ML19320B918

Comments on Proposed Addl Guidance on Potential for Low Fracture Toughness & Lamellar Tearing of LWR Component Support Structures.Nrc Generic Guidance Invalidates Many Support Designs Developed Per Past Applicable Codes & Stds

ML19320B918
Person / Time
Site:	Midland
Issue date:	07/08/1980
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Snaider R Office of Nuclear Reactor Regulation
References
REF-GTECI-A-12, REF-GTECI-ES, RTR-NUREG-0577, RTR-NUREG-577, TASK-A-12, TASK-OR 9293, NUDOCS 8007150497
Download: ML19320B918 (4)

Text

c-1 o

Ni wiwin i ) /* '.'*? E James W Cook

'- Vsce PressJent, %Jl.and Mject l [I

.%Q' General Omces: 212 W ret wcNgan Avenue, Jackson. Menegan 49201 e Area Code 517788-05S0 July 8, 1980 Mr Richard P Snaider Generic Issues Branch nuclear Regulatory Com=ission Washington, DC 20555 MIDLAND PRCJECT-CCICENTS ON PROPOSED CRITERIA FOR FRACTURE TOUGENESS OF MAJOR LWR C0!GONENT SUPPORT STRUCTURES FILE: OL92 UFI: 53*03*0h SERIAL: 9293 In response to a request contained in letters dated May 19, 1980 and May 20, 1980 from Darrell G Eisenhut to "All Power Reactor Licensees" and to "All Pending Operating Licensees and Construction Fernit Applicants and All Licensees of Plants Under Ocnctruction," Censumers Power Ccmpany hereby submits the folleving cc= rents cn the propcsed additional guidance on " Potential For Lov Fracture Toughness and La-illar Tearing, ete" centained in those letters.

Censumers vil arrange its cctments in two categories. The first category cencerns general implications of the proposed guidance and review schedule.

The second area of eccrents vill deal with the technical specifics of the proposed guidance.

The first general co==ent on the proposed requirements is that the staff and their consultants appear to have taken certain materials and velding problems identified at a few specific reactors and have developed generic guidance that, in effect, potentially invalidates many support designs that were developed in full ccepliance with the applicable codes and standards in effect at the time these facilities were designed and built. If the staff vishes to do this, there is a need for it to demonstrate that a safety problem exists. In our reading of NUREG-0577 it is not clear that the new guidance does anything other than impose current code requirements on older designs, despite the fact that past proble=s have been related to fabrication or installation quality lapses rather than any inadequacy of the codes utiliced.

It is clear that the requirements outlined in the enclosure to the Eisenhut letters vill have a significant impact on many licensees. Accordingly, the Commission is strongly urged to avait, and carefully evaluate the research currently underway at EPRI en this subject before issuing its final guidance. $0C)I 5

With respect to the implementation schedule in the Eisenhut letters, there f /0 appears to be particular hardship imposed on the Midland application which falls into Category 4 (OL expected after December 31, 1981). By requiring that these considerations be included in the operating license review, the May 20 letter establishes an accelerated schedule requirement unless it is agreed thr.t the staff vill accept and review this material separately from the issuance of the 800715 0%

A

2 s

SER. We believe it .is appropriate for those plants well along in the construction process to be given adequate tbne to respond to the final URC guidance in this matter. Therefore, we request that the final guidance either provide a uniform response period for all affected licensees or else reserve the prerogative for the staff to establish specific case-by-case schedules for the various applicants to respond te this guidance as part of their individual review schedules. -

The balance of Consumers' comments concern specific substantive provisiens of the proposed guidance, which are referenced to the appropriate page and paragraph in the Eisenhut letter.

1. The last paragraph on Fage 1, and continued on the top nalf of Page 2, of the May 20, 1980 letter defines the applicable suppcrt structures. The boundaries for these support structures should' also be clearly defined. It is reco= mended that these boundaries be consistent with Section III of the ASMZ Boiler and Pressure Vessel Code.

2. It is not pessible to adequately review Items 1 & 2 on Page 2 of the May 20, 1980 letter because the revisien to the ::EC Standard Review Flan is not available for review at this time.

3 Section 1. cf the enclesure to these letters should clearly define the fornat and ccntents for the materials " listing" that is desired. As an example, is the data listed in Table 2.2 of NURIG-0577 adequate to meet the intent of Section l?

h. It' appears that Part I, Subsections A&3 of the enclosure tre intended to exclude bolting. If this is the case, the exclusion should be clearly identified in the section/ subsection titles.

5 If Table k.h and Table h.6 of NUREG-0577 are identical in scope, with the exception of bolting, then Section 2, Part I.A.1(b) should be changed to reference only. Table k.h. If the scopes are not identical then this. Section should describe how the differences between the scopes of these tables are to be addressed.

6. Sectien 2, Part I.A l(d) should be revised to allow a ecmparison to temperatures higher than 75 F when it can be demonstrated that the temperature of the material in question is higher than 75 F during operating modes where the support function and loads are important.

7 Section 2, Part I.A.2, should be changed to permit evaluation of Charpy test results at other temperatures. Where a structure is in ecmpliance with ASNE Section NF-2300 it is possible that the test data may have been taken at some temperature other than 75 F.,

r 3

' 8. . Table 1 of. the enclosure should be revised. The scope of Section 2 Part I.A is " materials having minimum specified yield strength of 180 ksi or less",

but the maximum yield strength in Table'l is 105 ksi. What are the requirements for materials with specified minimum yield strengths between 105 and 180 ksi?

9 The last paragraph in Section 2, Part I.A 3 should be clarified. Presumably it is the intent of this paragraph to require ancillary heating to a tem-perature which exceeds that calculated in the criterior of Part I.A.1(d) or which exceeds the temperature at which the Charpy test results exceed the energy equirements of Table 1. This is not, however, what the paragraph requires.

Additionally, unormal operating temperatures =sy exceed the desired ten-peratures with no ancillary heating.

10. _ Depending on the boundaries specified for ecmponent supports and depending on the version of the ASME Code applied to supports, considerable bolting may be installed which do not meet Code requirements. This does not mean that the fracture properties for the bolting .are unacceptable. Therefore, it is necessary that Criterion C define the Code requirenents which the Staff believes to be applicable to the assurance of adequate fracture toughness.

Based on these definitions, it may be possible to de=cnstrate that the bolt $ ng in question does have adequate fracture toughness.

11. Is it necessary to perfern a Part II evaluation if a Part I. A.3 evaluation has been perfer:ed:

12. Presu= ably the hig'h strength steels to which reference is made in the second paragraph of Part' II are " quenched and tempered lov alloy steels." This terminology may be preferable to " lev allow heat treated types."

13 'In order to evaluate _K7g n data it is necessary to assu=e a rhape for the T/10 flav. Part II shouki provide sete guidance which defines the shape to be assumed.

14. ' Part II, should define -the' location of the assu=ed T/10 flav. (ie: is a surface flaw. to be assu=ed?) -

15 In view of _ the surface examinations conducted during fabrication and

. construction, a T/10 flav seems to be unrealistically large. Part II should allow the assumption of smaller flaws where fabrication and construction ,

examinations provide assurance of smaller flaws.

i

- 16. Further guidance on the type of inspections made reference to in Part II, I

-is necessary. Are the visual examinctions of the ASLE Section XI Code acceptable?

I i

1

tt 17 Without access to the data which was used to produce Figure 2, an adequate evaluation is not possible. It is, however, doubtful the straight line tjr nd for low alloy steels continues to a stress intensity value of 0 ksi c fin. at a yield stress of 215 ksi. If the value were zero, one would expect material with yield strengths higher than 215 ksi to exhibit stress corrosien cracking at flav sizes of.zero depth and/or zero stresses. Actually, it is reasonable for tb. low allow steels to approach a lower li=it of 5 to 8 ksi fin. as the yiel? acrength increases.

We appreciate this opportunity to provide our recon =endations and ask that these co==ents be considered in your future deliberations concerning the proposed guidance.

Yours very truly, t / l /

/

0460/f VU r WIL -

l l

1

, - _ _