ML20097E053

Suppls 901207 Response to NRC 901001 Safety Evaluation & Technical Evaluation Rept Re Suppl 1 to Generic Ltr 88-01, NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping. TS Changes Will Be Submitted for ISI Program

ML20097E053
Person / Time
Site:	Grand Gulf
Issue date:	06/05/1992
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-01, GL-88-1, GNRO-92-00070, GNRO-92-70, NUDOCS 9206120009
Download: ML20097E053 (7)

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U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D.C. 20555 Attention: Document Control Desk Subj ect: Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Response to Generic Letter 88-01, Supplement 1 GNRO-92/00070 Gentlemen:

By this letter, Entergy Operations. Inc. is providing its response to Generic Letter (GL) 88-01, Supplement 1 "NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel Piping" dated February 4, 1992. The supplement provided acceptable alternative staff positions to some of those delineated in GL 88-01 and also provided clarification for some. staff positions.

By a letter dated October 1, 1990, the NRC transmitted its Safety Evaluation and associated Technical Evaluation Report of Grand Gulf Nuclear Station's (GGNS) response to GL 88-01. The October 1, 1990 letter indicated that GGNS had acceptably implemented the technical aspects of GL 88-01 by accepting the Staff's recommendations on IGSCC inspection.

- mitigation and other aspects of IGSCC detection by incorporating necessary revisions into-the GGNS Inservice Inspection (ISI) Program. The Safety Evaluation also identified four licensing issues for which GGNS was requested to propose licente amendments. GGNS responded by a letter dated December 7, 1990.

Supplement 1 provided only one chcngc from tha staff puditions in GL 88-01 as they apply to GGNS. .One of the clarifications involves the addition of a statement in the ISI section of the Technical Specifications (TS) that the ISI program for piping covered by GL 88-01 will conform to the staf f's positions in the generic letter on schedules, methods, personnel and sample expansion. Since the ISI section will remain in the improved Standard Technical Specifications, GGNS will propose TS changes to incorporate this statement into the existing TS.

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June 5, 1992 GNRO-92/00070 Page 2 of 3 Supplement 1 provided no change to the staff position in GL 88-01 on leakage detection. GGNS will propose TS changes consistent with the sta f f's position.

GGNS has reviewed the alternative staff positions and clarifications provided in GL 88-01, Supplement 1 and each is presented in the attachment to this letter.

If you require additional information, please adviso.

Yours trul ,

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e WTC/SBM/ams attachment: GGNS Response to Generic Letter 88-01, Supplement 1 cc: Mr. D. C. Ilintz (w/a)

Mr. J. L. Mathis (w/a)

Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a)

Mr.11. L. Thomas (w/o)

( Mr. Stewart D. Ebneter (w/a)

! Regional Administrator l

U.S. Nuclear Regulatory Commission Region II 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor, Project Manager (w/2)

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13l13 Washington, D.C. 20555 l

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Attachment to GNRO-92/00070 Grand Gulf Nuclear Station Response to Generic Letter 88-012 Supplement 1 6

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Attachment to GNRO-92/00070

. 4 Background-On January 25, 1988, the NRC issued Generic Letter (GL) 88-01, "NRC position on IGSCC in-BWR Austenitic Stainless Stesi Piping." Grand Gulf Nuclear Station (GGNS) responded to GL-88-01 on August 8, 1988 (Reference 1). ~

Additional information was provided to the Staff on July 14, 1989-(Reference 2) Land April 23, 1990 (Reference 3).

The NRC transmitted its Safety Evaluation and associated Technical Evaluation Report on GGNS's response to GL 88-01 on October 1, 1990. This letter -indicated that GGNS had acceptab1" implemented the technical aspects of GL 88-01 by accepting the Staff's recommendations on IGSCC inspection, mitigation'and other aspects of IGSCC detection by_ incorporating necessary revisions into the GGNS Inservice Inspection (IFI) Program. GGNS was also requested to propose license amendments for four licensing issues.

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By a letter dated December. 7, 1990 (Reference 4), GGNS responded to each of

- the four IIcensing issues and stated that the current Techuk. d Specifications (TS) provided reasonable assurance of maintr utng the long-term structural integrity of austenitic stainless steet ,iping in GJNS, Generic Letter 88-L1, Supplement 1 Responses '

3n February 4, 1992, the NRC issued Supplement 1 to GL 88-01. Supplement 1 provided. acceptable alternative staff positions to some of those delineated in GL 88-01 with ~ regard to the inspection of reactor water cleanup (RWCU) system piping outboard of-the containment isolation valves and the leak

• detection requirements pertaining to the operability of leakage measurement instruments and the frequency of monitoring leakage rates. The supplement

! also provided clarification on the staf f's positions 'regarding the sample l expansion for Category-D welds, the effect of shrinkuges resulting from weld overlay repairs or stress improvement (SI) on the piping system and its supports and_ pipe whip restraints and the technical specification (TS) amendments for incorporating the inservice inspection statement and leak

- detection requirements as delineated in GL 88-01.

The Staff's Safety Evaluation found GGNS's responses to'GL 88 acceptable, with the exception of the responses regarding changes to-TS. Therefore, GGNS has reviewed the alternative staff positions and clarifications in GL 01, Supplement I with regard to the requested TS changes and provides the following response:

- Item .(1) of GL 88-01, Supplement 1 The, staff found that monitoring reactor coolant system (RCS) leakage every 4

- hours creates an unnecessary administrative hardship for plant operators.

l Thus, RCS leakage measurements should be taken at least once per shif t, not l- to exceed 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

_ GGNS's Response to Item (1J I-l- GGNS will propose TS changes consistent with Item (1) of GL 88-01, Supplement 1.

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Attachment to GNRO-92/00070 Item 12l of CL 88-Ol Supplement u 1 The staff found that the radiation level associated with the RWCU system piping outboard of the containment isolation valves is very high; and this portion of piping is designed to be isolable and is generally classified as nonsafety piping. Affected licensees requested that they be exempt from GL 88-01 with regard to the inspection of this piping. liow eve r , the service-sensitive stainless steel RWCU system piping is subject to the most aggressive environment with rega rd to IGSCC; therefore, until the actions associatA. with GL 89-10 on motor-operated valves (MOVs) are completed by licensees, the staf f determined that an inspection of the subject piping on c campling basis of at least 10 perennt of t he weld population should be performec ' wing each refueling outage to ensure the structural integrity of the piping.

GGNS's Regponse to Item (21 -

The NRC has accepted GGNS's program for piping inspections. This item does not affect that program or the GGNS TS.

Item (31 of GL 88-01, Supplement _1 The staff's position on leak detection in GL 88-01 requires that for BWR ,

plauts operating with any IGSCC Category D, E, F, or G welds, at least one of the leakage nessurement instruments associated with each sump be operable and the outage time for inoperable instruments be limited to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. If the outage time is longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the licensee should immediately initiate an orderly shutdown. The intent of this requirement is to ensure that the capability to quantitatively measure leakage is not lost for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> because this capability is essential for safe plant operation, Af ter discussing this position with the BWR operators, the staff found that leakage can also be quantitatively measured by manually pumping the sump or measuring the dif ferences in sump level. Therefore, the staff finds that manual leak rate measurements can hn acceptable alternatives during the -

period (30 days) when the drain sump monitoring systnm is being restored, -

provided the licensee demonstrates their suitability with regard to accuracy and inspectability.

GGNS's Response to item (31 Induction llenting Stress Improvement (1HSI) work was completed in Refueling Outage 4 for the 34 Category D welds identified in GGNS's response to GL 88-01. These welds have been 1HS1 treated and will qualify as Category C welds. All other welds are Category A or B weids. Thereforn, this alternative staf f position does not apply to GGNS and does not af fect the GGNS TS.

Item (4_) of GL 88-01,_ Supplement 1 GL 88-01 requested Category D welds to be 100?. Inspected every two refueling cycles. There is no need for sample expansion if all Category D welds are examined during each itv ~ ion. However, sample expansion is required if Category D welds are e-- _-1 on a sampling basis during each inspection and cracking is identifle. ng examination. With adequate justification the sample expansion for Cats iory D welds may be limited to the piping system where cracking was found.

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Attachment to GNRO-92/00070 GGNS's' Response to Item (4)

As stated in the response to Item (3) above, GGNS has no Category D welds; therefore, this alternative staff position does not apply to GGNS'and does not affect the GGNS TS.

Item -(5) of GL 88-01x Supplement 1 Consistent with Code requirements and the licensee's written commitments, when weld overlay repairs or stress improvement (SI) is applied, the licensee should assess the effect of shrinkages on the piping system and its supports and pipe whip restraints. In addition, the licensee should also assess.the effect of the increase in dead-weight and stiffness resulting from weld overlay repairs on the piping systems.

GGNS's Response to Item (5)

The NRC has accepted GGNS's ISI program. This alternative staff position does not affect the GGNS TS.

Item (6) of GL 88-01, Supplement 1 GL 88-01 requested that a plant's technical specifications be amended to include a statement in the section on inservice inspection (ISI) that the ISI program for piping covered by GL 68-01 will conform to the staff's positions in the generic letter.on schedules, methods, personnel, and sample expansion. It also stated that if the ISI section ir removed from the TS as a result.of the-TS improvement program this statement will remain in the IFI section. However, in preparing the improved BWR Standard Technical

= Specifications, the staff determined that the ISI section including the ISI  :

statement will remain in the TS and should not be incorporated in an administrative document.

.GGNS's Response to Item (6)

GGNS agrees to propose a change to add this statement to the current GGNS *

'TS. As- stated in Reference 4, the -current -ISI- Program reflects and is -in complience with the above staff position.

L Item (7) of GL-88-01, Supplement-1

- GL L 88-01 requested that the staf f's position on -1% 'inge detection be incorporated into the TS of all affected licensees. - The staff subsequently determined that incorporation of the leakage detection requirements in an administrative document is-not acceptable.

1 i GGNS's Response to Item (7).

l-L GGNS will propose TS changes consistent with the staff's position on leakage detection.

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Attachment to GNRO-92/00070 Referentes:

1) AECM-88/0153 dated August 8, 1988 regarding Generic I,etter 88-01

2) AECH-89/0130 dated July 14, 1989 regarding Request for AdditJr '

Information on Generic Letter 88-01: NRC Position on ICSCC in 4R Austenitic Stainless Steel Piping

3) AECM-90/0063 dated April 23, 1990 rega rding Addit.f onal Information regarding GGNS IGSCC Program

4) AECM-90/0198 dated December 7, 1990 regarding Revisions to Technical Specificetion per Generic Letter 88-01 i

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