BECO-87-003, Forwards Pilgrim Nuclear Power Station Recirculation Inlet Thermal Sleeve Mock-Up Fabrication and Evaluation, Per 830826 Order Re IGSCC Insp.Hydrogen Water Chemistry Chosen as Method of Mitigating Propagation of IGSCC

From kanterella
Jump to navigation Jump to search
Forwards Pilgrim Nuclear Power Station Recirculation Inlet Thermal Sleeve Mock-Up Fabrication and Evaluation, Per 830826 Order Re IGSCC Insp.Hydrogen Water Chemistry Chosen as Method of Mitigating Propagation of IGSCC
ML20207P191
Person / Time
Site: Pilgrim
Issue date: 01/02/1987
From: Lydon J
BOSTON EDISON CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
Shared Package
ML20207P192 List:
References
BECO-87-003, BECO-87-3, NUDOCS 8701150216
Download: ML20207P191 (2)


Text

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _

sosyontsotsoAt *

  • General Offices 800 Boylston Street Boston, Massachusetts 02199 James M. Lydon Chief Operating officer J>nuary 2, 1987 BTCo 87-003 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555 License JPR-35 Docket f0-293

Reference:

a) Response to IGSCC Inspection Order Confirming Shutdown, H.D. Harrington to H.R. Denton, September 11, 1984 (BECo letter #2.84.146) b) IGSCC Inspection per August 26, 1983 Order, H. R. Denton to H. D. Harrington, December 4,1984, >

(NRC Letter #1.84.357)

Dear Sir:

In reference (b), you requested that a study be conducted to determine the cause of the isolated cracks found on the outer diamete' of the Pilgrim Nuclear Power Station (PhPS) N-2 recirculation nozzler thermal sleeves. In response to your request, Boston Edison Company (BECO) contracted with General Electric Company (GE) to conduct that study.

The purpose of the study was to determine whetter it was possible to sensitize the material in the area of concern by utilizing similar material, geometry and procedures in preparing a mock-up to simulate the thermal sleeve configuration.

Based on this study, it has been determined that sensitization can occur in this area and therefore IGSCC is the most likely cracking mechanism. A copy of the final report is enclosed with this letter.

In your letter, you also requested that a plan for mitigating or repairing the thermal sleeves be submitted to you. He have chosen hydrogen water chemistry (HWC) as the method of mitigating the propagation of IGSCC. BECo, in reference (a) and as part of our Long Term Program (BECo Letter No.86-034, 3/24/86), informed the NRC of our intention to implement a permanent HWC program at PNPS.

8701150216 D.

870102 ADOCK 05000293

[

i@}

PDR "

(

( ,

4 BOSTON EDISON COMPANY January 2, ~ 1987 $.'

'Mr. Harold R. Denton, Director. , , ,

Page 2 Therefore, with the conclusion of the cracking mechanism study, the evaluation and identification.of IGSCC as the cause, and.the previously submitted HNC program to be used as the method to mitigate the thermal sleeve cracking, we believe we have addressed your concerns.

Should you have any questions please do not hesitate to contact us.

Very truly yours, f a, fs k dM d

Enclosure:

Recirculation Inlet Thermal Sleeve Mock Up Fabrication and Evaluation by General Electric Company cc: Mr. John A. Zwolinski, Director BWR Project Directorate #1 Division of Licensing Office of Nuclear Reactor Regulation -4 U.S. Nuclear Regulatory Commission Washington, D. C. 20555 J