ML20127L365

Responds to Util Position Concerning Leakage Rate Detection Re Generic Ltr 88-01, NRR Position on IGSCC in BWR Austenitic Stainless Steel Piping

ML20127L365
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	01/21/1993
From:	Butler W Office of Nuclear Reactor Regulation
To:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
References
GL-88-01, GL-88-1, TAC-M76638, NUDOCS 9301270113
Download: ML20127L365 (7)

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% January 21, 1993 Docket No. 50-271 Mr. W. P. Murphy, Senior Vice President, Operations Vermont Yankee Nuclear Power Corporation R.D. 5, Box 169 Ferry Road Brattleboro, Vermont 05301  ;

Dear Mr. Murphy:

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SUBJECT:

VERMONT YANKEE NUCLEAR POWER CORPORATION POSITION CONCERNING LEAKAGE RATE DETECTION RELATED TO GENERIC LETTER 88-01, "NRR POSITION ON IGSCC IN BWR AUSTENITIC. STAINLESS STEEL PIPING" (TAC NO. M76638)

In response to correspondence and discussions lbetween Vermont Yankee Nuclear Power Corporation (Vermont Yankee) and the NRC staff (the staff) as detailed below, this letter provides: (1) the basis for the staff's position that the leakage-detection commitments called for in Generic Letter (GL) 88-01 are required to reside in plant Technical Specifications.(TS), and (2) the staff's assessment of Vermont Yankee's alternative proposal and technical basis as .

provided in a letter dated March 8,1990, and supplemented by a letter dated September 21, 1992.

Backaround On January 25, 1988, the staff issued GL 88-01 to provide revised staff positions related to intergranular stress corrosion cracking (IGSCC) near weldments in BWR piping. These revised positions resulted from extensive research and considerable industry experience with IGSCC in austenitic stainless steel piping. The regulatory basis for GL 88-01 was the 4

Commission's determination that-BWRs may not be in conformance with their existing design and licensing bases. The staff requested,-pursuant to

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10 CFR.50.54(f), that BWR licensees " furnish ... current plans relating to piping replacement, inspection, repair, and leakage detection." The staff

. indicated that an acceptable response to the GL would. include confirmation of' L the licensee's plans to ensure that the TS related.to-leakage detection would-

! be in conformance with the staff position on. leakage detection-(Position.C of Regulatory Guide 1.45) which was attached-to the GL. . Vermont Yankee' responded to GL 88-01 by-letter dated July 27, 1988.

By letter dated February 14, 1990, the staff transmitted to Vermont Yankee a Safety Evaluation Report (SER) in which the staff found Vermont-Yankee's response acceptable except for (1) the proposed' incorporation of the leakage- j detection requirements into administrative. procedures rather than.TS, and (2)_

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the proposed averaging of leakage rate increases over a 24-hour period.

d staff also requested that Vermont Yankee submit a TS change "that would require-leakage detection::as outlined in GL 88-01." .Thef~[

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Mr. W. P. Murphy January 21, 1993 By letter dated March 8, 1990, Vermont Yankee provided its position on the staff's exceptions identified above, it stated that " existing administrative controls (which were described in the GL response] ... currently require compliance with the intent of this position."

On February 4, 1992, the staff issued Supplement 1 to GL 88-01 in which the staff stated that " incorporation of the leakage detection requirements in an g administrative document is not acceptable." In a letter dated May 22, 1992, the staff reaffirmed its position and renewed its request for incorporation of the leakage detection requirement into the Vermont Yankee TS.

Following several discussions between Vermont Yankee personnel and the staff, in a meeting on August 5, 1992, representatives of Vermont Yankee agreed to propose a TS change to incorporate the staff's position. However, in a letter dated September 21, 1992, Vermont Yankee again insisted that its administrative procedures complied with the intent of the staff's position and claimed that the staff's position was an unjustifiable backfit.

In a meeting on October 8,1992, the staff identified to Vermont Yankee representatives several reasons that the staff believed that the backfit analysis would support the staff's position. (See enclosed Meeting Summary).

In subsequent discussions, Vermont Yankee agreed to withdraw its backfit claim, and the NRC staff agreed to provide Vermont Yankee the staff's technical basis for requiring that the leakage rate detection requirements reside in plant TS and the staff's assessment of Vermont Yankee's alternative proposal and technical basis. Vermont Yankee withdrew the request for backfit analysis by letter dated October 27, 1992. This letter provides the technical basis for the TS leakage detection requirement.

Technical Basis for NRC Leakane Detection Position On February 6, 1987, the Nuclear Regulatory Commission published a Commission Policy Statement on Technical Specification Improvements for Nuclear Power Reactors (52 FR 3788). This policy statement addressed the scope and purpose of TS as required by 10 CFR 50.36 and established a specific set of objective criteria for determining which regulatory requirements and operating restrictions should be included in the TS. It noted that "the purpose of Technical Specifications is to impose those conditions or limitations upon reactor operation necessary to obviate the possibility of an abnormal situation or event giving rise to an immediate threat to the public health and safety by establishing those conditions of operation which cannot be changed without prior Commission approval and by identifying those features which are of controlling importance to safety." Based on that purpose, the Commission developed three criteria which delineate those " conditions and limitations" which " belong in the TS in accord with 10 CFR 50.36."

Criterion 1 states: " Installed instrumentation that is used to detect, and Indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary "

4 Mr. W. P. Murphy January 21, 1993 The discussion of Criterion 1 elaborates: "A basic concept in the adequate protection of the public health and safety is the prevention of accidents.

Instrumentation is installed to detect significant abnormal degradation of the reactor coolant pressure boundary so as to allow operator actions to either correct the condition or to shut down the plant safely, thus reducing the likelihood of a loss-of-coolant accident."

"This criterion is intended to ensure that the Technical Specifications control those instruments specifically installed to detect excessive reactor coolant system leakage." This ensures that the requirements set forth in General Design Criterion 14, (GDC 14) Reactor Coolant Pressure Boundary of Appendix A to 10 CFR 50 are continually satisfied.

The staff position that surveillance requirements related to detection of increases in reactor coolant system leakage related to IGSCC must reside in plant TS is consistent with the Commission Policy stated above. The staff position was accepted by the Commission in its review of GL 88-01.

Furthermore, the Committee to Review Generic Requirements (CRGR) reviewed the staff's positions stated in GL 88-01 relative to the Backfit Rule (10 CFR 50.109) and found that the staff's positions constituted a backfit which was justifiable pursuant to 10 CFR 50.109(a)(4)(i) in order to bring facilities into compliance with the rules of the Commission. The CRGR also reviewed Supplement I to GL 88-01 and again found that the staff's positions constituted a justifiable backfit.

NRC Assessment of Vermont Yankee's Alternative Proposal and Technical Basis The staff position requires that reactor coolant system operational leakage be limited to less than or equal to 2 gpm increase in unidentified leakage during a 24-hour period. The increase must be computed from actual measured leakage rates. This requirement must reside in the plant TS. This limit on increase in unidentified leakage assumes a failure mechanism of IGSCC that produces tight cracks. This flow increase limit is' capable of providing an early warning of such deterioration.

In the letter dated September 21, 1992, Vermont Yankee sttted that it believe6 that averaging leakage rate increases over a 24-hour period met the staff's intent because spikes which may go undetected due to averaging would not be related to IGSCC. Vermont Yankee also claimed in the letters of March 8, 1900, and September 21, 1992, that its administrative procedure met the intent of the staff's leakage detection requirements.

The staff has reviewed the proposal to base the leakage increase limit on the increase in the averages of the leakage rates measured during a 24-hour period. The staff has found that this would result in an unacceptable reduction in sensitivity to small increases in coolant leakage. For example, if the measured unidentified leakage was 1 gpm for two 8-hour intervals, then was measured as 4 gpm for a third 8-hour interval, the . calculated 24-hour

! average leakage rate would be 2 gpm. This average is compared to the lowest of the averages calculated by each of the two previous shifts, which were both

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Mr. W. P. Murphy January 21, 33 1 gpm thus, the calculated increase would be 1 gpm in the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

if the leakage rate subsequently remains at 4 gpm for a fourth 8-hour perioo, the calculated 24-hour average leakage rate would be 3 gpm with a calculated increase in leakage of 2 gpm. Since the specification is >29pm, no action is required. When, at the end of a fifth 8-hour period, the average calculated leakage rate reaches the actual leakage rate of 4 gpm, it is compared to the average leakage rate of 2 gpm (calculated two shifts before), and the increase is reflected as 1 gpm. Thus, no action is ever required for a 3 gpm increase in unidentified reactor coolant leakage. The staff finds this unacceptable.

The staff notes that a typical TS for this condition allows an appropriate grace period for identification of the leak source before action must be initiated to shut down the plant. This grace period should prevent most spiking conditions from resulting in spurious TS required shutdown events.

Such a grace period is not currently provided in Vermont Yankee's administrative procedures. The staff will work with Vermont Yankee to resolve this issue in the Technical Specifications.

Regarding the requested incorporation of leakage detection requirements into the TS, Vermont Yankee elected to propose the alternative measure of incorporation into administrative procedures rather than TS. The staff reviewed this proposal and, in the SER issued on February 14, 1990, found the proposed alternative unacceptable. Vermont Yankee responded by letter dated March 8, 1990, in which it stated that " existing administrative controls at Vermont Yankee currently require compliance with the intent of [the staff's]

position."

The staff's position, stated in GL 88-01 as augmented by Supplement 1, is that the surveillance requirement which Vermont Yankee has placed in administrative procedure OP 4152 should reside in the plant TS. Commission policy, as discussed above, calls for requirements related to detection of reactor coolant system pressure boundary degradation to be included in the TS. This ensures that any changes that could challenge the requirements set forth in GDC 14 of Appendix A to 10 CFR 50 be reviewed by the staff prior to implementation.

In the letter dated September 21, 1992, Vermont Yankee noted that it had

" modified its procedures to include the 2 gpm reactor coolant leakage rate detection requirement of Generic Letter 88-01 and specifically [ referenced]

Generic Letter 88-01 as the basis for such a requirement." The essence of this procedure needs to reside in TS. We feel that this can easily be accomplished with very little effort on the part of Vermont Yankee or NRC staff since there is no technical change that needs to be made to satisfy the requirements set forth in GL 88-01. The staff will work with Vermont Yankee to resolve this issue.

) Mr. W. P. Murphy January 21, 1993 If you have any further questions on this matter, please contact Mr. Daniel H. Dorman of my staff. Mr. Dorman can be reached at l (301) 504-1429.

Sincerely, Original signed by:

Walter R. Butler, Director Project Directorate 1-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation

Enclosure:

Meeting Summary cc w/ enclosure:

See next page DISTRIBUTION:

Docket File WButler JStrosnider NRC & Local PDRs TClark OGC PDI-3 Reading DDorman ACRS (10)

SVarga RClark JLinville, RI JCalvo WKoo

• see previous concurrence _

0FFICE PDI-3pfA P$[hfb *EMCB:C D:PDI-3f 'k NAME XCY,h h D;)okak JStrosnider WButlerb DATE /M//92 (/M/92 01/05/92 l/21/92 0FFICIAL RECORD COPY DOCUMENT NAME: A:\VYM76638.ltr I

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4 Mr. W. P. Murphy January 21, 1993 If you have any further questions on this matter, please contact Mr. Daniel H. Dorman of my staff. Mr. Dorman can be reached at (301) 504-1429.

Sincerely, Walter R. Butler, Director Project Directorate 1-3 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation

Enclosure:

Meeting Summary cc w/ enclosure:

See next page

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• j Mr. W. P. Murphy, Senior Vice Vermont Yankee Nuclear Power Station

President f CC

Mr. Jay Thayer, Vice President G. Dana Bisbee, Esq.

] Yankee Atomic Electric Company Office of the Attorney General i 580 Main Street Environmental Protection Bureau

! Bolton, Massachusetts 01740-1398 State House Annex 25 Capitol Street i

Regional Administrator, Region I Concord, New Hampshire 03301-6937 i

U. S. Nuclear Regulatory Commission l 475 Allendale Road Resident Inspector i King of Prussia, Pennsylvania 19406 Vermont Yankee Nuclear Power Station i U.S. Nuclear Regulatory Commission R. K. Gad, III P. O. Box 176-Ropes & Gray Vernon, Vermont 05354 j One International Place

! Boston, Massachusetts 02110-2624 Chief, Safety Unit j Office of the Attorney General j Mr. W. P. Murphy, Sr. Vice President, One Ashburton Place, 19th Floor i Operations Boston, Massachusetts 02108 l Vermont Yankee Nuclear Power Corp.

j R.D. 5, Box 169 Mr. David Rodham, Director l Ferry Road Massachusetts Civil Defense Agency

Brattleboro, Vermont 05301 400 Worcester Rd.

! P.0, Box 1496

! Mr. Richard P. Sedano, Commissioner Framingham, Massachusetts 01701-0317 i Vermont Department of Public Service ATTN: James Muckerheide i 120 State Street, 3rd Floor

, Montpelier, Vermont 05602 Mr. Raymond N. McCandless

! Vermont Division of Occupational i Public Service Board and Radiological Health i State of Vermont Administration Building l 120 State Street Montpelier, Vermont 05602 i Montpelier, Vermont 05602 i Mr. L. A. Tremblay.

j Chairman, Board of Selectmen Senior Licensing Engineer i Town of Vernon Vermont Yankee Nuclear Power

! Post Office Box 116 Corporation i Vernon, Vermont 05354-0116 580 Main Street l Bolton, Massachusetts 01740-1398 i

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ENCLOSURE

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E c9 kg UNITED STATES l

c NUCLEAR REGULATORY COMMISSION j WASHINoTON, D.C. 20085 i o,%, #[ October 26, 1992 DocYe1.io.50-271 LICENSEE: Vermont Yankee Nuclear Power Corporation i

l FACILITY: Vermont Yankee Nuclear Power Station 1

SUMMARY

OF OCTOBER 8, 1992, MEETING WITH REPRESENTATIVES OF VERMONT

YANKEE NUCLEAR POWER CORPORATION AND YANKEE ATOMIC ELECTRIC COMPANY i

On October 8, 1992, pursuant to notice, the NRC staff met with representatives

of Vermont Yankee Nuclear Power Corporation and Yankee Atomic Electric Company at One White Flint North, Rockville, Maryland, to discuss licensing issues related to the Vermont Yankee Nuclear Power Station (VY). Enclosure 1 is a list of attendees and Enclosure 2 is a copy of the licensee's handout provided j at the meeting.

! The staff requested the licensee's interpretation of their Technical l Specification (TS) requirements for alternate train testing. The licensee's representative indicated that he would discuss the question with plant staff i

and provide a response to the NRR Project Manager.

! The licensee's letter of September 21, 1992, claiming that the TS change on leakage detection requirements which was requested by the NRC in Generic Letter (GL) 88-01 constituted an unjustifiable backfit, was discussed. The staff stated: 1) that the TS change has been implemented for most operating j plants; 2) that the TS is part of the Standard TS (STS) and the revised STS; 1

3) that an alternative of placing a reference to the licensee's administrative procedure in the administrative TS would be more cumbersome to the licensee;

, and 4) that, if the backfit determination finds that the change is not a backfit, or is a justifiable backfit, the licensee would pay for the backfit

determination. The licensee requested, and was granted, a 2-week delay in the l backfit determination to discuss the staff's statements with licensee i management.

The NRR Project Manager agreed to provide a letter to the licensee to clarify

statements in the staff's approval of the FROSSTEY II computer code. The

{ approval indicated that further review would be required for any future reload

application of the code. The staff intended by that statement that the

licensee should review the reload application pursuant to 10 CFR 50.59, not that-the reload application should be submitted for NRC staff review. The new letter will also note that the staff's Safety Evaluation Report (SER) placed conditions on the licensee's applications of the code. . The licensee was

previously informed of these conditions during a meeting.in Rockville on

August 5, 1992.

4 f f) / Q ()L) 77 f ~

. October 26, 1992 The licensee expressed its need for the corrected SER on the LOCA analysis computer code, RELAP5YA, to allow incorporation into the TS by reference. The corrections to be made are administrative.

The licensee indicated that it will be providing two submittals on In-Service Testing (IST) during November 1992. The submittal for the third 10-year IST interval is due on November 30, 1992. A 6-month response to a Technical Evaluation Report (TER) on IST is due November 13, 1992. The licensee

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requested to include them both in one submittal not later than November 30, 1992. The staff tentatively accepted that schedule.

Regarding In-Service Inspection (ISI), the licensee noted that the ASME Code allows for ISI interval slippage due to extended outages, but the NRC i regulations set the ISI interval at ten years without reference to slippage or extended outages. The licensee requested an opportunity to discuss the possibility of interval slippage with the NRC technical staff. The staff will arrange such a discussion.

The staff informed the licensee that the 10 CFR 20.302 disposal permit application was being reviewed on a low priority basis. This was acceptable to the licensee.

The licensee indicated that it had questions regarding two conditions placed upon the staff's acceptance of the licensee's Station Blackout (5B0) coping

, period. The NRC requested the licensee to verify main steam tunnel habitability for the SBO. The licensee indicated that, for that event, entry l to the tunnel is not required. In addition, the staff required more frequent

, load capacity testing of the alternate AC power supply (the Vernon hydroelectric plant via the bus tie). The licensee indicated uncertainty over the nature of testing desired by the staff. The Project Manager agreed to arrange a discussion of these issues between the licensee and the NRC technical staff. The Project Manager subsequently contacted the NRR technical staff. They indicated that the licensee should submit its questions in writing. That information was relayed to the licensee by phone.

The staff reported that the licensee's submittals on water level instrumentation (response to Generic Letter 92-04) and fire barriers (response to NRC Bulletin 92-01) were under staff review.

Regarding the licensee's proposed TS change No. 147 on SLC/ARI changes due to the ATWS rule, the licensee believed that the staff would withdraw its June 5, 1992 letter, which found that there was an open issue and suggested a meeting-

' 8 October 26, 1992 i  !

! to discuss resolution. The staff feels that the letter expressed conditional '

i unacceptability of the licensee's proposal, and that withdrawal is not required to issue the TS change if the conditions have been met. A conference l call will be held to resolve this issue.

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i Daniel H. Dorman, Project Manager i Project Directorate I-3

Division of Reactor Projects - I/II ,

4 Office of Nuclear Reactor _ Regulation i

Enclosures:

$ 1. List of Attendees j

2. October 7 [ sic],1992 Meet ing at NRC/NRR Vermont Yankee

Licensing Issues cc w/ enclosures:

See next page Y

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Vermont Yankee Nuclear Power Station cc:

Mr. Jay Thayer, Vice President G. Dana Bisbee, Esq.

Yankee Atomic Electric Company Office of the Attorney General 4

580 Main Street Environmental Protection Bureau Bolton, Massachusetts 01740-1398 State House Annex 25 Capitol Street Regional Administrator, Region I Concord, New Hampshire 03301-6937 U. S. Nuclear Regulatory Commission 475 Allendale Road Resident Inspector King of Prussia, Pennsylvania 19406 Vermont Yankee Nuclear Power Station U.S. Nuclear Regulatory Commission R. K. Gad, III P. O. Box 176 l

Ropes & Gray Vernon, Vermont 05354 One International Place Boston, Massachusetts 02110-2624 Chief, Safety Unit Office of the Attorney General Mr. W. P. Murphy, Sr. Vice President, One Ashburton Place, 19th Floor Operations Boston, Massachusetts 02108 Vermont Yankee Nuclear Power Corp.

R.D. 5, Box 169 Mr. David Rodham, Director Ferry Road Massachusetts Civil Defense Agency Brattleboro, Vermont 05301 400 Worcester Rd.

P.O. Box 1496 Mr. Richard P. Cedano, Commissioner Framingham, Massachusetts 01701-0317 Vermont Department of Public Service ATTN: James Muckerheide 120 State Street, 3rd Floor Montpelier, Vermont 05602 Mr. Raymond N. McCandless Vermont Division of Occupational Public Service Board and Radiological Health State of Vermont Administration Building 120 State Street Montpelier, Vermont 05602 Montpelier, Vermont 05602 Mr. L. A. Tremblay Chairman, Board of Selectmen Senior Licensing Engineer Town of Vernon Vermont Yankee Nuclear Power Post Office Box 116 Corporation Vernon, Vermont 05354-0116 580 Main Street Bolton, Massachusetts 01740-1398

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J Enclosure 1

! LIST OF ATTENDEES LICENSING ISSUES MEETING f REGARDING VERMONT YANKEE NUCLEAR POWER STATION 2

i ROCKVILLE. MARYLAND.

OCTOBER 8. Q91 i

i NMiE AFFILIATION TITLE l Jose Calvo NRC/ Division of Reactor Projects Asst. Director, Reg i Walt Butler NRC/DRP/ Project Directorate I-3 Project Director-J

j. Pat Sears NRC/DRP/ Project Directorate I-3 -VY Project Manager

! Dan Dorman NRC/DRP/ Project Directorate I-3 Project Manager i

Stan Hiller Yankee Atomic Power Company VY Project Manager l Len Tremblay Yankee Atomic Power Company- VY Licensing Manager 4

I Dean Porter Vermont Yankee Nuclear Power Corp. Licensing Manager

! Dick Clark NRC/DRP/ Project Directorate.1-2 Lead Project Manager l GL 88-01 i

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l' Enclosure 2 )

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, OCTOBER 7.1992 NfEETING AT NRC / NRR

VERN10NT YANKEE LICENSING ISSUES i -

FROSSTEY II Fuel Performance Code Clarification regarding NRC statement on reload submittals LOCA Analysis (VY Specific RELAP5YA) i Visit with Lambrose Lois to determine the status of corrected SER issuance I -

IST Program l Submittal of Third 10 Year Interval and 6 month Response to TER - one submittal?

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! - ISI Program j Establish a telecon date with NRC technical staff to determine need for relief request for

extending interval by nine months as allowed by ASME Section XI Proposed Change No.147, SLC/ARI/RIT Changes due to ATWS Rule i Acceptability of ARI portion of change - status of NRC action item fmm previous 8/5/92 l  !! censing taceting 10CFR20.302 Application for Chem. Line Sink Drain

Status of permit application Station Blackout Supplemental SER j NRC request to verify steam tunnel habitability

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GL 92-04 Vessel Level Instrumentation VY response i

- Bulletin 92-01, Supplement 1 *Ihermo-Lag VY Response GL 87-02, Suppl.1 A-46 SQUG VY Response GL 88 20, Supplement 4 IPEEE Revised VY Plan and Schedule Submittal

! - GL 88-01 Leakage in Containment Backfit Issue 1

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