ML18030A235
| ML18030A235 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/25/1981 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| ER100450, IEB-80-07, IEB-80-7, PLA-670, NUDOCS 8103270713 | |
| Download: ML18030A235 (4) | |
Text
REGULATOt
. INFORMATION DISTRIBUTION "TEM (RIOS)
AC)ESS I ON NBR 8 1 03270 7'1 3 OOC ~ DATE 8 1 /03/25 NOTARIZED NO 'OCKET ¹ FACIL:5 usquehanna Steam Electric Station<
Un) t 1~ Pennsylva 05000387 50 38 squehanna Steam Electric Stationi Unit 2~ Pennsylva 05000388 AU
~ i E
AUTHOR AFFILIATION CURTIS'
~ W ~
Pennsylvania Power 3 Light Co.
REC IP ~ NAME RECIP IEiVT AFFILIATION YOUNGBLOODrB~ J ~
Licensing Branch 1
SUBJECT:
Responds.
to IE: Bulletin 80-07<
"BwR Jet Pump Assembly Failure" L Q112.10
~ BWR/rl beamsras presently designed L
installedrar e predicted to have longer life,Beams will be inspected per iodically as part of inservice insp programs DISTRIBUTION CODE!
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TITLE PSAR/FSAR'MOTS and Related Correspondence NOTES:Send IE,E 3 copies FSAR 5 all
- amends, 05000387 05000388 RECIPIENT ID CODE/NAME ACTION'/O LICENSNG RUSHBROOKIM ~
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"<<~6 1<8>~'Ii O3aLIII ~TORT r /
r NORMAN W. CURTIS Vice Prestdent-Engtneerlng tL Ccnstructtcn-Nuclear 770-5381 1 ~,
March 25, 198 Mr. B.J.
Youngblood Licensing Branch 1
U.S.
Nuclear Regulatory Commission Washington, D.C.
20555 Susquehanna Steam Electric Station Docket Nos.
50-387 and 50-388 Jet Pump Holddown Beam ER100450 Fi1 e 841-2 PLA-670
Dear Mr. Youngblood:
In regard to IE Bulletin 80-07 5 f112. 10 please note the following:
The BWR/4 beam design used for Susquehanna operates at peak stresses less than the BWR/3 type beams which have failed (72 versus 86 KSI).
Since time to failure is dependent on applied stress, the BWR/4 beams, as presently designed and installed are predicted to have a longer life.
2.
3.
4.
Additionally we are proceeding with reducing the 30 KIP preload currently applied to our Susquehanna beam to 25 KIPs.
This will result in a significant factor of improvement in predicted time to crack initiation (19 to 40 years).
It is very possible that the Susquehanna beams may not crack or fail during their life.
Additional tests by GE are scheduled through 1981 to make it possible to more accurately predi ct the expected life of beams with preload reduction.
We plan to conduct periodic inspections of the beams as part of our overall in-service inspection program.
Recommended inspection frequencies will be developed in the future based on lead plant inspection results and the outcome of future testing at GE.
The following surveillance program shall be put into effect and an evaluation shall be undertaken to see if it is a'n indication of a jet pump degradation or faulure when deviations are observed ttool 5
tj.
PENNSYLVANIA POWER 6
LIGHT COMPANY
~ O8 2po'g~p
Nr. B.J.
Youngbl od Page two March 25, 1981 a
~
Initially, individual jet pump differential pressure readings should be recorded and used to establish a
data base for expected characteristics of each jet pump.
When the diffuser to lower plenum differential pressure reading on an individual jet pump exceeds the expected characteristics established.
b.
The recirculation pump flow differs by more than 10Ã from the established speed-flow characteristics for that pump.
c.
The indicated total core flow is more than 10%
greater than the core flow value derived from esta-blished power-core flow relationships.
If it is determined that a jet pump is inoperable or signifi-cantly degraded, the reactor shall be shut down in accordance with technical specification requirement;.
5.
We strongly believe.,that the above facts and steps taken are sufficient and do properly address the concern of IE Bulletin 80-07.
However, additionally, we plan to procure X750 beam material with an improved heat treatment procedure.
It has been shown that such a procedure results in improved resistance to IGSCC by at least a
factor of two (2),
and improved time to crack initiation by a factor of two (2).
These factors apply when they are compared to current heat treatment processes at an equivalent applied stress ratio.
When and if it is established that a jet beam pump beam degradation or failure has taken place, steps. wi.ll be taken to replace them with the ones with improved material;..
Yery truly yours, geo ~/,
N. W. Curti s Yice President-Engineering and constructi.'on-Nuclear CC:
R.N. Stark bcc:
N.W.
W. E.
B.A.
C. T.
R.J.
Curtis Barberich Snapp Coddignton Shovlin