire analysis that have been made since the IPEEE submittal deal with implementation of changes from the Supplemental IPEEE Fire Analysis Report and revised base case fire initiating event frequencies.

The Catawba fire PRA model is integrated into the overall PRA model; therefore, quantitative fire risk insights can be obtained for this submittal. Internal fire events contribute approximately 10% of the CDF and 3% of the LERF. Whereas fire-induced loss of NSWS events are included in the PRA model, they do not appear in any core damage or large early release sequences (above the respective truncation limits).

Furthermore, in comparing the delta risk cut sets created in support of the submittal analysis (i.e., those cut sets whose values showed an increase in the submittal configuration when compared to their values in the "base case" configuration), no internal fire sequences of any type appear in the core damage and large early release results. Therefore, the contribution from fire events for the submittal configuration impacting the NSWS is negligible.

Finally, consider that the NSWS essential header discharge valves and the discharge valve to the SNSWP will remain open during the requested 14 day Completion Time with power removed. Therefore, fire events affecting power to these valves cannot cause their spurious operation and thus have no effect on the NSWS discharge alignment during the Completion Time. Page 30

Given the negligible influence of fires on the NSWS for the submittal configuration (i.e.,

no dominant contribution from fires), it is judged that the analyses assessing the influence of internal fire events provide an acceptable evaluation of the contribution of the fire risk for the requested Completion Time of 14 days.

Internal/External Floods PRA Flooding events at Catawba have been assessed via the IPE process and are noted in Sections 3.3.5 and 3.4 of the IPE. Internal flooding events are primarily caused by plant piping ruptures while external floods are mostly caused by very heavy precipitation events. The external events portion is recreated in Section 5.2 of the IPEEE report. As mentioned above, the IPE and IPEEE submittals have already been reviewed by the NRC.

Flood levels for the site were analyzed for the following flood-producing phenomena:

Probable Maximum Flood (PMF) resulting from the Probable Maximum Precipitation (PMP) positioned appropriately over the Catawba River Basin.

PMF resulting from the PMP positioned appropriately over the tributary area of the SNSWP.

Standard Project Flood (SPF) passing through Lake Wylie (positioned over each Catawba River Basin drainage area) combined with the failure of one of the upstream dams because of an Operating Basis Earthquake (OBE). The SPF is considered equal to one-half of the PMF.

Surge and seiche effects caused by probable maximum hurricane.

Coincident wave runup due to a 40 mph wind.

Local intense precipitation (PMP) occurring over the immediate project site.

In the IPEEE report, it was concluded that the contribution to plant risk from external flooding would be insignificant compared to the risk from internal flooding.

The plant-specific Catawba internal flooding analysis was performed in six steps:

Identification of the critical flood areas.

Calculation of flood rates.

Development of flood probabilities.

Identification of critical flood levels.

Assessment of human response for flood isolation.

Development and quantification of the flood core damage cut sets.

The major change made to the current internal flood analysis since the IPE and IPEEE submittals was the installation of concrete flood walls in the Turbine Building basement to protect essential 4160 VAC switchgear against large flooding events. As a result, Page 31

flooding initiator probabilities which would result in either a reactor trip or a loss of the transformers have been significantly reduced.

As with the fire analysis, the Catawba internal flooding PRA model is integrated into the overall PRA model; therefore, quantitative flood risk insights can be obtained for the submittal. The applicable cut sets were reviewed to determine the contribution level of the flooding initiating events. Internal flooding events comprise approximately 2% of the CDF and < 1% of the LERF. The majority of this contribution comes from a flooding event in the Auxiliary Building which results in a loss of the Auxiliary Shutdown Panel.

As indicated previously, the NSWS discharge piping associated with this submittal resides in the Auxiliary Building; thus, it could be postulated that this area could be more susceptible to flooding risk during the Completion Time. Per guidance provided in Duke Energy's risk configuration management Nuclear System Directives for both at power and shutdown conditions, the station is required to give consideration to plant configurations which could potentially cause internal flood hazards resulting in a failure of risk significant structures, systems, and components. Furthermore, per the failure analysis of the NSWS butterfly valves used in the NSWS single discharge header alignment, "[t]he manual and motor operated valves installed in this portion of the NSW system are Fisher Posi-Seal butterfly valves. When these valves are closed, there is not a credible failure that would cause them to change position or catastrophically come apart." In the closed position, the operator gearbox will hold the valve disc still. The gearbox operators are manufactured by Limitorque and have locking gear sets that will not move even during a seismic event. Therefore, exposing the isolated NSWS discharge piping during the 14 day Completion Time is considered to have a negligible impact on flooding risk in the Auxiliary Building. As a sensitivity study, the value for the Auxiliary Building flood initiator in the PRA model was increased by its error factor (7.5) from 5.5E-06 to 4.13E-05. As a result, the CDF for the Completion Time configuration increased by only 9.8% and the corresponding LERF increased only 2.2%. Thus, the impact on internal flooding is considered insignificant.

Given the negligible influence of flooding events for the submittal configuration, it is judged that the analyses assessing the influence of these events provide an acceptable evaluation of the contribution of the flood risk for the requested Completion Time of 14 days.

Tornado/High Winds PRA As with earthquakes, fires, and floods, an assessment for tornadoes and other high wind events at Catawba has been performed via the IPE process as well as with the IPEEE process. The Catawba tornado analysis was developed in the following steps:

The effects of tornado missiles and high winds on the plant were determined.

An event tree was constructed which mapped out possible sequences of events following a tornado strike.

The sequences were quantified using detailed fault trees to model the event tree.

A wind hazard analysis was developed that reflects available regional and site-specific information. A Monte Carlo simulation was performed to evaluate the effects of tornado Page 32

missiles on the targets of interest. Inputs to the plant model include plant structural design data and possible missiles located onsite.

The Catawba tornado PRA model is also integrated into the overall PRA model; therefore, quantitative tornado risk insights can be obtained for the submittal. The cut sets generated for the submittal analysis were reviewed to determine the contribution level of the tornado-initiating events. Only one event (Tornado Causes a Loss of Offsite Power) contributed to the CDF (- 3%) and the LERF (- 4%). Typically, these cut sets include a loss of the diesel generators and either auxiliary feedwater or the Standby Shutdown System. A review of the delta risk cut sets created in support of the submittal analysis found that, while tornado events were a significant contributor to the Incremental Conditional Core Damage Probability (ICCDP) and Incremental Conditional Large Early Release Probability (ICLERP), this contribution comes from the increased tornado frequency value ("seasonal factor") used in the risk assessment to account for historic increased tornado activity during the months of March, April, and May, rather than from interactions with the NSWS configuration.

Furthermore, even though the NSWS provides cooling to the diesel generators, as well as serving as the assured source of auxiliary feedwater, functionality of the NSWS following a tornado event is governed by the operability of the diesel generators and would not be altered per the configuration found in the 14 day Completion Time.

Therefore, the impact of tornadoes and high wind events is negligible.

Given the negligible influence of tornado and high wind events on the NSWS for the submittal configuration (i.e., no dominant contribution from tornadoes/high winds), it is judged that the analyses assessing the influence of these events provide an acceptable evaluation of the contribution of the tornado and high wind risk for the requested Completion Time of 14 days.

In conclusion, it is recognized that the PRA models do not meet all of the supporting requirements of Capability Category II of ASME/ANS PRA Standard RA-Sa-2009.

However, not all risk-informed applications need to meet CC II. Nevertheless, Duke Energy has evaluated the applicable SRs not meeting CC II to the CC II standard and has determined that they do not have a significant impact on this application. Therefore, Duke Energy considers the Catawba PRA models used to assess the risk impact as sufficient to support the requested 14 day Completion Time. Page 33

5.

REGULATORY EVALUATION 5.1 Applicable Regulatory Requirements/Criteria Discussion of GDC Requirements This discussion is contained in Section 4 of this submittal.

5.2 Precedent The NRC approved a comparable license amendment request to allow single supply header operation of the NSWS for Catawba via Amendments 243/237 on July 30, 2008 (CATAWBA NUCLEAR STATION, UNITS 1 AND 2, ISSUANCE OF AMENDMENTS REGARDING SINGLE SUPPLY HEADER OPERATION OF THE BURIED NUCLEAR SERVICE WATER SYSTEM (TAC NOS. MD6275 AND MD6276)) ADAMS Accession Number ML081980769. The approved amendments reference all of the Duke Energy correspondence associated with this license amendment request. This correspondence included the following:

Initial submittal dated July 30, 2007 (ADAMS Accession Number ML072640193)

Response to request for additional information dated May 27, 2008 (ADAMS Accession Number ML081510801)

Response to request for additional information dated June 23, 2008 (ADAMS Accession Number ML081770060) 5.3 No Significant Hazards Consideration The following discussion is a summary of the evaluation of the changes contained in this proposed amendment against the 10 CFR 50.92(c) requirements to demonstrate that all three standards are satisfied. A no significant hazards consideration is indicated if operation of the facility in accordance with the proposed amendment would not:

1.

Involve a significant increase in the probability or consequences of an accident previously evaluated, or

2.

Create the possibility of a new or different kind of accident from any accident previously evaluated, or

3.

Involve a significant reduction in a margin of safety.

First Standard Does operation of the facility in accordance with the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No. Page 34

The proposed single discharge header operation configuration for NSWS operation and the associated proposed TS and Bases changes have been evaluated to assess their impact on plant operation and to ensure that the design basis safety functions of safety related systems are not adversely impacted.

During single discharge header operation, the operating NSWS header will be able to discharge all required NSWS flow from safety related components. PRA has demonstrated that due to the limited proposed time in the single discharge header configuration, the resultant plant risk remains acceptable.

The purpose of this amendment request is to ultimately facilitate inspection and maintenance of the Unit 2 NSWS discharge headers within the Auxiliary Building.

Therefore, NRC approval of this request will ultimately help to enhance the long-term structural integrity of the NSWS and will help to ensure the system's reliability for many years.

In general, the NSWS serves as an accident mitigation system and cannot by itself initiate an accident or transient situation. The only exception is that the NSWS piping can serve as a source of floodwater to safety related equipment in the Auxiliary Building or in the diesel generator buildings in the event of a leak or a break in the system piping. The probability of such an event is not significantly increased as a result of this proposed request. Safety related NSWS piping is tested and inspected in accordance with all applicable inservice testing and inservice inspection requirements. Given the negligible influence of flooding events on the NSWS for the submittal configuration (i.e., no dominant contribution from floods), it is judged that the analyses assessing the influence of these events provide an acceptable evaluation of the contribution of the flood risk for the requested Completion Time of 14 days.

The proposed 14 day TS Required Action Completion Time has been evaluated for risk significance and the results of this evaluation have been found acceptable. The probabilities of occurrence of accidents presented in the UFSAR will not increase as a result of implementation of this change. Because the PRA analysis supporting the proposed change yielded acceptable results, the NSWS will maintain its required availability in response to accident situations.

Since NSWS availability is maintained, the response of the plant to accident situations will remain acceptable and the consequences of accidents presented in the UFSAR will not increase.

Second Standard Does operation of the facility in accordance with the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

Implementation of this amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed request does not affect the basic operation of the NSWS or any of the systems Attachment I Page 35

that it supports. These include the Emergency Core Cooling System, the Containment Spray System, the Containment Valve Injection Water System, the Auxiliary Feedwater System, the Component Cooling Water System, the Control Room Area Ventilation System, the Control Room Area Chilled Water System, the Auxiliary Building Filtered Ventilation Exhaust System, or the Diesel Generators. During proposed single discharge header operation, the NSWS will remain capable of fulfilling all of its design basis requirements.

No new accident causal mechanisms are created as a result of NRC approval of this amendment request. No changes are being made to the plant which will introduce any new type of accident outside those assumed in the UFSAR.

Third Standard Does operation of the facility in accordance with the proposed amendment involve a significant reduction in the margin of safety?

Response: No.

Implementation of this amendment will not involve a significant reduction in any margin of safety. Margin of safety is related to the confidence in the ability of the fission product barriers to perform their design functions during and following an accident situation. These barriers include the fuel cladding, the reactor coolant system, and the containment system. The performance of these fission product barriers will not be impacted by implementation of this proposed TS amendment.

During single discharge header operation, the NSWS and its supported systems will remain capable of performing their required functions. No safety margins will be impacted.

The PRA conducted for this proposed amendment demonstrated that the impact on overall plant risk remains acceptable during single discharge header operation. Therefore, there is not a significant reduction in the margin of safety.

Based upon the preceding discussion, Duke Energy has concluded that the proposed amendment does not involve a significant hazards consideration.

5.4 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.

Attachment I Page 36

6.

ENVIRONMENTAL CONSIDERATION Pursuant to 10 CFR 51.22(b), an evaluation of this license amendment request has been performed to determine whether or not it meets the criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) of the regulations.

Implementation of this amendment will have no adverse impact upon the Catawba units; neither will it contribute to any additional quantity or type of effluent being available for adverse environmental impact or personnel exposure.

It has been determined there is:

1.

No significant hazards consideration,

2.

No significant change in the types, or significant increase in the amounts, of any effluents that may be released offsite, and

3.

No significant increase in individual or cumulative occupational radiation exposures involved.

Therefore, this amendment to the Catawba TS meets the criteria of 10 CFR 51.22(c)(9) for categorical exclusion from an environmental impact statement. Page 37

7.

REFERENCES 7.1 Letter from John Stang, NRC to J.R. Morris, Duke Energy, "CATAWBA NUCLEAR STATION, UNITS 1 AND 2, ISSUANCE OF AMENDMENTS REGARDING SINGLE SUPPLY HEADER OPERATION OF THE BURIED NUCLEAR SERVICE WATER SYSTEM (TAC NOS. MD6275 AND MD6276)", July 30, 2008, ADAMS Accession Number ML081980769.

Attachment I Page 38

ATTACHMENT 2 MARKED UP TS PAGES

Inserts for TS 3.7.8 and TSB 3.7.8 INSERT 1 C.

NOTES -----......

1.

Entry into this Condition shall only be allowed for Unit 1 and for pre-planned activities as described in the Bases of this Specification.

2.

Immediately enter Condition A of this LCO if one or more Unit 1 required NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE.

3.

Immediately enter LCO 3.0.3 if one or more Unit 1 required NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE.

One NSWS Auxiliary Building discharge header inoperable due to NSWS being aligned for single Auxiliary Building discharge header operation.

C.1 Restore NSWS Auxiliary Building discharge header to OPERABLE status.

14 days

INSERT 2 While the NSWS is operating in the single discharge header alignment, one of the Unit 2 discharge headers is removed from service in support of planned maintenance or modification activities associated with the discharge header that is taken out of service. In this configuration, each NSWS train is considered OPERABLE with the required NSWS flow to safety related equipment being discharged through the remaining OPERABLE NSWS discharge header. While the NSWS is operating in the single discharge header alignment, an NSWS train is considered OPERABLE during MODES 1, 2, 3, and 4 when:

a.

The associated train related NSWS pumps are OPERABLE (except that for the discharge header that it removed from service, its associated train related NSWS pump may also be removed from service); and

b.

The associated piping (except for the discharge header that is taken out of service), valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

Operation of the NSWS in the single supply header alignment and the single discharge header alignment at the same time is prohibited.

INSERT 3 C.1 If one NSWS Auxiliary Building discharge header is inoperable due to the NSWS being aligned for single Auxiliary Building discharge header operation, the NSWS Auxiliary Building discharge header must be restored to OPERABLE status within 14 days. Dual Auxiliary Building discharge header operation is the normal alignment of the NSWS. The Completion Time of 14 days is supported by probabilistic risk analysis. While in Condition C, the single Auxiliary Building discharge header is adequate to perform the heat removal function for all required safety related equipment for its respective safety train. Due to the design of the NSWS, only the operating unit is required to enter this Condition when the NSWS is aligned for single Auxiliary Building discharge header operation. Pre-planned activities requiring entry into this Condition are only performed with Unit 2 in an outage (MODE 5, 6, or No MODE).

Condition C is modified by three Notes. Note 1 states that entry into this Condition shall only be allowed for Unit 1 and for pre-planned activities as described in the Bases of this Specification. Condition C is only allowed to be entered in support of planned maintenance or modification activities associated with the Auxiliary Building discharge header that is taken out of service. An example of a situation for which entry into this Condition is allowed is refurbishment of an Auxiliary Building discharge header. Entry into this Condition is not allowed in response to unplanned events or for other events involving the NSWS. Examples of situations for which entry into this Condition is prohibited are emergent repair of discovered piping leaks and other component failures. For unplanned events or other events involving the NSWS, Condition A must be entered. Note 2 requires immediate entry into Condition A of this LCO if one or more Unit 1 required NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE. With one remaining OPERABLE NSWS train, the NSWS can still perform its safety related function. However, with one inoperable NSWS train, the NSWS cannot be assured of performing its safety related function in the event of a single failure of another NSWS component. While the loss of any NSWS component subject to the requirements of this LCO can result in the entry into Condition A, the most common example is the inoperability of an NSWS pump. This occurs during periodic testing of the emergency diesel generators. Inoperability of an emergency diesel generator renders its associated NSWS pump inoperable. Note 3 requires immediate entry into LCO 3.0.3 if one or more Unit 1 required NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE. In this case, the NSWS cannot perform its safety related function.

INSERT 4 or if the NSWS Auxiliary Building discharge header cannot be restored to OPERABLE status within the associated Completion Time,

NSWS THIS PAGE 3.7.8 r OR I *i'ý-

3 A*T "3,

";*Y 3.7 PLANT SYSTEMS 3.7.8 Nuclear Service Water System (NSWS)

LCO 3.7.8 APPLICABILITY:

Two NSWS trains shall be OPERABLE.

MODES 1, 2, 3, and 4.

I ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A.

One NSWS train A.1 NOTES------

inoperable.

1.

Enter applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources-Operating," for emergency diesel generator made inoperable by NSWS.

2.

Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by NSWS.

Restore NSWS train to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> OPERABLE status.

(continued)

I Catawba Units 1 and 2 3.7.8-1 Amendment Nos. 243/237

NSWS 3.7.8 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME B.

---

NOTES------

1. Entry into this Condition shall only be allowed for pre-planned activities as described in the Bases of this Specification.

2.

Immediately enter Condition A of this LCO if one or more NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE.

3. Immediately enter LCO 3.0.3 if one or more NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE.

B.1 Restore NSWS supply header to OPERABLE status.

30 days One NSWS supply header inoperable due to NSWS being aligned for single supply header operation.

6ý-

4 I-Required Action and associated Completion Time of Condition B

not met. A 8, r C 1

M Be in MODE 3.

6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> AND I

Be in MODE 5.

36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> r

Catawba Units 1 and 2 3.7.8-2 Amendment Nos. (ý

NSWS 3.7.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.8.1 NOTE Isolation of NSWS flow to individual components does not render the NSWS inoperable.

Verify each NSWS manual, power operated, and In accordance with automatic valve in the flow path servicing safety related the Surveillance equipment, that is not locked, sealed, or otherwise Frequency Control secured in position, is in the correct position.

Program SR 3.7.8.2

.. I #",lr r I

r--

I-------

Not required to be met for valves that are maintained in position to support NSWS single supply~ede operation.

In accordance with the Surveillance Frequency Control Program Verify each NSWS automatic valve in the flow path that is not locked, sealed, or otherwise secured in position, actuates to the correct position on an actual or simulated actuation signal.

SR 3.7.8.3 Verify each NSWS pump starts automatically on an In accordance with actual or simulated actuation signal.

the Surveillance Frequency Control Program Catawba Units 1 and 2 3.7.8-3 Amendment Nos.(j 2

ATTACHMENT 3 MARKED UP TS BASES PAGES

Inserts for TS 3.7.8 and TSB 3.7.8 INSERT 1 C.

NOTES -----------

1.

Entry into this Condition shall only be allowed for Unit I and for pre-planned activities as described in the Bases of this Specification.

2.

Immediately enter Condition A of this LCO if one or more Unit 1 required NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE.

3.

Immediately enter LCO 3.0.3 if one or more Unit 1 required NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE.

One NSWS Auxiliary Building discharge header inoperable due to NSWS being aligned for single Auxiliary Building discharge header operation.

C.1 Restore NSWS Auxiliary Building discharge header to OPERABLE status.

14 days

INSERT 2 While the NSWS is operating in the single discharge header alignment, one of the Unit 2 discharge headers is removed from service in support of planned maintenance or modification activities associated with the discharge header that is taken out of service. In this configuration, each NSWS train is considered OPERABLE with the required NSWS flow to safety related equipment being discharged through the remaining OPERABLE NSWS discharge header. While the NSWS is operating in the single discharge header alignment, an NSWS train is considered OPERABLE during MODES 1, 2, 3, and 4 when:

a.

The associated train related NSWS pumps are OPERABLE (except that for the discharge header that it removed from service, its associated train related NSWS pump may also be removed from service); and

b.

The associated piping (except for the discharge header that is taken out of service), valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

Operation of the NSWS in the single supply header alignment and the single discharge header alignment at the same time is prohibited.

INSERT 3 C.1 If one NSWS Auxiliary Building discharge header is inoperable due to the NSWS being aligned for single Auxiliary Building discharge header operation, the NSWS Auxiliary Building discharge header must be restored to OPERABLE status within 14 days. Dual Auxiliary Building discharge header operation is the normal alignment of the NSWS. The Completion Time of 14 days is supported by probabilistic risk analysis. While in Condition C, the single Auxiliary Building discharge header is adequate to perform the heat removal function for all required safety related equipment for its respective safety train. Due to the design of the NSWS, only the operating unit is required to enter this Condition when the NSWS is aligned for single Auxiliary Building discharge header operation. Pre-planned activities requiring entry into this Condition are only performed with Unit 2 in an outage (MODE 5, 6, or No MODE).

Condition C is modified by three Notes. Note 1 states that entry into this Condition shall only be allowed for Unit 1 and for pre-planned activities as described in the Bases of this Specification. Condition C is only allowed to be entered in support of planned maintenance or modification activities associated with the Auxiliary Building discharge header that is taken out of service. An example of a situation for which entry into this Condition is allowed is refurbishment of an Auxiliary Building discharge header. Entry into this Condition is not allowed in response to unplanned events or for other events involving the NSWS. Examples of situations for which entry into this Condition is prohibited are emergent repair of discovered piping leaks and other component failures. For unplanned events or other events involving the NSWS, Condition A must be entered. Note 2 requires immediate entry into Condition A of this LCO if one or more Unit 1 required NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE. With one remaining OPERABLE NSWS train, the NSWS can still perform its safety related function. However, with one inoperable NSWS train, the NSWS cannot be assured of performing its safety related function in the event of a single failure of another NSWS component. While the loss of any NSWS component subject to the requirements of this LCO can result in the entry into Condition A, the most common example is the inoperability of an NSWS pump. This occurs during periodic testing of the emergency diesel generators. Inoperability of an emergency diesel generator renders its associated NSWS pump inoperable. Note 3 requires immediate entry into LCO 3.0.3 if one or more Unit 1 required NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE. In this case, the NSWS cannot perform its safety related function.

INSERT 4 or if the NSWS Auxiliary Building discharge header cannot be restored to OPERABLE status within the associated Completion Time,

NO CHANGES THIS PAGE.

NSWS FOR INFORMATION ONLY B 3.7.8 B 3.7 PLANT SYSTEMS B 3.7.8 Nuclear Service Water System (NSWS)

BASES BACKGROUND The NSWS, including Lake Wylie and the Standby Nuclear Service Water Pond (SNSWP), provides a heat sink for the removal of process and operating heat from safety related components during a Design Basis Accident (DBA) or transient. During normal operation, and a normal shutdown, the NSWS also provides this function for various safety related and nonsafety related components. The safety related function is covered by this LCO.

The NSWS consists of two independent loops (A and B) of essential equipment, each of which is shared between units. Each loop contains two NSWS pumps, each of which is supplied from a separate emergency diesel generator. Each set of two pumps supplies two trains (1A and 2A, or 1 B and 2B) of essential equipment through common discharge piping.

While the pumps are unit designated, i.e., 1A, 1 B, 2A, 2B, all pumps receive automatic start signals from a safety injection or blackout signal from either unit. Therefore, a pump designated to one unit will supply post accident cooling to equipment in that loop on both units, provided its associated emergency diesel generator is available. For example, the 1A NSWS pump, supplied by emergency diesel 1A, will supply post accident cooling to NSWS trains 1A and 2A.

One NSWS loop containing two OPERABLE NSWS pumps has sufficient capacity to supply post loss of coolant accident (LOCA) loads on one unit and shutdown and cooldown loads on the other unit. Thus, the OPERABILITY of two NSWS loops assures that no single failure will keep the system from performing the required safety function.

Additionally, one NSWS loop containing one OPERABLE NSWS pump has sufficient capacity to maintain one unit indefinitely in MODE 5 (commencing 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> following a trip from RTP) while supplying the post LOCA loads of the other unit. Thus, after a unit has been placed in MODE 5, only one NSWS pump and its associated emergency diesel generator are required to be OPERABLE on each loop, in order for the system to be capable of performing its required safety function, including single failure considerations.

Additional information about the design and operation of the NSWS, along with a list of the components served, is presented in the UFSAR, Section 9.2.1 (Ref. 1). The principal safety related function of the NSWS is the removal of decay heat from the reactor via the CCW System.

Catawba Units 1 and 2 B 3.7.8-1 Revision No. 4

NSWS B 3.7.8 BASES APPLICABLE SAFETY ANALYSES The design basis of the NSWS is for one NSWS train, in conjunction with the CCW System and a containment spray system, to remove core decay heat following a design basis LOCA as discussed in the UFSAR, Section 6.2 (Ref. 2). This prevents the containment sump fluid from increasing in temperature during the recirculation phase following a LOCA and provides for a gradual reduction in the temperature of this fluid as it is supplied to the Reactor Coolant System by the ECCS pumps.

The NSWS is designed to perform its function with a single failure of any active component, assuming the loss of offsite power.

The NSWS, in conjunction with the CCW System, also cools the unit from residual heat removal (RHR), as discussed in the UFSAR, Section 5.4 (Ref. 3), from RHR entry conditions to MODE 5 during normal and post accident operations. The time required for this evolution is a function of the number of CCW and RHR System trains that are operating. Thirty six hours after a trip from RTP, one NSWS train is sufficient to remove decay heat during subsequent operations in MODES 5 and 6. This assumes a maximum NSWS temperature, a simultaneous design basis event on the other unit, and the loss of offsite power.

The NSWS satisfies Criterion 3 of 10 CFR 50.36 (Ref. 4).

LCO Two NSWS trains are required to be OPERABLE to provide the required redundancy to ensure that the system functions to remove post accident heat loads, assuming that the worst case single active failure occurs coincident with the loss of offsite power.

,n A

While the NSWS is operating in the normal dual supply~eader alignment, an NSWS train is considered OPERABLE during MODES 1, 2, 3, and 4 when:

a.

1.

Both NSWS pumps on the NSWS loop are OPERABLE; or

2.

One unit's NSWS pump is OPERABLE and one unit's flowpath to the non essential header, AFW pumps, and Containment Spray heat exchangers are isolated (or equivalent flow restrictions); and

b.

The associated piping, valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

Catawba Units 1 and 2 B 3.7.8-2 Revision No.0

NSWS B 3.7.8 BASES LCO (continued)

While the NSWS is operating in the single supply header alignment, one of the supply headers is removed from service in support of planned maintenance or modification activities associated with the supply header that is taken out of service. In this configuration, each NSWS train is considered OPERABLE with the required NSWS flow to safety related equipment being fed through the remaining OPERABLE NSWS supply header. While the NSWS is operating in the single supply header alignment, an NSWS train is considered OPERABLE during MODES 1, 2, 3, and 4 when:

a.

The associated train related NSWS pumps are OPERABLE; and

b.

The associated piping (except for the supply header that is taken out of service), valves, and instrumentation and controls required to perform the safety related function are OPERABLE.

Te NSWS system is shared between the two units. The shared portions of the system must be OPERABLE for each unit when that unit is in the MODE of Applicability. Additionally, both normal and emergency power for shared components must also be OPERABLE. If a shared NSWS component becomes inoperable, or normal or emergency power to shared components becomes inoperable, then the Required Actions of this LCO must be entered independently for each unit that is in the MODE of applicability of the LCO, except as noted in a.2 above for operation in the normal dual supply header alignment. In this case, sufficient flow is available, however, this configuration results in inoperabilities within other required systems on one unit and the associated Required Actions must be entered. Use of a NSWS pump and associated diesel generator on a shutdown unit to support continued operation (> 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) of a unit with an inoperable NSWS pump is prohibited. A shutdown unit supplying its associated emergency power source (1 EMXG/2EMXH) cannot be credited for OPERABILITY of components supporting the operating unit.

APPLICABILITY In MODES 1, 2, 3, and 4, the NSWS is a normally operating system that is required to support the OPERABILITY of the equipment serviced by the NSWS and required to be OPERABLE in these MODES.

In MODES 5 and 6, the requirements of the NSWS are determined by the systems it supports.

Catawba Units 1 and 2 B 3.7.8-3 Revision NoAn W

NO CHANGES THIS PAGE.

NSWS FOR INFORMATION ONLY B 3.7.8 BASES ACTIONS A. 1 If one NSWS train is inoperable, action must be taken to restore OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. In this Condition, the remaining OPERABLE NSWS train is adequate to perform the heat removal function. However, the overall reliability is reduced because a single failure in the OPERABLE NSWS train could result in loss of NSWS function. Due to the shared nature of the NSWS, both units are required to enter a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Action when a NSWS Train becomes inoperable on either unit. Required Action A.1 is modified by two Notes. The first Note indicates that the applicable Conditions and Required Actions of LCO 3.8.1, "AC Sources-Operating," should be entered if an inoperable NSWS train results in an inoperable emergency diesel generator. The second Note indicates that the applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," should be entered if an inoperable NSWS train results in an inoperable decay heat removal train (RHR). An example of when these Notes should be applied is with both units' loop 'A' NSWS pumps inoperable, both units' 'A' emergency diesel generators and both units' 'A' RHR systems should be declared inoperable and appropriate Actions entered. This is an exception to LCO 3.0.6 and ensures the proper actions are taken for these components. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is based on the redundant capabilities afforded by the OPERABLE train, and the low probability of a DBA occurring during this time period.

B.1 If one NSWS supply header is inoperable due to the NSWS being aligned for single supply header operation, the NSWS supply header must be restored to OPERABLE status within 30 days. Dual supply header operation is the normal alignment of the NSWS. The Completion Time of 30 days is supported by probabilistic risk analysis. While in Condition B, the single supply header is adequate to perform the heat removal function for all required safety related equipment for both safety trains.

Due to the shared nature of the NSWS, both units are required to enter this Condition when the NSWS is aligned for single supply header operation. In order to prevent the potential for NSWS pump runout, the single NSWS pump flow balance alignment is prohibited while the NSWS is aligned for single supply header operation.

Catawba Units 1 and 2 B 3.7.8-4 Revision No. 4

NSWS B 3.7.8 BASES ACTIONS (continued)

Condition B is modified by three Notes. Note 1 states that entry into this Condition shall only be allowed for pre-planned activities as described in the Bases of this Specification. Condition B is only allowed to be entered in support of planned maintenance or modification activities associated with the supply header that is taken out of service. An example of a situation for which entry into this Condition is allowed is refurbishment of a supply header. Entry into this Condition is not allowed in response to unplanned events or for other events involving the NSWS. Examples of situations for which entry into this Condition is prohibited are emergent repair of discovered piping leaks and other component failures. For unplanned events or other events involving the NSWS, Condition A must be entered. Note 2 requires immediate entry into Condition A of this LCO if one or more NSWS components become inoperable while in this Condition and one NSWS train remains OPERABLE. With one remaining OPERABLE NSWS train, the NSWS can still perform its safety related function. However, with one inoperable NSWS train, the NSWS cannot be assured of performing its safety related function in the event of a single failure of another NSWS component. The most limiting single failure is the failure of an NSWS pit to automatically transfer from Lake Wylie to the SNSWP during a seismic event. While the loss of any NSWS component subject to the requirements of this LCO can result in the entry into Condition A, the most common example is the inoperability of an NSWS pump. This occurs during periodic testing of the emergency diesel generators. Inoperability of an emergency diesel generator renders its associated NSWS pump inoperable. Note 3 requires immediate entry into LCO 3.0.3 if one or more NSWS components become inoperable while in this Condition and no NSWS train remains OPERABLE. In this case, the NSWS cannot perform its safety related function.

If the NSWS train cannot be restored to OPERABLE status within the associated Completion Time, (D if the NSWS supply header cannot be restored to OPERABLE status within the associated Completion Time, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in at least MODE 3 within CE/Z 1 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.

Catawba Units 1 and 2 B 3.7.8-5 Revision Noj*

NSWS B 3.7.8 BASES SURVEILLANCE SR 3.7.8.1 REQUIREMENTS This SR is modified by a Note indicating that the isolation of the NSWS components or systems may render those components inoperable, but does not affect the OPERABILITY of the NSWS.

Verifying the correct alignment for manual, power operated, and automatic valves in the NSWS flow path provides assurance that the proper flow paths exist for NSWS operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.

SR 3.7.8.2 This SR verifies proper automatic operation of the NSWS valves on an actual or simulated actuation signal. The signals that cause the actuation are from Safety Injection and Phase 'B' isolation. The NSWS is a normally operating system that cannot be fully actuated as part of normal testing. This Surveillance is not required for valves that are locked, sealed, or otherwise secured in the required position under administrative controls. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.

This SR is modified by a Note that states that the SR is not required to be met for valves that are maintained in position to support NSWS single supply)header operation. When the NSWS is placed in this alignment, certain automatic valves in the system are maintained in position and will not automatically reposition in response to an actuation signal while the NSWS is in this alignment.

Catawba Units 1 and 2 B 3.7.8-6 Revision No.(71

\\Z/

NO CHANGES THIS PAGE.

NSWS FOR INFORMATION ONLY B 3.7.8 BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.7.8.3 This SR verifies proper automatic operation of the NSWS pumps on an actual or simulated actuation signal. The signals that cause the actuation are from Safety Injection and Loss of Offsite Power. The NSWS is a normally operating system that cannot be fully actuated as part of normal testing during normal operation. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.

REFERENCES

1.

UFSAR, Section 9.2.

2.

UFSAR, Section 6.2.

3.

UFSAR, Section 5.4.

4.

10 CFR 50.36, Technical Specifications, (c)(2)(ii).

Catawba Units 1 and 2 B 3.7-8-7 Revision No. 4

ATTACHMENT 4 LIST OF NRC COMMITMENTS

The following NRC commitments are being made in support of this amendment request submittal:

1.

The approved amendments will be implemented within 60 days from the date of NRC approval. "Implemented" means that the approved amendments will have been placed into the control room copies of the TS. However, the provisions afforded by the approved amendments may not actually be utilized until such time in the future that Duke Energy determines to be appropriate.

2.

Prior to actually utilizing the provisions afforded by the approved amendments, Catawba will have in place all required document and process changes necessary to support these provisions. In addition, all required design changes will have been fully implemented. Page 1