ML20093E159
| ML20093E159 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/13/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| EF2-72636, NUDOCS 8407170391 | |
| Download: ML20093E159 (5) | |
Text
,
W yne H. Jero Vce President Nuclear Operabona I
b IIe July 13, 1984 EF2-72636 I
Director of Nuclear Reactor Regulation Attention:
Mr. B. J.
Youngblood, Chief Licensing Branch No. 1 Division of Licensing U.
S.
Nuclear Regulatory Commission Washington, D.
C.
20555 CYGNA Energy Services Attention:
Mr. David A.
Ferg 150 North Wacker Drive Chicago, Illinois 60606
Reference:
(1) Fermi 2 NRC Docket No. 50-341 (2) NRC letter to Detroit Edison and CYGNA,
" Preliminary Evaluation of the IDVP Performed by CYGNA Energy Services for the Fermi 2 Facility", March 27, 1984 (3) Detroit Edison letter to CYGNA, " Supplement to CYGNA IDVP Report", EF2-64581, July 18, 1983.
(4) Detroit Edison letter to NRC, " Design Deficiency on the RHR Reservoir Freeze Over - 50.55(e), Item 111", EF2-69272, July 5, 1984.
Subject:
NRC Question to CYGNA on RHR Resa
.0.r Freezing 4
Enclosure (4) to Reference 2 requested CYGNA to justify its scope of evaluation of the Fermi 2 RHR Complex in light of two reportable deficiencies t'.au were submitted by Detroit Edison to NRC.
The deficiencies arose due to the occurrence of freezing in the RHR Complex (i.e., RHR reservoir).
In reviewing our previous comments provided in Reference 3 on CYGNA review Item ST-01-ll, Edison has concluded that additional information is required for clarification.
Accordingly, attached please find a revised page to Reference (3) concerning Item ST-01-ll.
Reference (4),
f5e2c>l j
8407170391 840713 PDR ADOCK 05000341 ll S
PDR j
Mr.-B. J.
Youngblood July 13, 1984
-EF2-72636 Page 2 forwarded-to you separately for information, is the formal response to the reportable deficiency concerning RIIR reservoir freezing.
- With respect to the concern identified in Reference 2 addressing the freezing of the supply line to the Division I Fire Protection System, Edison will provide both CYGNA and NRC-NRR a copy of the final report on the potential design deficiency [10CFR50.55(e)] Item 16.
If you have any questions, please contact Mr. Keener Earle at (313) 586-4211.
Sincerely,
[4u$
($46 cc:
Mr. P. M. Byron
- Mr. M.
D.
Lynch
- USNRC, Document Control Desk
- Washington, D.
C.
20555
- With attachment
Mr.,B. J.'Youngblood July 13, 1984 EF2-72636' R
Page 3 bec:
F.
E.:Agosti*
L.
P. Bregni W.
F.
Colbert*,'
O. K.
Earle W.
R.-liolland R.
S.
Lenart*
E.
Lusis P.
A. Marquardt T.
D.
Phillips*
H. Tauber A.-E. Wegele B.'Wehrung*
Approval Control
- i, O. K. Earle -(Bethesda Of fice)* ~
M..S.
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NRR Chron File *
- With Attachment 4
i L
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1 -
i c.-
I.
Cygna Observation Log Observation No. :
==
Description:==
Ice loading on the interior walls of the pool were not addressed in the calculations for foundation wall loading.
Remarks:
Invalid.
~
11.
Detroit Edison' Response Ice ' loading.was not-considered in the design of the RRR complex walls.
' This is in accordance with the Fermi project FSAR Section 9.2.5.3.1.3,
.which clearly states that the rooms above the reservoir will be kept at a minimum of 60*F.
In addition, 80 to 90 percent of the reservoir water is below the frost 'line, and no freezing or ice formation is anticipated.
The word " invalid" alone in the Observation Log gives the casual reader an uncomfortable feeling for the justification for dropping an apparently serious observation. A shortened form of the Observation Record Review response would have answered any such concerns.
Additional Detroit Edison Response Detroit Edison response to Observation No. ST-01-11 was not completely clear. Due to the ~ freezing of the RHR reservoirs this winter, we would like to provide a more complete response and clarify our posi-
~
tion by offering the following:
The RHR Complex is designed to operate as the ultimate heat sink for the plant. Once the plant becomes operational, the RHR
. reservoirs are not expected to be affected by ice for the following reasons:
e o
The RHR building is designed to protect the reservoirs from winter weather conditions. The floors of the RHR building i
are designed to cover and help protect.a large part of the reservoir, with the rooms in the building heated to a
_ nominal 60*F.
The remaining part of the reservoirs are i
covered by floor gratings and tower baffles, and protected by high walls around them.
o During unit outages, the RHR reservoirs are designed to receive core decay heat which will prevent freezing.
o During unit operation, the RHR reservoirs are expected to receive heat from surveillance testing of the EDG, HPCI, and RCIC systems and other plant activities (such as operating 100/LIC-12/13.4
.070984
'b
- the Torus Water Management System). This heat will go directly to the RHR Complex or the torus. Heat sent to the torus will be removed by sending it to the RHR Complex.
Because of these activities, no icing problems were anticipated during the winter months.
o The RHR Complex is designed to have cold weather bypasses around the cooling towers which will direct service water to the reservoirs instead of the cooling towers. This will help retain the heat sent to the reservoir.
o Study calculations on ice formation and its potential effects on the structure were made early in the design pro-cess.
Because of the heat which would be received by the ultimate heat sink. ice formation was not a major considera-tion.
However, the design of the Complex did not account for the period between the end of construction and initial plant operation.
For this period the reservoirs were full of water, but no heat was added to them.
Af ter Detroit Edison supplied the original response, the following actions were taken:
o As a contingency plan for cold weather spells, the plant has an operating procedure to add heat to the reservoir to help maintain the temperature of the water in the reservoirs above a minimum temperature. The source of this heat is f rom existing plant equipment.
o As a result of the CYGNA audit, a design calculation was performed which determined that the walls of the reservoirs would not be damaged by ice 18 inches thick in the reservoir.
100/LIC-12/13.5 071284
- -.