NRC Generic Letter 81-11, BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking (NUREG-0619)

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February 29, 1981

ALL POWER REACTOR LICENSEES AND LICENSE APPLICANTS (Generic Letter 81-11)

By letter dated November 13, 1980 you were forwarded a copy of NUREG-0619, "BWR Feedwater Nozzle and Control Rod Driven Return Line Nozzle Cracking" (November 1980). An error has been found in footnote 2 to Table 2 on page 18 of NUREG-0619. Because of the deltion of leak-testing requirments, footnote 2 should now read : "To be performed even if UT results are satisfactory."

Please make the change in your copy of the NUREG.

Also, comments received from GE and others since the publication of NUREG-

0619 note the difficulty in meeting the requiremtns for a low flow controller as described in Section 3.4.4.3 of the GE report NEDE-21821-A (BWR Feedwater Nozzle/Sparger Final Report, February 1980). They note that an exisiting controller may not meet the six charactieristics, yet the feedwater system may in fact meet the criterion of the crack growth analysis from which the characteristics were derived (assurance of crack growth to no greater than one inch in forty years).

They also note that strict adherence to the defined characteristics culd obviate the beneficial aspects of another recommended change, reactor water cleanup (RWCU) system rerouting to all feedwater lines, by increasing reactor vessel water level to the extent that discharging of the relatively hot RWCU water is necessary.

We concur in the assessment and will accept continued use of an existinf controller (or a controller modified to meet the basis stated above but not possessing all six characterisitics of NEDE-21821-A) based upon a plant-

specific fracture mechanics analysis or application of the analysis already exisitng in NEDE-21821-A Section 4. In order to be considered acceptable, this analysis must show that stresses from conservative controller temperature and flow profiles, when added to those resulting from the other crack growth phenomena, such as startup and shutdown cycles, do not result in the growth of a crack to greater than one inch during the forty year life of the plant. The analysis should be submitted as part of the reports required by NUREG-0619.

.February 29, 1981

Licensees or applicants not desiring to perform such ananalysis must meet the state requirments of Section 4.2 of NUREG-0619, i.e., the installation of a low flow controller having the six charateritstics stated in NEDE-21821-A.

In answer to a question that has been raised, NUREG-0619 was forwarded to PWR licensees and applicants for their information only, in consideration of the fact that the PWR steam generator feedwater line cracking has been attributed to the same phenomenon of thermal fatigue as existed in the BWR feedwater nozzles. No response from PWR licensees and applicants is required.

Sincerely,

Darrell G. Eisenhut, Director Division of Licensing