ML19275A572
| ML19275A572 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 09/28/1979 |
| From: | Mittl R Public Service Enterprise Group |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.031, RTR-REGGD-01.044, RTR-REGGD-1.031, RTR-REGGD-1.044 NUDOCS 7910050537 | |
| Download: ML19275A572 (6) | |
Text
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O PSEG Public Service Els.ctric and Gas Company 80 Park Place Newark, N.J. 07101 Phane 201/430-7000 September 28, 1979 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
HOPE CREEK GENERATING STATION DOCKET NOS. 50-354 AND 50-355 RESPONSE TO NRC STAFF POSITION ON THE USE OF AUSTENITIC STAINLESS STEEL IN BOILING WATER REACTOR FACILITIES
REFERENCES:
I '. )
K.
KNIEL (NRC) LETTER TO R.
L. MITTL (PSE&G)
FEBRUARY 17, 1978 (2)
R.
L. MITTL (PSE&G) LETTER TO NRC, APRIL 23, 1979 On February 17, 1978, you forwarded your staff position, Reference 1,
on the use of austenitic stainless steel in boiling water facilities and requested that we provide a response to NUREG-0313.
Our most recent correspondence with you, Reference 2, indicated that car response would be pro-vided in September 1979.
We have given considerable attention to the area of miti-gation of intergranular stress corrosion cracking (IGSCC) for the Hope Creek Generating Station and have been following technical developments within the industry to ensure our mitigation procedures are current.
Measures which have been taken include the following (applica-ble staff position number follows st atement) :
1.
Stainless steel piping in the ECCS systems has been replaced with carbon steel (NRC position 11.1.)
2.
All ASME III Class 1 stainless steel process piping pur-chased by our Architect-Engineer will be L-Grade (NRC position II.1.)
3.
Welding and heat treatment controls for stainless steel pipe in the reactor coolant pressure boundary, including field welding of non-L Grade pipe supplied by the NSSS contractor, are imposed by the architect-engineer as discussed in Attachments 1 and 2, cositions on NRC 9'h
\\
Regulatory Guides 1.31 and 1.44, respectively.
These Regulatory Guide positions revise and supersede those The Energy People 1101 35i n-cw 7 010050 5R
Director of Nuclear 9/28/79 Reactor Regulation submitted in the PSAR ( Amendment 17).
(NRC position II.1) 4.
In order to minimize the number of stagnant lines, the recirculation system bypass line and the control rod drive system retur.1 line have been eliminated.
(NRC position II.1 and V.1) 5.
The recirculation system piping has been shipped to a facility for corrosion resistant cladding of field weld ends and furnace solution heat treatment prior to in-stallation.
(NRC position II.2) 6.
Layout provisions are being made to assure access to Class 1 welds for inservice inspection.
(NRC position III.2.)
7.
A reactor coolant pressure boundary leak detection system has been designed to enhance the discovery of unidenti-fied leakage that may include through-wall cracks de-veloped in austenitic stainless steel piping.
(NRC posi-tion [III.2.A.(2)]
8.
An evaluation is continuing on the technical feasibility and associated cost of installing an oxygen control system.
Provisions in the design and layout have been made to allow installation at a later date, if deemed appropriate.
(NRC position V.2)
We believn that the above mitigation measures will minimize the susceptibility to stress corrosion cracking of austenitic stainless steel in the reactor coolant pressure boundary.
We will coittinue to monitor the results of the NRC Pipe Crack Study Group and evaluate any further findings for their applicability to the Hope Creek Generating Station.
Very truly yo rs, J;-
,/
//
1 1
R.
L.
Mittl General Manager -
Licensing and Environment Engineering and Construction CHil 1/2 l101 352
ATTACHMENT 1 Hope Creek Generating Station, Units 1 and 2 NRC Regulatory Guide 1.31 Control of Stainless Steel Welding (Rev 3, April 1978)
Non-NSSS procured items and field welding comply with Revision 3 of Regulatory Guide 1.31 except as discussed below:
(1) 3eference:
Paragraph C.1 of the Regulatory Guide.
The procedure for determining the amount of delta ferrite in each heat or lot of austenitic stainless steel filler material is based on the chemical analysis provisions of ASME Section III, NX-2430, using the Schaeffler or Delong Diagrams represented by Figure NX-2433.1-1.
Magnetic measurement of 3% delta ferrite (3 Ferrite Number) or less is cause to perform additional tests to determine the acceptability of the filler material.
(2)
Reference:
Paragraphs C.2 and C.3 of the Regulatory Guide.
As an alternate to the magnetic method of deter-mining the delta ferrite content of austenitic stainless steel filler material, the chemical analysis method as described in (1) above is used.
(3)
Reference:
Paragraph C.4 of the Regulatory Guide.
This paragraph is compiled with for filler material certifica-tion to the following extent:
Austenitic stainless steel welding filler materials used in the fabrication and installation of ASME Section III components are controlled to deposit from 8 to 15 percent delta ferrite (8.5 to 18 Ferrite Number), except for 309 and 309L welding filler materials which are controlled to deposit from 5 to 15 percent delta ferrite (5 to 18 Ferrite Number) and are used only for welding carbon or low alloy steel to austenitic stainless steel.
Use of 309L welding filler material is required for the overlay deposit on the carbon or low alloy steel component nozzles or connecting pipe when postweld heat treatment is re-quired.
The specified delta ferrite ranges as determined by chemical analysis are in accordance with the acceptable Ferrite Number range of 5 to 20.
+
NSSS items procured and fabricated after the issuance of the construction permit were controlled as stated in the GE posi-tions stated in their standard safety analysis report, gESSAR 251.
CH 12/1 1101 353
ATTACHMENT 2 Hope Creek Generating Station, Units 1 and 2 NRC Regulatory Guide 1.44 Control of the Use of Sensitized Stainless Steel (May 1973)
Non-NSSS procured items and field work will comply with the guide with the following exceptions or clarifications:
(1) The provisions of this guide, as modified below, are applied to ASME Section III equipment and piping in safety-related systems.
They are not generally applied to HVAC systems or to instruments.
(2)
Reference:
Paragraph C.1 of the Regulator Guide.
This paragraph is complied wi th as contaminatio. of austenitic stainless steel (Type 300 series) by compounds that could cause stress corrosion cracking is avoided during all stages of fabri.
nn and installation.
Except for TCTFE (trichlorotrif, Nethane) meeting the requirements of Military Specification MIL-C-81302B, cleaning is limited to solutions that contain not more than ?OO ppm of chlo-rides.
Rinsing or flushing is with water that contains not more than 200 ppm of chlorides.
Special rinsing techniques are used to assure complete removal of TCTFE when crevices or undrainable areas are present.
Foreign substances in contact with austenitic stainless steel (i.e.,
die lubricants, penetrant materials, marking materials, masking tape, etc.) are controlled so as not to contain more than 200 ppm of chlorides, or are removed immediately following the operation in which they were used.
Penetrant materials may conform to the higher con-taminant levels specified in Article 6,Section V o f the ASME Code, provided that the materials are thoroughly re-moved immediately after the examination has been completed.
Crevices and undrainable areas are protected prior to using materials containing more than 200 ppm of chlorides.
All substances in contact with austenitic stainless steel are removed prior to any elevated tempera-ture. treatment.
Completed components are packaged in such a manner that they will be protected from the weather, dirt, wind, water spray and any other extraneous environmental conditions' which may be encountered during shipment and subsequent site storage.
Ch 12/2
, In the field, austenitic stainless steel components are stored clean and dry.
Components either are stored in-doors or, if outdoors, are stored off the ground and covered with tarps.
Contamination of austenitic stainless steels in the field during installation is avoided as described above.
The system hydrostatic test is performed with water that con-tains not more than 200 ppm of chlorides.
The water quality during final flushing or pre-operational testing of the completed sy9 tem is at least equivalent to the quality of the op, rating system water.
Leachable chlo-rides and fluorides in non-metallic insulation materials which come in contact with austenitic stainless steel are held to the lowest practicable level by the inclusion of the requirements of Regulatory Guide 1.36 in the insula-tion purchase specifications.
(3)
Reference:
Paragraph C2 of the Regulatory Guide.
This paragraph is complied with as all grades of austenitic stainless steels (Type 300 series) are required to be furnished in the solution heat treated condition before fabrication or assembly into components or systems.
The solution heat treatment will vary according to the appli-cable ASME or ASTM material specification.
(4)
Reference:
Paragraph C3 of the Regulatory Guide.
All austenitic stainless steels are furnished in the solution heat treated condition in accordance with the material specification.
During fabrication and installation aus-tenitic stainless steels are not permitted to be exposed to temperatures in the range of 800 F to 1500 F, except for welding and hot forming.
Welding practices are con-trolled to avoid severe sensitization, as described in (6) below, and solution heat treatment in accordance with the material specification is required following hot forming in the temperature range of 800 F to 1500 F.
Unless otherwise required by the material specification, the maximum length of time for cooling from the solution heat treat temperature to below 800 F is specified in the equipment specification.
Corrosion testing in accordance with ASTM A 262-70, Practice A or E, may be required if the maximum length of time from cooling below 800 F is ex-ceeded or the solution heat treat condition is in doubt.
(5)
Reference:
Paragraph C4 of the Regulatory Guide.
No austenitic stainless steel is subjected to service temperatures in the range of 800 F to 1500 F.
The cnly exposure of austenitic stainless steels to this range of CH 12/3 1101 355
. temperatures subsequent to solution heat treating occurs during welding.
Welding practices are controlled as dis-cussed in item 6 below.
In addition, austenitic stainless steel piping and valves supplied by Bechtel Power Corpora-tion which form part of the reactor coolant pressure boundary are fabricated either from L-Grade wrought pro-ducts or castings with controlled ferrite content.
(6)
Reference:
Paragraph C5 of the Regulatory Guide.
Heat treating austenitic stainless steel in the temperature range of 800 F to 1500 F is not permitted and solution heat treatment is required following hot forming.
Since sensitization is avoided, testing to determine suscep-tibility to intergranular attack is not performed.
(7)
Reference:
Paragraph C6 of the Regulatory Guide.
Weld-ing practices are controlled to avoid severe sensitization in the heat-affected zone of unstabilized austenitic stainless steel as described below.
Unless otherwise stated, the position applies to both Bechtel and Bechtel suppliers and subcontractors.
Intergranular corrosion testing is not performed on a routine basis.
(a)
Weld Heat Input Bechtel controls weld heat input during field instal-lation by using shielded metal-arc welding (SMAW) and gas tungsten-arc welding (GTAW) processes only.
The size of electrodes for each process is limited to 5/32-inch and 1/8 inch dianc'ar maximum, respective-ly, for welding non-L Grade material, except for castings with controlled ferrite content.
In addi-tion to the above two processes, Bechtel suppliers and subcontractors are permitted to use automatic submerged-arc welding (ASAW) and gas metal-arc weld-ing (GMAW).
Hard surfacing operations are not in-cluded.
When automatic submerged-arc welding (ASAW) or gas metal-arc (GMAW) is used, or shielded metal-arc welding (SMAW) or gas tungsten-arc welding (GTAW) is used with electrodes larger than those specified above, testing in accordance with ASTM A262, Practice A or E is required unless welding is followed by solution heat treatment.
(b)
Interpass Tempecature The interpass temperature is controlled so as nce to exceed 350 F.
CH 12/4 1101 356
e
- NSSS items procured and fabricated after the issuance of the construction permit were controlled as stated in the GE posi-tions stated in their standard safety analysis report, GESSAR 251.
CH 12/5