ML050740009
| ML050740009 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/08/2005 |
| From: | Vanderheyden G Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-03-009 | |
| Download: ML050740009 (18) | |
Text
George Vanderheyden Vice President Calvert Cliffs Nuclear Power Plant Constellation Generation Group, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.4455 410.495.3500 Fax I
Constellation Energy March 8, 2005 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
SUBJECT:
Document Control Desk Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-3 1 8 Supplemental Data for Request for Relaxation from Interim Inspection Requirements for Reactor Pressure Vessel Head
REFERENCES:
(a)
Letter from Mr. G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated January 14, 2005, Request for Relaxation from NRC Revised Order EA-03-009, "Issuance of First Revised NRC Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors" (b)
Letter from Mr. G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated March 4, 2005, Request for Relaxation from NRC Revised Order EA-03-009, "Issuance of First Revised NRC Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors" (c)
Letter from Mr. R. William Borchardt (NRC) to Holders of Licenses for Operating Pressurized Water Reactors, dated February 20, 2004, "Issuance of First Revised NRC Order (EA-03-009) Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors" By letters dated January 14, 2005 and March 4, 2005, (References a and b), Calvert Cliffs Nuclear Power Plant, Inc. submitted a request for relaxation from the inspection requirements of Section IV.C(5)(b)(i) of the First Revised Order EA-03-009 (Reference c). Calvert Cliffs Nuclear Power Plant completed the inspections required by Reference (c) on March 6, 2005. This letter supplements our relaxation request by providing the final results of our ultrasonic testing examination. This letter also replaces the relaxation request of Reference (b) in its entirety with Attachment (4), and affirms our desire for the staff to continue reviewing the relaxation request of Reference (a), in accordance with Section IV(F)(2) of the First Revised Order EA-03-009 (Reference c).
The final reactor pressure vessel head control element drive mechanism penetrations' ultrasonic testing examination results, including specific nozzles for which relaxation is requested, are contained in
Document Control Desk March 8, 2005 Page 2 Attachment (1). The stress levels for nozzles that did not receive the expected examination coverage are contained in Attachment (2). The disposition of specific Ultrasonic Test (UT) indications which required further evaluation are contained in Attachment (3).
Please note that this is the last high susceptibility inspection of this reactor vessel head. We continue to plan for reactor vessel head replacement on this Unit in 2007.
Calvert Cliffs Nuclear Power Plant, Inc. requests approval of this relaxation request as soon as reasonably achievable. Calvert Cliffs Unit 2 is currently scheduled to start plant heat-up March 12, 2005.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly ours, GV/MJY/bjd Attachments:
(1)
Calvert Cliffs Unit 2 (Spring 2005) Extent of UT Coverage in RPVH Nozzle Material (2)
Calvert Cliffs Unit 2 (Spring 2005) RV Head Inspection Above the Weld Stress Levels for CEDM Nozzles Without Complete Coverage (3)
Calvert Cliffs Unit 2 (Spring 2005) RV Head Inspection: Disposition of Specific Nozzles Requiring Further Evaluation (4)
Revised Supplemental Request for Relaxation of Order cc:
C. W. Fleming, Esquire R. V. Guzman, NRC S. J. Collins, NRC Resident Inspector, NRC R. I. McLean, DNR
ATTACHMENT (1)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
EXTENT OF UT COVERAGE IN RPVH NOZZLE MATERIAL Calvert Cliffs Nuclear Pow ser Plant, Inc.
March 8,2005
ATTACHMENT (1)
Calvert Cliffs Unit 2 (Spring 2005)
Extent of UT Coveraae in RPVH Nozzle Material bCoverage Bowv ede Circumferential Scan Type (Blade EndLeak Path Pn Nozzle Welde Rot Telon thel Coverage Probe I Rotating)
Exmned tof Assessment Pe nl edRo o
nte Achieved Axial Blade: A En fPossible?
Age on Uphill Downhill Side (Degrees)
Circ Blade: C Nozzle (Yes I No)
(in )
(in)*_
CEDM 1 0.0 1.70 1.00 360 C
No Yes CEDM 2 11.1
>2 0.51 360 C
No Yes CEDM 3 11.1 1.91 N/A 360 A/C Yes Yes CEDM 4 11.1 1.50 0.65 360 C
No Yes CEDM 5 11.1
>2 0.85 360 C
No Yes CEDM 6 12.0
>2 0.70 360 C
No Yes CEDM 7 12.0 1.71 0.75 360 C
No Yes CEDM 8 12.0 1.20 0.85 360 C
No Yes CEDM 9 12.0
>2 0.80 360 C
No Yes CEDM 10 22.6 1.92 0.45 360 C
No Yes CEDM 11 22.6 1.90 0.60 360 C
No Yes CEDM 12 22.6
>2 0.40 360 C
No Yes CEDM 13 22.6
>2 0.80 360 C
No Yes CEDM 14 24.1
>2 N/A 360 A
Yes Yes CEDM 15 24.1 1.90 0.50 360 C
No Yes CEDM 16 24.1
>2 0.40 360 C
No Yes CEDM 17 24.1
>2 0.45 360 C
No Yes CEDM 18 25.5 1.61 NIA 360 A
Yes Yes CEDM 19 25.5 1.50 0.70 360 C
No Yes CEDM 20 25.5 1.61 0.50 360 C
No Yes CEDM 21 25.5 1.80 0.60 360 C
No Yes CEDMI 22 25.5 1.55 0.40 360 C
No Yes CEDM 23 25.5 1.61 0.40 360 C
No Yes CEDM 24 25.5
>2 0.40 360 C
No Yes CEDM 25 25.5
>2 0.74 360 C
No Yes CEDM 26 29.3 1.81 N/A 360 A
Yes Yes CEDM 27 29.3 1.75 0.60 360 C
No Yes CEDM 28 29.3
>2 0.40 360 C
No Yes CEDM 29 29.3 1.80 0.75 360 C
No Yes CEOM 30 29.3
>2 0.45 360 C
No Yes CEDM 31 29.3
>2 0.35 360 C
No Yes CEDM 32 29.3 1.84 0.50 360 C
No Yes CEDM 33 29.3
>2 0.75 360 C
No Yes CEDM 34 34.9 1.66 0.80 360 C
No Yes CEDM 35 34.9 1.48 0.40 360 C
No Yes CEDM 36 34.9 1.61 0.85 360 A/C No Yes CEDM 37 34.9 1.79 0.85 360 C
No Yes CEDM 38 38.5 1.63 N/A 360 A
Yes Yes CEDM 39 38.5 1.30 0.45 360 C
No Yes CEDM 4o 38.5 1.30 0.40 360 C
No Yes CEDM 41 38.5 1.55 0.50 360 C
No Yes CEDM 42 38.5 1.75 0.45 360 C
No Yes CEDM 43 38.5 1.77 0.70 360 C
No Yes CEDM 44 38.5 1.27 0.65 360 C
No Yes CEDM 45 38.5 1.40 0.80 360 C
No Yes I
ATTACHMENT (1)
Calvert Cliffs Unit 2 (Spring 2005)
Extent of UT Coverage in RPVH Nozzle Material Coverage Coverage Circumferential Scan Type (Blade Leak Path Pen Nozzle Wed R elon te Coverage Probe/ Rotating)
Examined to Assemnt Pn Angle onUpld Root oe oSide Achieved Axial Blade: A En fPossible?
on__Uphill__Downhi(in)Sidn (Degrees)
Circ Blade: C Nozzle (Yes / No)
CEDM46 41.8 1.56 N/A 360 A
Yes Yes CEDM47 41.8 1.21 0.40 360 C
No Yes CEDM48 41.8 1.50 0.45 360 C
No Yes CEDM49 41.8 1.44 0.64 360 C
No Yes CEDM5o 41.8 1.58 0.60 360 C
No Yes CEDM51 41.8 1.30 0.51 360 C
No Yes CEDM52 41.8 1.60 0.63 360 C
No Yes CEDM53 41.8 1.47 0.60 360 C
No Yes CEDM54 42.5 1.60 0.55 360 C
No Yes CEDM55 42.5 1.67 0.45 360 A/C No Yes CEDM56 42.5 1.75 0.90 360 C
No Yes CEDM57 42.5 1.60 0.40 360 C
No Yes CEDM58 42.5 1.55 0.55 360 C
No Yes CEDM59 42.5 1.47 0.65 360 C
No Yes CEDM6o 42.5 1.25 1.51 360 A
No Yes CEDM61 42.5 1.60 0.50 360 C
No Yes CEDM62 42.5 1.66 0.50 360 C
No Yes CEDM 63 42.5 1.36 0.50 360 C
No Yes CEDM 64 42.5 1.35 0.50 360 C
No Yes CEDM 65 42.5 1.37 0.50 360 C
No Yes ICI 66 54.8
>2 N/A 360 Rotating Yes Yes ICI 67 54.8
>2 N/A 360 Rotating Yes Yes ICI 68 54.8
>2 N/A 360 Rotating Yes Yes ICI 69 54.8
>2 N/A 360 Rotating Yes Yes ICI 70 54.8
>2 N/A 360 Rotating Yes Yes ICI 71 54.8
>2 NIA 360 Rotating Yes Yes ICI 72 54.8
>2 N/A 360 Rotating Yes Yes ICI 73 54.8
>2 N/A 360 Rotating Yes Yes Vent-Line 0-11
>2 N/A 360 Rotating/ECT Yes N/A
- N/A indicates we made it to the end of the nozzle 2
ATTACHMENT (2)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
RV HEAD INSPECTION ABOVE THE WELD STRESS LEVELS FOR CEDM NOZZLES WITHOUT COMPLETE COVERAGE Calvert Cliffs Nuclear Power Plant, Inc.
March 8, 2005
ATTACHMENT (2)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
RV HEAD INSPECTION ABOVE THE WELD STRESS LEVELS FOR CEDM NOZZLES WITHOUT COMPLETE COVERAGE Stres Leel Aove Minimum Axial StDistancevAchieved Stress Level Above M
Athe Uphill Weld Dthe Downhill Weld Miiu Ail Root at the Axial Above Downhill Root at the Axial CEDM Nozzle Distance Achieved Ditnefr Weld Root for Distance for Nubr Age Above Uphill Weld DizlsWtanehort Nozzles with Nozzles Without NotozzlesWthou Coverage <2" Complete NumbrcAgleRoo Competae Above Uphill Weld Coverage (inches)
Coverage Root (ksi)
(ksl)
~(inches)(s) 1 0.0 1.7 ID: 2.4 1.7 ID: 2.4 1O.D170:
-3.6 17OD:
-3.6 3
11.1 1.91 ID: -1.9 2.72 0D: 2.4 OD: 31.8 OD: 2.8 4
11.1 1.5 OD: -50 2.31 0D: 0.5 OD: 25.7 OD: 3.8 7
12.0 1.71 D: -423 2.52 ID: 3.8 OD: 54.4 OD: 4.1 8
12.0 1.2 D: -3.2 2.01 D0: 4-14 OD: 63.0 OD: 10.1 10 22.6 1.92 0D: 6.0 4.27 ID 10.1 OD: 53.9 OD: 10.1 11 22.6 1.90 0:D-5.9 4.25 D: 13.6 15 24.1 1.90 ID: 5.9 4.25 0D: 3.6 OD: 63.2 OD: 9.9 18 25.5 1.61 ID: 6.2 3.96 ID: 9.9 19 25.5 1.50 ID: 6.9 3.85 ID: 9.7 OD_
_0
- -6.6 00: 2.7 20 25.5 1.61 0D: 6.2 3.96 0D: 3.2 OD: 56.5 O0:10.0 21 25.5 1.80 0D: -45 4.15 ID 10 0 OD: 64.6 OD: 9.8 22 25.5 1.55 D: -6.6 3.9 ID: 9.8 OD: 6.2 OD: 9.9 23 25.5 1.61 0D: 6.2 3.96 0D: 3.2 OD: 56.5 O0:10.0 26 29.3 1.81 ID: 5.5 4.16 D0 3.6 OD: 54.3 OD: 9.9 27 29.3 1.75 0D: -5.1 4.1 0D: 3.7 OD: -5.5 OD: 10.0 29 29.3 1.80 0D: 5.5 4.15 ID 10 0 OD: 5.75 OD:10.0 32 29.3 1.84 iD: 5.7 4.19 0D:103.6 OD: 54.9 OD: 9.9 34 34.9 1.66 ID: 5.9 4.01 D: 93.4 OD: 76.0 OD: 9.6 35 34.9 1.48 ID: 7.0 3.83 D: 92.6 OD: -6.2 OD: 9.9 36 34.9 1.61 ID: 6.2 3.96 D: 93.2 37 34.9 1.79 iD: 5.5 4.14 ID 10 0 I
ATTACHMENT (2)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
RV HEAD INSPECTION ABOVE THE WELD STRESS LEVELS FOR CEDM NOZZLES WITHOUT COMPLETE COVERAGE Stress Level Above Minimum Axial Stress Level Above the Uphill Weld Dsabove Dowhille the Downhill Weld Minimum Axial RotRootaatthAxial CEDM Nozzle Distance Achieved Root atnte Axia Weld Root for Distance for Nubr Age Above Uphill Weld DizlsWtanehort Nozzles with Nozzles Without NotozzlesWthou Coverage <2" Complete NumbrcAgleRoo Competae Above Uphill Weld Coverage (inches)
(kso )
Root Coerg (ksl)
~(inches)(k) 38 38.5 1.63 ID: 9.9 5.47 ID: 15.7 38 3.O16 D: -7.7 OD_______
0: 1.6 39 38.5 1.30 D: -10.4 5.14 ID: 2.0 ID: -10.6 ID: 16.2 40 38.5 1.30 OD: -10.4 5.14 ID: 2.0 ID: -10.1 ID: 15.8 41 38.5 1.55 iD: 10.1 5.39 ID: 15 0
OD: 98.7 OD: 15.5 42 38.5 1.75 ID: 9.7 5.59 D0:15.45 OD: 96.7 OD: 15.4 43 38.5 1.77 iD: 9.7 5.61 D: 1.4 OD: 10.7 OD: 16.2 44 38.5 1.27 ID: 10.7 5.11 0D: 2.0 OD: -10.4 ID: 16.0 45 38.5 1.40 0D: -9.6 5.24 D: 1.8 O0:109.0 OD: 15.8 46 41.8 1.56 0D: -8.3 5.40 ID: 15.8 47 41.8 1.21 ID: 10.1 5.05 ID:16.3 00: -1 1.1 00: 2.1 48 41.8 1.50 OD: -8.8 5.34 D: 1.7 49 41.8 1.44 ID: 10.3 5.28 0D0:1.8 50 41.8 1.58 0D: -8.1 5.42 ID: 15.7 OD:10.61 ID: 1.6.
51 41.8 1.30 D: -10.4 5.14 ID: 2.0 OD: 10.0 OD:15.0 52 41.8 1.60 0D: -8.0 5.44 ID: 15.7 OD: 180.
OD: 15.9 53 41.8 1.47 ID 10.3 5.31 ID: 15.9 O0:109.0 O0:15.7 54 42.5 1.60 0D: -8.0 5.44 D 15.6 ID: 98.9 O0:15.6 55 42.5 1.67 iD: 9.9 5.51 D0 :15 56 42.5 1.75 iD: 9.7 5.59 D0:15.45 57 42.5 1.60 0D: -8.0 5.44 ID: 15.7 58 42.5 1.55 0D: -8.4 5.39 D0:15.78 ID: 10.3 I10:15.9 59 42.5 1.47 00: -9.0 5.31 00: 1.8 2
ATTACHMENT (2)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
RV HEAD INSPECTION ABOVE THE WELD STRESS LEVELS FOR CEDM NOZZLES WITHOUT COMPLETE COVERAGE Stress Level Above Minimum Axial Stress Level Above the Uphill Weld Dsabove Dowhille the Downhill Weld Minimum Axial RoatteAia-AbvDwnll Root at the Axial CEDM Nozzle Distance Achieved Rootathe Axa Weld Root for Distance for Number Angle RbootUhllWl Nozzles Without Covzerag wi2" Nozzles Without RotComplete Coeae<"
Complete (inches)
Coverage Above Uphill Weld Coverage (ksi) ~
Root ki (ksl)
~(inches)(s) 60 42.5 1.25 ID 10.7 5.09 ID: 16.3 60
- 4.
.5OD:
-10.8 5.0D0:
2.0 61 42.5 1.60 ID: 10.0 5.44 ID: 15.7 61 4.51600:
-8.0 OD_______
0:
1.6 62
- 4.
.6ID:
9.9 5.0ID:
15.6 62 42.5 1.66 D: -7.5 5.50 OD 1.5 63 42.5 1.36 ID: 10.5 5.20 ID: 16.1 63
- 4.
.6OD:
-9.9 5.2D0:1.9 64 42.5 1.35 ID: 10.5 5.19 ID: 16.1 64 42.5 1.35:
-10.0 5.19OD 1.9 65
- 4.
.7ID:
10.5 5.1ID:
16.1 65 4.51370:
-9.8 5.2D0:1.9 3
ATTACHMENT (3)
CALVERT CLIFFS UNIT 2 (SPRING 2005)
RV HEAD INSPECTION: DISPOSITION OF SPECIFIC NOZZLES REQUIRING FURTHER EVALUATION Calvert Cliffs Nuclear Power Plant, Inc.
March 8, 2005
ATTACHMENT (3)
Calvert Cliffs Unit 2 (Spring 2005) RV Head Inspection:
Disposition of Specific Nozzles Requiring Further Evaluation Angular P fe CEDM No.
Indication Location Position' Orientation Length Depth PT Results Excavation PTcafter (deg)
Ecvto 8
Nozzle base material @ OD 271 Axial 0.45" 0.065" No No N/A and intersection of weld toe Indications 12 Nozzle base material @ OD 234 Axial 0.35" 0.068" No No N/A and intersection of weld toe Indications 25 Nozzle base material @ OD 265 Axial 0.35" 0.096" 3/16" YES No Indications and intersection of weld toe Rounded Indication 30 Nozzle base material @ OD 19 Axial 0.30" 0.073" 1/8" YES No Indications and intersection of weld toe Rounded Indication 32 Nozzle base material @ OD 291 Axial 0.40" 0.089" 1/16" YES No Indications and intersection of weld toe Rounded Indication 41 Nozzle base material @ OD 179 Axial 0.45" 0.107" No No N/A
-1/4" below weld toe Indications 42 Nozzle base material @ OD 337 Axial 0.45" 0.077" No No N/A and intersection of weld toe Indications 44 Nozzle base material @ OD 67 Axial 0.40" 0.055" No No N/A and intersection of weld toe Indications 58 Nozzle base material @ OD 152 Axial 0.40" 0.064" No No N/A and intersection of weld toe Indications Clockwise looking down - 0 Degrees is downhill side.
I
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER Calvert Cliffs Nuclear Power Plant, Inc.
March 8, 2005
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER RELAXATION REQUEST:
Pursuant to the procedure specified in Section IV.F (2) of Nuclear Regulatory Commission (NRC)
Revised Order EA-03-009 (Reference 1), Calvert Cliffs Nuclear Power Plant, Inc. (CCNPP) hereby submits a supplemental request for relaxation from certain inspection requirements of the Revised Order.
Specifically, the relaxation request involves a requirement in Section IV.C(5)(b)(i) of the Revised Order as described below. The relaxation requested in this letter is identical to the relaxation requested in Reference (1). The information used to justify this supplement to our original request (Reference 5) is a reprise of the justifications used for relaxation of below-thie-weld requirements on Unit I in 2004 (Reference 2, 3, and 4).
A.
Order Requirement from Which Relaxation is Requested:
We request relaxation from the requirement in Section IV.C(5)(b)(i) of the Order for ultrasonic testing of each reactor pressure vessel head penetration nozzle (i.e., nozzle base material) to the bottom of the nozzle, specifically, missed examination coverage near tile bottom end of the control element drive mechanism (CEDM) nozzles due to instrument limitation.
Reference (5) noted our expectation for examination results consistent with those obtained during the 2004 Unit I inspection, due to the use of an identical axial ultrasonic test (UT) probe design. Initial results on Unit 2 this year, using the axial UT probes, have resulted in a decision to switch to circumferential probes to ensure adequate inspection coverage of the most critical weld areas. Our results are more consistent with those obtained during the 2003 Unit 2 inspection (Reference 6) because of this change. (Note: This relaxation request applies only to CEDM nozzles. The in-core instrumentation nozzles and vent line were inspected using a rotating probe that does not have the limitations described for the blade probe.)
B.
Specific Penetration Nozzles For Which Relaxation Is Renquested:
This relaxation request applies to all CCNPP Unit 2 CEDM penetrations I through 65, except nozzles 3, 14, 18, 26, 38, and 46, each of which were successfully scanned for the full length below the nozzle with an axial probe. For the remaining CEDM nozzles, the un-interrogated area at the bottom end of the nozzles is due to the configuration of the ultrasonic transducers in the circumferential probes that are used to examine the nozzles. These probes have separate transducers for sending and receiving the ultrasonic signal.
The transducers are arranged one above the other nominally 0.86-inch apart.
With this configuration, the lower transducer will not contact the inside wall on the nozzle until the upper transducer is inserted greater than approximately 0.86-inch into the nozzle. Since the scanning process requires that both transducers be in contact with the surface, the probe cannot scan the outer portion of the bottom of the nozzle.
Based on the geometry involved in the transducer location and nozzle configuration, the portion that cannot be scanned is the portion extending from the bottom of the nozzle upward for a distance of approximately 0.56-inch.
The value is half the distance between the two transducers plus a 1/8-inch radius at the bottom corner of the nozzle. The actual volume of unobtainable coverage is triangular in cross-section. The inside diameter of the nozzle receives relatively complete coverage (with a lateral wave), while the UT angle defines a triangle hypotenuse extending from the nozzle inside diameter lower end, to a spot on the nozzle outside diameter, located approximately 0.56-inch above the bottom of the nozzle. The other legs of the triangle are the lower portion of the nozzle outside diameter and the bottom surface of the nozzle. Figure I illustrates the un-interrogated area.
I
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER FIGURE 1 Circumferential Probe Inspection Coverage I Hozzle ID Minimum inspection distance below the weld 4
-0.56 inches Missed coverage on nozzle OD C.
Justification for Relaxation Request:
Compliance with the requirements specified in the Order would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Examination of the bottom of the nozzle could be accomplished by surface examination. However, this alternative has prohibitive worker dose implications without a commensurate increase in quality or safety.
Removal of thermal guide sleeves to provide access for a rotating probe has similar dose implications that present hardship with no commensurate increase in safety or quality as described in our January 14, 2005 submittal (Reference 5).
The UT coverage area achieved provides an acceptable level of quality and safety because the un-interrogated area involves a portion of the nozzle at the very bottom, below the J-groove weld. Below the J-groove weld, the nozzle is essentially an open-ended tube and the nozzle wall in this portion is not part of the Reactor Coolant System pressure boundary. To determine the significance of an axial flaw that is contained in the non-pressure boundary nozzle material in the un-interrogated region of the nozzle, plant specific flaw growth analyses were performed. The analysis methodology for the flaw tolerance approach is in Reference (3) and is summarized as follows.
We postulated through-wall axial flaws extending from the bottom of the nozzle towards the weld to determine the maximum-length-flaws that would not grow to the bottom of the weld in a single two-year inspection interval. We performed analyses for all four penetration angles.
2
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER The analyses were performed as follows:
Single Edge Crack Model for Axial Flaws The crack is modeled as a continuous surface crack of length a in a semi-infinite body, subjected to an arbitrary stress profile.
I (K) x Stress intensity factors are determined at the crack tip using the solution, K[=1.12 a[(Ao)+A()+A, (Ž+A2
+) A 3 3
]
where the average through-wall hoop stresses in the uncracked nozzle are represented by the third-order polynomial, cy= AO +AIx+A x2X+A 3x 3 and x = distance from the bottom of the nozzle Ao, Al, A2, and A3
= third-order stress coefficients AP = crack face pressure Finite element analyses specific to Calvert Cliffs were performed to determine the operating stresses in the CEDM nozzles.
Results from this finite element model (FEM) were used to define the loading (described in References 2, 3, 4, and 7). The FEM was performed for the 42 ksi yield strength material used to fabricate the CEDM penetrations in Calvert Cliffs Unit 1. The residual stresses at the nozzle surface scale with the yield strength, therefore, the tabulated stresses would all be proportionally slightly lower for Calvert Cliffs Unit 2 CEDM penetrations, which have a yield strength of 37.5 ksi. As a result, the FEM analysis is bounding for Calvert Cliffs Unit 2.
3
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER Crack Growth Rates:
a) Primary Water Stress Corrosion Cracking Basis: MRP-55 crack growth rate for Alloy 600 material as expressed in NRC flaw evaluation guidelines, referenced to a temperature of 3250C using an activation energy of 31,000 calories/mole.
dal dt = C. (2.67 x 1 0- 2) (Y nm/sec where K, is the applied stress intensity factor in MPa'm, and where Q
= 130 kJ/mole
= 31,000 calories/mole R
= 8.314 x 103 kJ/mole-0K
=1.987 calories/mole-0 K And T
= Operating temperature in degrees Kelvin Tref = Reference temperature in degrees Kelvin At an operating temperature of 5940F, the temperature correction term is C0 = 0.566 b) Fatigue Crack Growvth Basis: Crack growth rate for Alloy 600 material in a pressurized water reactor water environment as expressed in NRC flaw evaluation guidelines.
da
= CSRSrV(AX)n dN where AK is the stress intensity factor range in terms of MPanlm and da/dN is the crack growth rate in terms of m/cycle C = 4.835xI0-'4 + 1.622x10' 6T-1.490x10'I8T2 + 4.355xI0-21 T3 SR = [ - 0.82R]-2 '
SENV = I + A[CSRAK n] m-TRI-m A =4.4x107 M =0.33 N =4.1 T =degrees C R = Kmin / Kmax TR = rise time, set at 30 sec.
Table I and Figure 2 represent the minimum area that must be inspected to satisfy the flaw tolerance evaluation. As indicated in previous Requests for Additional Information (References 3 and 4), the crack growth analysis and acceptance criteria conform to NRC provided guidelines.
4
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER Table I Maximum Growth of Bounding Axial Through-Wall Flaws Below the Weld (Bounding for all Weld Lengths)
Location Downhill Side (A)
Uphill Side (B) 00 Nozzle 0.324" 0.324" 11 0 Nozzle 0.179" 0.386" 29° Nozzle 0.191" 0.361" 430 Nozzle 0.200" 0.360" See Figure 2 below for location of the downhill and uphill sides identified in Table 1 above.
FIGURE 2 We performed UT inspection on each CEDM nozzle to the maximum achievable axial distance below the toe of the weld. The minimum inspection distance below the toe of the J-groove weld on any CEDM nozzle wvas 0.35 inches on CEDM 31 on the downhill side. This is a 29 degree nozzle, which according to the flaw tolerance evaluation must be inspected a minimum of 0.191 inches at this location. The minimum inspection distance achieved on every nozzle exceeded the minimum distances defined by the flaw tolerance approach as tabulated in Table 1.
Calvert Cliffs Nuclear Power Plant acknowledges that the crack-growth methodology used in this letter, while consistent with MRP-55, has not been formally approved by NRC. Further, if the NRC staff finds that the crack-growth formula in industry report MRP-55 is unacceptable, CCNPP shall revise its analysis 5
ATTACHMENT (4)
REVISED SUPPLEMENTAL REQUEST FOR RELAXATION OF ORDER that justifies relaxation of the First Revised Order dated February 20, 2004, within 30 days after the NRC informs us of an NRC-approved crack growth formula. If our revised analysis shows that the crack growth acceptance criteria are exceeded prior to the end of the current operating cycle, this relaxation can be rescinded and CCNPP shall, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, submit to the NRC written justification for continued operation. If the revised analysis shows that the crack growth acceptance criteria are exceeded during the subsequent operating cycle, CCNPP shall, within 30 days, submit the revised analysis for NRC review. If the revised analysis shows that the crack growth acceptance criteria are not exceeded during either the current operating cycle or the subsequent operating cycle, CCNPP shall, within 30 days submit a letter to the NRC confirming that its analyses have been revised. Any future crack growth analyses performed for this and future cycles for reactor pressure vessel head penetrations must be based on an acceptable crack growth rate formula.
CONCLUSION:
As described above, compliance with the Order requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Therefore, in accordance with the provisions of Section IV.F(2) of the Order, we request relaxation of the requirement described in Section IV.C(5)(b)(i).
REFERENCES:
(I)
Letter from R. W. Borchardt (NRC) to Holders of Licenses for Operating Pressurized Water Reactors, dated February 20, 2004, "Issuance of First Revised NRC Order (EA-03-009)
Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors" (2)
Letter from Mr. G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated January 30, 2004, Request for Relaxation from NRC Order EA-03-009, "Interim Inspection Requirements for Reactor Pressure Vessel Ileads at Pressurized Water Reactors" (3)
Letter from Mr. G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated April 13, 2004, "Response to Request for Additional Information Regarding Interim Inspection Requirements for Reactor Pressure Vessel Head (TAC No. MC1921)"
(4)
Letter from G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated April 27, 2004, "Supplemental Data for Request for Relaxation from Interim Inspection Requirements for Reactor Pressure Vessel Head (TAC No. MC1921)"
(5)
Letter from Mr. G. Vanderheyden (CCNPP) to Document Control Desk (NRC), dated January 14, 2005, Request for Relaxation from NRC Revised Order EA-03-009, "Issuance of First Revised NRC Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors" (6)
Letter from P. E. Katz (CCNPP) to Document Control Desk (NRC), dated June 3, 2003,"60 Days After Restart Report - NRC Order EA-03-009, Interim Inspection Requirement for Reactor Pressure Vessel Heads at Pressurized Water Reactors (TAC No. MB7753)
(7)
Letter from P. E. Katz (CCNPP) to Document Control Desk (NRC), dated April 9, 2003, "Supplemental Data for Request for Relaxation from Certain Inspection Requirements in NRC Order (EA-03-009) for Reactor Pressure Vessel Head Penetration Nozzles (TAC Nos. MB7752 and MB7753)"
6