ML20244E520
| ML20244E520 | |
| Person / Time | |
|---|---|
| Issue date: | 12/15/1986 |
| From: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Rossi C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20244D710 | List:
|
| References | |
| NUDOCS 8612180137 | |
| Download: ML20244E520 (4) | |
Text
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UNITED STATES 4
4 NUCLEAR REGULATORY COMMISSION
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k MEMORANDUM FOR:
C. Ernest Rossi, Assistant Dire r
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Division of PWR Licensing - A M'
Office of Nuclear Reactor Regulation p
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FROM:
Edward L. Jordan, Director Division of Emergency Preparedness and Engineering Response j
Office of Inspection and Enforcement gg
SUBJECT:
COMMENTS ON GENERIC LETTER " CONTAINMENT INTEGRATED LEAK RATE TESTS" Although IE preferred a minor rule change to address this issue, we do not object to issuance of a generic letter. We understand that an opportunity for CRGR review will be provided to assure consistency with backfit provisions.
I have provided wording for page I that (1) recognizes a revision of Appendix J is under consideration and (2) recognizes that in some past instances NRC has accepted test results calculated by the mass point method.
Minor editorial changes are also provided on the enclosed copy of the letter.
Eyd'afd L. Jor an, Director T1 vision of mergency Preparedness and Engineering Response Office of Inspection and Enforcement
Enclosure:
As Stated
Contact:
D. C. Kirkpatrick, IE 492-8373 i
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UNITED STATES I
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TO: All Light Water Reactor Applicants and Licensees
SUBJECT:
CONTAINMENT INTEGRATED LEAKAGE RATE TESTS
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Gentlemen:
A recent NRC review of the different types of test computations used to determine leakage rate for containment integrated leakage rate test license (CILRTs) industry has indicated that applicants an
-perforned throughout the are frequently using a test computation methed that is not in ccmp iance witb' i
the explicit regulatory requirements of 10 CFR 50, Appendix J.
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f n computation is the mass point calculation described in ANSI /ANS-56.8-1981,
" Containment System Leakage Testing Requirements."
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In order to meet the regulatory requirements of Appen,d J applicants and licensees must measure the integrated leakage rate ysing one of the CILRT methods oescribed in ANSI N45.4-1972, " Leakage-Rate Testing of Containment Structures for Nuclear Reactors."Section III.A.
(a) of Appendix J requires that all CILRTs shall be conducted in accordance ith the provisions of ANSI Section III.A.3.(c) of Appendix J also quires that test leakage rates N45.4.
be calculated using absolut,e values corrected for instrument error. 4K Section 5.1 of ANSI N45.4, tWiel&Mf two methods f performing CILRTs, arc Fesided:
the absolute method and the reference-vessel ethod.
In addition, Section 7.9 of the standard describes the types of leaka e rate computations permitted for the 24-hour period absolute method CILRTs./The only types of leakage rate +he!
computations specified in,thii_s.tApdard ar the regulatory requirements'of time calculations. Messet compliance witfonly be achieved through the use of Appendix J for absolute method CILRTs cane rate computational methods, corrected the point-to-point or tot time a
for instrument errpr..
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Wy M w additionally, the total time test methodology p/M j
resented in the Bechtel Topical Report BN-TOP-1, Revision 1, " Testing Criteria for Integrated Leakage Rate Testing of Primary Containment Structures for Nuclear Power Plants" has been approved for use in accordance with ANSI N45.4, with a test duration as defined l
in BN-TOP-1.
l ANSI N45.4 also requires that a " statistically averaged" leakage rate be determined (Paragraph 7.9). However, ANSI N45.4 does not provide a specific method for accounting for random and instrument error during a CILRT, as required by Appendix J.
The NRC staff believes that the calculated leakage rate as determined by using the mass point method described by l
ANSI /ANS-56.8-1981 has technical merit. 5:ricr, compliance with the SE' bNhasA :+e~eS &
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regulatory requirements requires a CILRT leakage rate calculated by total time or point-to-point, with a test duration of at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> except as provided for in BN-TOP-1. Random and instrument error should be accounted for by an l
acceptable calculation of a statistically-determined 95% confidence level.
The 95% confidence level calculation will be acceptable if it is derived from either:
(1) the total time or point-to-point method; or (2) the mass point method, as provided in ANSI /ANS-55.8-1981. The calculated leakage rate, with the 95% confidence level added to it, must then meet the acceptance criterion of Appendix J (i.e., not exceed 0.75 La or 0.75 Lt, as appropriate).
The supplemental, or verification, test required by Section III.A.3 (b) of Appendix J must also have its leakage rate calculated by the total time or point-to-point method.
It is suggested that applicants and licensees review their CILRT programs with respect to the above to assure future consistency with regulatory requirements.
Sincerely, Harold R. Denton, Director Office of Nuclear Reactor Regulation W
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hNo written response or specific action is required by this letter.
Therefore, no clearance from the Office of Management and Budget is required.
If you have any questions on this matter, please contact your i
roject manager.
L irector D
ion of Licensi
Enclosure:
NUREG-0897, Revision 1 RG 1.82 Revision 1 SRP Section 6.2.2, Revision 4
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