Regulatory Guide 1.36
| ML003740046 | |
| Person / Time | |
|---|---|
| Issue date: | 02/28/1973 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-1.36 | |
| Download: ML003740046 (3) | |
2/23/73 U.S. ATOMIC ENERGY COMMISSION
REGULATORY
DIRECTORATE OF REGULATORY STANDARDS
GUIDE
REGULATORY GUIDE 1.36 NONMETALLIC THERMAL INSULATION FOR
AUSTENITIC STAINLESS STEEL
A. INTRODUCTION
General Design Criterion 1, "Quality Standards and through pipe fittings, valves, and equipment cannot be Records," of Appendix A to 10 CFR Part 50, "General entirely prevented, and contaminants present in the Design Criteria for Nuclear Power Plants," requires that thermal insulation may be leached by these liquidg and structures, systems, and components important to safety leposited on the stainless steel surfaces. Extensive test be designed, fabricated, erected, and tested to quality programs by Dana' and Karnes 2 have demonstrated that standards commensurate with the importance of the ;tress-corrosion cracking of both unsensitized and safety function to be performed. In addition, General ;ensitized austenitic stainless steel can be induced by Design Criteria 14 and 31 require assurance that the zhloride or fluoride ions leached from many reactor coolant pressure boundary will have an representative thermal lilh lation materials. Karnes has extremely low probability of gross rupture or rapidly further shown that leachable sodium and silicate ions at propagating fracture. Stress-corrosion cracking, which is least partially inhibit the adverse effects of the chloride promoted by certain contaminants, is one mechanism and fluoride ions.
whereby such failures may be postulated. This guide describes an acceptable method for implementing these Controls should be exercised to assure that criteria with regard to the selection and use of nonmetallic thermal insulations employed in nuclear nonmetallic thermal insulation to minimize any power plants do not contribute significantly to stress contamination that could promote stress-corrosion corrosion of stainless steel. A quality assurance program cracking in the stainless steel portions of the reactor should be implemented at all steps from manufacturing coolant pressure boundary and other systems important through installation to minimize pickup of contaminants to safety. This guide applies to light-water-cooled from external sources.
reactors. The Advisory Committee on Reactor Safeguards has been consulted concerning this guide and Each type 3 of insulation should pass an appropriate has concurred in the regulatory position. qualification test (such as those identified in C.2.a.
below) to demonstrate that under conditions
B. DISCUSSION
conservatively representing those encountered in reactor operation, the insulation does not induce excessive Whether sensitized or not, austenitic stainless steel is cracking in stressed stainless steel specimens. A further subject to stress corrosion and should be protected from qualification test should consist of a chemical analysis to certain contaminants that can promote cracking. demonstrate that the leachable chloride and fluoride ion Chloride and fluoride ions are the most serious contaminants, so it is necessary to minimize the levels of 'A. W. Dana, Jr., "Stress Corrosion Cracking of Insulated these ions (and others that have the potential to cause Austenitic Stainless Steel," ASTM Bulletin, October 1957.
stress-corrosion cracking) in all material that may come SH. F. Karnes, "The Corrosion Potential of Wetted Thermal in contact with austenitic stainless steel. Insulation," presented at American Institute of Chemical Engineers 57th National Meeting, September 1965 (Conf
"Thermal insulation is often employed adjacent to, 650905-2).
"aType means material of similar composition, form, and or m direct contact with, stainless steel piping and class and of consistent quality, formulation, and manufacturing components. Accidental spillages and leakages of fluids process.
USAEC REGULATORY GUIDES Copies of published guides may be obtained by request indicating the divisions desired to the US. Atomic Energy Commission, Washington, D.C. 20645, Regulatory Guides we lsued to describe end make available to the public Attention: Director of Regulatory Standards. Comments and suggestions for methods acceptable to the AEC Regulatory staff of implementing specific parts of Improvemants in thes guides ae encouraged and should be sent to the Secretary the Commission's regulations, to delineate techniques used by the staff in of the Commission, US. Atomic Energy Commission, Washington, D.C. 20545, evaluating specific problems or postulated accidents, or to provide guidance to Attention: Chief, Public Proceedings Staff.
applicants. Regulatory Guides are not substitutes for regulations end compliance with them Is not required. Methods and solutions different from those set out in The guides are Issued in the following ten broad divisions:
the guides will be acceptable if they provide a basis for the findings requisite to the issuance or continuance of apermit or license by the Commission. 1. Power Reactors
6. Products
2. Research end Test Reactors
7. Transportation
3. Fuels and Materials Facilities 5. Occupational Health Published guides will be revised periodically, asappropriate, to accommodate 4. Environmental and Siting 9. Antitrust Review comments and to reflect new information or experience. S. Materials and Plant Protection 1
0. General
concentrations are within acceptable levels and that 1. All insulating materials should sufficient quantities of the corrosion inhibiting ions be manufactured, processed, packaged, shipped, stored, and (sodium and silicate) are present in the insulation.
installed in a manner that will limit, to the maximum extent practical, chloride and fluoride contamination The following procedures may be used in the from external sources.
chemical analyses 4 for chlorides and fluorides: 2. Qualification Test: Each type3 of insulating
1. American Society foe Testing and Materials material should be qualified by the manufacturer or (ASTM) D512 - "Tests for Chloride Ion in Industrial supplier for use by:
Water and Industrial Waste Water;" and a. An appropriate test to reasonably assure
2. ASTM Dl 179 -Tests for Fluoride Ion in that the insulation formulation does not induce stress Industrial Water and Industrial Waste Water.p corrosion. Two acceptable tests are:
(1) ASTM C692-71, "Standard Method Silicates may be analyzed using ASTM E60, for Evaluating Stress Corrosion Effect of Wicking-Type
"Photometric Methods for Chemical Analysis of Thermal Insulations on Stainless Steel" (Dana Test). The Metals," by either of the following methods: material should be rejected if more than one of five
1. ASTM E62 Molybdisilicic acid method; or specimens crack; and
2. ASTM E120 or E146 - Molybdenum blue (2) RDT M12-1T, 7 "Test Requirements method. for Thermal Insulating Materials for Use on Austenitic Stainless Steel," Section 5, (Knolls Atomic Power Sodium ion concentrations may be obtained by Laboratory (KAPL) Test). The material should be either spectrographic or flame photometric methods. rejected if more than one of four specimens crack.
b. Chemical analysis to determine the ion Further, each lot5 of insulation should be analyzed concentrations of leachable chloride, fluoride, sodium, to demonstrate that chlorides and fluorides are being and silicate. Insulating material that is not demonstrated maintained at acceptable levels and that the composition by the analysis to be within the acceptable region of is representative of the material employed in the Figure 1 of this guide should be rejected. This analysis qualification test. The production lot is considered should also be used as a comparison basis for the representative if the levels of the principal leachable production test specified in C.3. below.
promotors (chloride and fluoride ions) and inhibitors
3. Production Test: A representative sample 8 (sodium and silicate ions) of stress-corrosion cracking are from each production lots of insulation material to be within fifty percent of the corresponding values used adjacent to, or in contact with, austenitic stainless determined for the qualification sample. steels used in fluid systems important to safety should be chemically analyzed to determine leachable chloride, fluoride, sodium, and silicate ion concentrations as in
C. REGULATORY POSITION
C.2.a. above. The lot should be accepted only if:
a. The analysis shows the material to be The levels of leachable contaminants in nonmetallic within the acceptable region of Figure 1; and insulation materials 6 that come in contact with b. Neither the sum of chloride plus fluoride austenitic stainless steels of the American Iron & Steel ion concentrations nor the sum of sodium plus silicate Institute (AISI) Type 3XX series used in fluid systems ion concentrations determined by this analysis deviates important to safety should be carefully controlled so by more than 50 percent from the values determined on that stress-corrosion cracking is not promoted. In the sample used to qualify the insulation in C.2. above.
particular, the 1-table chlorides and fluorides should 4. Requalification: When a change is made in the be held to the lo vest practicable levels. Insulation for type, nature, or quality of the ingredients, the the above application should meet the following formulation, or the manufacturing process, the conditions: insulation material should be requalified by repeating the tests described in C.2. above.
'Thermal insulating materials include block insulation, pipe
'Samples for chemical analysis may be prepared by the insulation, board and blanket and the cements and adhesives procedure described in Reactor Development & Technology employed in their application.
(RDT) M1 2-iT, Para. 6.1-6.3. Copies may be obtained from RDT
Standards Office, Oak Ridge National Laboratory, Building
"1Copies may be obtained from RDT Standards Office, Oak Ridge National Laboratory, Building 1000, P.O. Box X, Oak
1000, P.O. Box X,Oak Ridge, Tennessee 37830. Ridge, Tennessee 37830.
'A lot is defined as the thermal insulation material of the
$A representative sample should be fully representative of same composition, form, type, grade, and class produced at one the cross section of the material; that is, it should include plant under the same conditions over a limited time span and proportionate amounts of all components including facing designated by the producer as a production lot. fabrics and finishing layers.
1.36-2
10,000
1,000
E
0.
0.
100 J~ACCEPTIABLE ANALYSIS
pp (aI SO3
101 I I 1 11111 t11 IIfI 111
100 1,000 10,000 100,000
ppm (Na + SiO 3 )
FIGURE 1 ACCEPTABILITY OF INSULATION MATERIAL BASED ON THE
LEACHABLE (CI + F) AND THE LEACHABLE (Na + Si0 3 ) ANALYSES
1.36-3