ML20059A368
| ML20059A368 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/21/1993 |
| From: | Hebert J Maine Yankee |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| JRH-93-270, MN-93-120, NUDOCS 9312300136 | |
| Download: ML20059A368 (7) | |
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E MaineYankee RU55t{MfClR]diiY SINd[jM#
ED: SON DRIVE
- AUGUSTA MA!NE 04330 * {207) 02246G8 l
i December 21, 1993 MN-93-120 JRH-93-270 UNITED STATES NUCLEAR REGULATORY COMMISSION Attention:
Document Control Desk l
Washington, DC 20555
References:
(a) License No. DPR-36 (Docket No. 50-309)
(b) letten.
MYAPCo to USNRC, " Maine Yankee Inservice Inspection and Inservice Testing Programs for the Third Inspection Interval"; MN '
13, February 2, 1993.
(c) Letter:
USNRC to MYAPCo, " Request for Additional Information --
1 Maine Yankee Third 10-Year Interval Inservice Inspection Program Plan ~
(TAC No. M85887)"; October 20, 1993.
Subject:
Response to Request for Additional Information--Maine Yankee Third Interval ISI Program Gentlemen:
Enclosed is the additional information requested by' Reference (c) concerning the Maine Yankee third interval ISI-program. This program was submitted to the USNRC in Reference (b). The responses to the'NRC's questions are provided in the Attachment to this letter and are alphabetically sequenced to directly correspond with the questions asked in Reference (c).
Specific program changes resulting~ from developing these responses will be submitted to the USNRC under a different letter upon their completion. Those responses to the attached ite'ns B, C, D and F will require revision to the Maine-Yankee ISI Program and items B and F will additionally require the submittal of i
ASME code relief requests. It is expected that these program changes will be complete by June,1994, and the relief request submittals by April,1994.
1 Please contact us if you require any additional information or have any additional questions concerning the Maine Yankee ISI Program.
Very truly yours, M {.h{
~
James R. Hebert, Manager Licensing & Engina ring Support-c:
Mr. Thomas T. Martin l
Mr. E. H. Trottier i
Mr. J.. T. Yerokun
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Mr. P. J. Dostie
[n 9312300136 9312P1 PDR ADOCK 05000309 4
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ATTACHMENT MAINE YANKEE RESPONSE TO USNRC RE0 VEST FOR ADDITIONAL INFORMATION THIRD 10 YEAR INTERVAL ISI PROGRAM A.
Please find attached a list of all of Maine Yankee's current Ultrasonic l
Calibration standards including material and size. Maine Yankee's entire inventory has not been reviewed for compliance to our third interval program.
We anticipate having to make some alterations and possibly manufacturing some new blocks. Maine Yankee will not perform any exams without the appropriate calibration standard. All calibration standards to be used during our '95 Refueling will be reviewed and modified as necessary prior to use.
All 1
remaining calibration standards are scheduled to be reviewed and modified as necessary by our 1995 refueling; however, if a calibration standard (s) is i
determined not necessary until much later in the interval, its modification
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or purchase schedule may be delayed.
t B.
Maine Yankee and the USNRC held a telephone conversation relative to this issue on December 7, 1993. During that conversation it was concluded that an alternative selection of IWC-2500 category C-F-1 welds would be acceptable to both parties.
As a result of Maine Yankee's design and the ASME code allowable exclusion of examinations on piping-less than 3/8" thick in category C-F-1, nearly half of Maine Yankee's Safety Class 2 stainless steel piping welds were not included in the examination sample. This exclusion includes all of the Containment Spray System discharge pipin" and a significant portion of the Low Pressure Safety Injection System discharge piping. Because of the safety danificance of these systems, an alternative to the code allowable exclusion of this piping from the examination sample was proposed. This alternative is the l
selection of the required 7.5% sample from the entire Safety Class 2 weld population on a prorated basis for those welds under the 3/8" thickness limit. Alternately, Maine Yankee's program specified selecting the 7.5%
sample completely from the equal to or greater than 3/8" thick piping. With either case, however, the number of welds examined by the program in this category has not changed. The code requirements associated with the thicker 1
piping will be reviewed to determine if they may be applied to the thinner piping.
-i Pursuant with the requirements of 10 CFR 50.55a(a)(3), Maine Yankee will propose this alternative via an ASME code relief request.
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Page 2 of 6 C '.
During the same telephone conversation discus:.ed in "B" above, the topic of-i request C was also discussed. As supported by ASME Interpretation X1-1 '
33, it was concluded that Maine Yankee had improperly included six 3
pressurizer nozzle-to-safe end dissimilar metal welds'in both categories B-F and B-J. Therefore, Maine Yankee should remove them from category B-J and the
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corresponding B-J 25% sample size calculation.
It was also concluded that j
the remaining piping dissimilar metal welds were appropriately categorized in both categories B-F and B-J.
Maine Yankee will remove the six pressurizer nozzle dissimilar metal welds from category B-J and re-perform the category sample size calculation to determine the additional welds required to be selected.
D.
With respect to examinations of the reactor vessel heads, Table IWB-2500-1 of ASME Section XI, 1986 Edition is not completely clear as to whether one circumferential (Item B1.21) and one meridional (Item Bl.22) weld from both the lower and upper Reactor Pressure Vessel heads are required or just one of each item from either head. Maine Yankee believes that the latter interpetation is correct; however, Maine Yankee also recognizes that a l
different interpetation may exist.
We will therefore update the ISI program to reflect appropriate examinations on both heads. Maine Yankee will also pursue an interpretation from'the ASME-Section XI Committee on this issue.
If the ASME response agrees with Maine Yankee's interpetation,-then an ISI program change will be facilitated and submitted the USNRC.
If the ASME response requires exams on both heads, then J
it is likely that Maine Yankee will submit an ASME code relief request to'
- i preclude performing exams on the upper head. This request.will be based on both ALARA considerations and the unavailability of remote technologies.
i E.
Maine Yankee is currently involved with three other utilities and EPRI in
'j evaluating currently available technologies to effectively and consistently detect flaws in cast stainless. steel. The initial investigations are'
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complete; however, the conclusions have not yet been documented. The technologies evaluated were both manual and automated.
IntraSpect, Zipscan l
l (T0FD), Acusonex, P-Scan, SAFT-UT, Testpro, ALARA-II and the PC-based NDE workstation with VIPER software consisted of the automated technologies evaluated. The results and conclusions are in the process of being reviewed 4
and should be published by 1st quarter in 1994.
Maine Yankee does not intend to attempt these types of uncertain examinations in the field due to high area radiation fields and the excessive likelihood of false calls. Maine Yankee, with EPRI, will continue to investigate the industry claims to be able to consistently detect flaws in cast stainless steel. However, Maine Yankee will not implement any technology until it has been adequately proven under field conditions.
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Page 3 of 6 l
F' The NRC has requested Maine Yankee to confirm that the plant will comply with IAW-5250 (a)(2), which requires the removal of pressure-retaining bolting if leakage is observed to occur. Maine Yankee has submitted Felief Request.#9 as part of Reference (b), which would allow Maine Yankee's Plant Engineering r
Department to evaluate and determine the appropriate alternative corrective i
action to leakage on a case-by-case ba Ws. Maine Yankee does not believe that a generic ASME code requirement for the removal of bolting is reasonable and will certainly cause an undue hardship to the plant without a compensating increase in the level of quality or safety. There are many plausible scenarios which do not warrant removing a system or subsystem from service or potentially shutting down the plant in order to remove bolting that has not been degraded by a leak. The existence of a leak by itself does i
not justify the use of such potentially extreme measures. There are many other factors that must be considered in order to make a responsible and i
timely decision. It has been Maine Yankee's experience that factors such as:
location of the leak in the plant or system, time in the plant's cycle, leaking medium, materials exposed to leak (not just bolting), Technical Specification limitations, ability to monitor or isolate the leak, ability to redirect or capture the leak, may be important in assessing leakage through pressure-retaining bolted connections.
i Maine Yankee agrees that if insulation is not removed from pressure-retaining bolting at the time of the pressure test and VT-2 examination, then the system will be held at test pressure for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> regardless of IWA-5213 requirements. Maine Yankee reserves the option to remove the insulation for the pressure test and VT-2 examination while maintaining the holding time in accordance with IWA-5213.
1 Maine Yankee will also update Relief Request #8 to include a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> hold requirement consistent with the above discussion and Relief Request #9 to provide additional justification to preclude the generic requirement of IAW-5250(a)(2).
G.
Other than those defined in response to this-NRC request for information, Maine Yankee is not aware of any additional relief requests at this time.
However, 10 CFR 50.55a(g)(5)(iv) allows relief requests to be submitted up to i
12 months after the expiration of the 120 month interval that the examination j
is determined to be impractical.
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.i Page 4 of'6 ULTRASONIC CALIBRATION STANDARDS BLOCK INDEX CAL' BASE CLADDING SIZE ~
THICKNESS BLOCK MATERIAL MATERIAL l
TB-1 A312 N/A 2.50" NOM.
0.375" r
TYPE 316 PIPING SCH. 160 l
TB-2*
A376 N/A 4.00" NOM.
0.531" TYPE 316 PIPING SCH. 160 TB-3 A312 N/A 10.00" NOM.
1.265" TYPE 316 PIPING j
TB-4 A312 N/A 12.00" NOM.
1.318" j
TYPE 316 PIPING SCH. 160 TB-5 A540 N/A RPV NUT 7%"
l GR B-23 7" DIA.
TB-6 AS40 N/A RPV STUD N/A GR B-24 7" DIA.
TB-7 A194 N/A RCP NUT 4.75" CLASS 2H 4%"-8un-2B TB-8 AS40 N/A RCP STUD N/A GR. B-23 4.75" DIA.
TB-9 A106 N/A 6.00" NOM.
0.436" GR. B PIPING SCH. 80 TB-10 A106 N/A 4.00" NOM.
0.337 GR. B PIPING SCH. 80 TB-11*
A516 A264 S.S.
33.50" NOM.
3.50" GR. 70 PIPING' l
TB-12*
A515 N/A 30.00" NOM.
1.00" GR. 70 PIPING TB-13 A106 N/A 18" NOM.
0.75" GR. B PIPING SCH. 60 TB-14*
A106 N/A 14" NOM.
0.75" GR. B PIPING SCH. 80 l
TB-15*
A508 E309/308L VESSEL 5.875" CLASS 2 S.S.
BLOCK TB-16 A533 E309/308L VESSEL 7.25" GR. B S.S.
BLOCK i
TB-17*
A533 E309/308L VESSEL
-4.50" GR. B S.S.
BLOCK TB-18*
A451 N/A VESSEL 3.375" TYPE CPF8M BLOCK TB-19 A508 E309/308L VESSEL 12.00" CLASS 2 S.S.
BLOCK 3
TB-20*
A508 E309/308L VESSEL 9.00" CLASS 2 S.S.
BLOCK
- lhird Interval Review Complete i
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- p Page 5 of 6 ULTRASONIC CALIBRATION-STANDARDS BLOCK INDEX
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CAL BASE CLADDING SIZE THICKNESS hs BLOCK MAT'L.
MAT'L.
TB-21*
A508 E309/308L 14" DIA.
1.25"
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CLASS 2 S.S.
PIPING 1B-22 A508 E309/308L 6" DIA.
1.50" I
CLASS 2 S.S.
PIPING TB-23*
A508 E309/308L 3.5" DIA.
0.75" l
CLASS 2 S.S.
PIPING
-i TB-24 A351 N/A 14" DIA.
1.50" l
TYPE CF8M PIPING TB-25 A182 N/A 6" DIA.
1.50" TYPE 316 PIPING TB-26 A182 N/A 3.50" DIA.
0.75" TYPE 316 PIPING TB-27*
A451 N/A 14.00" DIA.
1.50" TYPE CPF8M PIPING i
TB-28 A312 N/A 6.00" NOM.
0.280"
.I TYPE 304 PIPING SCH. 40
.t TB-29*
A312 N/A 12.00" NOM.
0.406" TYPE 304 PIPING SCH. 40 TB-30 A358 N/A 10.00" NOM.
0.365" j
TYPE 316 PIPING SCH. 40'
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TB-31 A358 N/A 10.00" NOM.
1.0625
~l TYPE 316 PIPING TB-32 A358 N/A 16.00" NOM.
0.375" TYPE 304 PIPING SCH. 30 TB-33 A106 N/A 4.00" NOM.
0.337" GR. B PIPING SCH. 80 j
TB-34 A106 N/A 3.00" NOM.
0.216" GR. B PIPING SCH. 40 TB-35 A508 E309/308L VESSEL 11.00" CLASS 2 S.S.
BLOCK TB-36 A376 N/A 14.00" NOM.
1.406" TYPE 316 PIPING SCH. 160 TB-37 A312 N/A 3.00" NOM.
0.437" TYPE 316 PIPING SCH. 160 TB-38*
A312 N/A 10.00" NOM.
1.125" i
TYPE 316 PIPING SCH. 160 TB-39 A312 N/A 12.00" NOM.
1.312" TYPE 316 PIPING SCH. 160 i
18-40 A312 N/A 3.00" NOM.
0.120" TYPE 304 PIPING SCH. 10S i
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- Third Interval Review Complete
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Page 6;of 6 l
ULTRASONIC CALIBRATION STANDARDS BLOCK INDEX
-CAL
' BASE CLADDING SIZE THICKNESS BLOCK MAT'L.
MAT'L.
1B-41 A312 N/A 4.00" NOM.
0.237"-
TYPE 304 PIPING SCH. 40 TB-42 A312 N/A 3.00" NOM.
0.216" TYPE 316 PIPING SCH. 40 TB-43 A312 N/A 4.00" NOM.
0.531' TYPE 304 PIPING SCH. 160 TB-44 A312 N/A 6.00" NOM, 0.718" TYPE 316 PIPING SCH. 160 TB-45 A312 N/A 8.00" NOM.
0.322" TYPE 304 PIPING SCH. 40 TB-46 A312 N/A 14.00" NOM.
0.375"
'l TYPE 304 PIPING SCH. 30 i
TB-47*
A312 N/A 16.00" NOM.
0.500" TYPE 304 PIPING SCH. 40 TB-48 A312 N/A 18.00" NOM.
0.375" TYPE 304 PIPING STD. WT.
l TB-49 A312 N/A 10.00" NOM.
0.365" TYPE 304 PIPING SCH. 40 TB-50*
A312 N/A 14.00" NOM.
0.438"-
TYPE 304 PIPING SCH. 40 TB-51 A533 E309/308L VESSEL 9.00" GR. B S.S.
BLOCK TB-52 A533 A240 VESSEL 11.062" GR. 8 TYPE 304 BLOCK TB-53 A515 A240 VESSEL 1.375" i
GR. 70 TYPE 304 BLOCK TB-54 A182 N/A 8.00" NOM.
0.906" TYPE 304 PIPING SCH. 160 18-55 A533 N/A VESSEL 3.50" i
GR. B BLOCK r
1 18-56 ASIS N/A 30.00" DIA.
1.00" GR. 70 PIPING TB-57 A516 A264 S.S.
33.50" DIA.
3.50" GR. 70 PIPING TB-58*
A358 N/A 14.00" NOM.
0.?75" TYPE 304 PIPING SCH. 30 TB-59*
A358 N/A 18.00" DIA.
0.375" TYPE 304 PIPING STD. WT.
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- Third Interval Review Complete I
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