ML19354D207

Addresses Concerns Raised & Supplies Requested Info Re 890411 Ltr from Ln Olshan & to He Bliss.Ltr Provided SER for Unit 1 Inservice Insp Program & Contained Several Denied Relief Requests

ML19354D207
Person / Time
Site:	Byron
Issue date:	07/11/1989
From:	Chrzanowski R COMMONWEALTH EDISON CO.
To:	Murley T Office of Nuclear Reactor Regulation
References
NUDOCS 8907200278
Download: ML19354D207 (11)

Text

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Commonnealth Edison

' 72 West Acams Sveet. C%r y ,. enos Ao3'ess Reply to PoEFce 5~o7767~

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CNeago, HLas 60690 0767 July sti,,r1989-r*

i Dr. Thomas E. Murley, Director Of fice of Nuclear Reactor Regulation U. S. Regulatory Commission

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Washinjten, DC 20555 Subject Byron Station Unit 1 Inservice Inspection Program j NRC Docket No. 50-4$i Referencet April 11, 1989, letter f rom L. N. Olshan to H. E. Bliss Dear Dr. Murleyt The referenced letter provided the Safety tvaluation Report for the Byron Station Unit 1 Inservice Inspection Program. The letter contained several relief requests that were denied. On May 11, 1989, a teleconference was held between Commonwealth Edison and members of your staff to discuss the denied relief requests. This letter addresses the concerns that were raised and supplies the requested information.

The specific concerns and the Commonwealth Edison responses are itemised below.

tiRC Concernt The licensee's application of exemption criteria to the Containment Heat Removal.

System (CHRS).

Commonwealth Edison Resnonagl Commonwealth Edison interprets CHRS to mean the Containment Spray (CS) system (as confirmed in the May 11, 1989 conference call). A 7.51 augmented volumetric examination sample of class 2 welds from the CS pump to the first weld beyond the containment isolation valve is now in the ISI Program and esaminations were performed. This is the NRC recommended examination. Therefore, we believe this concern is satisfied.

. NRC concerns ~

The esemption from esamination of two integral attachment welds E-1-1 and E-1-2 on pipe line 1TW87CB-6".

Commonwealth Edison 2 The NRC letter and supporting attachments state that these integral attachment welds penetrate the pipe pressure boundary. The welds do NOT penetrate the pipe pressure boundary (see Attachment A). The integral attachment welds were made, inspected, and accepted por ASME Section III. Since a component support was never attached to this integral a*.tachment, it was never inservice. Therefore, these welds do not fall under the requirements of ASME Section XI, Table IWC-2500-1.

Category C-C, Item C3.20, per Note (1)(b). Also, ASME Section XI Code Interpretation 80-03 confirms this conclusion. Commonwealth Edison believes this exemption is justified.

occ. 05C O g ..

Dr. T.E. Murloy July 11, 1989 I URC.Concernt '

Insuf ficient justification for Relief Request NR-3, Pressuriser and Steam Generator inner radil ultrasonic examination.  ;

, Comc.nnalth Edissat }

Relief Request NR-3 has been removed from the ISI Program. Commonwealth Edison '

will continue to evaluate the feasibility of performing the examination. '

l 5RC_Conct1RL Insufficient justification for the Residual Heat Removal heat enchanger nossle  ;

Anner radil in liellef Request NR-12.

Conanonwenith Edlaon Responatl The revised Relief Request NR-12 is contained in Attachment B. The attachinent includes a picture of the reinforcement pad obstruction welded on the nossle inner radli. The reinforcement pad makes ultrasonic esamination of the inner radil Ampossible. Commonwealth Edison requests that the NRC review the updated information and grant Relief Request NR-12.

HRC Concernt O Insufficient justification for Rellef Request CR-2, Support Examination Boundarles for Non-onempt Supports on Insulated lines.

Cggponwealth Edlaen RegggAstl Compcnent Support Examination Relief Request CR-2 was removed from the ISI Program. 7 NRC ConegInt '

Insufficient justification for Relief Request SR-1, Support Examination Boundarles

• for Non-enempt Safety-Related Snubbers.

Com03)nal.th_ Edison Reanons31 As was discussed in the May 11, 1989, conference call, Snubber Examination Relief i Request SR-1 has been revised as described in Attachment C. The previous Snubber Examination Relief Request SR-1 has been removed from the ISI Program and will not be implemented until NRC approval is received. Commonealth Edison believes that the revised relief requests contains the requested information and that the relief p request is justified. The exact number of supports partially covered by insulation f I will be identified during the next scheduled snubber visual examination on each unit.

Utillaing the information contained in this letter and the attachments, l_ Corponwealth Edison requests reconsideration of the above mentioned tellef requests.

~

Please direct any further questions on this matter to this of fice.

I Very truly yours, M

R.A. C reanows i '

Nuclear Li nsing Administrator i

cca Resident Inspector-Byrtu l L.N. Olshan-NRR Region III Office Office of Nuclear racility Safety-IDNS

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1 ATTACBElrf S. Pg 1 of 5 Rev. 2 I

RELIEF R30UMT Nut-12 1.

5757 5 : Reactor Coolant (Steam Generator, Secondary Side): Residual i

' Heat Removal (Residual Heat Removal Heat Exchanger) ,

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Ceasenest Number Ites lhanber

! 1RC-01-th Attachment Ilyshers  !

i S3f-02, 33f-03 1&2 2RC-01-th 331-02, 33f-03

! 121-02-A8 1000f-01, West-02 1&2 3 l' l j 2NI-02-At 500f-41, 2001-02 i 3  ;

3. ABS CODE QAss: 2

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ARE C415 SElTIGI XI HENIRENTRI subsectica DIC, Table IWC-2500-1, i

a w a= ties Category C-8, Item C2.22 repires vehaustric  !

i the regians described in Figure IWC-2900-4(a) or (b), for nossle lasse-

===h*8= ef , ,,

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i radii in nossles without reinforclay plate in vessels ) 1/2 in. assimak ,

thicknees.  !

Item C2.32 repires surface and volumetric esamiastian of:

l the regione described in Figure DIC-2500-4(c) for nossles with j

Reinforcing plate in vessels > 1/2 idah amataal thiolunass.

Esaminations shall be conducted on noesles at-terminal ends of pipiap- l

runs selected for esamination under Essaimatica Category C-F. emelr i

inspection interval. In addition, Esamiestion Category C-N, Item C7.10 i requires a system leakage test, (INC-5221) each inspection period for pressure vessel pressure retalaims sempements.

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5. th818 M S IlE.IEP The nossles listed abspe oestein laherent gesestris . : '.C

( y constraints which limit the ability to periors meaniayful ultrasemis- ' " " '

esaminations. The main steam nossle tS S-43)iwas designed with an.

internal multiple venturi type flow restrictor with an equivalent thuent .

diameter of 16 in., see Attachment 1. This design is used to limit the ,

flow in the event of a postulated wteam line break. This design does ast ,

utilise a radiused nossle as described in figures INC-2500-4(a) or INC-2500-4(b), but instead has seven individual: inner radii, i I corresponding to each venturi. None of which could be esamined by l- ultrasonic esamination. The asin feeduster nossle (33f-02) also has an '

internal saltiple venturi type flow restrictor, and, in addition, an internal thornal sleeve, see Attachment 2. This design could not be emanined due to the geometry of the nossle's internal design. The Residual Heat Removal Heat Eschanger is approziantely 7/8 is, nestaal well thickness with nossles of 14 inch diameter and approsiastely 3/8 inch in nominal well thickness. Attachment 3 shows the actual nossie-to-ohell weld configuration for the Residual Heat Removal Heat Exchangers primary side nossles. This configuration is best '

characterised as a fillet welded nossle, which is most closely.

approzianted by Figure IWC-2500-4(c), and, thereby, is not analogous to .

a full penetration butt welded nossle. The esamination rsquirement associated with this figure, with the inside of the vessel . ,

inaccessible, is a surface ~esamination of the nossle-to-shell weld. In addition,- the inner radius of the reinforcement pad would be

! representative of the nossle inner radius required for inspection. The inherent geometric constraints of the nnssle design prevent the performance of the required ultra .

osaminations of the

• nossle-to-shell weld and the nossle 'll r radius.

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AL M TEST MFfMODt- Visual examination (V!-1) shall be performed .

j either directly or remotely to the extent practical when disassembly is i~

> required for maintenance purposes not to escoed once per inspection

, t intervm1. In addition, visual: examination (VT-2) shall be performed

! each inspection period on all prs 3sure retaining components.

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7.

JUBTIFKhTIW: The VF-1 esamination will assure early detection of.

detrimental flaws. Therefore, in performing the proposed alternative esaminations during disassembly for r.sintenance, an adequate level of structural. integrity can be assured for continued plant operation. ,

anoth This relief will be required for the first 120 C

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-. ' s ATTACHMENT C Relief Raouest SR-1 g

1. SYSTEM: ALL (Nonexempt positions)

2. NUMBER Or ITEMS: All ASME Codes Class 1, 2, and 3 snubbers with insuleted nonintegral attachments.

3. ASME CODE CLASS: 1, 2, and 3

4. ASME SECTION_XI CODE REQUIREMENT: The component support examination boundaries-are defined by IWF-1300 and Figure INT-1300-1. The IWF support exam boundary' for snubbers, which have nonintegral attachments, extends from the contact surface between the component and the support to the surface of the building structure.

5. BASIS FOR RELIEF: The visual exaninetion of the nonintegral support attachment

• to the component is limited due to the presence of insulation on the-component.- It is impractical to remove insulation from components solely for

,,, the purpose of performing a visual examination on the portion of the.

nonintegral attachment within the insulation. In additics to ASME Section XI

[g requirements, snubbers are visually examined and functionally tested in-accordance with Technical Specification requirements, which exceed.the ASME-Section XI requirements in both scope and frequency.

The total snubber visual radiation dose received through the Byron Unit 1 second refuel and Unit 2 first refuel outages is 7.7 manrem from approximately 3370 snubber exams. The combined dose rate average-for.the most recent refuel outages on both units was 0.0038 manrem per snubber visual inspection.. If the insulation were to be removed and reinstalled, the total dose for the exam would be expected to increase by a factor of three. This takes into account the-additional personnel involvement for insulation removal / reinstallation and ,

radiation protection. Past experience has-shown that the dose' received per ' '

anubber exam will increase over time as the plant ages and general area dose rates increese.

Removal of insulation would pose substantial ALARA concerns for plant employes t

~~s without providing a significant increase in system reliability or safety.

\ 6.

ALTERNATE TEST METHOD: The visual examination _("t-3/4) will be limited at the pressure retaining component boundary, to the visually accessible positions of the nonintegral attachment. Fenetrations of the component insulation at the nonintegral attachment allow for a limited examination of the attachment to the

• pressure retaining component. In general, the component support boundary will

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extend from the surface of the insulation and. include essentially 100% of the component support.

Evidence of nonintegral attachment indications beneath the insulation will be:

identified by the visual examiner es:- misalignment between the snubber and its nonintegral attachment, crushed insulation, dented insulation, boric acid on the exterior of-the insulation, nonintegral attachment discrepancies on

- adjacent supports'or any other abnormal conditions.

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When the insulation has been removed for other NDE methods which coincide with the performance of the visual examination, the examination will include 100%1of the nonintegral attachment. l l

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t i,e Attachment C  !

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7. JJISTIE1CATIQi In addition to ASME Section XI requirements, snubbers are }

visually examined in accordance with Technical Specification requirements. All '

ASME Code Class 1, 2, and 3 snubbers and snubbers which are "important to ~j

safety" are visually examined at a minimum frequency of once per 18 months. l This_ frequency increases if any snubbers are found to be inoperable. This I

l frequency is substantially higher than the once per interval (10 years) l

[ examination required by ASME Section XI.

l l The Technical Specification visual / functional snubber population is }

approximately 600.- This includes approximately 515 ASME Code Class 1, 2, and L

j' 3 snubbers plus an additional 85 snubbers which are "important to safety" for  !

Technical Specification purposes. These 85 anubbers increase by 16% the snubbers population which is required to be visually _ examined per ASME'Section ,

XI. >

l The Technical Specification snubber population is functionally tested in accordance with Technical Specification requirements. .To functionally test these snubbers, they are unpinned from the compbnent at the nonintegral.

attachment. The functional test demonstrates operability of the snubber and g provides another opportunity to identify any nonintegral attachment indications.

The nonintegral attachment between a snubber and its component consists.of a pipe clamp and bolting material. Indications beneath the' insulation will be identified ast misalignment between the snubber and its nonintegral attachment, crushed insulation, dented insulation, boric acid on the exterior

• of the'inculation, nonintegral attachment discrepancies on adjacent supports or any other abnormal conditions.

Portions of these systems;are noninsulated and therefore allow a visual examination of the entire: attachment portion. The support attachments and installation procedures used on the noninsulated components are essentially.-the same as those used on insulated components. Therefore, the examinations of the noninsulated ' components provide an adequate means of- identifying problems with a particular type cf attachment or installation procedure. Since the visual examination is a general examination of structual and mechanical integrity, ' the examinations performed on the noninsulated components and the limited examinations performed on the insulated components, along with a check of the-

[ \ insulation, provide'an adequate indication of the structural and mechanical

( ,, / integrity of the nonintegral attachments.

I The above visual examination methodology ensures that a high degree of system safety and reliability is maintained while providing substantial ALARA benefits to plant employes.

?

8. AEPLICABLE TIME PERIOD: This request for relief applies for the first ten year interval.

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