ML20128N563
| ML20128N563 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/09/1996 |
| From: | Jain S DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-96-001, IEB-96-1, NUDOCS 9610160431 | |
| Download: ML20128N563 (7) | |
Text
-
l D0guesne@ Company gg,vy r a 'siaa e
SNppingport, PA 1507T-0004 i
- FS"' M 7..wi.oi r., N ME n
M*' %"Lo, October 9, 1996 l
U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 l
Subject:
Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Response to NRC Bulletin No. 96-01:
Control Rod Insertion Problems l
Attached is the Duquesne Light Company report summarizing the data and documenting the results for Beaver Valley Power Station Unit No. 2 Fuel Cycle 6 end of life measurements of the control rod drop times and drag forces for all rodded fuel assemblies. This report is being submitted to satisfy the Required Response (3) of NRC Bulletin 96-01: Control Rod Insertion Problems.
l Based on the evaluation of the data obtained for control rod testing at the end of Cycle 6 at Beaver Valley Power Station Unit No. 2, no difficulties were encountered with control rods failing to insert completely on a scram signal. Three of the Cycle 6 fuel assemblies exhibited control rod drag forces which exceeded the acceptance criteria in the non-dashpot region of the assembly guide thimbles. These three fuel assemblies were discharged to the spent fuel pool and are not part of the Cycle 7 reactor core.
l Additional data is included in the attached report.
If you have any questions concerning this response, please contact Mr. Roy K.
Brosi at (412) 393-5210.
Sincerely, f9 WWk Sushil C. Jain Attachment I
i c:
Mr. D. M. Kern, Sr. Resident Inspector Mr. H. J. Miller, NRC Region I Administrator
'OEllVERING Mr. D. S. Brinkman, Sr. Project Manager QU ALITV 9610160431 961009
[g[ggy PDR ADOCK 05000412 l
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AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA)
) SS:
COUNTY OF BEAVER
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I
Subject:
Beaver Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Response to NRC Bulletin No. 96-01:
Control Rod Insertion Problems Before me, the undersigned notary public, in and for the County and Commonwealth aforesaid, this day personally appeared Sushil C. Jain, to me known, who being duly sworn according to law, deposes and says that he is Division Vice President, Nuclear Services of the Nuclear Power Division, Duquesne Light Company, he is duly authorized to execute and file the foregoing submittal on behalf of said Company, and the statements set forth in the submittal are true and correct to the best of his knowledge, information and belief.
Sushil C. Jain i
Subscribed and sworn to before me on this N day of Odfee / 9 9 6 j
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Notary Public NotarialSeal du0try rhea $tr l
My Commission Expires June 3, 099 n
Member,PimhnaktM4onof RMS
Attechment 1 Response to NRC Bulletin 96-01 l
Unit 2 Cycle 6 End of Life Control Rod Testing j
l Rod Drop Testing
)
l On August 31,1996, Control Rod Drop Time measurements were performed for all 48 control rods in the core. Drop times were measured from the beginning of voltage decay on the stationary gripper coil to rod entry into the dashpot region and from rod i
entry into the dashpot region to rod bottom. Each trace was also checked for rod bottom recoil to ensure all rods reached the rod bottom position. All drop times to dashpot entry were within the Technical Specification limit of 2.7 seconds.
All rods demonstrated rod bottom recoil to varying degrees (1 to 5 bounces). The rods with the least number of bounces (1) were at core locations K10, K12, and F12.
The control rods at core locations F12 and K12 were located in fuel assemblies with an approximate burnup of 39539 MWD /MTU and the rod drop times to rod bottom increased 0.40 and 0.29 seconds, respectively, from the Beginning of Life (BOL) test.
l The ccatrol rod at core location K10 was located in a fuel assembly with an approximate burnup of 38922 MWD /MTU and its rod drop time to rod bottom increased 0.12 seconds from the BOL test. The fuel assemblies in Cycle 6 core locations K10, F12, and K12
. ill not be reloaded into the core for Cycle 7. A sununary of the Beginning of. Life and w
End of Life (EOL) control rod drop time tests is listed below.
Time to dashpot (sec)
Time to rod bottom (sec)
Test Average Fastest Slowest Average Fastest Slowest BOL 1.40 1.35 1.50 1.86 1.79 1.99 EOL 1.41 1.36 1.53 1.87 1.79 2.29 All control rod drop times for the EOL test with the corresponding fuel assembly burnups are listed in Table 1.
Control Rod Drag Test Control rod drag tests in the reactor vessel were performed on September 9,1996.
All 48 control rods were drag tested by withdrawing the control rod approximately ten feet out of the assembly and reinserting it. During this time the initial dead weight, maximum weight during withdrawal, and minimum weight during insertion were measured using a spring scale and recorded. The maximum drag measurements in the dashpot region of the fuel assemblies for all control rods was equal to or less than the acceptance criteria value of 100 pounds. Maximum drag measurements in the non-i dashpot region for all control rods are listed in Table 1.
' Resp'onse to NRC Bulletin 96-01 Page 2 During the drag test the control rods at core locations F12, K12, K10, F4, and G13 failed the 40 pound acceptance criteria in the non-dashpot region. All of the above rods were retested. During the retest the maximum drag for the rods at core locations F4 and G13 was detennined to be 40 pounds. The table below illustrates the drag results for the above rods.
Drag Test Trial 1 (in reactor vessel)
Maximum Drag (Pounds)
Core Assembly Withdraw Insertion Location ID Dashpet Non-Dashpot Dashpot Non-Dashpot F12 G46 60 65*
75 50*
K12 G16 20 10 90 85*
K10 G38 45 30 65 55*
F4 G23 40 0
75 50*
G13 H37 40 45*
25 15 i
Drag Test Trial 2 (in reactor vessel)
Maximum Drag (Pounds)
Core Assembly Withdraw Insertion Location ID Dashpot Non-Dashpot Dashpot Non-Dashpot F12 G46 35 30 100 80*
K12 G16 25 40 95 90*
K10 G38 60 55*
50 35 F4 G23 60 40 55 40 G13 H37 35 40 20 15
- Indicates Acceptance Criteria exceeded.
All of the above fuel assemblies with the exception of H37 will be discharged to the Spent Fuel Pool. Assembly H37 will be reloaded into Cycle 7 but will be in a non-rodded core location. Additional drag tests for these control rods were also performed in the spent fuel pool using a load cell and recorder. These tests were performed before and after control rod changeouts for Cycle 7 reload. The results of these tests as shown below indicate that the control rods are acceptable for use in their Cycle 7 reload assemblies.
Attaghment 1 l
Response to NRC Bulletin 96-01 Page 3 Drag Test Cycle 6 Assemblies (in spent fuel pool)
Maximum Drag (Pounds)
Control Assembly Withdraw Insertion RodID ID Dashpot l Non-Dashpot Dashpot Non-Dashpot R25 (F12)
G46 65 10 70 45' R20 (K12)
G16 65 50' 65 48*
R24 (K10)
G38 64 45*
65 40 l
R19 (F4)
G23 65 45*
65 45' R35 (G13)
H37 25 20 25 15 l
- Indicates Acceptance Criteria exceeded.
l Drag Te.st Cycle 7 Assemblies (in spent fuel pool)
Maximum Drag (Pounds)
Control Assembly Withdraw Insertion
)
l Rod ID ID Dashpot Non-Dashpot Dashpot Non-Dashpot R25 (M6)
H45 40 30 35 25 i
R20 (G7)
H15 10 10 5
3 R24 (F4)
H55 10 10 10 10 R19 (F6)
H10 10 5
5 3
R35 (M4)
J37 10 5
5 1
l The results of the control rod drop timing test and rod drag testing reported above i
and in Table 1 demonstrate that all of the control rods were operable at Cycle 6 EOL despite several fuel assemblies exceeding the rod drag acceptance criteria in the non-dashpot region of the assemblies.
A drag test in the reactor vessel of all Cycle 7 control rods including those identified above will be performed for startup as part of the required testing for Unit 2 l
Cycle 7. A control rod drop timing test will also be performed for Cycle 7 startup. The
. results of these tests will be reported by separate submittal to meet NRC Bulletin 96-01 i
requirements and will demonstrate the operability of the control rods for Unit 2 Cycle 7.
l l
Table 1.
Response to NRC Bulletin 96-01 Beaver Valley Power Station Unit 2 Cycle 6 EOL Rod Drop and Drag Test Results Core Assembly Assembly Drop Time Dashpot to Drop Time Dead Max.or Min.
Max. Drag Location ID Burnup to Dashpot Rod Bottom Total Weight Weight Non-Dashpot (MWD /MTU)
(sec.)
(sec)
(sec)
(Ibs)
(ibs)
(Ibs)
D6 G35 39539 1.38 0.44 1.82 420 445 25 M6 G29 39539 1.37 0.45 1.81 430 425 5
D10 G39 39539 1.39 0.44 1.83 410 435 25 M10 G34 39539 1.40 0.47 1.87 440 415 25 F4 G23 39539 1.46 0.57 2.03 425 465 40 K4 G15 39539 1.39 0.47 1.85 425 440 15
_ 55 375 80 4
F12 G46 39539 1.53 0.66 2.19 K12 G16 39539 1.53 0.76 2.29 460 370 90 E5 G36 39518 1.42 0.45 1.87 420 450 30 L5 G21 39518 1.40 0.43 1.83 440 425 15 l
E11 G40 39518 1.44 0.42 1.87 430 410 20 L11 G43 39518 1.38 0.46 1.84 420 455 35 F6 G45 38922 1.37 0.46 1.83 450 415 35 K6 G14 38922 1.38 0.46 1.83 445 415 30 F10 G27 38922 1.39 0.45 1.84 450 410 40 K10 G38 38922 1.44 0.54 1.98 420 475 55 D4 G12 33527 1.46 0.45 1.91 415 440 25 M4 G11 33527 1.37 0.44 1.81 425 440 15 D12 G10 33527 1.38 0.43 1.81 410 445 35 M12 G09 33527 1.41 0.41 1.82 425 435 10 B6 G67 30716 1.50 0.45 1.95 425 430 5
P6 G57 30716 1.36 0.44 1.80 420 430 10 B10 G68 30716 1.41 0.45 1.86 425 435 10 P10 G59 30716 1.39 0.42 1.81 425 435 10
- Exceeds Acceptance Criteria Page 4
s Table 1.
Response to NRC Bulletin 96-01 Beaver Valley Power Station Unit 2 Cycle 6 EOL Rod Drop and Drag Test Results b
{ Core Assembly Assembly Drop Time Dashpot to Drop Time Dead Max.or Min.
Max. Drag Location ID Bumup to Dashpot Rod Bottom Total Weight Weight Non-Dashpot (MWD /MTU)
(sec.)
(sec)
(sec)
(Ibs)
(ibs)
(Ibs)
F2 G63 30649 1.41 0.49 i.39 420 450 30 K2 G62 30649 1.43 0.47 1.90 425 440 15 F14 G60 30649 1.40 0.45 1.85 420 450 30 K14 G58 30649 1.46 0.48 1.94 425 435 10 G7 H66 22064 1.36 0.47 1.83 420 460 40 J7 H65 22064 1.38 0.43 1.81 425 445 20 G9 H68 22064 1.36 0.52 1.88 430 460 30 J9 H67 22064 1.39 0.44 1.83 425 445 20 C7 H28 21704 1.41 0.40 1.81 415 430 15 N7 H40 21704 1.37 0.46 1.82 425 435 10 C9 H36 21704 1.39 0.42 1.81 420 430 10 N9 H35 21704 1.39 0.44 1.84 415 435 20 G3 H30 21605 1.43 0.46 1.89 415 450 35 J3 H27 21605 1.39 0.40 1.79 415 440 25 G13 H37 21605 1.40 0.52 1.91 420 460 40 J13 H25 21605 1.36 0.43 1,79 425 435 10 H6 H23 21426 1.39 0.42 1.81 420 435 15 F8 H07 21426 1.36 0.47 1.84 420 455 35 K8 H12 21426 1.38 0.42 1.80 445 420 25 H10 H05 21426 1.40 0.47 1.87 420 435 15 H2 H08 18220 1.42 0.44 1.86 425 435 10 B8 H09 18220 1.49 0.45 1.95 415 450 35 P8 H11 18220 1.36 0.43 1.79 425 435 10 H14 H16 18220 1.41 0.47 1.88 425 435 10
- Exceeds Acceptance Criteria Page 5