ML19256E077
| ML19256E077 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/24/1975 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| IEB-74-10B, NUDOCS 7910260570 | |
| Download: ML19256E077 (2) | |
Text
..
p Inspection and Enforcement Bulletin 74-10B January 24, 1975 FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN-2
(
REFERENCE:
RO BULLETIN NOS. 74-10, DATED 9/19/74 AND 74-10A, DATED 12/17/74)
Description of Circumstances (Amended):
Cracks similar to those described in R0 Bulletin 74-10 and 74-10A have been revealed during reexamination of the 4-inch bypass piping at five boiling water reactor facilities (including Dresden-2) since mid-Decem-ber 1974. All the facilities are of j et-pump design.
In each instance where cracks have been revealed, the same welds had been examined pre-viously (during September-November 1974) and no cracks were revealed at that time.
A special study group, comprised of key technical members of the Nuclear Regulatory Commission staff, is currently studying the causes of the cracks which have been experienced.
Consultants from other government agencies are also participating in the study.
In the interim, pending recommendations of the Commission's special study group, additional actions are necessary by licensees to insure continued close surveillance of reactor coolant leakage.
l Actions Requested of Licensees (Amended):
For all boiling water reactor f acilities of jet-pump design with opera-ting license:
1.
Upon completion of those actions described in R0 Bulletin 74-10A, implement the following reactor coolant leakage detection program:
If (within the sensitivity specified in paragraph C.S. of Regula-tory Guide 1.45) any reactor coolant leakage detection system indi-cates, within a period of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or less, either an increase in unidentified leakage to twice the determined normal rate of uniden-tified leakage or an increase in the rate of unidentified leakage by two (2.0) gym or more:
a.
Initiate plant shutdown immediately, and
\\441 \\2\\
6 0.DO 79102
. b.
Determine the source of increased leakage prior to resuming operation.
If there is evidence of leakage from the 4-inch bypass piping, c.
reexamine (by ultrasonic or other suitable volumetric inspec-tion technique), all accessible welds in the bypass piping lines.
In no case, however, shall the rate of leakage exceed that speci-fled in the technical specifications without those actions required by the technical specifications being taken.
2.
Notify this office, in writing within 10 days of your receipt of this Bulletin, of your intent to implement the actions described in 1., above.
i 3447 122 4
,