1CAN030801, License Amendment Request, Technical Specification Changes Regarding Reactor Building Spray Nozzle Test Requirements

License Amendment Request, Technical Specification Changes Regarding Reactor Building Spray Nozzle Test Requirements

ML080850905
Person / Time
Site:	Arkansas Nuclear
Issue date:	03/13/2008
From:	Mitchell T Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
1CAN030801
Download: ML080850905 (13)

Text

Entergy Entergy Operations, Inc.

1448 SR, 333 Russellville, AR 72802 To! 479-858-3110 Timothy G, Mitchell Vice President, Operations Arkansas Nuclear One 1CAN030801 March 13, 2008 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

License Amendment Request Technical Specification Changes Regarding Reactor Building Spray Nozzle Test Requirements Arkansas Nuclear One, Unit 1 Docket No. 50-313 License No. DPR-51

Dear Sir or Madam:

Pursuant to 10 CFR 50.90, Entergy Operations, Inc. (Entergy) hereby requests an amendment to the Arkansas Nuclear One, Unit 1 (ANO-1) Operating License regarding Surveillance Requirement (SR) 3.6.5.8 for testing the Reactor Building Spray nozzles. The proposed change will revise the SR to require verification that the reactor building spray nozzles are unobstructed following maintenance that could result in nozzle blockage in lieu of the current SR of performing the test every 10 years. Details of the proposed license amendment are contained in Attachment 1 to this letter. The technical specification (TS) mark-up pages and for information only mark-up TS Bases pages are contained in Attachments 2 and 3, respectively.

The proposed change has been evaluated in accordance with 10 CFR 50.91 (a)(1) using criteria in 10 CFR 50.92(c) and it has been determined that the changes involve no significant hazards consideration. The bases for these determinations are included in the attached submittal.

The proposed change does not include any new commitments.

Entergy requests approval of the proposed amendment by March 1, 2009. Once approved, the amendment shall be implemented within 90 days.

14ool Nee

1CAN030801 Page 2 of 2 If you have any questions or require additional information, please contact Bob Clark at 479-858-4663.

I declare under penalty of perjury that the foregoing is true and correct. Executed on March 13, 2008.

Sincerely, TGM/rwc Attachments:

1. Analysis of Proposed Technical Specification Change

2. Proposed Technical Specification Changes (mark-up)

3. Proposed Technical Specification Bases Changes (mark-up) cc: Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P. 0. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Alan B. Wang MS 0-7 D1 Washington, DC '20555-0001 Mr. Bernard R. Bevill Director Division of Radiation Control and Emergency Management Arkansas Department of Health & Human Services P.O. Box 1437 Slot H-30 Little Rock, AR 72203-1437

Attachment I 1CAN030801 Analysis of Proposed Technical Specification Change

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Attachment to 1CAN030801 Page 1 of 6

1.0 DESCRIPTION

Entergy requests an amendment to the Arkansas Nuclear One, Unit 1 (ANO-1) Operating License (DPR-51) by incorporating the attached change into the ANO-1 Technical Specifications (TS). The purpose of Surveillance Reqdirement (SR) 3.6.5.8 is to verify the spray nozzles are unobstructed. The proposed change requests revision to the frequency for the performance of SR 3.6.5.8 from once every 10 years to following maintenance that could result in nozzle blockage.

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2.0 PROPOSED CHANGE

The proposed change revises SR 3.6.5.8 to require verification that the reactor building spray nozzles are unobstructed following maintenance that could result in nozzle blockage (loss of foreign material exclusion control) rather than the current requirement of every 10 years. This license amendment request has included proposed changes to the associated TS Bases for information only. Entergy will update the TS Bases in accordance with the ANO-1 TS Bases Control Program.

3.0 BACKGROUND

The ANO-1 Safety Analysis Report (SAR) lists several design criteria that must be satisfied for safety related systems. Within the criteria are requirements for Reactor Building decay heat removal stating:

" A system to remove heat from the reactor containment shall be provided. The system safety function shall be to rapidly reduce, consistent with the functioning of other associated systems, the containment pressure and temperature following any Loss of Coolant Accident (LOCA) or a Main Steamline Break (MSLB) inside the reactor building and maintain them at acceptably low levels.

• Suitable redundancy in components and features, and suitable interconnections, leak detection, isolation, and containment capabilities shall be provided to assure that for on site electric power system operation (assuming off site power is not available) the system safety function can be accomplished, assuming a single failure.

The Reactor Building Spray and Emergency Cooling Units provide cooling to the Reactor Building atmosphere following a LOCA or MSLB. Both emergency cooling units have a combined heat removal capability of 100%. The two separate trains of Reactor Building Spray together are capable of providing 100% of the design cooling required from the system.

The Reactor Building Spray system has two major functions. The first of these functions is to reduce post accident containment temperature and pressure to nearly atmospheric. By reducing the pressure and temperature, the driving force for leakage will be reduced and thereby stay below 10 CFR 100 limits at the site boundary during a Design Based Accident.

The second function is to remove iodine from the containment atmosphere after a LOCA or MSLB. Iodine released from damaged fuel to the containment atmosphere during a LOCA or MSLB could be released to the outside environment if it was not removed.

Attachment to 1 CAN030801 Page 2 of 6 Iodine has a strong affinity for water and is "stripped" from the containment atmosphere when the spray system is operating. To enhance the affinity towards the water, NaOH is supplied to the spray pump suction which raises the pH of the water into a range that better facilitates the removal of iodine.

Each eight-inch discharge header piping from each Reactor Building Spray pump penetrates the Reactor Building at -366 foot elevation. The main headers then split into two 6-inch headers. These headers provide flow to the distribution headers. These distribution headers then supply the spray headers, which contain the spray nozzles used to "spray" the water into the Reactor Building atmosphere. Each distribution and spray header contains a 4-inch, 3-inch and a 2 and one half-inch section.

Each distribution header provides flow to 48 nozzles for a total of 96 nozzles per train. The spray headers are arranged in concentric overlapping pattern to provide redundant spray coverage when only one spray system is operable. This configuration along with spray nozzle spacing provides uniform spray coverage.

To provide this uniform spray coverage, the 192 spray nozzles are positioned no closer than 8 feet and no further than 10 feet apart from any adjacent nozzle. The spray nozzles are a one piece Spraco model 1713A whiich features a ramp bottom design. This nozzle design provides a uniform hollow cone spray pattern as the water flows through the nozzle. Nozzle design yields an average water droplet size of 400 microns with a maximum size of 700 microns. Each nozzle is designed to pass 15.5 gpm when operating at system design pressure and flowrates.

The spray nozzles have large, free and unobstructed passages, which reduce the potential for nozzle clogging when operating in the sump recirculation mode. Flow into the recirculation suction is totally screened. Debris larger than 3/8-inch in diameter (the diameter of the spray nozzle) can not enter the suction piping.

The spray solution is completely stable and soluble at all temperatures of interest in the containment and therefore will not precipitate or otherwise interfere with nozzle performance.

The Reactor Building Spray nozzles are tested via smoke, air or thermographic means every ten years per SR 3.6.5.8 to verify that the nozzles are unobstructed. The results of these tests, which have been performed several times since construction, have confirmed that the nozzles are free of obstructions that could have occurred following startup, operation and maintenance of the system.

The most likely cause of nozzle obstruction is the introduction of foreign material into the system. Foreign material can be introduced by corrosion of the piping /nozzles or through maintenance on the system. An acceptable method for prevention of obstructions due to foreign material is by assuring positive foreign materials exclusion controls.

Attachment to 1CAN030801 Page 3 of 6

4.0 TECHNICAL ANALYSIS

The ANO-1 spray ring headers are maintained dry even though the water level in the spray pipe headers are maintained at an elevation of - 394 feet. The reactor building spray header system header and nozzles are passive devices that are not normally exposed to fluids or debris. The system piping and nozzles are fabricated of Schedule 10, 304 stainless steel, which is highly resistant to corrosion products. Therefore, formation of any significant corrosion products is unlikely due to the resistance of the metal to rust or flaking.

At Entergy, the Foreign Material Exclusion (FME) Program is implemented by procedure EN-MA-1 18, Foreign Material Exclusion. This procedure describes the measures to be taken to ensure foreign material is not introduced into a component or system and measures to be taken if material or tool accountability is lost. This procedure applies to all station activities having the potential to introduce foreign material into systems or components which could impact plant safety. The requirements of the procedure apply when maintenance, modifications, repairs, inspections and operating activities are being conducted on open piping and equipment. The procedure establishes various levels for preventing the generation of debris when breaching a system and the removal of debris from the system if materials have entered a system. Pre-job briefs for FME are conducted prior to opening systems where foreign materials can be introduced. The procedure also requires personnel who are working on open components/systems receive FME training as part of their job qualifications.

The procedure requires that when closing a system or component, an inspection be performed to ensure that all foreign material is removed. If FME control is not maintained, the condition is entered in the Entergy Corrective Action Program, requiring assessment of the circumstances and implementation of appropriate corrective actions. This will ensure the containment spray nozzles remain operable after maintenance.

Fluid system/component breaches are to be covered when access for maintenance or inspection is not required. Due to their locations in the containment, introduction of foreign material into the spray headers is highly unlikely. Foreign material introduced as a result of maintenance is the most likely cause for obstruction; therefore, verification during and following such maintenance would suffice to assure no material is introduced that could cause nozzle blockage. Consequently, the potential for an unidentified nozzle obstruction is very low. Routine maintenance activities with effective application of foreign material exclusion controls should not require subsequent inspection or testing of the spray nozzles.

A review of the maintenance and modification history indicates that several work orders have been performed on the Reactor Building Spray system since the last thermographic test in 1998, which involved minor activities such as opening the system to perform IST examinations. Repairs of the piping system have been performed under strict FME controls.

There has been no maintenance or modification to the system that would have potentially impacted blockage of the nozzles. Cleanliness control and FME practices, including post-work inspections, have ensured that system cleanliness requirements are met.

The ANO-1 accident analyses are based on one of the two Reactor Building Spray trains operating. One operable reactor building spray train assures that the pressure across the upper spray ring nozzles is adequate to provide the design flow rate. The calculated spray coverage inside the reactor building assures that after a design-basis accident, the offiste

Attachment to 1CAN030801 Page 4 of 6 dose in within Part 100 limits and the 30-day control room dose is within GDC 19 guidelines.

The ANO-1 Probabilistic Safety Assessment does not address the reduction of reactor building spray capability as a result of partial nozzle blockage or reduced spray flow.

However, a plugged nozzle would have negligible impact on the capability of the Reactor Building Spray System to respond to a LOCA or MSLB.

Confirmation that the spray nozzles are unobstructed may be obtained by such means as FME controls during maintenance, a visual inspection of the affected portions of the system, by an air or smoke flow test following maintenance involving opening portions of the system downstream of the containment isolation valves, or by draining/flushing the filled portions of the system inside containment, as appropriate. Reduced spray nozzle testing is justified where operating experience has shown that routinely passing a surveillance test performed at a specified interval has no apparent connection to overall component reliability.

5.0 REGULATORY ANALYSIS

5.1 Applicable Regulatory Requirements/Criteria Compliance with ANO-1 Safety Analysis Report - No changes to the ANO-1 Safety Analysis Report are required as a result of this license amendment request.

Compliance with 10CFR50, Appendix A, General Design Criteria -

Criterion 39, Inspection of Containment Heat Removal Systems, requires that the containment heat removal system be designedto permit appropriate periodic inspection of important components, such as the torus, sumps, spray nozzles, and piping to assure the integrity and capability of the system.

Evaluation - Provisions have been made to facilitate periodic inspections of active components and other important equipment in the Reactor Building Spray system.

Criterion 40, Testing of Containment Heat Removal Systems, requires that the containment heat removal system be designed to permit appropriate periodic pressure and functional testing to assure (1) The structural and leaktight integrity of its components, (2) The operability and performance of the active components of the system, and (3) The operability of the system as a whole, and under conditions as close to the design as practical performance of the full operational sequence that brings the system into operation, including operation of applicable portions of the protection system, the transfer between normal and emergency power sources, and the operation of the associated cooling water system.

Evaluation - The Reactor Building Spray system is provided with sufficient test connections and isolation valves to permit periodic pressure testing. System piping, valves, pumps, heat exchangers, and other components of the Reactor Building Spray system are arranged so that each component can be tested periodically for operability, including transfer to the standby power system. The delivery capability of the Reactor Building Spray system' has been tested to the extent practicable and Section XI testing is periodically performed to verify pump capacity. The delivery capability of the spray nozzles has been tested periodically by blowing low-pressure air/smoke through the nozzles and verifying the flow.

Attachment to 1CAN030801 Page 5 of 6 5.2 No Siqnificant Hazards Consideration Entergy Operations, Inc. has evaluated whether or not a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

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

Response: No The Reactor Building Spray System is not an initiator of any analyzed event. The proposed change does not have a detrimental impact on the integrity of any plant structure, system, or component that may initiate an analyzed event. The proposed change will not alter the operation or otherwise increase the failure probability of any plant equipment that can initiate an analyzed accident. This change does not affect the plant design. There is no increase in the likelihood of formation of significant corrosion products. Due to their location at the top of the containment, introduction of foreign material into the spray headers is unlikely. Foreign materials exclusion controls during and following maintenance provides assurance that the nozzles remain unobstructed.

Consequently, there is no significant increase in the probability of an accident previously evaluated.

The Reactor Building Spray system is designed to address the consequences of a Loss of Coolant Accident (LOCA) or a Main Steamline Break (MSLB) inside the reactor building.

The Reactor Building Spray system is capable of performing its function effectively with the single failure of any active component in the system, any of its subsystems, or any of its support systems.

Therefore, the consequences of an accident previously evaluated are not significantly affected by the proposed change.

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

Response: No The proposed change will not physically alter the plant (no new or different type of equipment will be installed) or change the methods governing normal plant operation.

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

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

Response: No The system piping and nozzles are made if material that is not susceptible to corrosion.

Obstruction from sources external to the system is highly unlikely due-to the location high in the reactor building and not being readily accessible. Strict controls are established to

Attachment to 1CAN030801 Page 6 of 6 ensure the foreign material is not introduced into the Reactor Building Spray system during maintenance or repairs. Maintenance activities that could introduce significant foreign material into the system require subsequent system cleanliness verification which would prevent nozzle blockage. The spray header nozzles are expected to remain unblocked and available in the event that the safety function is required. The capacity of the system would remain unaffected.

Therefore, the proposed change does hot involve a significant reduction in a margin of safety.

Based on the above evaluations, Entergy concludes that the proposed amendment(s) present no significant hazards consideration under the standards set forth in 10CFR50.92(c).

5.3 Environmental Considerations The proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 PRECEDENCE Similar NRC license amendment requests were sought by Entergy Operations, Inc. for ANO-2 on March 15, 2007, and approved by the NRC on July 2, 2007; Texas Utilities Power for the Comanche Peak Station on September 9, 2004 and approved by the NRC on October 14, 2005; and by South Texas Project Nuclear Operating Company for the South Texas Project Electric Generating Station on May 14, 2003 and approved by the NRC on August 20, 2003.

Attachment 2 1CAN030801 Proposed Technical Specification Changes (mark-up)

Reactor Building Spray and Cooling System 3.6.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.5.1 Verify each reactor building spray manual, power 31 days operated, and automatic valve in each required flow path that is not locked, sealed, or otherwise secured in position is in the correct position.

SR 3.6.5.2 Operate each required reactor building cooling train 31 days fan unit for Ž 15 minutes.

SR 3.6.5.3 Verify each required reactor building cooling train 31 days cooling water flow rate is Ž1200 gpm.

SR 3.6.5.4 Verify each required reactor building spray pump's In accordance with developed head at the flow test point is greater than the Inservice or equal to the required developed head. Testing Program SR 3.6.5.5 Verify each automatic reactor building spray valve in 18 months each required 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 3.6.5.6 Verify each required reactor building spray pump 18 months starts automatically on an actual or simulated actuation signal.

SR 3.6.5.7 Verify each required reactor building cooling train 18 months starts automatically on an actual or simulated actuation signal.

SR 3.6.5.8 Verify each requiFed4FaiR-spray nozzle is Followinq unobstructed. maintenance which could result in nozzle blockage 10qyeas

-ANO-1 3.6.5-3 Amendment No. 2-15,

Attachment 3 1 CAN030801 Proposed Technical Specification Bases Changes (mark-up)

Reactor Building Spray and Cooling Systems B 3.6.5 SURVEILLANCE REQUIREMENTS (continued)

SR 3.6.5.5 and SR 3.6.5.6 (continued) administrative controls. During testing of the spray pump, the reactor building isolation valve in the spray line is closed with its breaker open to prevent spraying the reactor building. After spray pump performance is verified, the pump is stopped.

Its breaker is racked down to prevent restart. Power is then restored to the reactor building isolation valve for valve testing. The 18 month Frequency is based on the need to perform these Surveillances under the conditions that apply during a unit outage and on the potential for an unplanned transient if the Surveillances were performed with the reactor at power. Operating experience has shown that these components usually pass the Surveillances when performed at the 18 month Frequency. Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

SR 3.6.5.7 This SR requires verification by control board indication that each required reactor building cooling train actuates upon receipt of an actual or simulated actuation signal. The 18 month Frequency has been shown to be acceptable through operating experience. See SR 3.6.5.5 and SR 3.6.5.6, above, for further discussion of the basis for the 18 month Frequency.

SR 3.6.5.8 With the reactor building spray header isolated and draincd of any solu1tion,lo pesure, air*oremokecran F be bloew through teSt on*RectionsR. P*n*rFmance of this Sur~eilanco Emonstratos that oach spray nozzlo is unobs661tretd and provido a~ssuranco th-ýat spray co)Vorago of the FroActrF building durFing an cietiRo d.egraded. Duo to the passive na.ture of the design of the nozzles, a test at 1h0isar inteR'als iSconSidered adequate to detect obstruction Of the spranyL no-ZzlosThis surveillance ensures that each spray nozzle is unobstructed and provides assurance that spray coverage of the containment during an accident is not degraded.

Confirmation that the spray nozzles are unobstructed may be obtained by such means as foreign materials exclusion (FME) controls during maintenance, a visual inspection of the affected portions of the system, by an air or smoke flow test following maintenance involving opening portions of the system downstream of the containment isolation valves, or by draining/flushing the filled portions of the system inside containment, as -appropriate. Maintenance that could result in nozzle blockage is generally a result of a loss of FME control. If loss of FME control occurs, an inspection or flush of the affected portions of the system should be adequate to confirm that the spray nozzles are unobstructed since water flow would be required to transport any debris to the spray nozzles.

REFERENCES

1. SAR, Section 1.4.

ANO-1 B 3.6.5-4 Amendment No. 215 Rev.