ML20055A335
| ML20055A335 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 07/15/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-06-01, TASK-6-1, TASK-RR LSO5-82-07-037, LSO5-82-7-37, NUDOCS 8207160172 | |
| Download: ML20055A335 (8) | |
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b qy July 15,1982 Docket No. 50-213 LS05-82-07-037 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Co.
Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
SEP TOPIC VI-1, ORGANIC MATERIALS AND POST ACCIDENT CHEMISTRY FOR HADDAM NECK PLANT Enclosed is our final evaluation of SEP Topic VI-l for the Haddam Neck facility. This evaluation is based on the safety analysis reports provided in your letter dated February 9,1982, as supplemented by letter dated May 3,1982, and a phone conversation on June 23, 1982.
We have detennined that Haddam Neck does not meet current licensing criteria with regard to post accident water chemistry.
This evaluation will be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility. This assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this subject are modified before the integrated assessment is completed.
Sincerely.
Originni cihed by T Dennis H. Crutchfit1d, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
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Docket No. 50-213 Revised 3/30/82 Ar. W. G. Counsil CC 3
Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424
. Mr. Richard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Board of Selectmen Town Hall Haddam, Connecticut 06103 State of Connecticut 0Ffice of Policy and Management ATTN:
Under Secretary Energy i
Division i
80 Washington Street Hartford, Connecticut 06115 U. S. Environmental Protection Agency Region I Office ATTN:
Regional Radiation Representative JFK Federal Building l
Boston, Massachusett3 02203 Resident Inspector Haddam Neck Nuclear Power Station l
c/o'U. S..NRC East Haddam Post Office
. East Haddam, Connecticut 06423 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 l
o SYSTEMATIC EVALUATION PROGRAM TOPIC VI-l HADDAM NECK TOPIC:
VI-1, Organic Materials and Post Accident Chemistry I.
INTRODUCTION The design basis for selection of paints and other organic materials is not documented for most operating reactors. Topic VI-l is intended to review the plant design to assure that organic materials, such as organic paints and coatings, used inside containment do not behave adversely during accidents when they may be exposed to high radiation fields.
In particular the possibility of coatings clogging sump screens should be minimized.
Low pH solutions that may be recirculated within the containment after a Design Basis Accident (DBA) may accelerate chloride stress corrosion cracking and increase the volatility of dissolved iodines. The objective of Topic VI-l is to assure that appropriate methods are available to raise or maintain the pH of solutions expected to be recirculated within contain-ment after a DBA.
Organic Materials: An assessment of the suitability of organic materials in the containment includes the review of paints and other organic materials used inside the containment including the possible interactions of the de-composition products of organic materials with Engineered Safety Features (ESF), such as filters, Post Accident Chemistry: An assessment of post accident chemistry includes a determination of proper water chemistry in the containment spray during the injection phase following a DBA and that appropriate methods are avail-able to raise or maintain the pH of mixed solution in the containment sump.
II.
REVIEW CRITERIA Organic Materials: The plant design was reviewed with regard to General Design Criterion 1, " Quality Standards and Records" of Appendix A to 10 CFR Part 50, " General Design Criteria for Nuclear Power Plants" which requires
- hat structures and systems important to safety be designed and tested to quality standards comiensurate with the importance of the safety function to be performed. Also, contained in the review was Appendix B to 10 CFR 50,
" Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants." This guide describes an acceptable method of complying with the Commissions quality assurance requirements with regard to protective ~ coatings.
Post Accident Checistry: The design was reviewed with regard to General Design Criterion 14, " Reactor Coolant Pressure Boundary" of Appendix A to 10 CFR Part
- 50. This requires that the reactor coolant pressure boundary to designed and erected so as to have an extremely low probability of abnormal leakage and groc rupture.
Also, regarded in the review was General Design Criterion 41,
" Containment Atmosphere Cleanup," of Appendix A to 10 CFR Part 50.
This requires that systems to control substances released in reactor containment be provided to reduce the concentration and quality of fission products released to the environment following a postulated accident.
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. III.
RELATED SAFETY TOPICS The effectiveness of the iodine removal system is evaluated as part of Topic XV-19, for a spectrum of loss-of-coolant accidents.
Topic VI-7.E reviews the ECCS in the recirculation mode to confirm the effectiveness of the ECCS.
IV.
REVIEW GUIDELINES Organic Materials: Current guidance for the review of organic materials in containment is provided in Sections 6.1.1, " Engineered Safety Features Materials" and 6.1.2, " Organic Materials" of the Standard Review Plan and in Regulatory Guide 1.54, " Quality Assurance Requirements for Protective Coatings Applied to Water-Cooled Nuclear Power Plants." Regulatory Guide 1.54 endorses the requirements and guidelines described in detail in ANSI N101.4-1972, " Quality Assurance for Protective Coatings (Paints) for the Nuclear Industry" and ANSI N5.12-1974, " Protective Coatings (Paints) for the Nuclear Industry."
Post Accident Chemistry: Guidance for the review of post accident chemistry is provided in Section 6.1.1 and 6.5.2 of the Standard Review Plan.
Section 6.1.1 is related to assuring that appropriate methods are available to raise or maintain the pH of the mixture of the containment spray, ECCS water, and chemical additives for reactivity control and iodine fission product removal in the containment sump during the recirculation phase and to preclude long term corrosion problems after the accident. Section 6.5.2 is related to providing proper water chemistry in the containment spray and sump during the injection phase following a Design Basis Accident.
V.
EVALUATION:
l Organic Materials:
By letters dated February 9,1982 and May 3,1982, the licensee provided references to the types and amounts and the environmental testing of organic coating materials used in the plant.
Protective coating systems comprise the bulk of the organic materials (outside of electrical cable insulation) in the containment. Accident effects on cable insulation l
are reviewed under NUREG-0458 (Ref. 1) l Protective coatings of types commonly used for severe industrial service were applied to the containment interior surfaces using acceptable industrial pro-cedures.
The coatings on the 93,000 square feet of concrete surfaces are of the generic epoxy type. Coatings of the epoxy type have been shown by tests I
to be highly resistant to the effects of radiation (Ref. 2, 3, 4) and of exposure to the temperature and mildly basic containment spray solutions during l
a DBA.
The steel containment liner (area: 59,000 square feet) was coated with vinyl chloride and vinyl acetate based paints. Miscellaneous steel surfaces (tanks, fans, crane, etc.) were painted with silicone alkyd enamels.
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. Paint bases utilizing vinyl and silicone alkyd resins are less resistant than epoxy paints to the effects of radiation. However, tests have shown (Ref. 2, 3, 4) that coatings of the vinyl and silicone types on concrete and steel substrates have remained in serviceable conditions after radiation doses in excess of 108 rad which is a conservative DBA dose estimate.
Silicone alkyd resins are resistant to attack by alkalis and have a high maximum service temperature (450 F) (Ref. 5).
The vinyl polymers have good resistance to chemical attack by mildly basic agueous solutions, but only limited resistance to heat.
Polyvinyl chloride begins to soften with release of hcl at 150 F, below the estimated maximum DBA temperature inside the containment of about 285 F.
However, the steel containment liner would be at a lower temperature and would be cooled by the containment spray. Therefore, the degree of degradation of the vinyl coatings under DBA conditions would be moderate, and no delamination nor gross failure would be expected.
This is confirmed by the qualification tests on vinyl coated steel specimens irradiated at temperatures up to 176 F (Ref. 3, 4).
In a phone conversation witn the licensee on June 23, 1982, it was identified that portions of the containment liner are insulated with a polyurethane foam to an elevation of approximately 17 feet.
The foam is bolted to the containment liner in sheets varying in thickness from 1 to 2 inches. The foam is then covered by 1/2 inch thick sheets of J.M. Marinite - 36 ( a calcium-silicate-asbestos composition) which is also bolted to the containment liner.
During testing, polyurethane typically showed degradation of some physical properties (such as a 50 percent decrease in tensile stress) following 8 rati.
However, the test exposure to a maximum estimated radiation dose of 10 specimens remained intact and did not disintegrate.
Radiation damage was enhanced by the presence of moisture but was not significantly affected by temperature up to 260 F.
The Marinite - 36 covering would provide a signifi-cant barrier to the intrusion of moisture into the polyurethane foam.
In addition, the Marinite -36 cover prevents the foam from falling into the containment and subsequently plugging the sump.
On the basis of the above discussion, we find that there is reasonable assurance that the radiation, thermal and chemical resistance of the organic coatings used in the plant is sufficiently high that deterioration under DBA conditions would not interfere with the operation of engineered safety features.
Certain small surface areas of plant equipment were coated with industrial coatings whose radiation resistance has not been tested. However, because only small areas of these coatings are exposed in the containment, we conclude that their failure under accident conditions would not present a significant safety hazard.
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l Gas yields from the irradiation of plastics range from 1.5 to about 100 cc (STP) per gram for a dose of 109 rad (Ref. 4). On the conservative assumption that the yield for the plant coatings was 50 cc (STP) peg gram, about 450 cubic feet of gas would be generated by a radiation dose of 10o rad. The major components of the gas would be hydrogen and carbon dioxide.
Less than a tenth of the gas would be volatile organic compounds.
The small amount of hydrogen and organic gases generated by the decomposition of polyurethane during a design basis accident will not add significantly to the amount produced by other organic materials.
The presence of this small amount of organic gases in containment after a DBA would not interfere with the absorption of organic iodides by the charcoal filters in the standby gas treatment equipment.
The amount of hydrogen from this source is small compared to that which could be produced in a DBA from the zirconium-water reaction, from the radiolysis of water, or from the reaction of the zinc in inorganic zinc coatings with high temperature borate solutions (Ref. 6). Hydrogen generation from the latter sources is reviewed independently of the SEP program as part of the TMI Action Plan (Task II.B.7, NUREG-0660).
Periodic inspection of the protective coatings inside containment will provide added assurance of the integrity of the coatings.
In the letter of May 3, 1982, the licensee stated that plant practice is to inspect and repair painted surfaces during each refueling outage or forced outage in accordance with ANSI N-101.2 - 1973. We find that the inspection procedure and frequency are acceptable for monitoring the condition of coatings.
On the basis of our review we conclude that the organic materials used in the plant are acceptable and will not interfere with the operation of required safety features.
Qualification tests demonstrate that the types of organic coating materials used in the containment will maintain their integrity and remain in serviceable condition after exposure to the severe environmental conditions of a DBA.
Insignificant quanitites of organic gases and of hydrogen would be generated under these conditions.
To provide further assurance that delamination, flaking or peeling of coatings materials will not interfere with the operations of engineered safety features, the licensee has proposed an acceptable inspection program for coated surfaces in containment according to ANSI guidelines during each refueling outage.
All significantly degraded areas will be repaired according to the ANSI standards.
The results of the inspection and repair will be documented.
Post Accident Chemistry:
In the February 9,1982 Safety Assessment Report, as supplemented by letter dated May 3,1982, the licensee indicated that the l
pH of the recirculating sump water would be approximately 5.2 following a design basis accident and subsequent injection. This is based on a reactor coolant t
system boron concentration of 1000 ppm and a refueling water storage tank (safety injection) boron concentration of between 2200 to 2400 ppm. The accept-able pH value is a minimum of 7.0, in accordance with Branch Technical Position MTEB 6-1.
The licensee has indicated that there are no chemical additives added for controlling the acidity of the containment spray and sump water. The licensee also indicated that the amount of leachable chloride in the thermal insulation materials inside containment is within the acceptable l
. limits of Regulatory Guide 1.36, " Nonmetallic Thermal Insulation for Austenitic Stainless Steel." The licensee has not provided the detailed information we requested for our independent evaluation on the chloride concentration in the containment sump water up to 30 days following an accident. Although the amount of leachable chloride in the thermal in-sulation materials inside containment is stated by the licensee to be within the acceptable limits of Regulatory Guide 1.36, the r iloride con-centration in the recirculating water co0ld be such that, wnen combined with a low pH of 5.2, stress corrosion cracking of austenitic stainless -
steel in the engineered safety feature materials may occur after the accident.
Therefore, the staff has determined that maintaining the pH of the recircu-lating water inside icontainment at 5.2 following a design basis accident does not meet the acceptance criterion of a minimum of 7.0 of Standard Review Plan Sectivo 6.1.1 and Branch Technical Position MTEB 6-1 for pressurized water reactors.
VI.
CONCLUSIONS Organic Materials:
Based on the above, we conclude that there is reasonable assurance that the integrity of paints and organic coatings within the containment will be maintained under normal operating conditions and those of a DBA, and that there will be no undue hazard to the health and safety of the public, and therefore, the paints and organic coating materials are acceptable.
Post Accident Chemistry:
Based on the above evaluations, we conclude that, although the Haddam Neck Plant can be operated with an acceptable degree of safety under normal conditions when containment spray and sump water recircu-lation are not required, the post accident water chemistry does not meet the acceptance criterion of Standard Review Plan Section 6.1.1 and Branch Technical Position MTEB 6-1 and is, therefore, not acceptable.
In order to reduce the potential of stress corrosion cracking of the engineered safety feature equipment inside the containment following a design basis accident, the licensee l
should either show that the post accident water chemistry meets the acceptable criterion II.B.1 in Standard Review Plan Section 6.1.1 and Branch Technical Position MTEB 6-1, or provide an acceptable alternative.
VII.
REFERENCES 1.
NUREG-0458, "Short Term Safety Assessment on the Environmental Qualifications of Safety-Related Electrical Equipment of SEP Operating Reactors," May, 1978.
2.
ORNL-3589, " Gamma Radiation Damage and Decontamination Evaluation of Protective Coatings and Other Material for Hot Laboratory and Fuel Processing Facilities," G.A. West and C.D. Watson, February,1965.
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3.
ORNL-3916 " Unit Operations Section Quarterly Progress Report, July -
September 1965," M.E. Whatley et al., March 1966 pp. 66-75.
4.
" Radiation Effects on Organic Materials," edited by R.0. Bolt and J.G. Carroll, Academic Press, New York and London,1963, Chapter 6, p.239.
5.
" Chemical Engineers Handbook," J.H. Perry, Editor, 5th Edition, pp. 23 -
54 to 23 - 57.
6.
H.E. Zittel, " Post Accident Hydrogen Generation from Protective Coatings in Power Reactors," Nuclear Technology 17, 143-6 (1973).
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