ML073090068

Duane Arnold - Response to Request for Additional Information Related to the Relief Request for Drywell Stabilizer Examinations

ML073090068
Person / Time
Site:	Duane Arnold
Issue date:	10/31/2007
From:	Anderson R L Duane Arnold
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NG-07-0808
Download: ML073090068 (23)

Text

0 FPL Energy.Duane Arnold Energy Center FPL Energy Duane Arnold, LLC 3277 DAEC Road Palo, Iowa 52324 October 31, 2007 NG-07-0808 10 CFR 50.55a U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Response to Request for Additional Information Related to the Relief Request for Drywell Stabilizer Examinations References

1. Letter, Gary Van Middlesworth (FPL Energy Duane Arnold) to Document Control Desk (USNRC) Relief Request for Drywell Stabilizer Examinations, dated May 15, 2007 (ML071430227)

2. Letter, Karl D. Feintuch (USNRC) to Gary Van Middlesworth (FPL Energy Duane Arnold), Request For Additional Information Re: Relief Request From IWE-2500 Requirement For Drywell Stabilizer Examinations (TAC NO. MD5670), dated October 15, 2007 (ML072750506)

Reference 1 provided a request for relief from performing the VT-3 visual examinations of the reinforcing structure and integral attachment of Drywell Stabilizers X-58C and X-58G.By letter dated October 15, 2007 (Reference 2), the Staff issued a request for additional information regarding Reference

1. The response to the requests of Reference 2 is provided in the enclosure to this letter.FPL Energy Duane Arnold requests approval of the request of Reference 1 by the end of May 2008.This letter contains no new commitments nor revises any previous commitments.

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NG-07-0808 October 31, 2007 Page 2 of 2 If you have any questions, please contact Steve Catron at (319) 851-7234.Richard L. Ander n Vice President, Duane Arnold Energy Center FPL Energy Duane Arnold, LLC Enclosures cc: Administrator, Region III, USNRC Project Manager, DAEC, USNRC Senior Resident Inspector, DAEC, USNRC Enclosure 1 to NG-07-0808 Page 1 of 4 Enclosure 1 Response to Request for Additional Information (RAI) Related to the Relief Request for Drywell Stabilizer Examinations Enclosure 1 to NG-07-0808 Page 2 of 4 Response to Request for Additional Information (RAI) Related to the Relief Request for Drywell Stabilizer Examinations NRC Question #1: Please provide relevant drawings that show the relative location, structural configuration and general arrangement of Drywell Stabilizers X-58C and X-58G and the drywell coolers to enable the staff to understand the nature of the interference from the upper elevation drywell coolers that prohibits access for removal of the bolting and manhole covers for examination of Drywell Stabilizers X-58C and X-58G.FPL Energy Duane Arnold Response: Attached are three drawings (BECH-M004, BECH-M341, and BECH-M041) in Enclosure

2. Blowups of sections of BECH-M341 are also provided in Enclosure 2.Drawing BECH-M004 provides the plan view of the drywell at elevations 812 feet 0 inches and 833 feet 6 inches. Drawing BECH-M341 shows the elevation view of the drywell as well as the drywell cooler location and size compared to the other components in the drywell. Drawing BECH-M041 shows the locations of the manholes.

As shown in the three drawings and the attached blowups, in conjunction with the photographs already submitted in Reference 1, the drywell coolers interfere with the removal of the Stabilizer manhole covers, thus preventing the visual examination of the integral attachment on the outside of the containment.

NRC Question #2: In the last paragraph of the "Reason for Request" section of the Relief Request, the licensee stated that "Examination of the Drywell Stabilizers X-58C and X-58G, which includes ... and a very disproportionate impact on expenditures of plant manpower and radiation exposure." Please provide a quantitative estimate of the effort involved, time duration required, the area dose-rate and the resulting personnel dose that could result from radiation exposure for each of these drywell stabilizers if the VT-3 examinations were to be performed as required by ASME Code,Section XI.FPL Energy Duane Arnold Response: Engineering Change Package ECP-1650 replaced the drywell coolers in the lower portion of the drywell (total of 12) which resulted in 41 REM of accumulated dose.Dividing the total accumulated dose for the cooler replacement by 12 results in 3.4 REM per cooler. The total dose to remove the two subject drywell coolers is estimated to be significantly higher than 3.4 REM per cooler since the involved coolers are in the upper elevations of the drywell where clearances are tighter. Even if the total dose to remove both coolers was 3.4 REM, it would not be consistent with the principles of "As Low As Reasonably Achievable" (ALARA) for the performance of the two visual examinations of Stabilizers X-58C and X-58G.

Enclosure 1 to NG-07-0808 Page 3 of 4 To provide an estimate of the amount of work required to remove the drywell coolers and reinstall them after performing the visual examination, a copy of the "Cooler Moving Plan 1V-CC-2A/2B" from ECP-1650 is attached in Enclosure

3. The weight of each cooler is approximately 2500 pounds. The steps for removing the cooler would consist of removing the structural steel, installing a gantry crane, removal of the necessary fasteners, draining the coolers, prying up the coils for removal, and rigging the coils out of the way. Reinstallation would consist of moving the coils back into position with the gantry crane, reinstallation of the fasteners and reinstalling the structural steel. This is considered to be a significant amount of work to allow access to remove the manhole cover to perform the visual examination of Stabilizers X-58C and X-58G. Based on the amount of work involved as outlined in Enclosure 3, it is clear that the time to prepare for, perform, and restore from the inspections would be significant, on the order of weeks.NRC Question #3: With regard to the "Proposed Alternative and Basis for Use" section of the Relief Request, since there is no alternative action(s) proposed, please confirm if a general visual examination (as proposed in previous Relief Request MC-R008 listed as Precedent

1) of the accessible surfaces of the Drywell Stabilizers X-58C and X-58G have been or will be performed during the current (last) inspection period of the first 10 year interval of the Containment Inspection Program for which the relief is requested.

If already performed, please indicate when and discuss the findings.Indicate schedule if it is planned to be performed.

Indicate, with schedule and results, if a Type B test was performed on the manhole penetrations of drywell stabilizers X-58C and X-58G during the current inspection interval.FPL Energy Duane Arnold Response: A General Visual Examination as required by Category E-A, Item Number E1.11 was completed satisfactorily in Refueling Outage RFO19 (2005) and RFO20 (2007).DAEC Surveillance Test Procedure STP 3.6.1.1-01, "Suppression Chamber and Drywell Visual Inspection," was used to document the examination and results. STP 3.6.1.1-01 requires a visual examination of the following areas above the 822 foot level inside the drywell:* interior of Drywell section for signs of deterioration,* shell welds and drywell head flange,* stabilizer inspection ports at 827 foot level,* visual portions of male stabilizers at 816 foot level, and* coating material on the containment, structural steel, and components.

The drywell stabilizers X-58C and X-58G were included in these inspections.

Also STP 3.6.1.1-01 requires a more detailed visual examination of the stabilizer shear lug bolting. This examination was performed satisfactorily on the bolting of all eight stabilizers in RFO1 9 (2005) and four of the stabilizers were examined in RFO20 Enclosure 1 to NG-07-0808 Page 4 of 4 (2007). The 2007 examination results do not distinguish whether X-58C or X-58G were part of the four that were examined.

It is important to note that five of the eight stabilizers have been examined under the IWE Program with no indications identified.

Each of the Drywell Stabilizer Access Ports (X-58A through X-58H) is part of the Performance Based Containment Testing Program. They are leak rate tested on a 10 year frequency with X-58C and X-58G last being leak rate tested in RFO16 (1999) and RFO19 (2005) respectively.

Both tests were found acceptable and meet the criteria under 10 CFR 50, Appendix J, Option B. The next scheduled type B test for X-58C and X-58G will be in RFO21 (2009) and RF024 (2014) respectively.

The type A test (Integrated Leak Rate Test) was last performed in RFO20 (2007)with a 95% Upper Confidence Leakage Rate of 0.3422% weight/day.

The maximum allowable leakage rate, La is 2.0% weight/day.

Enclosure 2 to NG-07-0808 Enclosure 2 Drawings 5 Pages Follow 1t

Enclosure 3 to NG-07-0808 Enclosure 3 Cooler Moving Plan 1V-CC-2A/2B 10 Pages Follow NUCLEAR MANAGEMENT COMPANY DUANE ARNOLD ENERGY CENTER DW COOLER REPLACEMENT PROJECT ENGINEERING CHANGE PACKAGE ECP 1650; INDEX ITEM NO. 7.04 COOLER MOVING PLAN IV-CC-2A/2B Prepared By: Lal Rijhsinghani Date This is document is for information only and will not be controlled for subsequent revisions.

The steps listed are conceptual based on sequences envision by the preparer.

Field may deviate from these steps to better sequence the cooler removal/instailation process.

COOLER MOVEMENT PLAN IN DRYWELL FOR 1V-CC-2AN2B PURPOSE: The purpose of this plan is to provide guidance (to the craft) for the removal of the old cooling coils and reinstallation of new cooling coils in the drywell.The intent of this plan is to safely transport cooling coils in and out of drywell without hindering refueling (outage) related activities while protecting plant system, structure and component from any damage.This plan requires involvement of quality control (QC) and project lead personnel in the process of rigging and transportation of the cooling coils and coordination of these activities with the Plant Operations department.

COOLER DETAILS: Note that the new cooers 2A/2B are of same existing design (like-for-like replacement).

Location:

-Drywell, EL. 775'-10", 191 degree Azimuth.NO. OF COILS EACH COIL SIZE WEIGHT/COIL 2 21 7/8" X 55" X 100 3/8" 3250 lb

REFERENCES:

1) BECH-M681

-DW Cooling Plans & Sections Between 775'-10 & 793'-2 2) BECH-C523

-DW Interior Floor & Framing Plan @ EL. 775'-10" 3) BECH-M339

-DW Piping Drawing Section B-B 4) BECH-C522

-DW Interior Floor & Framing Plan @ EL. 775'-41/" 5) CAL-C02-001

-Design of Lifting Lug for attachment to Drywell Shell 6) PENTALIFT Model No. 54TSLC0844 Triple Scissor Lift Table 7) AHA-4-12-12

-Adjustable Gentry Crane 8) AIRFLOAT -Model No. SS-4-17 Steel Air Skid Specification Catalog Sheets 9) AIRFLOAT Platform design sketches.10) M95-10 and 11 1V-CC-2 (A+B) Drywell Cooler drawings.PRECAUTIONS/LIMITATIONS:

1) Cooler loads in drywell are not considered critical loads.2) Slings, hoists, and beam clamps shall comply with GMP-MECH-06.

3) Lifting Lugs are qualified for 4000 lb, which include cooler load and rigging devices.4) PENTALIFT Triple Scissor Lift Table is capable of handling max load of 5000 lb.5) Maintain horizontal stability of AIRFLOAT Platform while moving coolers.6) Adjustable Gentry is capable of handling 4000 lb load.7) A project quality control (QC) inspector to verify safe load path and rigging prior to moving the coolers in the drywell.8) Project Lead to keep Operations informed of each step while moving coolers in the drywell.9) All new load-handling devices are load tested, prior to its use in the power block.INDEX ITEM PL(~~Pts=

COOLER MOVEMENT PLAN IN DRYWELL FOR 1V-CC-2A/2B OLD COOLER REMOVAL: Use following instructions for each coil 1. Remove existing "A" frame, located over the opening (between azimuth 210 and 240 degree) at 775'-10" elevation.

2. Install gantry crane over steel opening on 775 elevation near cooler.3. Remove (10) 518" bolts/washers/nuts used for mounting cooler base to the structural steel.4. Remove filter frame from A-coil.5. Remove 3/8" bolts connecting HVAC duct to A and B coils.6. Remove 318" bolts to separate A and B coils.7. Drain coolers and disconnect well water piping to coils.8. Jack up or pry up the coils. Secure coils using chokers attached to adjacent whip restraints/structural steel.9. Roll out the separated coil to the floor framing opening, between 210 and 240-degree azimuths, on 775'-10" elevation.

10. Before proceeding to next step, following requirements shall be fulfilled:

a. QC to verify Safe Load Path per attached sketch: 11. Lower coil on to 757'-6" elevation.

12. Lay down steel plate and AIR FLOAT assembly on grating at 757-6" elevation.

See attached details.13. Transport coil section to CRD build room per attached plan. Stay as close to drywell exterior wall as possible.14. Use 1 H-005A (12 Ton) hoist/monorail at North hatch to remove coil section from drywell to reactor building first floor.15. Helpers to remove coil section from reactor building for disposal using cart/truck.

INDEX ITU.1. 2 o'QIl~s Po COOLER MOVEMENT PLAN IN DRYWELL FOR 1V-CC-2A12B NEW COOLER INSTALLATION:

Use following instructions for each coil 1. Move new cooler units from warehouse to the reactor building railroad bay. Position cooler on cart/truck for transporting to the north end of reactor building equipment hatch.2. Use 1H-005A (12 Ton) hoist/monorail at North hatch to transport coil section from reactor building to drywell 3. Place coil on to AIRFLOAT Platform.

Transport coil section, along established path on 757 elevation, to area between azimuth 210 and 240 degree. Stay as close to drywell exterior wall as possible.4. Lift coil section to 775'-10" elevation.

5. Lift coil onto rollbacks and position it to its permanent position on the steel frame.NEW COOLER ASSEMBLY 1. Upon transportation of all new coil sections to the 775'-10" elevation, assemble coils per drawing M95-1 1.2. Install (10) 5/8" anchor bolts to mount cooler to the structural steel 3. Install HVAC duct to A and B coils using 3/8" bolts.4. Install well water connections to A and B coils 5. Install back interferences, if removed.1;:D" Y12 ILE; 4 Heavy Load Data Sheet.i Description of load movement (include plant location, level, and hoist): DW Cooler 1V-CC-2A/2B, located at 180 azimuth at 775 elevation, will be removed and reinstalled using gentry rated for 2 Tons @ 5:1 safety factor. The maximum weight of each coil is 3000 lbs. The load is not treated as critical load per ACP 1408.19 section 3.5 (6), (7), (8), and Attachment 3 (B), (C). With the plant in cold shutdown, the RHR system is required for the shutdown cooling.Movement of coolers the RHR piping and its components will be prohibite

, L( Crosshatched areas on attached drawings, BECH-M331, and M-332," efine safe ?Ly P.L o a d P a th .,D o p oao v tf c Ceo s- -r 9 r) -TL &.Review Performed by: Engineer or S erviso Date* If this procedure does not apply, then no further information is needed.1. Safe Load Path defined.Engineer, Supervisor, or-Signalman

1.1 Inspection

Witness Point: (Applies to heavy loads only)Verify Safe Load Path is defined.Q.C. Inspector 2. Inspection of Rigging Equipment Performed by: _____Engl-eer, Superv, or, or Signalman 2.1 Inspection Hold Point: (For critical Ii s only)Date Date Date Verify that all rigging meets the requirements of this procedure and is rigged in accordance with General Rigging Guidelin s.3 Q.C. Inspector Date Safe Load Path followed:

-'_.'_-, SupervisoK, or 'nalman Date THIS FORM SHALL BE FILED WITH THE HEAVYCADS COORDINATOR.

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THIS PAGE IS AN OVERSIZED DRAWING OR FIGURE, THAT CAN BE VIEWED AT THE RECORD TITLED: "EQUIPMENT LOCATION PLANS AT ELEVS 812? -0"& 833' -6" DRAWING NO. BECH-M004, REV. 17 WITHIN THIS PACKAGE...

OR BY SEARCHING USING THE DOCUMENT/REPORT NO.D-01 THIS PAGE IS AN OVERSIZED DRAWING OR l FIGURE, rHAT CAN BE VIEWED AT TH]RECORD TITLED: "CONTAINMENT VESSELS REQUIREMENTS DRY WELL PENETRATIONS" DRAWING NO. BECH-M041, REV. 22 WITHIN THIS PACKAGE...

OR BY SEARCHING USING THE DOCUMENT/REPORT NO.E D-02 THIS PAGE IS AN OVERSIZED DRAWING OR FIGURE, THAT CAN BE VIEWED AT THE RECORD TITLED: "DRYWELL PIPING DRAWING SECTION D-D" DRAWING NO. BECH-M341" DRAWING NO. BECH-M341, REV. 14 WITHIN THIS PACKAGE...

OR BY SEARCHING USING THE DOCUMENT/REPORT NO.D-03X