ML19326C685
| ML19326C685 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/28/1976 |
| From: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| 4327, NUDOCS 8004250499 | |
| Download: ML19326C685 (4) | |
Text
U.S. NUCLE AR REGULATORY COMidlSSION DOCKET NUMBE R l
..RC Fcnu 195 u.rai 50-313 1
't WRC DISTRIBUTION PCs PART 50 DOCKET MATERIAL TO#
FROM OATE OF oOCUMENT
!G D L ZIEMANU ARKANSAS PGWER & LICHT CO 4-28-76 LI'ITLE ROCK, ARK g,7,, _.,, y,,
W CAVANAUGH III 4-30-7o, Cl.ETTER O NOTORIZ E D PROP INPUT PORM NUMBER OF COPIES RECEIVED CORICINAL Q UNC LASSIF IE D OCOPv 1 SIGNED........
DESCRIPTION ENCLOSU R E LTR RE OUR 4-2-76 LTR..... FURNISHING DETAILS ON THE DOSE RATE CAICUIATIONS OF THE RE-EVAL OF ECCS PERFORMANCE...........
l l
.~_.;
l PI.AE NAME:
ARKANSAS UNIT #1 SAPI.Y1 FOR ACTION /INFORMATION ENVIRO ASSIGNEL" AI' ;
ASSIGNED AD ;
p" BRANCH CIN.F (4J Ll Em Am BRANCH CHIEF ;
)tf PROJECT Me,.iAGER:
PROJECT MANAGER :
y LIC. ASST. T
'bt Gr,s LIC. ASST. :
i INTERNAL OISTR;8UTION m
EAdtEG FILE 3 SYSTEMS SAFETY I PATP MYSTFMR vmtrun 'Prcu N WR MEIN 7 MAN Y.
TFDERcn ERNST L-
'v I
- E (.O scunnyngn BENAROYA BALLARD v'
OEL]
X LAINAS SPANGLER
_>- GOSSICK & STAFF ENGINEERING IPPOLITO MIPC MAccAny SITE TECH
- CASE KNIGHT I OPERATING REACTORS cal @11LL HANAUER SIHWEIL STELLO STEPP HARTFSS PAWLICKI HULMAN OPERATING TECH PROJECT MANAGEMENT REACTOR SAFETY M
EISENHW SITE ANALYSIS BOYD Y
ROSS SHAO VOLLMER P. COLLINS NOVAK (3 )
BAER BUNCH HOUSTON A
ROSZTOCZY SCHWENCER J. COLLINS PETERSON CHECK GRIMES KREGER MELTZ 1
HELTEMES AT & I l SITE SAFETY & ENVIRC SKOVHOLT SALTZMAN I ANALYSIS l RUTEERG l l DENTON & MULLER D
EXTERNAL DISTRIBUTION CONTROL NUMBER M
LPDR:h.T%A.4%RL Ad NATL LAB BROOKHAVEN NATL LAB TIC REG. V-IE ULRIKSON(ORNL)
l ASLB CONSULTANTS I
i ACRS lbHOLDINCfSENM o s1 04250 999 w/
-v FCnM 105 Q.76)
.~
H ELPIN G B UILO ARKANSAS ARK ANS AS POWER & LIGHT COMPA NY 97H & LoulSIAN A STAEETS
- LITTLE ACCK A AK ANSAS 722o3. (501) 371-4000 April 28, 1976 y
e
. *(
W@ l t O 2
x.
p Director of Nuclear Reactor Regulation V'
f "To (W>4
,g, '
ATTN:
Mr. Dennis L. Ziemann, Chief
(
f 'P l.
Operating Reactor Branch #2 h g*g, U. S. Nuclear Regulatory Commission g
Washington, D. C.
20555 g
g?
N. V,, O
Subject:
Arkansas Power 6 Light Company b
Arkansas Nuclear One-Unit 1
_.g)
Docket No. 50-313 A
0 License No. DPR-51 Re-Evaluation of ECCS Performance Gentlemen:
In response to your letter of April 2, 1976, to Mr. J. D. Phillips, we are providing the following detail.s on the dose rate calculations as performed to justify operator action for valve lineup in the decay heat pump rooms. The calculation has been re-done to assure that sufficient conservatism has been taken into account to limit resultant dose rates.
The assumptions utilized were as follows:
1.
The activity associated with the gap of all fuel rods is released following LOCA. This is in accordance with the assumptions stated in Section 14.2.2.5.6 of the ANO-1 FSAR.
2 It is assumed that the curie inventory of the water will be 100% of the iodines released from the fuel rod gap.
3.
The iodines curie inventory as presented in Table 14-49 of the ANO-1 FSAR is assumed to be diluted by the volume of the Reactor Coolant System (%11,356 ft ) and the Borated Water Storage Tank (350,000 gallons) to obtain a source concentration by which to calculate the resultant dose rates.
We have investigated those assumptions related to orientation of the valve stems in relation to the piping from which the dose would be received.
Our investigation has revealed that the minimum distance an operator would be from the piping would be one (1) foot. As seen on the attached table of resultant dose rates, the dose rate at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following LOCA falls off to 36.7 rea/hr at this distance.
- 1((. *
- 1,.
a
Mr. Dennis L. Ziem y - April 28, 1976 We have also determined that at least two (2) operators will be required to line up those valves in one of the two pump rooms (only one pump has need to be lined up for either Mode 1 or 2).
The time for valve lineup is estimated to be a maxioum of 5 minutes.
For Mode 2, one of the pumps will not be running, thereby making the valve lineup easier as no Ap will be occurring across the valve.
For Mode 1, one of the pumps will be stopped, the valve lineup accomplished (again there will be no op across the valve (s) assuring a minimum amount of time necessary for valve lineup),
and the pump will be restarted. This procedure is also in keeping with the committment made in our December 31, 1975, letter to you to satisfy your concern related to operation in Mode 1 (i.e., your concern of cavita-tion of the pump due to gas or steam entrainment in the decay heat drop line). When the pump is restarted to proceed into Mode 1, the operator will be available at the room to determine whether or not cavitation is occurring within a short time after restart.
If indications of cavitation appear, the pump will again be stopped and the lineup for Mode 2 will take place (this involves opening one valve). No operator will be allowed to remain in the room for a period of time longer than 5 minutes, thereby limiting the dose received to less than 3.1 rem.
This dose is less than that specified in Criterion 19, Appendix A, 10CFR50. These operators will not be allowed to perform any further functions during post-accident activities where they would increase their dose substantially above this level.
Another factor of conservatism in this analysis is the fact that we have considered a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following LOCA as the time frame that the valve lineup will be made. As stated in our April 21, 1975, letter to A. Giambusso, boron concentration buildup will be slow enough to allow in excess of 30 days before alignment into any of the three modes will become necessary.
Based on the above assumptions and considering the amount of conservatism involved, we still feel that operator action in there rooms is justified with no changes to plant systems required.
If you have any further questions concerning this matter, please advise.
Very truly yours, 0]
v=
/
William Cavanaugh III Manager, Nuclear Services WC:ay
' /
~./
~
DOSE RATES IN DECAY HEAT PUMP ROOMS A 4 B FOLLOWING LOCA Time following Surface Dose Rates in Air (rem /hr)
LOCA Dose Rate l'
2' 3'
5' 10' (rem /hr) 0 351 95.1 46.9 27.3 12.2 3.5 5 hrs 212 57.9 28.7 16.7 7.5 2.18 12 hrs 161 44 22 12.8 5.8 1.7 24 hrs
~133 36.7 18.3 10.7 4.8 1.4 7 days 65.8 18.2 9.1 5.33 2.4 0.7 14 days 35.4 9.8 4.9 2.9 1.3 0.4 30 days 9.06 2.5 1.25 0.73 0.33 0.095 D
+
J 1
i l
l W '