ML20205D006

Porposed Tech Spec 3/4.6.1.6,eliminating Need for Shutdown When Nonconforming Surveillance Parameters Indicated & Verifying That Voids in Tendon Sheath Filler Grease Less than 5% of Net Duct Vol

ML20205D006
Person / Time
Site:	Callaway
Issue date:	09/18/1985
From:	UNION ELECTRIC CO.
To:
Shared Package
ML20205C927	List: ML20205C922 ML20205D006
References
NUDOCS 8509230384
Download: ML20205D006 (4)

Text

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Enclosure 3 to ULNac-1173 l

Page 1 of 3

/} CONTAINMENT SYSTEMS CONTAINMENT VESSEL STRUCTUdAL INTEGRITY LIMITING CONOITION FOR OPERATION 3.6.1.6 The structural integrity of the containment vessel shall be maintained at a level consistent with the acceptance criteria in Specification 4.6.1'.6.

APPLICABILITY: MODES 1, 2, 3, and 4.

i ACTION:

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a. With more than one tendon with an observed lift-off force between '

i the predicted lower limit and 90% of the predicted lower limit or I with one tendon below 90% of the predicted lower limit, restore the I

tendon (s) to the required level of integrity within 15 days and perform an engineering evaluation of the containment and provide a Special Report to the Commission within 30 days in accordance with S

• %pecification hours and in COLD 6.9.2 or be in at least SHUTOOWN HOT within theSTAN08) following 30 within hours. the next

b. -Vit' :.y e n:-.-l &,;- tien

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-within 15 ty: ' ::: -en:: with Speci'icatien S.9.2 er 5: f :t le::t ."0T ST^MOSY uithin the a:xt 0 h: r: :nd in COLO SiiUT00W" within th: f:ll: tin; 30 5:e n.

. SURVEILLANCE REQUIREMENTS 4.6.1.6.1 Containment Vessel Tendons. The containment vessel tendons' struc-

tural integrity shall be demonstrated at the end of 1.5, 3.5, and 5.5 years l

following the initial containment vessel structural integrity test and at 5 year j intervals thereafter. The tendons' structural integrity shall be demonstrated by:

i a. Determining that a random but representative sample of at least 11 ,

i' tendons (4 inverted U and 7 hoop) each have an observed lif t-off force within predicted limits for each. For each subsequent inspec-tion one tendon from each group may be kept unchanged to develop a '

history and to correlate the observed data. If the observed lift-off .

force of any one tendon in the original sanple population lies between the predicted lower limit and 90% of the predicted lower limit, two tendons, one on each side of this tendon should be checked i for their lift-off forces. If both of these adjacent tendons are found to be within their predicted limits, all three tendons should be restored to the required level of integrity. This single deficiency may be considered unique and acceptable. Unless there is abnormal .

. degradation of the containment vessel during the first three inspec-

.',. tions, the sample population for subsequent inspections shall include

' ~. at least 6 tendons (3 inverted U and 3 hoop);

CALLAWAY - UNIT 1 3/4 6-8 l W"iNE! B@ga a - .

Enclosure 3 )

e to'ULNRC-1173'

• Page 2 of 3 CONTAINMENT SYSTEMS ,

s SURVEILLANCE REQUIREMENTS (Continued)

b. Performing tendon detensioning, inspections, and material tests on a previously stressed tendon from each group (inverted U and hoop).

A randomly selected tendon from each group shell- be completely detensioned in order to identify broken or damaged wires and deter-mining that over the entire length of the removed wire that:

1) The tendon wires are free of corrosion, cracks, and damage,

2) There are no changes in the presence or physical appearance of the sheathing filler grease, and

3) A minimum tensile s d .sth of 240,000 psi (guaranteed ultimate strength of the tendon .iatorial) exists for at least three wire samples (one from eacP end and orie at mid-length) cut from each removed wire. Failuru of any one of the wire samples to meet the minimum tensile surength test is evidence of abnormal

• g degradation of the centainment vessel structure.

c. Performing tendon retensioning of those tendons detensioned for inspection to their observed lift-off force with a tolerance limit M of +6%. During retensioning of these tendons, the changes in load

[ and elongation should be measured simultaneously at a minimum of three approximately equally spaced levels of force between zero and the seating force. If the elongation corresponding to a specific .

load dif fers by more than 5% from that recorded during installation, an investigation should be made to ensure that the difference is not related to wire failures or slip of wires ,in anchorages;

d. Assuring the observed lif t-off stresses adjusted to account for .

elastic losses exceed the average minimum design value given below i

Inverted U 139 ksi Hoop: Cylinder 147 ksi i Dome 134 ksi

( e. Verifying the OPERA 81LITY of the sheathing filler grease by assuring:

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@ !.oi, adpyef grew.ha%. A. 93..v!.59(iM. ..*d. -,len cf ccdamm%f ex.brice.

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2) Minimum grease coverage exists for the different parts of the l

anchorage system, and ,

{ 3) The chemical properties of the filler material are within the tolerance limits as specified by the manufacturer, j

~ > l CALLAWAY - UNIT 1 3/4 6-9 .

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Enclosure 3 to ULNRC-Il73 Page 3 of 3 INSERT A

b. With any abnormal degradation of the structural integrity at a level below the acceptance criteria of Specification 4.6.1.6.1.b, .c, or .d, perform an engineering evaluation to demonstrate continued containment structural integrity and provide a Special Report to the Commission within 30 days in accordance with~ Specification 6.9.2, or be in at least HOT SHUTDOWN within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

c. With the structural integrity of the containment otherwise not conforming to the requirements of Specification 4.6.1.6, prepare and submit a Special Report to the Commission pursuant to Specification 6.9.2 within 90 days after completion of the inspection describing the tendon condition, the condition of the concrete (especially at tendon anchorages) the inspection procedures, the tolerances on cracking, and the corrective actions taken.

d. The provisions of Specification 3.0.4 are not applicable.

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- . . , _ _ - - . _ _ _ . . . , . - . . .. , , , . . . _ , _ _ ~ . . . _ . . . . . . , _ , _ . _ _ _ . _

Enclo:ure 4 to ULNRC-1173 Page 1 of 1 INITIAL FILL VOID FACTORS The voids in the tendon sheathing, as indicated by the refill volumes, may be attributed to a number of factors:

1) Visconorust 2090P-4 has a coefficient of expansion which yields an expansion of about 1% per every 20*F. Initial filling temperatures of the filler material averaged 160*F. Cold weather conditions can cool the filler material to 40*F., giving a contraction of 6% of the net duct volume. During the first inservice surveillance of the tendons, the temperature of insitu filler material averaged 90*F.,

giving a contraction of 3 to 4% from initial fill.

2) Calculated voids between the wires which comprise the tendon bundle are approximately 7%, or greater, of the net duct volume. During the initial filling operations, the tendon bundle was cold (ambient temperature of 65'F.) and as the filler material was pumped into the sheathing void, it solidified on the surface of the tendon bundle, leaving small voids between the wires. As the filler material gradually heated the tendon bundle, it is likely that the voids between the wires allowed migration of the filler material into the tendon bundle. Because this process is slow and gradual, it is reasonable to expect that it took place substantially after the filling operation was complete and possibly during the surveillance refill operation. In addition, this type of migration could also occur at other areas such as where tendons are in contact with the sheathing.

3) Characteristics of the initial filling method may induce air entrapment into the filler material. Pumping operations can introduce air into filler material and may add up to as much as 2%

of the net duct volume. This void value could be higher for horizontal tendons due to the lower pumping head used when compared to the vertical tendons.

In summary, even under optimum filling conditions, voids ranging from 12-15% could be expected after the initial filling operation.