ML20083R786

Forwards Response to 730122 Request Re Drywell Vacuum Breaker Valves.Status of Investigation to Be Provided by 731115.Illustrative Diagrams Considered Proprietary Will Be Forwarded Under Separate Cover

ML20083R786
Person / Time
Site:	Oyster Creek
Issue date:	10/08/1973
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Schemel R US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20083R791	List: ML20083R786
References
NUDOCS 8304050019
Download: ML20083R786 (5)

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6 Jersey Central Power & Light Company M ADISoN AVENUE AT PUNCH DoWL Ro AD e MoRRISToWN, N.J. 07960 e 539 6111 October 8, 1973 ca t  %

Mr. Robert J. Schetel, Chief p '

JO Operating Pasctors Branch #1 /7 /

O (/ [d Directorate of Licensing 1 2

Office of Regulation U.S. Atomic Energy Concission Ne h 0 /g7 ~_

M Washington, DC 20545 g ,

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Dear Mr. Schemel:

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SUBJECT:

OYSTER CREEK NUCLEAR GENERATING STATION DOCKET No. 50-219 INFORESTION REGARDING THE DRYWELL VACUUM BREAKER VALVES Upon receipt of your January 22, 1973 letter, the position of the subject valves was checked and verified to be closed. Consequently, no remedial action was necessary.

Subsequent to that time, we contacted General Electric and have employed their services to prepare the analytical data requested in your letter. The information is not yet available. General Electric cannot specify a completion date at this time, but we will inform you by November 15, 1973 of the status of this request. Upon receipt of this information, the answers to your questions 3 through 13 will be submitted.

The responses to questions 1 through 7 are attached. Illustrative diagrams, which are to be considered proprietary, are being submitted under separate cover.

During the spring 1973 refueling outage, a leak rate test was conducted to determine the bypass area from the drywell to the torus.

The results indicated a leakage area which was significantly less (1-2%)

than the bypass area which G.E. has determined to be limiting for several of its other plants.

The details of this test and other related tests were reported in semi-annual report #8. However, the allowable bypass area was in error and a correction to the report will be made.

Very truly yours, 8304050019 731008 gI / _ -

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/ D. A. Ross

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qne. tion Manufacturer, ncdel number, ratings , and modi fications , if any ,

-- ~No. 1:

of the vacuun breakers.

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The torus to drywell vacuum breakers were bulIt by Atuood f, Mor rill Company of Salen, Massachusetts. The follewing infor-natica is pertinent to the valves:

Atucod ti Morri11 Drawing No. 20464-ll- Allf. I SI:e: 18 inches Petting: 150; ASA Standard

. .y,0.]: Installed assenbly drawing, including tesi.ing equipment.

Thir d aving is considered proprietory information by the Atuced f, t:orri 11 Ca.pany and uny not be relecsed to the liablic without thei r urit c en consent . The only dif t'erence lvtwoon the drawin; nad the installed valves is that t!w cast irca neights , Part t5, ha.ce hwa re: caved, as they were not required for proper valve operatiea, e igi_ ; p., '!ateriale used in the vacuum breal ecs , including seals, seats, beariny, lubrican t , body and operating parts.

9 'ihe list of noterials is she.n on t he proprietory drawin'; refe: red to -

.: chac p s t ; o. S c. . J: Capchility of part t,  :.nd the.:.r design life in the mast severe suppressica chase: operational transient and recident envirca-rent:. Direurs pessiMc delete: iou: cifects of chemicale present ,

during the surface preparation and application of the suppression cha.bc_ corting and of nitrogen en vacuna brechen systcc natcriuls.

Advisc s. hat tests have beca perforc.ed on the vec*:ua breai crs and their poritica indication system in a simulated accident environ-Lent. .

, , . All parts of the valves are designed for sustained operatica at tenpe c.tures in excer..; e,f 300

• F . *1he naximo.' temperature expceted during the desir.n basis accident is 275* F at. '3 psi,9, .

rhich is i; ell helcw the capabilities of the velve. Darinr. con-s t.: u ct 100 of the supprossion ch: ter, no chemicals were used ta prepar e the . surface priur to painting,. The inside surfaces were marcly sandblasted. Furthermore, because the vacuum breakers and their associated piping are located outside the suppression chader, it is unlikely that the valves' internals were expmd N to an enf as orable environment. at that time.

Discussions. with the valve manufacturer have indicated that the inert n'.t ro/,en atmosphere to which the valver.' incernnis are expost d during ol'erati.cn should have no adverse effects. No tests have bcea performed with theae valves in a simulated hceident envirom.2nt.

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e6 6a Question No. 5: For the tests ;. ~ forced en each vacuun breaker system, provide a brief description of acceptance criteria and test results including:

a) Preoperation und periodic surveillance tests.

b) Other tests and reasons for the tests.

Aq n.e: a) The following preoperational tests were conducted:

1. f$usure the force to open the vacuum breakers and the force necessary to hold then open.

a) This was performed by Gcneral Elcetrie and has designed to insure the vacuum breakers would open at 0.5 psi across the valvo. The test uas done by means of a spring scale attached to the ucipht icver at a distr.nce 20 inches from the shaft center-lino, in order to verify ,that the valve would open with a pulling f6rce icss than 20 pounds. This is equivalent to a differential pressure of about

.25 psi. The last step of this test was to insure the valve disc returned freely when the spring scale

.:as rcleaa d.

b) All vacum. breakers successfully passed the pro-cporational test outlined above.

2. Each valve and associated piping was checked to assurc that they were cicar of foreign matter.

3. Checks ucre made to insure there was no restriction to valve lever movement.

4. A drywell leak rate test was conducted to insure that the valves scated.

5. Each valve was actually tested to insure it opened with 0.5 psi across it. This test was done by installini, and inflatable seal on the torus side of the valve piping and pressurizing the piping between the seal and the valvo.

b) The following surveillence tests are performed:

1. Each torus to drywell vacuum breaker is exercised during each refueling outage to insure proper operability.

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2. Each r2 fueling outage, the vacuum breakers are tested by means of the sprinP scale at the end of the weignt lever. The force to open and hold open is measured and recorded. In the event the force to hald the valve cgen does not fall within the allowabic range, corrective action is taken and the valvo is retested.

Oacstion No. 6: A description of corrective action taken to remedy any failure

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of the vacuum breakers, including a discussion of the cause of the failurc.

Amute r: The vacutta breaker valves have established a history of maintenance

{ requirc: cents. The valve bushings are me.nufactured of teflon i which hes a characteristic of " growing" and occasionally carses the vacuun breakers to fail the surveillance test. When dis-covered, the valve bushings have been repaired and the valves testcJ to insure that they pass the tests before startup. The "groteini;" characteristic has been e.xperienced by several plants with teflon bushings. The ::cchnnism by which this occurs is inot fully understood at this time. It is suspected, however, I that both rediatica and naisture will cause teflon to grow.

lEccause these valves are operated very infrequently, the bushin;,s i do not near enough to conpens:tte for the growth, in so:n c as c s ,

l this causes the valves to operate sluggishly and fail a survcdicace

{ test.

As reported to the AEC by both telephone and lettcr dated January 17, 1973, the bushing problem has been recognized and discussed by the Plant Operations review Con.:.littee (PORC) . In '

this regard, the PORC has required that an investigation be conducted as to the suitability and long range applicability of the present packing material .

The bushing difficulty has becn discussed uith Atucod G Morrill Company and a long term solution is being investigated. The probable solution vill be te replace the bushings with a material that is more suit obic for the application. The material and bushing design is under study by the General Electric Company and Atuood G "arrill Cempany. As a continuin/, cction, Jersey Central Power 6 Light Company's personnel will test the valves each re-fueling outage per the plant procedures, as well as insuring the valves are closed prior to startup after a refueling outage.

There have been no other maintenance problems experienced with the valves.

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i d?_2 0 : . acur breakers are t asted a mee i ith plant procedures i.

. i:.ge, the vacuun c hueJ position by tcJ and tested each re-  !

.iN.or;.nlity is discovered,

.uy abnor:nality is re-i :i red, the :tanufacturer

- ..a and assistance.

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