ML20137V446

Responds to Which Commented on from Nrc.Ltr Provided Addl Clarification Re Concerns on Info Contained in Insp Repts

ML20137V446
Person / Time
Site:	Millstone, Haddam Neck  File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	11/26/1996
From:	Vito D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Stankoski J AFFILIATION NOT ASSIGNED
Shared Package
ML20137V413	List: ML20137V405 ML20137V428 ML20137V446
References
NUDOCS 9704170302
Download: ML20137V446 (7)

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uMTED STATES NUCLEAR REGULATORY COMMISSION e, REGloN 1 i 475 ALLENoALE RoAo

• • • • • KING oF PRusslA, PsNNsYLVANIA 1:40s 141s )

i ' November 26, 1996 Mr. Joseph M. Stankoski 895 Mount Vernon Road

Southington, CT 06489

REFERENCE:

YOUR LETTER TO THE NRC DATED JULY 24,1998

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Subject:

CONCERNS YOU RAISED TO THE NRC REGARDING MIL NECK

Dear Mr. Stankoski:

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! This letter is in response to your letter dated July 24,1996, which commented on ou t letter of July 9,1996. Your letter provided additional clarifications regarding your I concerns and made observations on information contained in our inspection reports .

} provided to you. We apologize if you feel our initial response did not completely i your concerns and we offer the following additionalinformation.

4 1ssue 1 t' i

i The NRC letter dated July 9,1996 stated that NRC Inspection Reports 50-423/85-2 '

! 50-423/8314 addressed your concerns about the 2T hole in the penetrameter n

) discernable for Millstone 3 primary piping welds. You noted however, that page 5 of ll

inspection Report 50-423/83-14 stated that the radiographs submitted by Tubeco of th

! centrifugally cast pipe going from the Millstone 3 reactor vessel to the steam generators 3

and back were not acceptable. You further stated that NRC Inspection Report 50 423/

22 did not address your concerns about Millstone 3 radiographs, 5 Resoonig 1 -

j 4 Your otiginal concern indicated that there was a problem with radiographs represent j primary piping welds. The problem you identified was the inability to discern the 2T penetrameter hole image on the radiographs.

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4 The NRC mobile nondestructive examination (NDE) laboratory was staffed with personne

{ qualified to the American Society for Nondestructive Testing (ASNT) requirements, which j are used by the nuclear industry and mandated by the Code of Federal Regulations. The i

NDE team was headed by a certified ASNT Level til supervisor and 2 Level 11 technician i

They were highly experienced professionals and inspected nuclear power facilities all over i the United States for the NRC. In inspection Report 50-423/83-14,Section 4, the repor discussed the inspection of Tubeco, incorporated radiographs, the subject of your concern The inspectors examined 130 radiographs for radiographic technique, which included the

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( ability to see the required penetrameter hole image. The inspectors did not identify any

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i difficulty in being able to see the rea .:! red penetrameter hole image. However, the NRC issued a violation for improper placement of the penetrameter in the area of interest and for I l film that exceeded the density limits. The followup inspection, inspection Report 50- I 423/85 22, page 8, Section 4, also noted poor film quality. In response to the earlier NDE ,

laboratory findings, the licensee performed a 100% film review of Tubeco shop welds.  !

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The licenses performed between 600 -700 weld re-radiographs due to film quality problems. These corrective actions supported your observation that there were problems j with Tubeco radiographs; however, our NDE laboratory identified similar problems at the

4 same time that you were employed by NUSCO, and verified that proper actions were

taken. This violation was closed in Inspection Report 50-423/85-69.

J l j lasue # 2 j

The NRC letter dated July 9,1996, stated that NRC Inspection Repc,rt 50-423/91-05 addressed your concerns about the UT examination of Millstone 3 reactor coolant piping  !

l welds. You stated that this report, reference page 4, discussed indications in the Millstone i j 3 pressurizer spray line and RHR line missed by liquid penetrant examinations. You also j cited page 10 of NRC inspection Report 50-423/85 22,which indicatsd that the UT J

examinations of Millstone 3 cast piping was not acceptable.

Resoonse '

j Westinghouse-designed nuclear steam supply systems use contrifugally cast stainless steel (CCSS) for the primary loop piping for the reactor coolant system. CCSS was chosen l because of its unique metallurgical properties in this environment. The ASME Code requires inservice inspection (ISI) of ASME Class 1 and 2 components; the preferred volumetric examination for ISI is ultrasonic (UT) examination. UT is preferred because the l primary loops do not have to be emptied of water to perform the examination. However, i j CCSS introduces a different obstacle for UT because the grain size of CCSS is large. The  !

large grains cause the ultrasonic sound to attenuate and/or divert from the intended angle  ;

i of inspection,

' j The NRC has recognized the difficulty in performing UT on CCSS. For the past ten years -

the NRC has funded research on performing UT on CCSS and developing new inspection techniques. Many round robin testing sessions have been conducted on performing UT on

' CCSS. These round robin sessions have been sponsored.by the Westinghouse Owners Group (WOG) and utilities as well as the NRC. The NRC also performed an independent i

evaluation of the manual UT techniques and equipment available to the industry. The i r I

results of the independent evaluation are due to be published. Considering the low failure '

! rate of this material, the ASME Code Committee for Section XIis currently reviewing the need to ever perform UT on CCSS. The Code Committee is drafting a Code Case that i j would allow utilities to defer the inspection for long periods of time.

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Mr. J. M. Stankoski 3 lasue # 3 h,

i The NRC letter dated July 9,1996, stated that storage of actual radiographs is not

required by the ASME Code. You stated that Northeast Utilities radiographic procedure NU-RT-1 and their Quality Assurance Program require storage of radiographs in accordan

. with the ANSI standards and that the NRC approved these. documents.

j Response I The storage of the actual radiographs is not an ASME Code requirement. The NRC will i review the current licensing basis for Millstone 3 for commitments on radiograph storage.

This review will be part of a future NRC QA/ISI inspection.

Issue # 4 The NRC letter dated July 9,1996, stated that there was never any intention that the i

baseline UT examination of the Millstone 2 reactor pressure vessel (RPV) be repeatable.  !

You stated that Section XI of the ASME Code requires that all UT examinations and calibrations shall be repeatable, and that is why Section XI requires calibration blocks. You also stated that the new UT examination of the Millstone 2 RPV requires the entire core of l the vessel to be removed.

Resoonse it is standard operating procedure to fully offload the core of a pressurized water reactor prior to performing RPV UT examinations.

UT of the RPV is required by the ASME Code,Section XI. The ISI UT is performed to '

identify service induced flaws. If flaws are identified, the flaws are tracked and trended from one inspection to the next. The initialinspection of the Millstone 2 RPV was to identify fabrication flaws prior to start up; not service induced flaws.

1 The calibration blocks used for the RPV UT are to calibrate the UT instruments. The calibration of the UT instruments is to set the examination parameters, or bounds, of the initlei examination. During the examination, the calibration is checked to verify the examination parameters have not drifted out-of bounds. The final calibration is a verification the parameters remained within bounds throughout the examination. Each UT l examination requires a separate calibration of the UT instruments. The settings of the instruments may vary from instrument-to-instrument, but the examination sensitivity should be the same.

l The results of the examinations are then compared from examination to examination to identify unknown flaws. The results are the report of flaws or unflawed areas. It is not necessary for the calibration of one instrument, used during one examination, be repeated during the subsequent examination with a different instrument it is however a j

t requirement that the results of the examinations be repeatable. This process is assured by using the same set of calibration blocks from one examination to another; a process that has been successfully implemented at Millstone, s 1

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i e Mr. J. M. Stankoski 4 You stated that NRC Inspection Report 50-245/96-01 made no mention of the Millstone 1 UT standards used to inspect the Millstone 1 RPV welds. You feel that the NRC should be l very concerned that most of the Millstone 1 reactor welds cannot be examined according i

to the ASME Code because they are not accessible.

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Response v l (Il l(a l

9b 6 The UT of the Millstone 1 RPV was performed earlier this year. The licensee has submitted a request for relief from the ASME Code requirements on accessibility of the RPV welds.

l The calibration blocks used for the RPV UT met the requirements of the ASME Code. The i

calibration of the UT was in accordance with the ASME Code,Section XI, Appendix 11. I

! The nozzle welds were not performed during the NRC inspection of the Millstone 1 RPV i inspection, j

l The NRC perfor,med an inspection of the RPV UT examination. No concerns or violations were identified. l Regarding the issue of the UT standards used to inspect the Haddam Neck reactor vessel nozzle welds, safe ends, and primary coolant piping welds, we asked you in cur July 9, ,

1996 letter to supply specific information to demonstrate that the standards did not I comply with ASME Section XI within 30 days (mid-August 1996). In your letter dated July l 24,1996, you stated that you would provide this information at a later date. As of the date of this letter, we have not received any additional information to support your concem regarding Haddam Neck. Therefore, we plan no further action at this time.

Thank you for informing us of your concerns. We feel that our actions in this matter have

, been responsive to those concerns. Should you have any questions, or if I can be of l further assistance in these matters, please call me via the NRC Safety Hotline at 1-800-695 7403. .

1

, Sincerely, David J. V o Senior Allegation Coordinator Docket Nos. 50 245 50-336 50-423 50-213 1 Filo No. RI-96-A-0055 g

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