ML19294B735
| ML19294B735 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/27/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Rubenstein L Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8003050443 | |
| Download: ML19294B735 (4) | |
Text
.
~ :'
~.2 2 : 2 400 Chestnut Street Tower II February 27, 1980 Director of L telear Reactor Regulation Attention: Mt L. S. Rubenstein, Acting Chief Lig..t Water Reactors Branch No. 4 Division of Project Management U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Rubenstein:
In the Matter of the Application of ) Docket No. 50-327 Tennessee Valley Authority
)
Enclosed is the Tennessee Valley Authority's response to the NRC staf f informal questions related to the human engineering of the Sequoyah Nuclear Plant control room panels which we received by telephone February 27, 1980. The questions are related to concerns expressed in a memorandum from Mr. T. Sheridan, Massachusetts Institute of Technology to Mr. Z. Kozinski, General Physics Ccrporation dated July 19, 1979.
Very truly yours, TENNESSEE VALLEY AUTHORITY
., f /i ' b,' ' '
L. M. Mills, Manager Nuclear Regulation and Safety Enclosure
_1 8 003050 3
i l
ENCLOSURE SEQUOYAH NUCLEAR PLANT The following are the concerns expressed by Mr. Tom Sheridan and our responses to his concerns.
Items are numbered as they are in Mr.
Sheridan's letter.
1.
A selection switch for boration has four positions:
0-550, 500-1050, 1550, 2050. The last two indications really mean 1000-1050 and 1500-2050.
But that is not what they say.
Response
The selection switches at the Sequoyah Nuclear Plant have four positions; they are 0-550, 500-1050, 1000-1550, and 1500-2050. No change is necessary.
2.
Two digital borating controllers are side by side and look exactly the same. The left one is for concentrating and the right one is for diluting. The only difference is that the operator has to remember that the decimal point is one digit from the end on the left controller.
Whereas, the decimal point is after the last digit on the right one.
Response
The decimal point for the digital borating controllers has been corrected.
3.
Water flows through seven feedwater heaters in succession.
Each heater has numbered controls on the panel. The controls are numbered in inverce order to the way the water flows.
Response
Feedwater heaters were numbered from the steam generator (high pressure) to the hotwell (low pressure). This numbering scheme is common to all of TVA's fossil and nuclear generating plants.and TVA sees no need to alter this practice.
_2 4.
Af ter heater 3 (above) there are three pumps, A, B, C and af ter heater 7 there are two pumps. The switches for these are arranged in two rows: 3A and 3B in one row and 7A, 73, and 3C in the other row.
Response
This item has been corrected.
5.
Four meters on the lef t are for neutron flux, and four meters on the right are for the rate of change of neutron flux. The two on the far left correspond to the two on the far right, i.e.,
they are for intermediate range, a nd the two which are just left of center go with the two just to the right of center for source range.
7.
There are four steam generators in this plant. There are four pen recorders to indicate temperature in the hot and cold legs of each steam generator. Each pen recorder has two pens, red and grr.en.
The first recorder on the lef t has red for hot 1, green for hot 2.
The next one has red for cold 1, green for cold 2.
The third recorder from the left has red for hot 3, green for hot 4.
The right hand recorder has red for cold 3, green for cold 4.
9.
The valves for safety injection of coolant are all nicr.ly arranged in a cluster. The cluster is 60 identical switches arranged 3 high by 20 wide, with only small engraved alphanumberic tags underneath to indicate which valve is which. Mostly, tha alphanumberies are in order, except for one lost soul which is completely out of order and a long distance away from any other switches it corresponds to functionally.
Response
Items similar to these were discussed with the NRC staff during their control room review of Sequoyah during the week of February 4, 1980.
.. All of the above items, along with those specifically identified by the NRC, are being carefully reviewed as a part of TVA's overall control room review which is now in progress. Specific cominitments concerning TVA's control room review are contained in L. M. Mills letter to L. S. Rubenstein dated February 14, 1980.
6.
The auxiliary feedwater meters are labeled A (on lef t) and B on right.
The corresponding switches are also labeled A and B, but B is on the left and A on the right.
Response
This item has been corrected.
8.
The procedures during a loss-of-coolant accident call for the operator to check whether all of the lights are lit in a matrix of check-indicators.
They forget to tell you that if some of the lights do not have lettering on them, they are not supposed to be lit.
Response
This item has been corrected by blanking out the unused lights to clearly indicate their unused status to the operator.