Text

Application for Amends to Licenses DPR-32 & DPR-37, Establishing Requirements for Use of Temporary Supply Line (Jumper) to Provide Svc Water to Component Cooling Heat Exchangers
	ML18152A076
Person / Time
Site:	Surry
Issue date:	11/05/1997
From:	Ohanlon J; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18152A077	List: ML18152A076; ML18153A176;
References
	97-496, NUDOCS 9711120263
	Download: ML18152A076 (31)
	v • d • e

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e VIRGINIA ELECTRIC AND PowER CoMPANY RICHMOND, VIRGINIA 23261 November 5, 1997 U.S. Nuclear Regulatory Commission Serial No.97-496 Attention: Document Control Desk NL&OS/GDM: RO Washington, DC. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 PROPOSED LICENSE CONDITION AND TECHNICAL SPECIFICATIONS CHANGE TEMPORARY SERVICE WATER SUPPLY LINE TO THE CCHXS Pursuant to 10 CFR 50.90, the Virginia Electric and Power Company requests changes to Facility Operating License Nos. DPR-32 and DPR-37 for Surry Power Station Units 1 and 2 in the form of a new license condition and a change to the Technical Specifications. The proposed license condition and Technical Specifications change establish the requirements for the use of a temporary supply line Uumper) to provide service water (SW) to the component cooling heat exchangers (CCHXs). The temporary SW supply jumper is necessary to facilitate repairs on the existing single, concrete-encased, service water supply piping to the CCHXs and/or integral components (e.g., pipe recoating, weld repair, replacement of expansion joints or SW isolation valves). A discussion of the proposed changes for Surry is provided in Attachment 1.

The proposed changes have been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Management Safety Review Committee. It has been determined that the proposed changes involve an unreviewed safety question as defined in 10 CFR 50.59 due to an increase in the probability of equipment malfunction as a result of the decreased missile protection for the temporary SW supply jumper. However, the increased probability is considered insignificant based on the reasoning provided in Attachment 1. The proposed changes do not result in a significant hazards consideration as defined in 10 CFR 50.92. The proposed license condition and Technical Specifications pages and the basis for our determination that the change does not involve a significant hazards consideration are provided in Attachments 2 and 3, respectively.

The pipe repair activities associated with the SW supply line to the CCHXs will begin during the Fall Unit 1 refueling outage currently scheduled to begin in October 1998. t(

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We therefore request NRC review and approval of the proposed changes by August 1, 1998.

Should you have any questions or require additional information, please contact us.

Very truly yours, James P. O'Hanlon Senior Vice President - Nuclear Attachments

1. Discussion of Changes

2. Proposed License Condition and Technical Specifications Change

3. Significant Hazards Consideration Determination cc: U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303 Mr. R. A. Musser NRC Senior Resident Inspector Surry Power Station Commissioner Bureau of Radiological Health Room 104A 1500 East Main Street Richmond, Virginia 23219 Commitment Summary

1. The commitments made in this letter are as indicated in the proposed License Condition and Technical Specifications change.

COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. P. O'Hanlon, who is Senior Vice President - Nuclear, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this 5To day of {)[yJ HYLho/ , 19 Cf7 .

My Commission Expires: March 31, 2000.

Notary Public

-- (SEAL-) ,:c

PROPOSED CHANGE TO TECH SPECS R~ TEMP SERVICE WATER SUPPLY LINE TO THE COMPONENT COOLING 'HEAT EXCHANGERS REC'D W/LTR DTD 11/05/97 .... 9711120263

- NOTICE -

THE ATTACHED FILES ARE OFFICIAL RECORDS OF THE INFORMATION &

RECORDS MANAGEMENT BRANCH.

THEY HAVE BEEN CHARGED TO YOU FOR A LIMITED TIME PERIOD AND MUST BE RETURNED TO THE RECORDS & ARCHIVES SERVICES.

SECTION, T5 C3. PLEASE DO NOT SEND DOCUMENTS CHARGED OUT THROUGH THE MAIL. REMOVAL OF ANY PAGE(S) FROM DOCUMENT

FOR REPRODUCTION MUST BE REFERRED TO FILE PERSONNEL.

... NOTICE m

,r :l Attachment 1 Discussion of Changes

DISCUSSION OF CHANGES

1.0 INTRODUCTION

Virginia Electric and Power Company has been cleaning, inspecting, repamng, and recoating the Service Water (SW) System piping at Surry Power Station over the last several unit outages. The SW piping was originally coated with a coal tar epoxy which has exhibited signs of degradation, thus exposing the carbon:steel pipe wall to general corrosion from the brackish river water used for cooling. The SW piping restoration project began in the fall of 1990 and has repaired several of the piping subsections during various refueling outages. The next section to be addressed is the SW supply piping to the Component Cooling Heat Exchangers (CCHXs). To allow continued operation of the required number of CCHXs during maintenance activities on the SW supply line, a license condition and Technical Specifications change are necessary to permit the use of a temporary SW supply jumper.

Service water is supplied to the CCHXs by a single concrete-encased line. To remove the SW supply line from service for extended maintenance, an alternate temporary SW supply path is required to support the operation of the CCHXs and thus permit access to the existing piping for the pipe restoration work to be completed. The alternate SW supply line will be installed as a safety-related and seismic system, but will not be completely missile protected over its entire length. This will result in an insignificant increase in the probability of equipment malfunction due to a postulated missile strike and consequent failure of the alternate SW supply piping. Therefore, this activity results in an unreviewed safety question, and a license condition and Technical Specifications amendment are required to permit continued operation of the CCHXs with a degraded but operable temporary SW supply line.

The temporary SW jumper may be used for up to 35 days during each of the next two Unit 1 refueling outages to complete the currently planned pipe repair activities.

Compensatory measures (including a contingency plan) will be put into place to virtually eliminate the possibility of a loss of SW flow to the CCHXs. The conditional use of the temporary SW jumper in conjunction with the compensatory measures described below will be documented in the Operating Licenses for Surry Units 1 and 2 as a license condition, as well as in the Technical Specifications and Bases. The repair work to the SW supply line will be performed during the planned Unit 1 refueling outages presently scheduled for the years 1998 and 2000. However, the proposed changes to the Operating Licenses and the Technical Specifications will also permit the installation and use of the temporary SW supply jumper to the CCHXs for other maintenance activities in the future (e.g., periodic/preventive maintenance activities such as repair/replacement of the SW motor-operated valves or expansion joints in the CCHX SW supply line, periodic pipe cleaning) with prior notification of the NRG .

Minor administrative changes are also being made to Technical Specification Table 3.7-2 and the references in the Technical Specification 3.14 Basis section.

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2.0 BACKGROUND

The SW piping at Surry Power Station is constructed of carbon steel piping that is coated on the internal wall with a coal tar epoxy coating. Over the years of operation, the coating has experienced failures which expose the pipe wall to brackish water and general corrosion of the exposed pipe. Surry initiated a long term project for SW pipe restoration in 1990. The general procedure for the piping repairs is to drain the piping and clean the pipe wall of any marine growth before removing the old coating, inspect and repair the pipe wall (if required) and recoat the pipe wall with a new epoxy coating product. The objectives of the overall project are to minimize corrosion, prolong the remaining service life of the currently acceptable portions of the piping system, and repair any degraded sections of pipe.

The next section of piping to be cleaned, repaired and recoated is the SW supply piping to the CCHXs. The CCHXs are shared by both Units at Surry and are supplied through one flow path. The CCHXs are continuously required to cool Unit operating and/or shutdown loads and Spent Fuel Pool (SFP) cooling loads. Therefore, the common SW inlet piping to the CCHXs cannot be removed from service for cleaning, inspection, etc.,

without providing an alternate source of cooling water. An engineering evaluation was performed and concluded that the condition of the CCHX SW inlet piping is comparable to SW piping of similar service life (e.g., Bearing Cooling Heat* Exchanger supply piping). The corrosion found in the piping sections has been general in nature where coating failures have occurred, with some localized pitting. The pitting has not been considered significant due to the system operating condi_tions (i.e., low temperature and pressure) of the piping. However, repair of the SW piping is necessary to meet the overall* project objectives stated above.

To -facilitate removal of the common SW inlet piping to the CCHXs from service, a temporary, alternate SW flow path Uumper) must be provided. The temporary jumper will serve as the safety-related SW supply with sufficient flow to two CCHXs to cool the heat loads from Unit 1, which include Residual Heat Removal (RHR) and SFP cooling, and Unit 2 operating loads. The use of the jumper is expected to be for a maximum of 35 days during each of two consecutive Unit 1 refueling outages.

The general sequence of activities for the project is as follows (Figure .1 ):

1) Install the SW jumper from the 11 C11 Circulating Water (CW) supply piping to the 11 A 11 and 11 8 11 CCHX inlets. Place the jumper in service.

2) Stop log, blank and dewater 11 8 11 and 11 0" inlet bays and 96-inch CW piping. Dewater all SW piping to be cleaned.

Note: Only one SW supply motor-operated valve (MOV) will be removed at any one time. The inlet bay on the flow path to the removed MOV will be stop logged and blanked to provide double isolation. Only the inlet bay 2 of 24

on the flow path to the installed MOV will be stop logged, with the closed MOV acting as the second barrier. The alignment is reversed to access and clean the piping upstream of the previously installed MOV. In each step involving the installation, use, and removal of the jumper, double isolation is maintained from significant sources of flooding to provide for personnel and plant safety ..

3) Clean pipe wall of marine growth and remove the existing coal-tar epoxy coating. Inspect and perform weld repair, as required.

4) Apply coating* to piping internal wall surface from the connection to the CW piping to a point downstream of the MOVs. The actual amount of coating work completed at this time will depend on progress during the allowable outage duration.

5) Restore the normal SW supply and remove the jumper from service. The remainder of the pipe coating will be performed during the next Unit 1 refueling outage.

During the next Unit 1 refueling outage, the general sequence will be similar to the above, however, the alignment of intake bays blanked and stop logged will not need to

be reversed. The uncoated piping will be cleaned, inspected and coated.

While the jumper is in service, the SW supply MOVs in the normal CCHX SW supply line will be taken out of service to support the repair work. These valves receive an isolation signal to close and conserve Intake Canal inventory on low Intake Canal level.

Removing the valves from service defeats the normal supply line automatic isolation feature of the normal SW flow supply line to the CCHXs during the repair work.

However, this feature will not be required since the line will either be isolated or under strict administrative control to ensure isolation in accordance with the procedural requirements for a loss of intake canal inventory throughout the duration of the piping repairs. The alternate supply line will also not be provided with automatic isolation features since this function can be accomplished by manual operator action. Adequate time is available for manual operator action to meet safety analysis assumptions. The functional equivalent of the MOVs during jumper operation will be the installed temporary valve controlling jumper flow. Since this valve is operated under administrative (manual) control, this represents replacing automatic isolation of the non-essential SW to the CCHXs with manual action. Manual action to isolate non-essential SW to the CCHXs has been previously approved by the NRC and is discussed further in the Licensing Basis section below.

Intake bays "B" and "D" will be dewatered during most of the project implementation.

These bays are the locations of two of the four intake canal level probes. The signal from these probes is used to trip both Units' turbines and close CW and non-essential SW valves to conserve water in the intake canal for use during design basis accidents.

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The instrumentation has two logic channels, either of which will provide the actuation signal if three out of four canal probes indicate low level in the intake canal. If Unit 1 "B" and "D" bays are dewatered, their level probes will be inoperable, and so placed in trip. The resulting condition is such that only one of the remaining two operable probes is required to trip to produce the actuation signal. Technical Specification 3.7 allows only one canal probe to be inoperable/tripped, consequently, a Technical Specifications change is required to allow a second probe to be tripped.

Several alternative approaches were considered to provide CCHX cooling during the pipe repair project. These included 1) a new permanent SW supply to the CCHXs, 2) routing other closed cooling systems to the CCHXs, and 3) providing temporary "packaged" cooling for the heat loads. The design philosophy was to provide an alternative cooling method which had as many of the design attributes of the existing SW supply as possible. Where it was impractical to meet some attribute, the probability of failure due to that attribute must be low. A_ Contingency Plan must be in place to minimize or eliminate the threat of such a failure, or appropriate compensatory actions must be implemented. A new, permanent SW supply was not considered practical due to routing interferences and anticipated construction difficulties associated with excavation under the Turbine Building floor. The use of another closed cooling system (Bearing Cooling Water System) was eliminated since it is a non-safety, non-seismic system and is located on the other side of the Turbine Building basement. "Packaged" systems were considered impractical for reasons including location, piping routes, and the feasibility of supplying the required cooling capacity. Therefore, the use of an appropriately designed SW jumper was evaluated to be the only practical alternative for supplying cooling water flow to the CCHXs.

2.1 Design 2.1.1 Design Basis The Component Cooling (CC) Water System is an intermediate cooling system that transfers heat from heat exchangers containing reactor coolant or other radioactive liquids to the Service Water (SW) System. Four heat exchangers are located in the Unit 1 Turbine Building basement and serve both Units' cooling requirements. Each heat exchanger is designed to remove the entire heat load from one Unit plus half of the heat load common to both Units during normal operation.

Cooling water for the CCHXs is SW from the Unit 1 "B" and "D" Circulating Water (CW) inlet piping by gravity flow (Figure 1). Each source of SW is controlled by a SW supply isolation MOV upstream of a common supply line to the four CCHXs. These SW MOVs receive a signal to isolate SW supply to the CCHXs to conserve intake canal inventory to meet design basis accident requirements. Common SW piping is 42-inch carbon steel with 1/2-inch wall, originally coated with coal-tar epoxy. Individual lines to each heat exchanger are 30-inch carbon steel pipe with the same wall thickness and coating.

The SW supply piping is concrete encased beneath the Turbine Building basement 4 of 24

floor, except in the SW MOV valve pits, the manway in the 42 inch piping, and at the CCHXs where they emerge to connect to the heat exchangers. The major SW System valves in the supply piping are butterfly valves. The SW supply piping and components are designed for low pressure and low temperature o'perating conditions.

The major heat loads on the CC System are the Residual Heat Removal System during cooldown and shutdown conditions, Spent Fuel Pool Cooling System, Reactor Coolant Pump Motor coolers, Chemical and Volume Control System (cooling letdown flow),

Reactor Coolant Pump Seal Water, Containment Cooling, and Neutron Shield Tank cooling.

The CCHXs serve no design basis accident (OBA) mitigating function. During a postulated OBA with a loss of offsite power, the CC System is assumed to be out of service for the time required to restore power to the CC pumps. The system can then be restored to effect a cooldown of the non-accident Unit. Throttling of SW to the CCHXs may be required, in accordance with Station Abnormal Procedures, to maintain Intake Canal inventory.

2;1.2 Design of the Temporary Alternate SW Supply Header The temporary alternate SW supply header Uumper) is a seismic, safety-related pipe which is installed from the "C" 96-inch CW inlet piping manway to the inlet piping of the "A" and "B" CCHXs (Figures 1 and 2). The piping is uncoated, 30-inch carbon steel, standard wall pipe. The construction is flanged with butterfly valves at the inlet and the two heat exchanger supply connections. The design pressure and temperature ranges for this piping are 25 psig (10 to 15 psig, normal) and 32°F to 80°F, respectively. The line is sized to deliver adequate cooling water flow to two CCHXs to remove design basis heat loads. The jumper will be in service during* times of the year when SW supply temperatures are at or below 80° F to provide additional margin for heat transfer capability under tubesheet fouling conditions. Use of the jumper with SW supply temperature greater than 80° F will require an evaluation by Engineering.

The safety-related function of the jumper is to provide the system pressure boundary to deliver cooling water flow to the CCHXs while precluding flooding. Although the CCHXs are not required for accident mitigation, a reliable source of cooling water is required to ensure a heat sink for the spent fuel and residual heat loads.

The temporary jumper routing has been evaluated for vulnerability to turbine or tornado driven missiles. Regulatory Guide 1.115, "Protection Against Low-Trajectory Turbine Missiles" indicates that low-trajectory turbine missile strikes will concentrate within an area bounded by lines inclined at 25 degrees to the turbine wheel planes and passing through the wheels of the low pressure stages. UFSAR Figures 14.2-103 and 14.2-104 show positions of the turbine missile strike zone. It can be seen that the low-trajectory

missile strike is not possible. 1.n addition,- the possibility of turbine speeds above design is very remote since the turbine has redundant means of overspeed protection.

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Furthermore, the Unit 1 turbine will not be operating while the jumper is functioning as the operable SW flow path.

The probability of a tornado of sufficient severity to produce significant damage, occurring in Surry County, Virginia in the fall or late winter during the short time periods when the jumper is in service, is insignificant. For example, data from the National Climatic Data Center indicates that there have been eleven recorded tornadoes during the 45 year period (1950 - 1995) within 0.5° latitude and longitude of Surry Power Station during the months of October to February, inclusive. Of these eleven, only three were rated F-2 (significant damage, 113 mph winds) or higher. Additionally, none of the eleven were in Surry County. The contingency plan for the project requires that if environmental conditions exist which are conducive to such extreme weather, the normal SW supply will be restored to a configuration such that it can be placed into service and the jumper isolated, as required.

Surry UFSAR Section 15.2.3 states that a tornado can generate either of the following potential missiles:

1. Missile equivalent to a wooden utility pole 40' long, 12" in diameter, weighing 50 lbs. per cubic foot and traveling in a vertical or horizontal direction at 150 mph.

2. Missile equivalent to a 1 ton automobile traveling at 150 mph.

For purposes of assessing the jumper's exposure to a postulated vertical missile, the utility pole was assumed, as it is the more penetrating of the two missiles.

The total length of the jumper is approximately 205 feet, with 91 feet or 44% of the total run protected by either the turbine pedestal or the CCHX missile shield from a vertical utility pole missile strike. The operating floor at Elevation 58'-6" is a 9" thick reinforced concrete slab supported by steel framing. This will provide missile protection for approximately 66 feet or 32% of the total run from a vertical utility pole missile of approximately 25% of the design basis missile energy. The remaining 48 feet, or 24%

of the jumper, are not protected by either the turbine floor or any other missile protection. However, there are energy absorbing interferences in the way of a direct missile hit such as steel grating, structural steel, piping and other equipment. The elevation of the jumper is well below outside finished grade and would present a relatively small target to a missile that would have to pass through these interferences.

The possibility of damaging the SW jumper by dropping heavy loads on the piping was also considered. Appropriate controls on the movement of heavy loads will be invoked for the Turbine Building bridge crane for any lifts which pass over the SW jumper while the jumper is in service.

The temporary SW jumper has been rigorously analyzed for stresses arising from load cases consisting of deadweight, thermal and seismic loads. The loads generated at the 6 of 24

selected support locations have been used to evaluate conceptual support structures attached to the basement floor of the Turbine Building. Additionally, the jumper routing has been walked down and inspected in accordance with the IPEEE criteria included in the guidelines provided for pipe runs in EPRI NP-6041-SL, "A Methodology for Assessment of Nuclear Power Plant Seismic Margin," Revision 1, August 1991, to assess any potential system interaction during a seismic event. No concerns were identified in this review.

2.2 Licensing Basis 2.2.1 Applicable Technical Specifications Table 3.7-2, Item 5: This item specifies the channel requirements (i.e., total # of channels, minimum operable channels, channels to trip, and operator actions) for non-essential service water isolation on low intake canal level. Revised channel requirements when the temporary SW jumper is in use are discussed below. Adequate protection will be maintained to effect a Unit 2 trip should a low intake canal level condition occur.

3.7 Basis

"The operability of [the Non-essential SW Isolation System] ensures that adequate intake canal inventory can be maintained by the Emergency Service Water Pumps." Maintenance of this function relative to the temporary SW jumper is discussed below.

3.13: Technical Specification 3.13 requires two CCW pumps and heat exchangers to be operable for one unit operation. For two unit operation, three CCW pumps and heat exchangers are required to be operable. The Technical Specification only allows one of the required components to be inoperable for up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months before the Units are required to be shut down. Furthermore, RHR and SFP cooling require CCHX operation even when both Units are shutdown. Consequently, the single SW supply line to the CCHXs cannot be isolated without first providing an alternate means of cooling. The installation of the temporary SW jumper will provide the necessary SW supply to maintain CCHX operability as required by TS 3.13.

3.14.A.2: "Unit subsystems, including piping and valves, shall be operable to the extent of being able to establish the following: ... b. Flow to and from the component cooling heat exchangers required by Specification 3.13." Installation of the temporary SW jumper will satisfy this Technical Specification requirement.

3.14 Basis: "A minimum level of+ 17.2 feet in the High Level Intake canal is required to provide design flow of Service Water through the Recirculation Spray Heat Exchangers during a loss-of-coolant accident for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . If the water level falls below

+23' 6", signals are generated to trip both unit's turbines and to close the nonessential Circulating and Service Water valves." Maintenance of this function relative to the temporary SW jumper is discussed below.

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2.2.2 Non-essential SW Isolation The automatic isolation of the SW MOVs will be defeated during the time period that the jumper is in service. Defeating the non-essential SW automatic isolation function will not affect SW flow to/from the CCHXs, therefore, compliance with TS 3.14.A.2 will be maintained. The Technical Specifications do not explicitly address the operability requirements for the non-essential SW automatic isolation function. However, the Bases sections of Technical Specifications 3.7 and 3.14 describe this function and indicate that it is a required actuation. The use of operator (manual) action to isolate the CCHX SW supply line has been previously submitted for NRC review and approval in our letter dated March 27, 1989 [Reference 15]. This submittal addressed several design issues associated with the SW system and High Level Intake Canal (HLIC) management. Operator action was determined to be necessary to isolate non-essential SW within 60 minutes, including SW to the CCHXs, to conserve Intake Canal inventory under certain design.:basis accident (OBA) conditions or a loss of offsite power. As noted in the above submittal:

"With a OBA or Loss of Off-Site power, the 3 Emergency Diesel Generators (EOG) are signaled to startup .... Assuming Unit 2 as the accident unit, the swing EOG aligns to Unit 2, leaving Unit 1 with only a single EOG. The design of the BC and CCHX isolation valves provides for parallel flow paths to these heat exchangers. The two parallel isolation valves for the BC and CCHXs are powered by separate EDGs. With only one EOG available for Unit 1, one set of isolation valves will always remain open as a flow path even before a single failure is taken, requiring operator action to isolate the open valves to conserve inventory .."

The Technical Specifications and Bases were revised in Amendment Nos. 130/130 dated June 19, 1989, to address the design issues noted above [Reference 16]. The NRC's Safety . Evaluation Report (SER) associated with these amendments acknowledged that there were potential single failure issues related to HLIC level drawdown during a loss of coolant accident coincident with a loss of offsite power. The possible single failure issues included "a failure to close any one of the isolation valves to heat exchangers not essential for post-OBA heat removal. To resolve this issue, emergency operating procedures (EOPs) were revised for operation of ESW pumps and SW heat exchangers, and require manual confirmation/action for closing specific SW isolation valves." The SER also states that, "the minimum required HLIC level [was increased] to support SW heat exchanger flow by allowing for automatic and operator action times to isolate nonessential SW system flowpaths."

Consistent with this position, should non-essential SW isolation be required in the event of a loss of Intake Canal level during the time the temporary SW jumper is in service, an

operator stationed at a temporary valve installed in the SW pipe jumper will be directed to close the valve and isolate the SW flow to the CCHXs and conserve Intake Canal 8 of 24

inventory. The operator will maintain close communication with the control room by hand-held radio, sound-powered phones, or other suitable communication device.

Temporary changes to Station Abnormal Procedures will implement this manual operator action. The administrative controls that will be established for the subject maintenance activity, in conjunction with the applicable Station Abnormal Procedures, will ensure that the non-essential SW isolation function can be initiated manually within the allowable design basis time frame (60 minutes). Furthermore, as noted above, the use of manual action in place of the non-essential SW automatic isolation actuation is consistent with the licensing and design bases that were reviewed and approved by the NRC with the issuance of Technical Specifications Amendment Nos. 130/130.

As previously discussed, this project will require that both Unit 1 "B" and 11 0 11 intake bays be dewatered, placing two of the four intake canal level probes in trip. The protective function is assured using one out of two signals to actuate from the remaining two Unit 2 level probes through two logic channels. Thus, the single failure criterion is preserved. There is an increased probability of a spurious trip of Unit 2 in this condition, however, the reliability of the Intake Canal level probes supports the conclusion that this is acceptable for Unit 2 operation.

2.2.3 Previous Use of the Temporary SW Jumper Virginia Electric and Power Company previously requested NRC approval to use the temporary SW supply jumper to the CCHXs in a letter dated February 23, 1988

[Reference 13]. The jumper was required to facilitate the replacement of the CCHX SW supply isolation valves (MOV-SW-102A and B) and the CCHX inlet valves (1-SW-25, 29, 33, and 37). [See Figure 1]. However, the temporary jumper was non-seismic and was only allowed to be used for two periods of up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months each while Unit 2 was in operation. The NRG approved the use of the temporary jumper by enforcement discretion in their letter dated March 30, 1988 [Reference 14].

2.2.4 Administrative Changes Minor administrative changes are also being made to Technical Specification Table 3.7-2 and the references in the Technical Specification 3.14 Basis section. Technical Specification Table 3.7-2 is being revised to correct a format inconsistency, and the references in the Technical Specification 3.14 Basis section are being revised to indicate that they are UFSAR references rather than FSAR references.

3.0 SPECIFIC CHANGES Virginia Electric and Power Company proposes to add a license condition, Technical Specification and additional wording to the TS Bases to allow operation with a temporary service water supply jumper to the CCHXs for a period of up to 35 days provided appropriate compensatory measures and a contingency plan are in effect.

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The proposed change also allows 2 out of 4 intake canal level channels to be in the tripped condition, and the automatic closure feature of the SW isolation valves to the CCHXs to be defeated during the 35 day period provided appropriate administrative controls are in place to invoke manual operator action to obtain isolation within the design basis time limit of sixty minutes. Although this Operating License and Technical Specifications change request has been prepared specific to the pipe repair activities to be accomplished during the next two Unit 1 refueling outages, the proposed changes will also permit use of the temporary jumper for future maintenance activities with prior NRC notification and approval.

The proposed changes are provided below:

Operating License Condition Item O is added to the Operating Licenses:

0. The use of a temporary, seismic, non-missile protected supply line to provide service water to the component cooling heat exchangers required by TS 3.13, to facilitate maintenance activities on the existing SW supply line and/or components, shall be in accordance with the basis and compensatory measures (including a Contingency Action Plan) provided in Virginia Electric and Power Company's letter 97-496 dated November 5, 1997. The NRC shall be notified prior to the use of the temporary service water supply line.

Technical Specification Table 3.7-2 is revised as follows:

Item 3, Auxiliary Feedwater - The item number (3) is included in the "Auxiliary Feedwater (continued)" header, and the margin for the header is adjusted to match the table format of the other items in the table. This is an administrative change only.

Item 5, Non-Essential Service Water Isolation - This item is revised to provide separate instrument channel requirements for low Intake Canal level for normal operation (Item 5.a.1) and for when the CCHX SW jumper is in use (Item 5.a.2).

Specifically, two minimum operable channels are required when the SW jumper is in use since the two channels associated with the dewatered Unit 1 intake bays will be placed in trip. Therefore, only one channel is required to initiate the isolation function. A footnote (Note A) is also added to Item 5.a.2 to address the different channel requirements when the CCHX SW jumper is in use, and the existing Note A for Item 6 will be revised as Note B. Item 5 is revised as follows:

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5. NON-ESSENTIAL SERVICE WATER ISOLATION

a. Low intake canal level

1) Normal 4 3 3 20

2) Under TS 3.14E 4 2 20A (CCHX SW Jumper) - Note A

b. Automatic actuation logic 2 2 14 Note A Two Channels are tripped for the duration of the SW jumper use. In this condition, only one additional channel is required to trip to actuate the isolation function.

A new Operator Action (20A) associated with Item 5.a.2 is added to address the required action with less than the required number of non-essential SW isolation channels operable.

ACTION 20A With the number of OPERABLE channels two less than the Total Number of Channels, REACTOR CRITICAL and/or POWER OPERATION*may proceed provided the inoperable channels are placed in the tripped condition within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

New Technical Specification Item E will be added to TS 3.14:

E. For the purpose of performing periodic repairs (e.g., pipe cleaning, coating and repairs, valve/expansion joint repair or replacement) associated with the SW supply piping to the component cooling water heat exchangers (CCHXs), a temporary 30" seismic, non-missile protected SW supply line (jumper) may be provided to supply SW flow to the CCHXs required by TS 3.13.

1. The use of the temporary jumper is only permitted for a duration of up to 35 days during a Unit 1 outage.

2. If the temporary jumper becomes inoperable during the 35 day period, the requirements of Specification 3.0.1 shall apply.

The following paragraph will be added to the TS 3.14 Basis and the References will be updated:

Should repairs be required to the SW supply line to the CCHXs, a temporary, seismic, non-missile protected SW supply line Uumper) may be used. The temporary jumper is required since service water is supplied to the CCHXs by a single concrete-encased line. To remove the SW supply line from service for extended maintenance (e.g., pipe cleaning, coating and repair, valve/expansion joint repair or replacement), an alternate temporary SW supply path is required to support the operation of the CCHXs during the maintenance activities. The basis for using the temporary SW supply jumper to the CCHXs is provided in Virginia Electric and Power Company's letter 11 of 24

97-496 dated November 5, 1997. The use of the temporary jumper is only permitted for a duration of up to 35 days during a Unit 1 outage and shall be operated in accordance with the compensatory measures (including a Contingency Action Plan) provided in the letter referenced above and in the Operating License. The only automatic function in the normal supply line when Unit 1

is in COLD SHUTDOWN or REFUELING SHUTDOWN is provided by the SW supply MOVs which close on low Intake Canal level. If non-essential SW isolation is required during the time the jumper is in service, it will be accomplished consistent with design and licensing bases requirements by using operator: (manual) action to close the SW isolation valve in the temporary jumper within the time constraints established by the Station Abnormal Procedures.

TS 3.14 Basis References will be revised to indicate UFSAR section references rather than FSAR section references.

4.0 SAFETY SIGNIFICANCE The proposed Operating License and Technical Specifications and Basis changes are necessary to permit work activities to be accomplished to properly maintain the SW supply line to the CCHXs. The SW and CC systems will function as designed under the Unit operating constraints specified by this project (i.e., Unit 2 in operation and Unit 1 in a refueling outage), thus the probability of occurrence of an accident previously evaluated in the UFSAR is not increased. The CCHXs serve no Design Basis Accident (OBA) mitigating function, therefore, the consequences of an accident or malfunction of equipment previously evaluated in the UFSAR are not increased. Unit 1 will be in a plant condition which will provide adequate time to restore the normal SW supply if required. The administrative control of the SW supply valve to the CCHXs is bounded by the time assumed in the Intake Canal inventory calculation for non-essential SW isolation to maintain adequate canal level. Therefore, completion of this function is assured to be within safety limits. Since the SW and CC systems will basically function as designed and will be operated in their basic configuration, the possibility of a different type of accident or equipment malfunction than previously evaluated in the UFSAR is not created. Although placing two of the four Intake Canal level probes in trip increases the probability of a spurious Unit 2 trip, single failure protection is maintained with the two remaining level probes, and their historical reliability indicates a spurious trip would be unlikely. The margin of safety as defined in the Technical Specifications Bases is not reduced since an operable SW flowpath to the required number of CCHXs is provided with Unit constraints and contingencies to ensure its integrity.

However, an unreviewed safety question exists for the proposed change since the temporary SW supply line is not fully missile protected and has an increased vulnerability to missiles or heavy loads when compared to the normal SW supply line which is encased in concrete. The project constraints, compensatory measures and 12 of 24

contingency plan minimize the increase in the probability of an equipment malfunction and maintain the consequences of such events within those previously analyzed. The result is that the increase in the probability of equipment malfunction is insignificant.

The minor revisions to Technical Specification Table 3.7-2 for format consistency, and the 3.14 Basis section to reflect UFSAR references rather than FSAR references, are strictly administrative in nature and as such would not result in an unreviewed safety question.

4.1 Analysis of Existing Structures, -Systems, and Components Affected The four CCHXs at Surry are supplied with SW from the Unit 1 "B" and "D" CW supply lines through 42 inch piping which forms a common header (Figure 1). During normal operation, the manual isolation valves are open and temperature control is performed by throttling the manual SW outlet valves at the individual heat exchangers during conditions when SW -temperatures are low. The jumper is capable of supplying sufficient flow to the two CCHXs required for single Unit operation. Use of the jumper will be limited to conditions when the maximum SW supply temperature is at or below 80°F. Engineering will evaluate continued operation of the temporary SW jumper if the SW supply temperature increases above 80°F. The only automatic function in the normal supply line when Unit 1 is in Cold or Refueling Shutdown is provided by the

MOVs which close on low Intake Canal level. This function will be provided by administrative control of a temporary valve by around-the-clock operator coverage. The appropriate Station Abnormal Procedure(s) will be revised to provide the necessary operator action instructions.

Instrument channels from Intake Canal level instrumentation 1-CW-LE-102 and 1-CW-LE-103 will be placed in trip while the "B" and "D" intake bays are dewatered. This level instrumentation provides a signal on low level in the canal to trip both Units' turbines and close all CW and non-essential SW valves to preserve Intake Canal inventory.

Canal level probes are located in Unit 1 "B" and "D" bays and Unit 2 "A" and "C" bays.

The trip logic is 3 out of 4. Placing the two Unit 1 channels in trip results in an effective 1 out of 2 trip logic. The probability of a spurious plant trip is increased; however, the reliability of the canal probes supports the conclusion that this risk is minimal.

Furthermore, single active failure protection is maintained for the protective function.

Prior to removing the Unit 1 "B" and "D" inlet bays from service, surveillance testing will be performed on the Unit 2 canal level probes and the trash racks will be cleaned.

One of the three 8" SW supply lines to the Main Control Room Chiller (MCR) condensers (in Mechanical Equipment Room 3) and the Charging Pump SW pumps branches off one of the 42" SW lines upstream of the SW supply MOVs (1-SW-MOV-102 A and B) and will also be out of service during the project work. The two other SW supply lines are from diverse sources in Unit 2, therefore, these safety-related functions remain operable in accordance with Technical Specifications requirements.

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Plant instrumentation for SW flow used in surveillance procedures to determine the heat transfer capability of a CCHX will be bypassed during implementation of the project work. Provisions will be made for appropriate instrumentation and temporary procedure changes to assess CCHX operability while the jumper is in service.

Flooding protection and personnel safety will be provided by requiring double isolation for system boundaries which present a significant source of water. Passive boundaries which have no credible failure through inadvertent operation or significant leakage may have single isolation (e.g., blanked pipe). The flood dikes around the valve pits containing the SW MOVs will be removed to allow jumper installation. A flood watch will be present with administrative control of the temporary SW supply isolation valve and the installed SW MOVs in accordance with existing station procedures.

4.2 Analysis of Safety Implications of the Proposed Action The SW Pipe Repair for the CCHX SW Inlet Piping project and the proposed Operating License and Technical Specifications and Bases changes have been evaluated to assess their impact on the normal operation of the SW and CC Systems and to ensure that the design basis functions of these systems are preserved.

4.2.1 SW System The SW System at Surry Power Station is connected to each Unit's CW inlet piping, and thus shares the Intake Canal as a common source of cooling water. However, individual loads are supplied from diverse CW and SW lines in each Unit so that the system is not shared between Units. In the case of the Charging Pump SW coolers and three of the Main Control Room (MCR) Chiller condensers, supply can be from Unit 1 (one supply line) or Unit 2 (two supply lines).

Portions of the SW System are required to function during normal and emergency operating conditions. Although the CCHXs are not required to mitigate any design basis accident function, they are continuously required to function to remove decay heat from the Residual Heat Removal System and the Spent Fuel Pool. They are also required to provide cooldown capability for any operating Unit. The SW piping is designed such that isolation of the supply to the CCHXs does not affect SW flows to any other safety-related heat loads. If Charging Pump SW and MCR Chiller condensers are supplied from the two Unit 2 SW supply headers, non-safety-related Turbine Building SW is isolated for Unit 1, and a temporary alternate supply of SW to the required number of CCHXs is provided, the existing SW supply piping to the CCHXs can be removed from service.

The limiting OBA condition for the SW System is a loss of coolant accident (LOCA) on one Unit with simultaneous loss of offsite power to both Units. In response to a LOCA, a safety injection/consequence limiting safeguards (Sl/CLS) signal would open all SW valves for establishing flow to the Recirculation Spray Heat Exchangers (RSHXs) on the 14 of 24

accident Unit. When the Intake Canal level reaches approximately 23.5 ft, a signal will be generated to close the CW valves and non-essential SW valves to isolate the Intake Canal to conserve water inventory for the accident Unit's RSHXs, Charging Pump SW and MGR Chiller condensers. The SW supply MOVs to the CCHXs isolate non-essential SW flow. Station Abnormal Procedures verify these valves are closed and also isolate non-essential flow paths which may remain open due to a single active failure. During the periods when the jumper is in service, the response to a limiting OBA would be the same, with the operator present on watch directed by procedure to close the temporary manual inlet valve. It should be noted that, during the project, the installed SW MOV will already be closed and the flow through the jumper, until closed by manual action, is bounded by the Intake Canal inventory analysis. The analysis assumes isolation of SW to the CCHXs within one hour. At some period of time into the accident scenario, SW flow is re-established to two CCHXs to effect a cooldown of the non-accident unit. Unit 1 will be in Cold Shutdown or Refueling, therefore, the heat removal requirements would be less than for cooldown of an operating unit. The jumper is sized to provide the required flow at reduced canal level. As an option, time would be available to restore integrity to the normal 42" SW supply and flow to the CCHXs by that flow path.

If a shutdown of Unit 2 is required while the jumper is in service, the jumper will provide adequate flow to cooldown the Unit to Cold Shutdown within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . As an

alternative, the integrity of the normal 42" supply line can be restored and the SW supplied to the CCHXs by that flow path within an acceptable time frame.

4.2.2 . CC System During the implementation of this project the CC System will function as designed for one Unit in a refueling outage and one Unit at power. Two of the four CCHXs will be out of service while the other two CCHXs are supplied with SW by the jumper. The design basis for each CCHX is to provide heat rejection capability for the loads of one operating Unit and one-half of the heat loads common to both Units.

The loss of SW cooling to the CC System is considered highly unlikely due to the safety related design, precautions, contingency and compensatory measures provided during the use of the jumper. Any conditions which render the temporary SW flow path to the CCHXs inoperable would be responded to within the existing action statements in Technical Specifications. Station abnormal procedure 1-AP-27.00, "Loss of Decay Heat Removal Capability," provides procedural guidance to the operators to establish alternate cooling in the event of a loss of heat sink for the RHR System for Unit 1. Unit 2 will be at power, so a loss of heat sink for the CC System due to jumper loss will subsequently require entry into 1-AP-15.00, "Loss of Component Cooling". Where practicable, additional project constraints are applied to provide added conservatism to ensure a significant time period to complete any contingency actions associated with a complete loss of heat sink to the CC System. The constraints require that the Unit 1 reactor core has been shutdown for 150 hours0.00174 days 0.0417 hours 2.480159e-4 weeks 5.7075e-5 months prior to flowing the jumper as the 15 of 24

operable SW flow path. Additionally, while the jumper is flowing as the operable SW flow path, the Unit 1 reactor cavity will be flooded to at least 23 feet above the reactor vessel flange with the upper internals removed or the core offloaded to the Spent Fuel Pit. At 150 hours0.00174 days 0.0417 hours 2.480159e-4 weeks 5.7075e-5 months after shutdown, with the core in the reactor vessel, the reactor cavity flooded, and an initial temperature in the RCS of 100°F, a loss of the jumper would result in bulk boiling in the refueling cavity at a time over 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months following loss of heat sink, without any mitigating action. Normal SW supply to the two standby CCHXs can be restored in less than 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . After a decay time from shutdown of 360 *hours (15 days), the heat load will be reduced and the constraints of upper internals/reactor vessel head removed and cavity flooding will be lifted. From this time on in the outage, a loss of the SW jumper would be responded to in accordance with 1-AP-27.00, while immediate actions are being taken to restore normal SW supply.

4.3 Compensatory Measures (Contingency Plan)

The SW jumper is a safety-related seismic pipe which provides cooling water to the two operating CCHXs for Unit 2 operation and Unit 1 shutdown/refueling heat loads.

Conditions which may require isolation of the jumper and restoration of the normal 42" SW supply line include moderate-to-high volume leakage, extreme weather conditions, or particular plant conditions. Specific compensatory actions and a Contingency Action Plan will be in place to provide added assurance of safe operation of the facility during this project. An overview of the plan follows:

The Contingency Action Plan has four phases of activity:

Phase I Evacuation All equipment, debris and personnel are removed from the piping.

Phase II Restore System Integrity Establish flow path integrity by installing manways and blanks.

Phase Ill Reflood Remove stop logs and flood up to installed SW-MOV-102 valve.

Phase IV Flow Open SW-MOV-102 valve and restore flow to 11 C 11 and 11 D11 CCHXs.

The entry conditions of the Contingency Action Plan involve the use of an appropriate response depending on the nature of the failure/condition. Isolation of the temporary SW supply jumper should only be performed when it is absolutely necessary to limit Turbine Building flooding or to respond to Unit conditions which require operation of the normal SW supply. Failures which relate to Turbine Building flooding are classified as low, moderate, and high volume leakage.

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Low volume leakage is that which is easily terminated by exterior means without requiring isolation of the jumper. A repair must be justified by an engineering evaluation to remain in place and provide an acceptable pressure boundary for the duration of the implementation phase of the project. Any necessary repairs must be able to be performed without removing the jumper from service. The Contingency Action Plan will not be entered for low volume leakage. During the time periods when the jumper is in service, temporary pipe clamps and other emergency repair equipment will be staged in the area of the jumper in the basement of the Turbine Building to facilitate emergency repair of the jumper, if required, and to assist in recovery from a postulated flooding event. Procedures and training will be provided to the construction personnel to ensure the effectiveness of this measure.

Moderate volume leakage is that which can be coped with for a period of time until the necessary actions can be. performed to re-establish flow to the normal SW supply before the jumper is isolated. The Turbine Building sump pumps' capacity will be the limiting flow for moderate volume leakage. Additional compensatory measures may be required to preclude spraying or flooding of specific components/areas. If moderate volume leakage is encountered, the SW jumper would be declared inoperable and the appropriate Technical Specification action statement for Unit 2 would be entered.

High volume leakage is that which requires immediate isolation of the jumper due to an

inability to cope with the leak flow rate. Attempts to throttle the jumper flow to a rate low enough to cope, while still providing some CCHX cooling flow, are acceptable, however, actions to restore the normal SW supply shall be taken immediately. If high volume leakage is encountered, the SW jumper would be declared inoperable, the Contingency Plan would be entered through Phase IV, and the appropriate Technical Specification action statement for Unit 2 would be entered.

Extreme weather conditions which threaten the survivability of the jumper require the restoration of normal SW supply. Extreme weather conditions include a tornado or hurricane onsite. Upon notification that such an extreme weather event is imminent

("watch 11 ), for the Surry site, the Contingency Action Plan will be entered up through Phase II. All preparations required to enter Phase Ill will be taken without initiation of reflood. Upon notification of a tornado or hurricane 11 warning" for the Surry site, Phase Ill will be entered and operators will stand ready to initiate Phase IV, if required.

A Unit condition which would require entry into the Contingency Action Plan would be one in which RHR is the only cooling available for Unit 2 (e.g., no unisolated RCS loop).

This condition would make RCS cooling dependent on the SW jumper for its ultimate heat sink with no alternative method of cooling. This is undesirable since the short duration of time for heat up of the RCS does not provide sufficient time to implement the contingency plan if the heat sink to CC was lost. If an alternate method of decay heat removal is not available using an unisolated RCS loop (natural circulation through a Steam Generator), then the normal SW supply capability shall be restored. The Contingency Action Plan will be entered, up to and including Phase Ill, before the last 17 of 24

available RCS loop is removed from service. Phase IV will be entered if the jumper becomes inoperable.

ACTIVITIES ASSOCIATED WITH CONTINGENCY ACTION PLAN PHASES PHASE I Evacuation

1. Remove all equipment and ventilation from the piping (42" and 96"}.

2. Remove all debris from the piping. Material w~ich is small enough to pass through the heat exchanger tubes may be left in the piping. . (Largest dimension of object must be smaller than 0.375").

3. Evacuate all personnel from the piping.

4. Complete preparation for reflooding the system.

PHASE II Restore $ystem Integrity

1. Close manways at CCHXs. ("C" and "D")

2. Close manway at 42" piping.

3. Blank remaining openings in the system (e.g., 42" piping at piping flange downstream of removed 1-SW-MOV-102X.)

PHASE Ill Reflood

1. Remove stop logs on unblanked 96" inlet bay, as required, to fill piping up to the closed 1-SW-MOV-102X.

PHASE IV Flow

1. Open 1-SW-MOV-102X and establish flow to the "C" and "D" CCHXs.

Flowing the 42" SW piping after application of the new coating, but before adequate cure time has elapsed was evaluated for potential coating failure. The coating manufacturer has stated that short term effects from premature immersion will not cause any significant debris as a result of coating failure, provided strict controls are invoked during surface preparation and coating application by qualified personnel, as required by Surry's safety-related coating application procedure.

A loss of the alternate SW supply during some phases of the project work may require placing the normal SW supply in service before adequate weld repair is completed to declare the piping operable in accordance with station procedures. Engineering will evaluate the existing condition of the pipe wall and the capability of the piping to maintain the expected system pressures and sustain minimal leaks, while still meeting emergency system flow requirements. Since the majority of the piping is concrete-encased and the system pressure is low, there would likely be insignificant leakage and effect on supply flow under these emergency actions. Once the plant is in a stable 18 of 24

condition and alternate SW supply is restored, the normal SW will be removed from service and the piping wall repair will be completed.

4.4 Probabilistic Safety Assessment A review of the proposed project activities was performed to consider the potential impact on the operating Unit from an internal flooding hazard. (The risk associated with the SW pipe repair activities that impact the availability .of plant systems is addressed by the guidelines contained in the on-line maintenance configuration matrix so that the risk is maintained within acceptable limits.) The analysis of internal flooding hazard concluded that the changes in plant system and operating configuration during the implementation of the CCHX SW supply line restoration project will have a negligible impact on the risk associated with the operating Unit. A summary of the analysis is provided below.

Flooding Threat From Operations-Induced Failures The contribution to the internal flooding-induced risk from long term isolable floods will be reduced for the proposed SW system configuration necessitated by the pipe restoration work (i.e., temporary SW jumper installed) compared with the existing system configuration because the potential risk contributors for the proposed configuration (and therefore the frequency) will be less.

The contribution to the internal flooding-induced risk from short term isolable floods will remain the same or will be slightly reduced based on the following: The frequency for short term isolable flooding will be slightly higher in the proposed SW system configuration compared to the normal system configuration because more SW-related piping elements are exposed in the proposed configuration. However, the probability of failing to isolate such flooding scenarios is lower (in some cases significantly lower) in the proposed SW system configuration compared with the normal configuration. The risk evaluation assumes the proposed SW system configuration includes implementation of the mitigative measures listed below. Thus, the overall risk (i.e.,

frequency multiplied by the failure to isolate probability) from the short term isolable floods will actually be lower in the proposed SW system configuration compared with the normal configuration. This conclusion assumes the risk associated with the removal of equipment from service is evaluated and controlled by the on-line maintenance configuration matrix prepared in response to the Maintenance Rule.

Flooding Threat From Construction-Induced Mechanisms The following three potential errors were identified as the major contributors to the construction (maintenance)-induced flooding hazard: 1) maintenance attempted on the wrong component, 2) the wrong stop log is removed and 3) a component is

inadvertently left open after maintenance. These three potential errors were analyzed and it was concluded that the change in risk contribution of maintenance-induced 19 of 24

flooding during the conduct of the CCHX SW supply line restoration project will be negligible compared with the base case maintenance-induced flooding since the following precautionary measures will be in place to decrease the consequences of the potential flood-inducing errors:

The section of existing SW pipe downstream of the SW supply isolation MOVs (1-SW-MOV-102A and B) will be filled with water using a controllable process.

This will allow a positive leak check of piping integrity prior to fully removing a stop log. This measure will reduce the consequences of the second and third type of errors noted above.

Components will be opened under preventative measures that will allow any potential leaks to be controlled prior to the component being fully opened. This will allow personnel to reclose a wrongly selected component before it becomes a significant flooding hazard. For example, before. fully removing a manhole cover, the retaining bolts will first be loosened so the manhole cover can be moved sufficiently to ensure the related piping section is dry. If significant leakage is observed, the manhole cover can be re-tightened. These preventative measures will reduce the consequences of the first and second type of errors noted above.

Mitigative Measures The following planned mitigative measures are included in the project to ensure that only an insignificant change to core damage frequency would be realized from this activity:

1. Visual barriers (e.g., ropes, placards, cones, etc.) will be placed around the jumper routing to minimize the likelihood of inadvertent collision of moving vehicles with the piping.

2. Appropriate controls on the movement of heavy loads will be implemented for the Turbine Building bridge crane for any lifts which pass over the SW jumper while it is in service.

3. A 24-hour flood watch will be present with the capability and authorization to isolate the SW jumper within 20 minutes of identifying a potential flooding event. The 20 minute time frame for operator action is consistent with the assumptions included in our Individual Plant Examination for responding to a flooding event. The project implementation will include adequate measures to ensure that the consequences of a pipe rupture will not preclude the ability to isolate jumper flow.

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5.0

SUMMARY

OF PROJECT CONSTRAINTS AND . COMPENSATORY MEASURES

A safety-related, seismic, non-missile protected, alternate SW flow path (jumper) will be required to provide SW to two CCHXs for Unit 2 operating loads, Unit 1 shutdown/refueling loads, and common heat loads.

The CCHXs will be cleaned prior to placing the temporary jumper into service to reduce the probability that a CCHX will be rendered inoperable due to a tubesheet becoming clogged from biofouling.

Prior to removing "B" and "D" inlet bays from service, surveillance testing will be performed on the Unit 2 installed probes and the trash racks will be cleaned.

Unit 1 shall be defueled or the refueling cavity filled to at least 23 feet above the reactor vessel flange, whenever the SW jumper is in service as the operable SW flow path. The reactor will be shutdown for 150 hours0.00174 days 0.0417 hours 2.480159e-4 weeks 5.7075e-5 months prior to placing the jumper in service as the operable SW flow path. (An engineering analysis may be performed to show that the heat load in the core is less than that assumed in the heat up calculation to allow operation prior to 150 hours0.00174 days 0.0417 hours 2.480159e-4 weeks 5.7075e-5 months .) After a decay time from shutdown of 360 hours0.00417 days 0.1 hours 5.952381e-4 weeks 1.3698e-4 months (15 days), the heat load will be reduced and the constraints of upper internals/reactor vessel head removed and cavity flooded will be removed. From this point forward in the outage, a loss of the SW jumper would be responded to in accordance with station abnormal procedures. The appropriate operating procedure(s) will be revised to control operation of the jumper in accordance with the implementing design change package (DCP).

Two CCHXs will be out of service during implementation of the project. TS Section 3.13 requires two CCHXs to be operable for one Unit operation and three CCHXs for two Unit operation. TS 3.14 requires the ability to establish SW flow to and from the CCHXs specified in TS 3.13. Therefore, Unit 1 cannot be operating when the jumper is in service as the operable SW flow path. The design change package which implements the CCHX SW supply pipe restoration project ensures proper Unit conditions during the use of the jumper.

The jumper is not expected to be operated when SW supply temperatures are above 80°F. Operator logs will be revised to indicate maximum allowable SW temperature while the jumper is in service in accordance with the implementing design change package. Engineering will evaluate continued operation of the temporary SW jumper if the SW supply temperature increases above 80°F.

The jumper will require a 24 hour/day flood watch and administrative control of the temporary SW supply valve with the capability to isolate the SW jumper within 20 minutes of identifying a potential flooding event. The normal SW 21 of 24

supply isolation MOVs (1-SW-MOV-102A and 1-SW-MOV-102B) will be out of service during implementation of the project. Valve operation will be controlled by abnormal and operating procedures. Flood watch requirements will be delineated and controlled by design change implementing procedures and in accordance with station procedures.

When the jumper is in service, a Contingency Action Plan will be in effect through administrative action statements, requiring restoration of the normal SW supply capability -if specific plant or environmental conditions exist. These conditions include leakage rates which render the jumper inoperable, weather conditions which are conducive to tornadic activity, hurricane warnings for the Surry site, or plant conditions on Unit 2 which result in RHR being the only available cooling for the reactor coolant system (e.g., no unisolated RCS loop).

Applicable plant procedures will be revised to control actions required by the Contingency Action Plan.

Appropriate controls on the movement of heavy loads will be implemented for the Turbine Building bridge crane for any lifts which pass over the SW jumper while it is in service. The implementing DCP ensures proper implementation of the controls on the movement of heavy loads in the vicinity of the jumper.

SW supply to the control room chiller condensers in Mechanical Equipment Room 3 and the charging pump SW pumps will be from the two Unit 2 supply lines. The Unit 1 supply will be out of service for the duration of the pipe repair work. This will be controlled by the implementing DCP.

Flood dikes around the valve pit containing 1-SW-MOV-102A and 1-SW-MOV-102B will be controlled by existing station procedures. During this time these MOVs will be closed or under administrative control. This will be controlled by the implementing DCP.

Flooding protection and personnel safety will be provided in accordance with station procedures. Passive boundaries which have no credible failure through inadvertent operation or significant leakage may have single isolation (e.g.,

blanked pipe).

Provisions will be made for temporary instrumentation and procedure changes to assess CCHX operability.

The jumper will be hydrostatically tested prior to use in accordance with the design change testing requirements and existing station procedures.

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Visual barriers (e.g., ropes, placards, cones, etc.) will be placed around the jumper routing to minimize the likelihood of inadvertent collision of moving vehicles with the piping.

The section of existing SW pipe downstream of the SW supply isolation MOVs (1-MOV-SW-102A and B) will be filled with water prior to stop log removal using a controllable process.

Components* will be opened under preventative measures that will* allow any potential leaks to be controlled prior to the component being fully opened.

6.0 CONCLUSION

S The planned repair work on the SW supply piping to the CCHXs will involve the use of a temporary, non-missile protected, seismic supply line to two of the four CCHXs.

Whenever conditions exist which could render the jumper inoperable, a Contingency Action Plan will require that project work cease and normal SW supply capability be restored. This evolution can be completed in time to meet the design basis functions of the CCHXs and within established design limits of supported systems. A complete and immediate loss of SW supply to the operating CCHXs is not considered credible, given the project constraints and the unlikely probability of a generated missile. At worst, loss of SW supply to the operating CCHXs would require Unit 2 to shutdown and enter the abnormal procedure for a loss of component cooling, and would require Unit 1 to use alternate cooling in accordance with the loss of decay heat removal abnormal procedure.

During project implementation, the automatic isolation of the SW MOVs in the normal supply piping to the CCHXs will be defeated. This automatic function, which serves to conserve Intake Canal inventory will be replaced by administrative control of the installed MOV and/or the temporary SW supply valve. The manual action can be completed within the time allowed by the analysis of Intake Canal inventory level. This project also requires that both Unit 1 "B" and "D" intake bays be dewatered, placing two of the four intake canal level probes in trip. The protective function is assured using one out .of two signals to actuate from the remaining two Unit 2 level probes through two logic channels, thus, the single failure criterion is preserved. There is an increased probability of a spurious trip of Unit 2 in this condition, however, the reliability of the Intake Canal level probes supports the conclusion that this is acceptable for Unit 2 operation.

The completion of the restoration of the SW supply to the CCHXs will m1rnm1ze corrosion of the piping wall and prolong the service life of the piping. It will also provide full assessment of the wall condition for this normally inaccessible piping section.

Consequently, the assurance of pipe wall integrity for the SW supply to the CCHXs will be enhanced. Therefore, the proposed changes to the Operating License and 23 of 24

Technical Specifications and Bases are necessary to allow the use of the temporary SW supply jumper to provide SW flow to the CCHXs for two 35 day periods to facilitate the currently planned pipe repair work activities. The proposed changes also allow the use of the temporary SW jumper to support future maintenance activities on the CCHX SW supply line with prior NRG notification.

The minor revisions to the Technical Specification Table 3.7-2 for format consistency, and the 3.14 Basis section to reflect UFSAR references rather than FSAR references, are strictly administrative in nature.

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N B -t==================:t- + -t::===~

N PLAN IO

-..J 0 SERVICE WATER TEMPORARY JUMPER PIPE ROUTING IO (J1 TURBINE AREA - GROUND FLOOR (J1

~

121!1121 l'ICBCI.IOI SURRY POWER STATION - UNIT 1

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ML18152A076

Contents

Text

1.0 INTRODUCTION

2.0 BACKGROUND

3.7 Basis

SUMMARY

6.0 CONCLUSION

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ML18152A076

Text

1.0 INTRODUCTION

2.0 BACKGROUND

3.7 Basis

SUMMARY

6.0 CONCLUSION

Navigation menu

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